WO2018035353A1

WO2018035353A1 - Front touchscreen and back touchpad operated user interface employing semi-persistent button groups

Info

Publication number: WO2018035353A1
Application number: PCT/US2017/047404
Authority: WO
Inventors: Tong LUO; Yifan Chen; Chuan Lin
Original assignee: Handscape Inc., A Delaware Corporation
Priority date: 2016-08-17
Filing date: 2017-08-17
Publication date: 2018-02-22

Abstract

Software implemented user interface oriented for one-hand operation of small handheld computerized devices, such as smartphones, which in addition to a front touchscreen additionally have been augmented with rear mounted touchpads. With one hand operation, the user typically holds their thumb in front of the device, and holds their other various fingers in back of the device. The disclosed user interface can be viewed a semi-persistent button group, typically invoked by either simultaneous front and back touches or double taps. The semi-persistent button group can contain multiple virtual touch sensitive buttons, and can be maneuvered to be within easy reach of the user's thumb so that various buttons can then be easily thumb activated.

Description

FRONT TOUCHSCREEN AND BACK TOUCHPAD OPERATED USER INTERFACE EMPLOYING SEMI-PERSISTENT BUTTON GROUPS

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of, and claims the priority benefit of, US patent application 15/239,652, filed August 17, 2017.

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention is in the field of user interfaces for touch sensitive computerized devices. DESCRIPTION OF THE RELATED ART

Handheld computerized devices (i.e. devices equipped with microprocessors and

sophisticated displays) such as cell phones, personal digital assistants (PDA), game devices, tabletPCs (such as iPad), etc., are playing a more and more important role in everyday life, and are becoming more and more indispensible. With the advance of technology, and improvements in the handheld computerized devices' processing power, both function, and memory space is increasing at an amazing pace. Meanwhile the size of the handheld computerized devices continues to get smaller and smaller.

To meet this challenge, the designers of handheld computerized devices typically use two approaches. One approach is to make the device keys smaller and smaller, minaturizing the keys. Additionally the device keys may be given multiple functions - i.e. overloaded, and more complex function device keys may be introduced as well.

The other approach is to use touch screen buttons, or so called "soft keys", on the front panel. Here a user may use a stylus pen or finger to select the soft keys through a graphical user interface. Due to the optical illusions introduced by the display screen, and the size of the user fingers, the soft keys cannot be too small, because otherwise a single finger press will activate multiple keys. As a result, the designer may have to divide the keys into different groups and hierarchies, and only display a small number of keys on the screen.

Both current approaches have some severe drawbacks: the user input area occupies a significant portion of the front panel, and the user input process, although requiring a large amount of user attention to operate, still is very error prone. Often a user has to use one hand to hold the handheld computerized device, and use the other hand to input data, thus occupying both hands. A user will often have to go through a long sequence of key strokes, and switch back and forth among different user interface screens, in order to complete a fairly simple input. As a result, there is a significant learning curve for a user to learn the overloaded keys, function keys, key grouping, and key hierarchies in order to operate the handheld computerized devices efficiently;

BRIEF SUMMARY OF THE INVENTION

Although the methods and devices described herein may be used for a wide variety of computerized devices, these methods are particularly useful for small portable computerized devices equipped with front mounted touchscreens and back mounted touchpads. Here rear mounted touchpads need not be part of the original computerized device, but instead may be mounted as a retrofit or additional peripheral, as per the teaching of commonly owned and invented parent US patent application 13/223,836, the entire contents of which are incorporated herein by reference.

The present invention is based, in part on insights obtained by considering the problems of operating a smartphone (e.g. an iPhone or Android type smartphone), which often may need to be operated using only one hand while the user's other hand may be unavailable because it is holding a different object. This one hand must both support the smartphone (often with the thumb in front, and the other fingers behind the device), and operate any touch sensitive buttons displayed on the front touchscreen. The thumb has a limited reach, and typically cannot easily access the entire screen, particularly for larger screens with dimensions of 4 inches or more. Prior art devices will typically display buttons or groups of buttons displayed on the screen located in places that are simply out of reach of the thumb.

The present invention is also based on the insight that what is needed is a way to use the user's rear fingers (i.e. fingers located on the back side of the computerized device when held by the user) to, using a rear mounted touchpad, trigger the display of new button groups as needed by the user, and also optionally move the location of the button groups to a portion of the display screen where it is then more convenient for the user to trigger individual buttons in the button group.

In some embodiments, the invention may be viewed as a user interface that allows for more optimal one-hand operation of small handheld computerized devices, such as smartphones. Note however, that in contrast to typical smartphones, which only have a front facing touchscreen, the present disclosure contemplates use with small handheld computerized devices that, in addition to a front touchscreen, additionally have been augmented with rear mounted touchpads.

With one hand operation, often the device user will typically hold the device between the thumb of the hand, often positioned on or near the front of the device, and will often have the other fingers of the hand positioned behind (in back) of the device.

The user interface disclosed herein may be viewed as being a semi-persistent button group, typically invoked by either simultaneous front and back touches or double taps. The semi- persistent button group can contain multiple virtual touch sensitive buttons. As will be discussed, this semi-persistent button group is configured to be easily maneuvered, using one hand, to be within easy reach of the user's thumb so that various buttons can then be thumb activated.

Note that although one hand operation is discussed in order to better emphasize the utility of the invention, this discussion of one-hand operation is not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 A shows a front view of a computerized device, such as a smartphone with a front mounted touchscreen and a rear mounted touch pad (100), shown in more detail in Figure 1M. Here assume that the front mounted touchscreen is the same size and shape as the rear mounted touchpad. Further assume that the front mounted touchscreen is exactly in front of the rear mounted touchpad, and that any bezel surrounding the front mounted touchscreen is not shown. Here the user is gripping the computerized device with a left hand, and that one of the user's finger's (102) is touching the rear mounted touchpad at contact point (104).

Figure IB shows the same computerized device (100), except that now another digit on the user's hand, such as the thumb, is now touching a corresponding position on the front touchscreen. When this happens, according to some embodiments of the invention, the system processor will recognize that an initialization touch sequence is now present.

Figure 1 C shows that in response to an initialization touch sequence, in some embodiments the invention can be configured to then display a semi-persistent button group, comprising at least one touch sensitive button. This semi-persistent button group can be set to be initially displayed at various default locations, and/or to move in response to changes in touchscreen or touchpad input. Figure ID shows how in response to a further touch or click on at least one touch sensitive button (here button 0), the system can record that this button has been pressed by the user, and trigger or stop triggering a particular activity (here Action 0).

Figure IE shows how another touch sensitive button in the semi-persistent button group, here button 2, can be triggered by the same method as discussed above.

Figure IF shows how once the user lifts one or both fingers from the semi-persistent button group for a period of time exceeding the semi-persistent time, then the system will know to remove the semi-persistent button group from the display.

Figure 1 G shows an alternative embodiment of the invention. Here the system has been configured to recognize a rapid double touch (double tap) on the back touchpad as an initialization touch sequence.

Figure 1H shows another alternative embodiment of the invention. Here the system has been configured to at least initially display the semi-persistent button group at a default location near a screen location where, for example, the user's thumb may often reside. This makes it easy for the user to then control buttons using his or her thumb.

Figure II shows how, in some embodiments, the default location of the semi-persistent button group can be set to follow the position of one of the user's fingers, such as the position of the user's trigger finger on the rear touchpad, so that the user can move the position of the semi- persistent button group to a more convenient location for later button pressing by the user's thumb.

Figure 1J shows how, in some embodiments, the semi-persistent button group need not merely be a two dimensional semi-persistent button group. Instead the semi-persistent button group can be two dimensional (2D) projection of a (virtual) three-dimensional (3D) semi- persistent button group. This 3D semi-persistent button group can further be configured to rotate in 3D space in response to various finger touches or finger swipes, and thus hide and expose additional touch sensitive buttons for the user to interact with.

Figure IK is a front panel view of a small handheld computerized device (previously shown in simplified forms in Figures 1A-1J) displaying an optional bezel surrounding the front touchscreen and back touchpad, an example of the user's hand holding the device, and the position and motion of one finger in contact with the touchpad of the device's back panel. Figure 1L is a block diagram showing the major components and data flow among the front panel touchscreen, back panel touch pad, system software, and the device memory.

Figure 1M depicts a simplified exemplary front panel view of the handheld computerized device displaying the position and motion of the user's fingers holding the back panel.

Figure 2 depicts a simplified exemplary back panel view of the handheld computerized device depicted in Figure 1M.

Figure 3 depicts a simplified exemplary front panel view of the handheld computerized device depicted in Figure 1M displaying a multitude of groups of keys.

Figure 4 depicts a simplified exemplary front panel view of the handheld computerized device depicted in Figure 1M displaying the position and motion of the fingers holding the back panel and the multitude of groups of keys depicted in Figure 3 in the same time.

Figure 5 depicts a simplified exemplary front panel view of a smaller handheld computerized device displaying the position and motion of at least one finger in contact with the touchpad of the back panel.

Figure 6A depicts a simplified exemplary front panel view of the smaller handheld computerized device depicted in Figure 5 displaying the position and motion of at least one user's finger in contact with the touchpad of the back panel at the touchpad touch points and a multitude of groups of virtual keyboard keys similarly depicted in Figure 3 in the same time.

Figure 6B depicts a simplified exemplary front panel view of a smaller handheld

computerized device displaying the position and motion of one finger in contact with the touchpad of the back panel. The position of a small virtual keyboard, composed of a plurality of groups of keys, is also shown. Here this virtual keyboard was previously software aligned to correspond to the direction of the user's fingers and hand.

Figure 6C depicts a simplified exemplary front panel view of a smaller handheld

computerized device displaying the position and motion of one finger in contact with the touchpad of the back panel. The position of a small virtual keyboard, composed of a plurality of groups of keys, is also shown. Here the keys were previously software aligned to correspond to the direction of the user's fingers and hand, and the spacing between the keys has also been user adjusted by software. Figure 6D depicts a simplified exemplary flowchart how biomechanical models of hand and finger movement may be used to display a virtual image of at least a portion of a hand of a user on a display screen of the computerized system of Figure 8.

Figure 7 depicts a simplified exemplary front panel view of the handheld computerized device displaying another embodiment of the layout of virtual keys as the standard virtual keyboard.

Figure 8 depicts a simplified exemplary block diagram of a computerized system capable of executing various embodiments of the invention.

Figure 9 depicts a simplified exemplary flowchart how biomechanical models of hand and finger movement may be calibrated and adapted to help turn the raw touchpad data into an accurate model of the user's hand and finger positions.

Figure 10 depicts a simplified exemplary flowchart how predictive typing methods may be used to improve the accuracy of the appearance of the virtual hand and fingers while typing.

Figure 11 depicts a simplified exemplary flowchart how dynamic changes in touchpad sensitivity may, for finger proximity touchpads, assist in highlighting the virtual keys about to be struck by a user while typing on the virtual keyboard.

Figure 12 depicts a simplified exemplary flowchart for generating images of the virtual hand and fingers on the device's graphics display screen.

Figure 13 depicts a simplified exemplary biomechanical and/or anatomical model of the human hand, showing the internal skeletal structure with a skin overlay.

Figure 14 depicts how the simplified exemplary user's hand or hands may be photographed by the device's camera or other camera, and this image information may be used to refine the default parameters of the biomechanical and/or anatomical model of the user's hand.

Figure 15 depicts how an exemplary device camera may be used to obtain a partial image of the user's hand while using the device's touchpad, and this information also used to update and refine the biomechanical and/or anatomical model of the user's hand.

Figures 16A - 16B depict how a simplified exemplary palm angle rotation transformation may help the system relate raw touchpad data to a standard biomechanical and/or anatomical model of the human hand. Figure 17 depicts more exemplary details of the relationship between the finger roots and the hand's overall palm angle.

Figure 18 depicts more exemplary details of the relationship between the hand's palm direction or palm angle and the tips of the user's fingers.

Figure 19 depicts how simplified exemplary biomechanical and/or anatomical model data pertaining to the width of the fingers may be used to help interpret raw touchpad data.

Figure 20 depicts how in a more accurate exemplary model, the location of the various finger roots will be displaced to some extent from the palm line (which forms the palm angle) by various amounts 5ri.

Figure 21 depicts how the simplified exemplary system may attempt to correlate detected fingertip data from some fingers with finger root data from other fingers, determine that some fingertip data is missing, and thus deduce that these fingers are elevated above the touchpad.

Figure 22 depicts how the simplified exemplary system may further assign raw touchpad data to two different hands of the same user, based on the assumption that the range of possible hand angles for the same user is limited by the user's anatomy.

Figure 23 depicts a first simplified exemplary example of angle based finger matching algorithms.

Figure 24 depicts a second simplified exemplary example of angle based finger matching algorithms.

Figure 25 depicts a simplified exemplary flowchart how biomechanical models of hand and finger movement may be used to display a virtual image of at least a portion of a hand of a user on a display screen of the computerized system of Figure 8.

Figure 26 depicts a simplified exemplary flowchart of a "lift and tap" technique of key entry for controlling an input from a user to the computerized system.

Figures 27A - 27F depict a series of simplified exemplary display screen shots of the "lift and tap" technique of key entry depicted in Figure 26 being used to type the first two letters of a "Hello World" message on the computerized system.

Figure 28 depicts a simplified exemplary flowchart of a "lift and drag" technique of key entry for controlling an input from a user to the computerized system. Figure 29 depicts a simplified exemplary flowchart of a "lift and tap" technique of key entry modified to use force applied per finger for controlling an input from a user to the computerized system.

Figure 30 depicts a simplified exemplary flowchart of a modified "lift and tap" technique of key entry modified to use a third force applied per finger for controlling an input from a user to the computerized system.

Figures 31A - 3 IB respectively depict simplified exemplary side and top views of a portion of the touchpad using the contact area resulting from a first force.

Figures 32A - 32B respectively depict simplified exemplary side and top views of a portion of the touchpad using the contact area resulting from a second force.

Figure 33 depicts a simplified exemplary flowchart of a "push and lift" technique of key entry for controlling an input from a user to the computerized system.

Figure 34 depicts a simplified exemplary time-line of the "push and lift" technique depicted in Figure 33.

Figure 35 depicts a simplified exemplary flowchart of a "hover and tap" technique of key entry for controlling an input from a user to the computerized system.

Figures 36A - 36F depict a series of simplified exemplary display screen shots of the "hover and tap" technique of key entry depicted in Figure 35 being used to type and enter the numeral "0" on the computerized system.

Figure 37 depicts a simplified exemplary flowchart of a method 3700 for controlling a control region on a display screen of a computerized system.

Figures 38A-38F depict a series of simplified exemplary illustrations, 3800, 3802, 3804, 3806, 3808 and 3810 of controlling a control region displayed in a display screen of a handheld computerized device by a user operating a touchpad.

Figures 39A-38F depict a series of simplified exemplary illustrations, 3900, 3902, 3904, 3906, 3908 and 3910 of controlling a control region displayed in a display screen of a handheld computerized device by a user operating a touchpad.

DETAILED DESCRIPTION OF THE INVENTION

Figure IK is a front panel view of a small handheld computerized device (100), such as a smartphone with an attached rear mounted touchpad (101) that is the same size of front touchscreen (102). This device will be shown in simplified form in Figures 1 A-1J. Here an optional bezel (104) that surrounds the front touchscreen and back touchpad is also shown, but this bezel will be minimized or omitted in Figures lA-1 J.

This rear mounted touchpad (101) can either be built in to the smartphone or other computerized device (100), or alternatively can be mounted on the back of the smartphone or computerized device (100), following the techniques of parent application 13/223,836 (now US patent 9,310,905), the contents of which are incorporated herein by reference.

Here the user is holding the device in one hand (106), with the thumb of the hand (108) in front, and the remainder of the fingers of the user's hand in the back of the device. Here two of the user's fingers (1 10, 1 12) are touching the touchpad mounted on the back of the device.

In some embodiments, the device may further attempt to estimate and display the relative location of the user's fingers on the back of the device, as per the teaching of parent application 12/773,075, now US patent 8,384,683, the entire contents of which are incorporated herein by reference. Indeed many of the techniques of applicant's various parent patent applications, as referenced in the cross-references to related applications section, and also as disclosed in this application as well (see, for example, figures 1M-39F and related discussion), may be employed in some embodiments of the present invention.

However in other embodiments of the present invention, it will not be necessary to show the locations of these back fingers, although it may at least be useful to show the regions of the back touchpad where the back fingers are touching on the front mounted touchscreen.

Although, to make the distinction between the touchscreen on the front of the device, and the touchpad on the back of the device, easier to distinguish, the terms "touchscreen" and "touchpad" will be used throughout, this distinction is not intended to be limiting. In some embodiments, the back mounted touchpad can be either a back mounted touchpad or a back mounted touchscreen. Irrespective of this, in a preferred embodiment, the dimensions (e.g. length and width) of the back mounted touchpad or back mounted touchscreen will often be the same dimensions as the front mounted touchscreen. In less preferred embodiments, however, the dimensions of the back touchpad/touchscreen can be different from the dimensions of the front touchscreen.

As previously discussed, the methods described herein are typically software implemented methods, intended to be encoded on software stored in the computerized device's memory, and run or implemented using the computerized' device's processor(s). Figure 1L shows a block diagram showing the major components and data flow among the front panel touchscreen (102), back panel touch pad (101), system software, and the device's memory.

Figure 1 A shows a front view of a computerized device, such as a smartphone with a front mounted touchscreen and a rear mounted touch pad (100), shown in more detail in Figure IK. Here assume that the front mounted touchscreen is the same size and shape as the rear mounted touchpad. Further assume that the front mounted touchscreen is exactly in front of the rear mounted touchpad, and that any bezel surrounding the front mounted touchscreen is not shown. Here the user is gripping the computerized device with a left hand, and that one of the user's finger's (102) is touching the rear mounted touchpad at contact point (104). Thus in some embodiments, the invention may be a software implemented method of operating a computerized device such as (100). As previously discussed, this device will typically comprise a front mounted touchscreen, a back mounted touchpad, and at least one processor (often containing one or more cores such as an ARM, MIPS, x86 or other type core).

This method will typically comprise using the processor(s) to receive touch location input from either the front mounted touchscreen and/or the back mounted touchpad, and in response to an initialization touch sequence (which will be defined in more detail later), the device will display an image of a semi-persistent button group.

This semi-persistent button group will typically comprise one or more one touch sensitive buttons (e.g. virtual buttons, indicating what regions of the screen or touchpad will be sensitive to user presses) at a default location on the device's front mounted touchscreen. As will be discussed, this default location can vary, and need not always be fixed in the same region of the screen.

More specifically, this semi-persistent button group will typically comprise an image of at least one touch sensitive button, and typically each button image will have a touch sensitive button location on (or with respect to) this semi-persistent button group. Often this semi-persistent button group will not be initially displayed on the screen, in order to free up as much screen area for other purposes. Note that in these examples, the semi- persistent button group is not shown in Figures 1A, IB, and IF

Figure 1 C shows that in response to an initialization touch sequence, in some embodiments the invention can be configured to then display a semi-persistent button group (300), comprising at least one touch sensitive button (302). In Figure 1C, five touch sensitive buttons (302), numbered 0, 1 , 2, 3, and 4 are shown.

As will be discussed, this semi-persistent button group (300) can be set to be initially displayed at various default locations, and/or to move in response to changes in touchscreen or touchpad input. For example, in Figure 1C, the default location may been initially positioned higher in the display at (300a), and the user may have used a rear finger such as Figure IK (1 10) to move (304) the semi-persistent group down to a different location (300) that is closer to the user's thumb.

However when triggered by the user's initialization touch sequence, this semi -persistent button group (302) will then be displayed on the front touchscreen. Typically the semi- persistent button group will be displayed at least while the initialization touch sequence is being received, and often for a short period of time, such as a few seconds afterwards. The time that this semi-persistent button group remains on the screen after the initialization touch sequence is no longer being received is termed the "semi-persistent time". Usually the semi- persistent time will be between about 1 second and 30 seconds inclusive, but other time values may also be used.

Then, according to the method, if while the semi-persistent button group (302) is being displayed, if a front touch or a back touch is detected at a location of at least one of the touch sensitive buttons in that group (302), then the system will detect that this button has been pressed by the user. This will in turn activate whatever action has been previously associated to that button. To do this, the system will typically record or register (for at least a short or transient period of time) that this button has been pressed by the user, and then initiate an action (or stop an action) previously associated with that particular button.

Figure ID shows how in response to a further touch or click on at least one touch sensitive button (here button 0), the system can record that this button has been pressed by the user, and trigger or stop triggering a particular activity (here Action 0). Note that as a result of the movement (304) in Figure 1C, the semi-persistent button group (300) and button 0 is now in a more convenient location for the user's thumb (108) to press.

Figure IE shows how another touch sensitive button in the semi -persistent button group (300), here button 2, can be triggered by the same method as discussed above. Again, note that as a result of the movement (304), button 2 is also now in a more convenient location for the user's thumb to press.

Figure IF shows how once the user lifts one or both fingers from the semi -persistent button group for a period of time exceeding the semi-persistent time, then the system will know to remove the semi-persistent button group from the display. Alternatively, the system may be configured to maintain the semi -persistent button group on the display so long as at least one finger is touching the semi-persistent button group, but then more quickly or even instantly remove the semi-persistent button group neither the front nor the back finger (or thumb) is touching either side of the device.

In some embodiments the initialization touch sequence can alternatively or additionally comprise a touch sequence where the touch location input from the front mounted touchscreen matches a location of a back touch on the back mounted touchpad. When this happens, this can define a "matching location". In some embodiments, the default location can be set to the same location (on the touchscreen) as this matching location.

Figure 1 G shows an alternative embodiment of the invention. Here the system has been configured to recognize a rapid double touch (e.g. a rapid "tap tap") on the back touchpad as an initialization touch sequence. Here a "rapid" double touch might be two touches occurring in a time window such as is shown and discussed for Figure 34. The idea here is to distinguish a deliberate double touch or double tap from an accidental double touch or double tap.

In some embodiments, at least during the semi-persistent time where only one of a front touch or a back touch is detected, if the matching location (e.g. location of both the front and back touches) changes simultaneously, then the system processor(s) will change the location of the semi-persistent button group according to a present location of either said matching location.

Alternatively and/or additionally, in the case that only one of a front touch or back touch is detected, but during the semi-persistent time where the semi-persistent button group is displayed, then the device processor(s) will change the location of the semi-persistent button group according to the present location of only one of a front touch or back touch.

This latter embodiment is shown in Figure II. Figure II shows how, in some embodiments, the default location of the semi-persistent button group can be set to follow changes in the position of one of the user's fingers, such as the position of the user's trigger finger (from 100b to 100c) on the rear touchpad, so that the user can move the position of the semi- persistent button group from 300b to 300c to a more convenient location for later button pressing by the user's thumb (108).

Various types of multiple touch type initialization touch sequences

In some embodiments, the initialization touch sequence can comprise a plurality of rapid taps on the back mounted touchpad. In these embodiments, the default location of the semi- persistent button group (300) can be determined according to at least one of: a) a location based on a function of the location(s) of the plurality of rapid taps on the back mounted touchpad, or b) a location that is deliberately set to be different from the location of the various of rapid taps on the back mounted touchpad.

Here, for example, this plurality of rapid taps can be as little as two taps (e.g. a double tap) within a double tap duration of time (typically on the order of about a second, such as between 0.1 and 2 seconds.

Alternative types of semi-persistent button groups

Although Figures 1A-1I show a semi-persistent button group (300) that is a flat disk, it should be evident that other shapes will also work. Indeed, in addition to other shapes, the semi-persistent button group need not be flat. Instead it can be a projection of a three dimensional shape, such as a sphere, cube or other shape, with buttons dispersed in three dimensional space. Here, since most touchscreen displays display two dimensional objects, the system may produce a projection of the three dimensional shape onto the two dimensional touchscreen. Thus in some embodiments, the semi-persistent button group can be a 2D (two dimensional) projection of a 3D (three-dimensional) semi-persistent button group. Indeed, in these embodiments, the 3D semi-persistent button group can be configured be rotated in 3D space according to finger swipes according to either of said front touchscreen or back touchpad. This 3D type semi-persistent button group is shown in Figure 1J.

As previously discussed, Figure 1J shows how, in some embodiments, the semi-persistent button group need not merely be a two dimensional semi-persistent button group. Instead the semi-persistent button group can be two dimensional (2D) projection (300-3D) of a (virtual) three-dimensional (3D) semi-persistent button group. This 3D semi-persistent button group can further be configured to rotate in 3D space in response to various finger touches or finger swipes, and thus hide and expose additional touch sensitive buttons for the user to interact with.

Further background on specific techniques that optionally may be used by the invention

As previously discussed, certain aspects of the invention relate to a handheld computerized device including a bit mapped display screen on the front panel, and a touchpad often installed on the back panel, or alternatively on the side panel or other area other than that of the display screen. More particularly, certain aspects of the invention relate to a method and graphical user interface that may optionally enable the user to see the user's finger position and motion from behind the device or other portion of the device superimposed upon a virtual keyboard layout, semi-persistent button group, or other icons on the front panel.

It is desirable to have a more efficient and user-friendly way to do user input for handheld computerized devices. Certain aspects of the invention present an effective solution for these above problems. Certain aspects of the invention free the original keyboard space on the front panel for applications by utilizing the previously mostly unused back panel space for user input. Certain aspects of the invention are able handle both keyboard input and mouse input. Certain aspects of the invention present a stunning graphic user interface on the front panel screen where a user may see the real-time position and motion of his/her fingers holding the back panel, on top of the display of keyboard layout, which is also referred to as a virtual keyboard. Certain aspects of the invention are more precise than current touch screen keyboards by removing the display layer that presently exists between the fingers and touch pad. Certain aspects of the invention also move the user's fingers away from the front panel, so that the user's fingers will not block the view of the soft key or area that the finger is presently operating on. For smaller handheld devices, such as cell phone, iPhone™ or iPad™, the hand that holds the device may now also do input, hence freeing the other hand for other activities.

Thus an obj ect of certain aspects of the invention are to provide a method for a more efficient and user-friendly user input for a handheld computerized device.

Another object of certain aspects of the invention are to free up the space currently occupied by the keyboard on the front panel of small electronic devices, and utilize the mostly unused space on the back panel of the handheld devices for user input purposes.

Another object of certain aspects of the invention are to present a visually compelling user- interface design that enables the real time position and motion of the fingers that hold the device, which normally would be hidden from view by the device itself, to be displayed on the front panel as "virtual fingers" together with an optional display of a virtual keyboard layout. The user's finger positions and keyboard layout may be displayed either as background image, or as a transparent layer on top of some of all of the applications currently running on the handheld device. These semi-transparent representations of the user's finger positions and virtual keyboard allow the user to easily enter data while, at the same time, continuing to allow the user unimpeded access to the various applications running on the handheld device. Thus, for example, applications originally written for a computer device that had a physical keyboard may be easily run, without code modification, on a tablet computer device that lacks a physical keyboard. Thus, these virtual semi-transparent keyboards and methods that also give information of finger motion of the user may be highly useful.

Another object of certain aspects of the invention are to enable the hand that is holding the device to also do user input operations, hence freeing the other hand for other inputs or other purposes.

According to one embodiment, a device and method include a display screen on the front panel, which may be a bit-mapped display screen, a touchpad embedded on the back panel capable of sensing the user's finger positions and motion, and a graphical user interface. This graphical user interface will normally include both software and optional graphics acceleration hardware to enable complex graphics to be rapidly displayed on the display screen. The device also has an optional virtual keyboard processor that displays the keyboard layout, as well as computes and displays the user's finger positions on a real-time basis. The user's finger position and motion on the touchpad of the back panel may thus be computed and displayed on the front display screen as a layer, which may be a semi-transparent layer, on top of all of the other applications. The virtual keyboard processor may also interpret the finger motions, i.e. strokes, and invoke corresponding operations based on the known location of the finger position on the keyboard.

Unlike previous approaches, the user's fingers do not need to be constrained to fit onto particular regions of the touchpad, but rather may be disposed in any arbitrary location. Unlike some previous approaches, although embodiments of the invention may be aided to some extent by real-time video that may provide video information pertaining to at least some portion of the user's hand, visualization of the user's fingers, in particular the tips of the user's fingers is not necessary. This makes it feasible to use handheld device video cameras designed for general photographic purposes to be used to help in visualizing the user's hand, without requiring that much of the user's hand in fact be photographed. There is no requirement at all that the user's fingertips be photographed while operating the device. Figure 1M depicts a simplified exemplary front panel view of a handheld computerized device (100) displaying the position and motion of the user's fingers (108) holding the back panel, in accordance with one embodimnet of the invention. The user is holding the handheld electronic device (100), similar to an Apple iPad™ or equivalent pad device. The front panel of the device is occupied by a large graphics display screen (102), which may be a bit- mapped graphics display screen. In some embodiments, the whole front panel screen or front panel may be occupied by this graphics display screen (102). The user is holding the handheld computerized device (100) using his or her hands (104), where a portion of the user's thumb (106) is in front of the device over a portion of the front panel, and the user's fingers (108) are behind the device. Although device (100) is not transparent, nonetheless the graphics display screen (102) is shown representing a graphical representation of the user's fingers (108) as well as regions where the user's fingers are apparently touching an obscured from view or "invisible" surface at touchpad touch points (110) at the back panel of the device. Each of the touchpad touch points (1 10) may correspond to a real time finger print image of the tip of the user's finger.

Figure 2 depicts a simplified exemplary back panel view of the handheld computerized device (100) depicted in Figure 1M, in accordance with one embodiment of the invention. In contrast to the front panel of device (100), previously depicted in Figure 1M, which included a large graphics display screen, the back panel of the handheld computerized device as depicted in Figure 2 does not include a large graphics display screen, but instead includes a large touchpad (200). As may be seen, the user's fingers (208) may now be seen positioned above the touchpad with the tips of the user's fingers (210) touching the touchpad. It is understood that the expression "above the touchpad" refers to the relative position of the fingers with respect to the touchpad when the touchpad is facing upward.

Note that in some embodiments, this back touchpad may be provided as a retrofit or add-on to a handheld computerized device that otherwise lacks such a back touchpad. Such methods and systems, such as "clip on" back touchpads, are described at more length in parent application 13/223,836, the contents of which are incorporated herein by reference in its entirety.

Figure 3 depicts a simplified exemplary front panel view of the handheld computerized device depicted in Figure 1M displaying a multitude of groups of keys (300, 302, 304), in accordance with one embodiment of the invention. Figure 3 depicts one possible optional multitude of groups of keys, i.e. a "virtual keyboard," being displayed on graphics display screen (102) of device (100). In this example, the "virtual keyboard" includes a symbol keypad (300), a numeric keypad (302), and a QUERTY keypad (304). Note that in many embodiments, the keys may be drawn in outline or semi-transparent form so as not to obscure any other graphical applications running on graphics display screen (102).

The scheme depicted in Figure 3 allows the user to optionally use a touchpad keypad on the back of the device to input keystrokes and mouse actions, and these inputs will be reflected on the display screen on the front of the handheld computerized device as "virtual fingers" or equivalent. As previously discussed, this virtual keyboard layout displayed on graphics display screen (102) at the front panel may be a standard or modified QUERTY keyboard or keypad, a numeric keyboard or keypad, i.e. number entry keyboard, or alternatively some less standard keyboard or keypad such as a musical keyboard, a Qwerty, Azerty, Dvorak,

Colemak, Neo, Turkish, Arabic, Armenian, Greek, Hebrew, Russian, Moldovan, Ukranian, Bulgarian, Devanagari, Thai, Khmer, Tibetan, Chinese, Hangul (Korean), Japanese, or other type of keyboard. Often, this keypad will be a semi-transparent keypad in order to allow the user to continue to view various application programs that are running on display screen (102) below the virtual keyboard.

Figure 4 depicts a simplified exemplary front panel view of the handheld computerized device (100) depicted in Figure 1M displaying the position and motion of the user's fingers (108) holding the back panel and the multitude of groups of keys (300, 302, 304) depicted in Figure 3 in the same time, in accordance with one embodiment of the invention. Figure 4 depicts an example of how a user, typing on a touchpad mounted on the back of the electronic device, may see a graphical representation of his or her fingers (108) displayed on graphics screen (102) of device (100), as well as a display of virtual keyboard layout (300, 302, 304). The user's ability to enter input data to the handheld computerized device (100) is thus enhanced because the user may visually judge the distances between his or her fingers (108) and the keypad keys of interest (300, 302, 304) and move his or her fingers appropriately so as to hit the desired key. The user may also click on hyperlinks, such as linkl . Iink2. and the like, or other clickable objects or command icons.

Because the user's operating fingers are moved away from the display screen, the fingers will not block the view of the display screen's soft keys, soft buttons, links or other areas. These areas on the display screen may now be seen more precisely, which in turn allows for more precise operation of the device.

The virtual display of the user's fingers may be a valuable feature for some of the newer tablet computers, such as the Microsoft Surface™ series, Windows 8, and the like, which may alternate operating modes between a first tablet operating mode designed for traditional touch input, and a second desktop operating mode, derived from legacy desktop operating systems, that is optimized for more precise mouse input. By enabling such tighter control, it becomes more feasible for a user to operate such "Surface" like devices in legacy desktop mode without the need to use a mouse or other hand operated pointing instrument.

Because a front keyboard, i.e. mechanically actuated keys, is no longer necessary, certain aspects of the invention free up the space on the device that might otherwise have been used for original mechanical keyboard space on the front panel, and create room for additional larger displays and applications. Certain aspects of the invention make use of the presently mostly unused back panel space, thus, enabling the front display to show substantially larger virtual keys, or virtual keys including more space between them that are easier for the user to use.

Certain aspects of the invention may create compelling visual effects, as well as useful visual effects, because the user may see his or her fingers (108), which are holding the back panel and thus normally blocked from view, being virtually displayed on the front panel along with a virtual, i.e. computer generated, keyboard layout display (300, 302, 304). Because both the user's finger position, finger touch area, each depicted as a circle surrounding a cross, finger motion and the virtual keyboard are visible from the front panel, the user finger inputs on the touch panel located on the back panel of the device are both intuitive and easy to use. There will be no learning curve, and no need for special training. The user input methods of certain aspects of the invention are more precise than traditional touch screen keyboards because these methods remove the obscuring layer between the finger and touchpad, and the operating fingers will not block the view of the display screen. For small handheld devices such as cell phones and iPhones, the current embodiments of the invention enable the hand that holds the device to perform text input and other commands, hence freeing the other hand for other activities.

Note that although often a virtual keyboard will be presented, alternative data entry points of interest, such as hyperlinks on an internet browser, and the like, may also be used according to these methods as well.

In one embodiment, the layout of a multitude of groups of virtual keyboard keys (300, 302, 304), including numbers, letters, and symbols may be displayed on an area separated from concurrently running other software applications that are being displayed simultaneously on the screen of the front panel (much like the traditional separately displayed area often used for soft keys near the bottom of the display screen). The virtual keyboard keys (300, 302, 304) may be advantageously displayed in different size or in locations that are not the same locations that are determined by the other software applications and/or programs because the virtual keyboard keys (300, 302, 304) may be displayed translucently so as to display both the virtual keyboard keys (300, 302, 304) and the underlying concurrently running application or program display content.

Devices and systems utilizing the virtual fingers and optional virtual keyboard embodiments of the invention advantageously need not have mechanically actuated and/or permanently dedicated physical QWERTY keypads or QWERTY keyboards, or any other type of mechanically actuated and/or permanently dedicated physical keypad or keyboard such as one dedicated to number entry. Eliminating mechanically actuated and/or permanently dedicated keypads or keyboards improves device ergonomics, allow for larger graphics display screens, and also reduces device costs.

Figure 5 depicts a simplified exemplary front panel view of a smaller handheld computerized device (500) displaying the position and motion of at least one finger in contact with the touchpad of the back panel, in accordance with one embodiment of the invention. Smaller handheld computerized device (500) may include a cellular phone sized device (e.g. an Apple iPhone™ sized device) including a smaller graphics display screen (502) virtually displaying the position and motion of a multitude of fingers (108) in contact with the touchpad touch points (110) at the back panel of smaller handheld computerized device (500).

Figure 6A depicts a simplified exemplary front panel view of the smaller handheld computerized device (500) depicted in Figure 5 displaying the position and motion of at least one user's finger (108) in contact with the touchpad of the back panel at touchpad touch points (110), and a multitude of groups of virtual keyboard keys (300, 302, 304) similarly depicted in Figure 3 in the same time, in accordance with one embodiment of the invention. Figure 6 may include similar features as Figure 4 with the exception of using smaller handheld computerized device (500) being held in just one user hand (104), the other hand of the user being free to do other tasks.

Adjusting the virtual keyboard

Because the virtual keyboard (or keypad) is software generated, it need not always be presented in the same position. However, in embodiments of the invention, at least temporary persistence of the various keys of the virtual keyboard is desirable, so that the user always knows the relative location of the key that they are going to strike, and so that the system can accurately compute the relative distance between the user's various fingers (as predicted by the anatomical and biomechanical model of the user's hand) and the various keys.

In some embodiments, it may be useful to allow the user to adjust the position, orientation, and spacing between the virtual keys of the virtual keyboard either prior to beginning a typing session, or even during a typing session. Here, for example, a user may indicate to the system by keypress, voice command, virtual key selection, other touchpad input, etc. that virtual keyboard repositioning is desired. The system may then use various options to reposition the virtual keyboard.

In some embodiments, the virtual keyboard will be essentially allowed to float on the screen, and the user can then rotate the virtual keyboard, stretch and shrink it, change key spacing, etc., by multi -touch type commands either on a front display panel touchpad, a back panel touchpad, or other touchpad device. In other embodiments, the user may control the position, orientation, and spacing between the virtual keys of the virtual keyboard by verbal commands such as "rotate right 30 degrees", or "go up one inch", and so on.

In some embodiments, the position and orientation of the virtual keyboard can be set to track the position and orientation of the user's hand(s). In embodiments of the invention, design tradeoffs are taken into consideration. If the position and orientation of the virtual keyboard tracks the position and orientation of the user hand(s) too closely, then the ability of the software to determine which virtual key the biomechanical and anatomical model of the user's hand is striking may be reduced. Thus, in some embodiments, it may be useful to set the virtual keyboard generation software to track a time averaged position and orientation of the user's hand (usually over periods of at least several seconds, or even minutes).

In other embodiments, the virtual keyboard generation software can be set to initialize the position and orientation of the virtual keyboard based on the position and orientation of the user's hand during a specified time. This can be as simple as having the user place his or her (hands) on the back touchpad and giving an "initialize keyboard orientation and position" command, either verbally, by pressing a real or virtual key, or by other activation system. Once so initialized, the virtual keyboard can then maintain its position and orientation until the user then decides to reset it.

Figure 6B depicts a simplified exemplary front panel view of a smaller handheld

computerized device displaying the position and motion of one finger in contact with the touchpad of the back panel, in accordance with one embodiment of the invention. The position of a small virtual keyboard, composed of a plurality of groups of keys, is also shown. Here this virtual keyboard was previously software aligned to correspond to the direction of the user's fingers and hand.

Figure 6C depicts a simplified exemplary front panel view of a smaller handheld

computerized device displaying the position and motion of one finger in contact with the touchpad of the back panel, in accordance with one embodiment of the invention. The position of a small virtual keyboard, composed of a plurality of groups of keys, is also shown. Here the keys were previously software aligned to correspond to the direction of the user's fingers and hand, and the spacing between the keys has also been user adjusted by software.

Figure 6D depicts a simplified exemplary flowchart how biomechanical models of hand and finger movement may be used to control a virtual keyboard on a display screen of the computerized system of Figure 8, in accordance with one embodiment of the invention. Figure 6D depicts the method includes obtaining data from a touchpad, the data being associated with the location and movement of a finger and/or hand of a user when the user operates the computerized system using the touchpad, the data not being associated with an image of the finger of the user from an image sensor (620). The method further includes communicating the data from the touchpad to the computerized device, the touchpad being located in a location that is different from the location of the display screen (622). The method further includes analyzing the data in accordance with a model of a human hand, and assigning the data to at least one of a plurality of fingers of the mode (624), computing a graphical representation of at least one finger of the user in accordance with the model (926), generating a virtual keyboard on the display screen (628), and repositioning the virtual keyboard according to either a verbal command from the user or a user input from the touchpad (630).

Figure 7 depicts a simplified exemplary front panel view of handheld computerized device (100) depicted in Figure 1M displaying another embodiment of the layout of virtual keys

(700) as the standard virtual keyboard, in accordance with one embodiment of the invention. Figure 7 depicts another embodiment of the layout of virtual keys (700) may include a modified QWERTY keyboard or keypad that includes splitting the keyboard in half and displaying each half of the keyboard at an angle adapted for better ergonomic typing than the keyboards depicted previously.

In one embodiment, a computer-implemented method includes a handheld computerized device, including a screen on the front of the device capable of displaying a graphical user interface, and a touch sensitive back panel or side panel or other area other than the display screen, and a user interface, such as a two dimensional touch sensor. For simplicity, this touch sensitive panel, which need not necessarily be flat, and need not necessarily be mounted on the back side of the device, hereinafter also referred to as a "touchpad," "touch sensor," or "touch sensitive back panel", but this use is not intended to be limiting.

The touch sensor will determine the motion of the fingers in real time, and the computerized system's or device's software and processor(s) will use the touch sensor data to compute the real time position and motion of the user's fingers that are touching the touch sensor on the back panel. These "virtual fingers" will then be displayed on the device's graphical user interface on top of a static background where optionally a multitude of groups of keys, including numbers, letters, and symbols (e.g. a virtual keyboard) or hyperlinks may be displayed. By watching the motion of the user's virtual fingers on the virtual keyboard, the user may easily operate the device, and optionally determine precisely where to strike a finger in order to hit an intended virtual key.

In one embodiment, the back panel user interface (UI) may be outlined in a distinctive yet non-obstructive color and displayed as a transparent layer over the current applications; hence all the details of current application and back panel UI are shown to the user at the same time.

In one embodiment, the real time position and motion of the fingers holding the back panel may be displayed on the screen of the front panel.

In one embodiment, the layout of a multitude of groups of keys, including numbers, letters, and symbols may be displayed on the screen of front panel as background of real time position and motion of the fingers holding the back panel.

In one embodiment, the real time position and motion of the fingers holding the back panel may be displayed on the static background of a multitude of groups of keys, including numbers, letters, and symbols, enabling the user to precisely strike a finger on an intended key.

In one embodiment, the display of the virtual hand may be creative and artistic. For example, the display may instead show a skeleton, an animal claw, a furry hand, a tattooed hand, and the like to achieve more compelling or amusing effects.

In one embodiment, a computer-implemented method, including a handheld computerized device includes a touchpad installed on the back panel. The touchpad is able to sense the touch point positions, movement, and stroke motion data of a multitude of fingers. The data information of the finger motion of one or a multitude of fingers, including the motion type, e.g., touch, movement, and stroke patterns, and the like, and motion position, is passed to a virtual keyboard processor, such as a computer processor. The virtual keyboard processor may analyze the finger motion, compare the finger positions with the registered position of the keys, hereinafter referred to as virtual keys, as well as the hyperlinks and other touch buttons of the application program, e.g., generically the "user entry area", and then will decide which item in the user entry area was stroked or actuated. The virtual keyboard processor may then invoke the corresponding operation. The virtual keyboard processor may also update the real time image of the fingers, or finger pads or touch points, or indeed the user hand(s) on the front screen after each finger motion. In one embodiment, the touchpad may be installed on the back panel of the handheld computerized device, and may be able to sense the touch, movement, and stroke motion of a multitude of user fingers.

In one embodiment, the information pertaining to the finger motion of a multitude of user fingers, including the motion type, e.g., touch, movement, and stroke action, and the like, as well as motion position, may be passed to a virtual keyboard processor.

In one embodiment, the virtual keyboard processor may analyze the finger motion, compare finger position with the registered position of the keys, determine which key was stroked, and invoke the corresponding operation, In one embodiment, virtual keyboard processor may update the real time position and motion of the fingers holding the back panel.

One embodiment of the invention includes a graphical user interface (GUI) for a handheld computerized device. The interface may include a display of a multitude of groups of keys, including numbers, letters, and symbols. The keys may be displayed on a graphical user interface on the front panel display screen, and indeed this display area may occupy the whole screen. Thereby, the content of the graphic user interface is not blocked by applications, and is shown together with the applications.

One embodiment of the invention includes a graphical user interface for a handheld computerized device. This interface includes a display of the real time position and motion of the fingers holding the back panel. Here the display is on the front panel screen, and in fact may occupy the whole screen. Due to the advantages of this approach, the content of the user's finger position and motion is not blocked by applications, or by the display of groups of keys, including numbers, letters, and symbols.

One embodiment of the invention includes a method of assisting user data entry into a handheld computerized device. This handheld computerized device includes at least one touchpad in one embodiment being located on a side of the handheld computerized device that is behind the side of the device that holds the graphics display screen, at least one graphics display screen, at least one processor, memory, and software. Often, however, the handheld computerized device will lack a mechanically actuated and/or permanently dedicated physical QWERTY keypad or keyboard, and may also lack a mechanically actuated and/or permanently dedicated physical numeric keypad or keyboard as well. The method will usually include displaying at least one data entry location on the at least one graphics display screen of the device. Often this at least one data entry location will be a graphical display of a keyboard or keypad that may be included of a multitude of data entry locations. Here, the system will use the touchpad to obtain data on the location and movement of the user's fingers and/or hand. The system may analyze the data on the location and movement of the user's fingers and/or hand according to a biomechanical and/or anatomical model of a human hand, and will assign data on the location and movement of the user's fingers and/or hand to specific fingers on this biomechanical and/or anatomical model of a human hand (usually the user's hand). The system may then use this biomechanical and/or anatomical model of the human hand to compute a graphical representation of at least the user's fingers, and frequently both the user fingers and the user hand(s). The system will then display the graphical representation of at least the user's fingers (and again frequently both the user's finger and hand), on the device's graphics display screen. Thus the distance between the graphical representation of the user's virtual fingers on the graphics display screen, and the virtual data entry location (such as the virtual keyboard) will give information that will help the user properly position his or her real fingers and/or hand on the touchpad, which in turn will facilitate data entry.

Figure 8 depicts a simplified exemplary block diagram of a computerized system 800S capable of executing various embodiments of the invention, in accordance with one embodiment of the invention. Computerized system 800S includes software and hardware that may be used to implement one embodiment of the invention such as a front panel screen (804), a back panel touch pad 800, a virtual keyboard processor (802), an application process (806), and a device memory(808). Finger position and motion data are first collected from back panel touch pad (800), and then passed to virtual keyboard processor (802). The virtual keyboard processor (which will often be implemented by a combination of software and hardware such as a microprocessor, graphics processor, touchpad controller, and memory) displays the virtual finger position and motion together with the keyboard layout on front panel screen (804). The virtual keyboard processor also analyzes the finger position and motion information data, compares the data with the registered position of the keys (or hyperlinks) and invokes proper operation in application process (806). The keyboard position information may be programmed in a virtual keyboard process, or alternatively may be saved in system memory (808). The key-press or hyper-link information that the user intends to relay to the applications may be passed to the virtual keyboard controller either through memory, or alternatively through inter-process communications. Other touchpad and screen locations.

In one embodiment, the display screen may be located at some distance from the touchpad. Indeed, the display screen and the touch pad may not even be physically connected at all. Rather the touchpad may transmit data pertaining to the user's hand position to a processor, which in turn may then generate the virtual image of the user's hand and display the virtual hand on the display screen, and neither touchpad, processor, or display screen need to be physically connected (although they may be). For example, data pertaining to the user's hand and finger position relative to the touchpad may be transmitted by a wired, wireless, or optical (e.g. infrared) method to the processor. The processor in turn may transmit the virtual image of the user's fingers and hand to the display screen by a wired, wireless, or optical (e.g. infrared) technique. As a result, the user's real hand will be moving close to a touchpad at a different place other than the current display screen. The display screen may thus be in nearly any location, such as on a regular monitor, TV screen, projector screen, or on a virtual heads-up eyeglass display worn by the user (e.g. a device similar to Google Glass).

Touch pads including non-flat surfaces.

Although touch pads are often flat and roughly rectangular devices, there is no constraint that the touch pads using embodiments of the invention be either flat or rectangular. Indeed in some embodiments, there is advantage to employing touch pads that include variably shaped and curved surfaces. Such curved and/or variably shaped touch pads could be then placed on various non-traditional locations, such as on the surface of a ball or cylinder, on the surface of various common devices such as glasses frame stems for virtual heads-up displays such as windshields, eyeglasses, and the like, other wearable computerized devices such as smart watch bands, steering wheels - either for a vehicle or a game interface, joysticks, and the like, and/or, dashboards, instrument panels, and the like.

Touchpad technology.

In principle, many different types of touchpad technology may be used for this device, including capacitive sensing, conductance sensing, resistive sensing, surface acoustic wave sensing, surface capacitance sensing, projected capacitance sensing, strain gauges, optical imaging, dispersive signal technology, acoustic pulse recognition, pressure sensing and bidirectional screen sensing. However, in a preferred embodiment, touchpad sensing technology that is capable of sensing multiple finger positions at the same time may be used. Such an ability to sense multiple finger positions or gestures at the same time hereinafter also referred to as "multitouch" or "multi-touch" sensing technology. Touchpads are thus distinguished from previous mechanical keyboards or keypads because touchpads are not mechanically actuated, that is, since the surface of a touchpad is substantially rigid and responds to touch instead of a mechanical deflection, the touchpad gives the user

substantially no indication that the immediate surface of the touchpad moves where touched, except perhaps for the entire rigid touchpad moving as a result, even with pressure sensitive touchpad technology. Touchpads are further distinguished from previous mechanical keyboards or keypads because the shape and/or location of input keys or buttons on a touchpad are not fixed because the keys and/or buttons are instead displayed on an electronically controlled screen with the flexibility of software control and not limited by fixed mechanical elements located on the device.

One example of a multi-touch touchpad embodying the invention may use a touch sensing device commercially available from Cypress Semiconductor Corporation, San Jose,

California and commonly known as the Cypress TrueTouch™ family of products. This family of touchpad products works by projective capacitive technology, and is suited for multi-touch applications. The technology functions by detecting the presence or proximity of a finger to capacitive sensors. Because this touchpad system senses finger proximity, rather than finger pressure, it is well suited to multi-touch applications because, depending upon the tuning of the capacitance detection circuit, various degrees of finger pressure, from light to intense, may be analyzed. Although often used on touch screens, the projective capacitive technology method may function with a broad range of substrates.

Virtual finger and hand position software (virtual keyboard processor)

As others have noted, one problem with attempting to create "virtual fingers" is that at best, usually just certain regions of the hand, such as the fingertips and perhaps the palms, may usually be detected by conventional multi-touch sensors. To overcome this issue

bootstrapping from hand-position estimates has been suggested, which overcomes the invisibility of structures that link fingertips to palms. Suitable algorithms could be obtained by using context-dependent segmentation of the various proximity image constructs, and by parameterizing the pixel groups corresponding to each distinguishable surface contact. It was found that by path-tracking links across successive images, those groups which correspond to the same hand part could be determined, and it was possible to reliably detect when individual fingers touched down and lifted from the multi-touch pad surface. It has been proposed that a number of different combinatorial optimization algorithms that used biomechanical constraints and anatomical features to associate each contact's path with a particular fingertip, thumb, or palm of either hand. Such algorithms further operated by assigning contacts to a ring of hand part attractor points, using a squared-distance cost metric, to effectively sort the contact identities with respect to the ring of hand part attractor points. A skeletal linked model of the human hand based software that creates a biology-based

(biomechanical and/or anatomical) model of joint motion and associated set of constraints has been proposed. The skeletal linked model approach also is based on a software model of the skin that may stretch and bulge in order to accommodate this internal skeleton. The software models a natural joint axis for four different types of joints in the human hand, as well as takes into account the relative lengths of the underlying hand bone structure, and also accounts for the space occupied by the hand's muscles and skin.

Figure 25 depicts a simplified exemplary flowchart how biomechanical models of hand and finger movement may be used to display a virtual image of at least a portion of a hand of a user on a display screen of the computerized system of Figure 8, in accordance with one embodiment of the invention. Figure 25 depicts the flowchart includes obtaining data from a touchpad, the data being associated with the location and movement of a finger and/or hand of the user and not associated with an image of the finger of the user from an image sensor, when the user operates the computerized system using the touchpad (2510). The flowchart further includes communicating the data from the touchpad to the computerized device, the touchpad being located in a location that is different from the location of the display screen (2520). The flowchart further includes analyzing the data in accordance with a model of a human hand, and assigning the data to at least one of a multitude of fingers of the model (2530), computing a graphical representation of at least one finger of the user in accordance with the model (2540), and displaying the graphical representation on the display screen (2550).

Figure 9 depicts a simplified exemplary flowchart how biomechanical models of hand and finger movement may be calibrated and adapted to help turn the raw touchpad data into an accurate model of the user's hand and finger positions, in accordance with one embodiment of the invention. The system may work with adequate accuracy using standardized models of hand and finger relationships. For example, the system may perform adequately by an initial calibration step where the system invites the user to place his or her hand on the display screen, the system displays various sized hands, and the user is invited to enter in which standardized hand size best fits his or her own hands. The system may then use this data for its various calculations. Even more simply, the system may default to an average hand size for initial use, allowing some degree of functionality to be achieved with no preliminary calibration.

In one embodiment, it will be useful to better calibrate the system by employing one or more active calibration steps. These steps may refine the initial hand model under actual use conditions, and make appropriate adjustment to the various portions of the hand model as will best fit data that has been obtained under actual use conditions. An example of this active calibration process is shown in Figure 9. Here the system may invite the user to do an active calibration step, or alternatively the user will voluntarily start an active calibration step, in step (900). In one embodiment, the model includes calibration information in accordance with pressing a portion of the user's hand on the touchpad in a specified manner. To facilitate this calibration step, the system may optionally display one or more targets on the screen, which may be keyboard targets, or alternatively may be specially designed calibration targets specifically designed for the active calibration step. Optional photographic calibration steps are described for Figure 14.

In one embodiment referring to Figure 9, to reduce complexity, the system may optionally request that the user calibrate one hand at a time, and indeed may request that the user operate the fingers on his or her hand in a manner different from normal typing so as to gather additional data. For example, a user may be requested to first extend a specific finger to a maximum length and press, then to a minimum length and press, then to the extreme left and press, then to the extreme right and press and so on, potentially through all fingers and the thumb on a one at a time basis. It should be apparent that such a data set may then naturally be translated into a reasonably detailed model of that particular user's hand and its capabilities to maintain a number of different configurations. During the calibration process, the system will accumulate touch data by invoking touchpad sensing hardware and calibration software (902). The system will also make predictions as to the location of the user's hand and fingers by bootstrapping from various hand position estimates (904). Often the system will track the positions of the hand and fingers across successive time intervals to do the predicting, and compute probable finger paths (906). The system will often use its internal model of the user's hand biomechanical features and anatomical features to do the computing, and to help associate the various projected paths with the user's fingertips and thumb position, which at least during the active calibration process will be known (908). Here a path is understood to be the line or linkage between at least one finger root and the associated fingertip or touchpad touch point for the associated finger. The system will then refine its models of the user's hand biomechanical and/or anatomical features by comparing the predicted results with real data, and determine if its user hand model is working with sufficient accuracy in step (910). If it is, then this user hand model will then be adopted and used for subsequent user virtual keyboard data entry purposes (914). If the user hand model is not working with sufficient accuracy, then the system will attempt to adjust the hand model by varying one or more hand-model parameters (912), and often will then continue the calibration process until acceptable performance is obtained.

Thus the calibration software enables the biomechanical and/or anatomical model of the human hand to be calibrated more accurately, so as to match the biomechanical and/or anatomical characteristics of a particular user's fingers and/or hand.

In one embodiment, the realism of the simulated virtual fingers on the screen may optionally be facilitated by the use of predictive typing models. The predictive typing model approach will be particularly useful when the user is typing text on a virtual keyboard, because the system may scan the previous text that has been entered, and utilize a dictionary and other means, such as the statistical distribution of letters in the particular language, to make educated guesses as to what letter is going to be typed next. This educated guess may then be used to supplement the touchpad data as to last fingertip position and movement to tend to direct the appearance of the simulated finger towards the logical next key. Because this system will occasionally tend to guess wrong, however, the user may find it useful to adjust this predictive typing "hint" to various settings depending upon the user and the situation. Thus, a user who is an experienced touch typist and who tends to type both fairly quickly and fairly accurately will tend to find the predictive typing hints useful, because the predictive approach will tend to work well for this type of user. On the other hand, a user who is more of a slow and uncertain "hunt and peck" typist may find the predictive approach to be less useful, and may wish to either reduce the strength of the hint or potentially even turn the predictive typing "hint" off altogether.

Figure 10 depicts a simplified exemplary flowchart how predictive typing methods may be used to improve the accuracy of the appearance of the virtual hand and fingers while typing, in accordance with one embodiment of the invention. In a predictive typing system, the software will first access both the biomechanical and/or anatomical model data for the user's hands (1000), and the latest fingertip and thumb position data from the touchpad sensors (1002). The system will then use this information to display the user's virtual hands and fingers on the device's display screen (1004). If a predictive typing mode is on (1006), then the system will attempt to deduce (based upon typing speed, as well as the user's consistency in typing speed, and context) what is the most probable letter or letters that the user is likely to type next. The system will also attempt to predict the most probable finger or fingers that the user will use to type this most probable letter (1008). For example, if the user is typing quickly and consistently, and the context of the word or sentence indicates that a vowel such as "e" is likely, then the system may use this factor in its analysis of the somewhat noisy finger position data from the touch sensor to increase the probability that the user's left index finger (often used to type "e" on a keyboard, and which in-fact may not be registering on the touch pad because the user has lifted the left index finger to move to strike the "e" key), is moving towards the "e" key. When used properly, such predictive typing algorithms may help increase the illusion that the user is looking through the display and onto his or her hands below the display even though the display/computerized device is not actually transparent. Conversely, if the predictive typing mode is turned "off or set to reduced intensity (1010), then the system will not take the probable next letter into account in its display of the user's hand and fingers and instead just displays using the virtual hand(s) model.

In one embodiment, the efficiency of the predictive typing may be further enhanced by incorporating the user's history of finger use for each particular key. For example, one user may have a strong tendency to use the right index finger to type the keys "H" and "J", and as another example the same user may have a tendency to user his or her left pinky finger to type the letter's "A" and "Z". Here the system may observe the individual user's typing patterns over time, either as part of an initial calibration step, or later (and in one embodiment even continually) while monitoring the user's typing patterns, and use the user's

individualized finger-to-letter correlation habits as part of the predictive typing algorithm.

Thus the predictive typing software enables the computerized device to compute the graphical representation of at least the user's fingers, and often the user's fingers and hands, with better precision by additionally using keystroke predictions, in addition to the data on the location and movement of the user's fingers and/or hand obtained using the touchpad. In one embodiment, in order to improve the realism of the virtual fingers, additional "finger hover" algorithms may also be used. As used in this specification, "finger hover" means highlighting or otherwise graphically altering the appearance of a virtual key on a virtual keyboard whenever the system believes that the user's finger is either hovering above that virtual key, or about to strike that virtual key. For this type of algorithm, use of touchpads that may sense relative finger proximity to the touchpad surface, such as projective capacitive technology touchpads, may be particularly useful.

The sensors and algorithms that detect relative finger-height above a surface may be tuned to various degrees of sensitivity, and indeed this sensitivity level represents an important engineering tradeoff. If the touchpad is tuned to too high a sensitivity, then it will tend to generate spurious (false) signals, and also lack precision as to precisely where on the touchpad a finger is about to land. If the touch pad is tuned to a lower sensitivity, then the touchpad will tend to detect fingertips that are exerting a considerable amount of pressure on the touchpad surface.

Although many prior art touchpads tend to use a continual or fixed level of touchpad sensitivity at all times, in one embodiment for the "finger hover" option described in this specification, use of a dynamic or variable level of touchpad sensitivity may be

advantageous. For example, to detect finger hovering above a key, a touchpad might first operate at a normal level of sensitivity until it detects that a fingertip within strategic striking distance of a particular key has left the surface of the touchpad. At this point, in order to detect "finger hover" above the key, the touchpad circuitry might temporarily reset its sensitivity to a higher level, designed to more precisely detect when the user's finger is hovering above the key. If the higher level of touchpad sensitivity detects the fingertip proximity, the key may be highlighted. If the higher level of touchpad sensitivity does not detect the hovering fingertip, then the key will not be highlighted. After a short period of time, about on the order a tenth of a second, the touchpad may then be reset to the normal level of sensitivity to more precisely determine if the finger has then actually touched the touchpad, or not.

Figure 1 1 depicts a simplified exemplary flowchart how dynamic changes in touchpad sensitivity may, for finger proximity touchpads, assist in highlighting the virtual keys about to be struck by a user while typing on the virtual keyboard, in accordance with one embodiment of the invention. In other words, Figure 11 depicts an example of an algorithm to detect and indicate "finger hover". Here the system displays the virtual keyboard (1100), as well as an overlay of the user's virtual fingers on or near this virtual keyboard (1102).

When the system detects that a finger, suspected of being a finger about to press a key due to the finger's proximity to the key and or predictive typing considerations, leaves the touchpad (most likely because the user has raised the finger above the touchpad in preparation for striking the virtual key), (1104) the system will momentarily turn the touchpad finger proximity detector to a higher level of sensitivity (1 106), and the software will look to see if finger hover over the suspected key or keys may be detected (1108). If the system does not detect that a finger is suspect of leaving the touchpad, the system returns to step 1102. If a finger hover signal may be detected over the suspected key, then this key will be highlighted to help guide the user (11 10). After a period of time that will not normally exceed about a tenth of a second or if no finger hover is detected, the system will once again lower the sensitivity of the finger proximity detector down to the normal level (11 12), in order to precisely detect if the finger is about to strike the key (11 14). If the touchpad, now operating at normal sensitivity, now detects that the virtual key has been struck by the user, the system will appropriately indicate the keystroke on the virtual key board by further graphical changes to the key (11 16) and optionally may issue an audible key -press or key-click sound as well to give further feedback to the user. Then the system may record the key strike (1 118). If the appropriate finger press was not detected at (1114), then the system repeats the flow at step (1102).

More generally, the finger hover algorithm approach allows at least one data entry location (key) to be highlighted on the device's graphics display screen whenever the computerized device determines that at least one finger on the user's hand has left the touchpad, and the position and motion history of the finger is consistent with an ability of that finger to strike a position on the touchpad that is consistent with the location of the data entry location (key) on the graphics display screen.

Graphical representation of the user's human hand(s) and fingers.

Once the computerized device has obtained data from the touchpad, as well as any additional predictive typing data, hover detection method data, calibration data, and the like, and has updated its internal biomechanical and/or anatomical model of the user's hand or hands

(including the fingers) to reflect this new data, then the system may utilize this biomechanical and/or anatomical model of the user's hand or hands to compute a graphical representation of at least the user's fingers, and often the user's hand and figures, suitable for display on the device's graphics display screen.

A life-like graphical representation of the user's hand and fingers is not necessary. Often, a more shadow-gram like or cartoon-like two-dimensional model (or representation) of the user's hand and fingers will be all that will be necessary. Often these two-dimensional representations of the user's hand and fingers need not include much, if any internal detail. Rather, these representations, may for example, look much like a translucent gray or other colored shadow projection of the user's hands and fingers on a surface. Here, the sharpness and the contrast and the detail of the user's hands and fingers may have reduced sharpness, and have enough distinguishing contrast from other areas of the display screen, so as to enable the user to accurately place his or her hands and fingers on the appropriate virtual buttons or virtual keyboard that is being shown in the graphical display. More fanciful or artistically inspired hand representations are also discussed later in this specification.

Figure 12 depicts a simplified exemplary flowchart for generating images of the virtual hand and fingers on the device's graphics display screen, in accordance with one embodiment of the invention. Many ways to graphically represent the user's hands and fingers, or at least the user's fingers, are possible. In one embodiment, based upon the biomechanical and/or anatomical model of the human hand(s) (1200), and optionally specific data on the location and movement of the user's fingers and hand based on the touchpad data (as well as any additional data from predictive typing software, or hover detection) a three-dimensional virtual model may be constructed in the device's memory that depicts the user's hand(s) and fingers (1202).

Based upon the 3D model, a two-dimensional projection of the general outlines of the user's hand and fingers may be made upon a mathematical surface that corresponds to the surface of the touchpad (1204). This projection may be in the form of a hand and/or finger outline, or alternatively a virtual hand and finger shadow may be produced. This projection may then be combined with the any other data that is being sent do a memory buffer or graphics display buffer for the display screen of the device, and then displayed to the user (1206).

Thus, in one embodiment, the graphical representation of at least the user's fingers, and often both the user's hand and fingers, on the graphics display screen may be done by using the previous assignment of the data on the location and movement of the user's fingers and/or hand(s) to specific fingers on the biomechanical and/or anatomical model of the human hand(s) to create a three dimensional model of the user's hand(s) and fingers in the computerized device's memory. Next, a two-dimensional projection of this three dimensional model of the user's hand(s) and fingers in memory may be made. Here the two- dimensional projection may be on an imaginary plane that corresponds in both distance and orientation from the model of the user's fingers to the touchpad. Thus if, for example, the real user's finger is ¼" above the touchpad, then the distance between the three dimensional model of the user's finger and the imaginary plane that corresponds in distance and orientation to the touchpad will also be ¼". This two-dimensional projection on the imaginary "touchpad" plane (virtual touchpad) may be used to generate the graphical representation of at least the user's fingers on the graphics display screen, and often the user's fingers and hand(s) as well.

Alternatively, in a less computationally intensive scheme, a two dimensional model of the user's hands and fingers may be manipulated to best fit the previously discussed hand and finger position and motion data, and this two dimensional model then used for the graphical representation.

This two dimensional model may be further user selected according to the user's hand size, and indeed may be calibrated by asking the user to place his or her hand on the touchpad, thus allowing the system to sense the dimensions of the user's hand directly.

Figure 13 depicts a simplified exemplary biomechanical and/or anatomical model of the human hand, showing the internal skeletal structure with a skin overlay, in accordance with one embodiment of the invention. This illustration shows the major bones of the hand, with the bones of the index finger and thumb separated in order to allow the joints to be better visualized. The internal skeletal structure of the hand (1300) is depicted, along with an outline of the skin on the left side of the hand (1302). The bones of the fingers include the distal phalanges (1304), the intermediate phalanges (1306), the proximal phalanges (1308) and the metacarpals (1310). The thumb lacks the intermediate phalange.

Here the various finger joints include the distal inter-phalangeal joint (dip) (1312), the proximal inter-phalangeal joint (pip) (1314), and the metacarpophalangeal joint (mcp) (1316). The thumb lacks the distal inter-phalangeal joint (dip), and instead includes the

interphlangeal joint (ip) (1318) as well as the carpometacarpal (cmc) joint (1320). In one embodiment for higher accuracy, it may be useful to replace the default parameter values of at least the lengths of these various bones with actual user hand parameters. In general, the closer the various default parameters of the biomechanical and/or anatomical model of the human are to the actual user hand parameters, the better. In some embodiments, even the range of joint motion may also be experimentally determined, and used to replace one or more j oint motion range default parameters .

Finger identifying algorithms. In some embodiments, the biomechanical and/or anatomical model of the human hand used in certain aspects of the invention for finger identifying algorithms may be based on the following observations. First, the average human hand has four fingers and one thumb. Second, in contrast to the fingers and thumb of the human hand (e.g. Figure 13 bones (1308), (1306), (1304), which are relatively flexible above the metacarpophalangeal joint (mcp) (1316), the palm of the average human hand is relatively inflexible below the

metacarpophalangeal joint (mcp) (1316). Indeed the positions of the various

metacarpophalangeal joints (mcp) (1316) tend to be relatively invariant with respect to rotation of the hand. The various metacarpophalangeal joints (mcp) (1316) may hereinafter also be referred to as the "finger roots". Finger roots will be represented by the variable "r". Alternatively, finger roots may be referred to as the junction between the finger and the palm.

Third, due to the relatively invariant shape of the palm, the orientation of the user's palm and its angle with respect to other hand structures, such as the relative orientation of the fingers (e.g. middle finger (1330) is relatively constant. In particular, the orientation or position of the various "finger roots" (1316) may define a palm line direction (1332) that will in turn, when the angle of the palm line with respect to the coordinates of the touchpad are known, help to define the location of the various fingers and fingertips.

Fourth, users may generally desire to manipulate symbols using the area underneath the uppermost bone of the finger or thumb (1304). Here, the touch pad data will include various touchpad touch points, identified in (x, y) coordinates in later figures, which will often but not always correspond to the area underneath the uppermost bone of the user's finger and thumb (1304), hereinafter also referred to as the "finger tips". The touchpad observed location of any given finger or thumb tip will often be referred to as (xj, yO, where x and y are the observed touchpad data, and "i" refers to or is associated with the finger that ultimately produced the touch pad touch data.

The raw touch pad data does not include such (xj, y labels. Instead, the system

embodiments may have to make sense of various incoming touch pad data, attempt to make sense of the data using the underlying biomechanical and/or anatomical model of the human hand, and then generate a virtual hand model that is consistent with both the touchpad data and the underlying biomechanical and/or anatomical hand model.

It may be simpler to first consider a model of the human hand as it rotates to various positions and touches the touchpad with various fingers, and determine what sort of mathematical transformations are at work in generating the raw touchpad data. Once the above is determined, the process may be worked in reverse to generate a virtual model of the user's hand.

In one embodiment, it is desired to be able to determine which touch point belongs to which finger when the system detects multiple touch points on the touch pad. Naming convention are described as follows. Thumb = finger 0 = F0, index finger = finger 1 = Fl; middle finger = finger 2 = F2; ring finger = finger 3 = F3, and little finger (pinky) = finger 4 = F4. As previously discussed, the finger number may be represented by the variable "i". Thus, when fingers F0 to F4 are present on the touch pad, the problem becomes one of determining the coordinates (xj, y of the fingertips of F0 to F4, and then mapping the coordinates to the biomechanical and/or anatomical model of the human hand.

Neglecting, for the moment, hand location on the touchpad issues, one problem is that users will usually operate the touchpad with the palm line direction of their hands (1322) at an arbitrary angle Θ with respect to the coordinate system of the touchpad. Thus, an early step to making sense of the touchpad data is to determine this angle Θ, and to transform the raw touchpad data by a rotation of angle Θ and see if the raw touchpad data matches up to a sensible biomechanical and/or anatomical model of the human hand. This transformation problem is depicted in Figure 16A through Figure 19.

In one embodiment, a simplified exemplary palm angle (Θ) rotation transformation may help the system relate raw touchpad data to a standard biomechanical and/or anatomical model of the human hand, in accordance with one embodiment of the invention. If the user touches both the tips of all fingers and thumb and the base or finger root of all fingers and thumb onto the touchpad, then the raw touchpad data would include a series of (xj, y values for the finger tips, and a series of (xri, yri) values for the finger roots.

In one embodiment, the system may determine how much the user's hand is rotated relative to the coordinate system of the touch pad using palm angle Θ, then the process of mapping the raw data into the biomechanical and/or anatomical model of the human hand may be simplified. Thus, a determination of palm angle Θ is useful.

Figure 18 depicts more exemplary details of the relationship between the hand's palm direction or palm angle and the tips of the user's fingers, in accordance with one embodiment of the invention. When using touchpads, users will often touch the pad with the fleshy area of the palm underneath their finger roots (1822). If the finger root touch area information is detected by the touch pad, the system may detect the direction of the palm line of the hands (1322) from the finger root touch area. Alternatively, the system may use a relaxed finger position direction depicted as dashed - dotted line (1825) from touchpad touch point (1810) on Fl to touchpad touch point (1820) on F3, or a relaxed finger position direction from touchpad touch point (1810) on Fl to touchpad touch point (1830) on F4 to approximate the palm line direction (1322) and adjustment angle σ between the relaxed finger position direction and the palm line direction, e.g., between line (1825) and palm line (1322). The system may then determine the angle Θ between the palm line, and the touch pad coordinates such as the touchpad x-axis.

Figures 16A - 16B depict how a simplified exemplary palm angle rotation transformation may help the system relate raw touchpad data to a standard biomechanical and/or anatomical model of the human hand, in accordance with one embodiment of the invention. The process of rotation transforming the raw touchpad data (xj, y into palm angle corrected touchpad data (x'i, y'i) may be done using the following coordinate rotating formula;

^X = \^C0S^ ^s^ⁿ^ Γ 1 _wh_{ere x}' = xcos9— vsin9 and v' = xsin9— vcos9 (1). y J -sin0 -cosQi LyJ

The system may find the palm angle using the finger root and/or finger touch points as shown in Figures 16A and 18.

The system may also calculate the finger touch coordinates (xj, yj), where i= 0, 1, 2, 3, 4 for each finger, as well as the palm line rotation angle Θ, and the new coordinates (x'i, y'i). These calculations may be done using the formula (1) coordinate rotating formula shown above. Figure 16A depicts the before the rotation transformation (correction) and the before and after results of this rotation transformation or correction and Figure 16B depicts the results after the rotation transformation or correction depicting the palm line direction being substantially parallel to the touchpad' s x-axis. It is understood that the word substantially herein refers to an accuracy sufficient to achieve proper guidance of the virtual finger(s) displayed on the display screen to the extent that the user may be able to guide the hand to properly strike a virtual key or other control object displayed on the screen and not intending to imply any more accuracy than so required. Thus, more accuracy is required for smaller virtual keys or control objects than for larger virtual keys or control objects but exact anatomical matching to the hand is not required. In one embodiment, the system may also determine the finger root (xn, y_ri) location coordinate for one or more of the fingers Fl, F2, F3, F4. Then the system may perform the analysis often based on the assumption that the Fl root coordinate (x_rl, y_rl) is the most available (i.e. most frequently found in the raw touchpad data), which is often true because the finger 1 finger root commonly touches the touchpad surface. Alternatively, because the palm does not bend much, the finger Fl root coordinate may be calculated from the other palm touch points, i.e. other finger roots (x„, yri).

Figure 17 depicts more exemplary details of the relationship between the finger roots (x_ri, y^), i.e., roughly finger joint region (1316), and the hand's overall palm angle, in accordance with one embodiment of the invention. Often there will be missing finger root position data. Here various assumptions, based on the anatomical characteristics of the human hand, may be used to fill in the missing data.

For example, the root coordinates for finger 1 are available (x_rl, y_rl), then based on hand anatomy considerations, the position of the finger 2 root is likely to be, or may be calculated to be: x_r2 = x_rl + ~ (^wi + w₂)cos9 and

where Wi is the width of finger i and - (w₁ + w₂) = L₁₂ as depicted in Figure 17.

Figure 19 depicts how simplified exemplary biomechanical and/or anatomical model data pertaining to the width of the fingers, such as L₁₂ , may be used to help interpret raw touchpad data, in accordance with one embodiment of the invention. A palm line vertical direction (1930) may be defined running substantially through touchpad touch point (1820) on finger F2 and substantially perpendicular to palm lines (1322). The intersection of palm lines (1322) and palm line vertical direction (1930) passing through the longitudinal axis of F2 may pass through the finger root for F2 at (x^, y^), which may be used for the origin of the coordinate rotation axes X, Y. In the same manner, the system may also calculate the likely finger root coordinates for fingers F3 and F4 (in this simplified approximation, the model may assume that the finger roots are substantially on the same palm line (1322) as per Figure 16A, 16B, 19, Figure 13, and elsewhere). The system may also calculate the new coordinates for any given finger "i" root assuming that the hand is rotated at palm angle Θ by also using rotation formula (1). Here, for example, for finger roots i

rotation transformed finger root locations may be expressed as:

Figure 20 depicts how in a more accurate exemplary model, the location of the various finger roots will be displaced to some extent from the palm line (which forms the palm angle) by various amounts 5ri, in accordance with one embodiment of the invention. Referring simultaneously to Figure 17 and Figure 20, the rotation transformed positions (x'n, y'ri) of the various finger roots after rotation by palm angle Θ may be calculated by the following process. First, calculate the rotation transformed finger 1 root position (x'_rl, y'_rl) from (x_rl, y_ri) using formula 1. Second, apply the formulas x_r'₂ = x_r'_l + i (w_± + w₂) and y_r'₂ = y_rl + 5_r2

Here often, for a still better approximation, the system may assume that any of finger roots F2, F3 and F4 might be displaced somewhat from the palm line (1322) by a small amount, represented by δπ as depicted in Figure 20. Note that δπ may be either positive or negative.

Referring simultaneously to Figure 17 and Figure 20, similarly for fingers F3 and F4, the system may use the approximation that the finger roots are usually separated by the width of the fingers to make further approximations or educated guesses such as:

Xri = Xr(t-!) + (wci-D + w_t) and y_r'_i = _(i__1} + AS_ri

Similarly, for the thumb (finger F0): o = xn' - \ (^wo + M¾) and y_r'₀ = y_r'_l + δ_τ1 , where - (w₀ + w^) = L₀₁ as depicted in Figures 19 and 20.

Alternatively, using the various rotation transformed finger root coordinates

y'ri), the system may also perform the inverse transformation using formula (1) to calculate the raw touchpad data root position coordinates (χ„, yri) in the original touch pad coordinate system. This later technique is often especially useful for determining if any of the raw touchpad data might represent the thumb root location (xio, yio). The raw thumb root touchpad data is often difficult to obtain because sometimes the thumb root does not touch the surface of the touchpad. Using the techniques described above, the system may make sense of the raw touchpad data by sorting the set of rotation transformed fingertip positions {(x'i, y'i)} and finger root positions {(x'ri, y'ri)} according to ascending (or descending) x value, and then attempt to pair the rotation transformed possible fingertip data (x'i, y'i) with the rotation transformed possible finger root data (x'n, y'_ri).

Missing finger detection algorithms.

Often the user will have real fingers elevated far enough above the touchpad to produce a "missing finger" problem - that is the touchpad raw data will lack the coordinates of one or more user fingers, and the system software may have to attempt to deduce the existence and location of these one or more "missing fingers".

In one embodiment, a unique touchID may be assigned for each continuous touch. Thus when a finger "i" was previously touched to the touchpad and was lifted later, one may use the touchpad history data obtained by the system at earlier time points (usually a fraction of a second earlier, i.e. time (t-i)) to determine the missing finger. Such time data may also be used in another alternative approach, to be discussed shortly. For example, at time (t-1) (i.e. the previous history of stored touchpad data in a time indexed stack of such touchpad data, with fingers F0-F4 identified, one has:

{(½,(t-i> yo,(t-i< touchlDoft- ) ... ( ₄(i-i)< y4(i-i)< touchlD^^)}

Assume, for example, that currently at time t, the system has a raw set of data for just three touch points from three fingers, such as fingers F0, Fl, F2 (although this example is using and numbering fingers F0, Fl, F2, other fingers and other finger Fi could be alternatively used). The raw data would be:

{(x_to> y_to> touchlD_to) ... , (x_tl, y_tl touchID_tl) ... , {x_t2, y_t2, touchlD_t2) ... }

If one finds, for example, that touchID_{0 ,(t}_i₎ = touchID_t0 and touchID_{3 (j:}_₁^ = touchID_tl and touchlD^_t-^ = touchID_t2 , then one may tell from the current data set at time "t" that; (x_t0, yt₀, touchlD_t0) belongs to finger 0, and (x_tl, y_tl, touchID_tl) belongs to finger F3, and (x_t2, y_t2> touchID_t2) belongs to figure F4. Then one may further determine that fingers Fl and F2 are missing, i.e. likely elevated from the touchpad. The positions of various combinations of other fingers may also be analyzed by the same methods. However at the initial starting time t=0, the history data may not be available. Thus, one should determine the missing (e.g. elevated) fingers by one or more various alternate methods, such as the methods described below.

Figure 21 depicts how the simplified exemplary system may attempt to correlate detected fingertip data from some fingers with finger root data from other fingers, determine that some fingertip data is missing, and thus deduce that these fingers are elevated above the touchpad, in accordance with one embodiment of the invention. The "missing fingers" include fingers Fl and F2, which are depicted with shading. Missing fingers include a finger that might have been elevated too far above the touchpad in order to register a touch point imprint on the touchpad. To cope with missing fingers the system may operate as follows. First, from the touchpad data set, the system may calculate the palm angle Θ coordinates for the various fingertips and finger roots. Second, for each fingertip, the system may check if the position of the fingertip is inside of the range of likely finger root j positions using a formula such as:

X_rj — < Xj < X_rj +— , where wj is the width of finger i.

If the fingertip "i" is within this range j, then the system will attempt to match the fingertip "i" with root j . The system, may for example, even attempt to match potential fingertip locations from one finger with the potential finger root data from another finger. For example, the system may attempt to match the fingertip data (x' i, y'i) with the finger root position (x'_r3, y'_r3).

For the thumb finger F0 root (χΊο, y'_ro), and pinky finger (finger F4) root (x'_r4, y'_r4), the range may be calculated as follows: x_r'₀— length₀≤ x₀' ≤ x₀' + and xr'A — - ≤ x₄ ≤ length^ , where lengthy and lengthy correspond respectively to L₀ and L₄ and where corresponds to

L_B as depicted in Figure 21. Note that in this example, the system is also incorporating finger length (i.e. the length between the fingertip (x'i, y'i) and the finger root (x'n, y'n)) into its biomechanical and/or anatomical model of the human hand.

In the frequent cases where finger tips may not be successfully matched with corresponding finger roots, for each un-matched finger root, the system may mark that finger as missing (i.e. likely raised above the surface of the touchpad, rather than touching the touchpad). See for example, fingers Fl and F2 in Figure 21. Here in Figure 21, the shading of fingers 1 and 2 shows that the system has recognized that the fingers tips are missing, probably because the finger tips are elevated a sufficient distance above the touchpad.

Missing finger move/display algorithms.

In order to show a virtual image of the moving finger, along with fingers that are touching the touchpad, in some embodiments it will also be useful for the system to maintain a stack of the latest n (where n≥ 1) sets of finger position history information - i.e. retain a history of the most recent finger positions.

In one embodiment, when, as will frequently be the case, the finger position data is insufficient, but the missing finger "i" may be identified by using the previous algorithm or other methods, one may approximate the missing finger's position by assuming that as per a normal biomechanical and/or anatomical hand, the change x and y position of the missing finger's neighboring fingers (e.g. neighboring change Δχ and Ay) will also pertain to any change in location of the missing finger as well, as described in the following examples.

Assume that the current time is time "t", and that the locations of the fingers at earlier times (i.e. within a second or a few fractions of a second) have been saved as frames data such as of t-1 in the stack. The system may compute a weighted mean value such as:

_∑_j=1(weightj * x_jt - x_(Kt-i₎)

U^~ ∑}₌₁ weightj and

₌∑_j=1 weight_j * ((y_jt - y_Kt-p)

]^{t ~} ∑;₌₁ Weight, , where j = [1, n] are the touching fingers.

Using the above scheme, then the current position for the missing finger "i" may be calculated as follows.

Xit = ^xi(t-i) + ^Δ¾ and y_lt = y_i(t__1} + Ay_it

Note that for (Ax_it Ay_it) calculations, one may also use other mathematical methods such as arithmetic mean, median geometrical mean, harmonic mean, and so on.

Finger to hand matching algorithms. Often, particularly for larger devices, the user may operate the device using two hands.

When the user is operating the touch pad with two hands at the same time, the system additionally should be able to decide to which hand the touch points belong to in order to show the user's two hands properly in the display. The system may use various algorithms to help with this decision.

In one embodiment, the system may use the range information on the coordinates after rotating the data by palm angle Θ, as is shown on Figure 21. In this example, all touch points within the following range may be assumed (i.e. mapped into) one hand. The criteria here may be:

For x [x_r'₀— length₀, x_r'₄ + length^ and for y:

[0, length₂] or [0, max{length₀ ... length₄}]

The system may also use the touch angle information for touch points and palm line angles to help assign the raw touchpad data to one hand or the other. Here, for example, the system may assume that both hands belong to the same individual, and essentially extend the biomechanical and/or anatomical model of the human hand to also put in some simplified human anatomical constraints regarding the relationships between the angles of one hand and the angles of the other hand.

Figure 22 depicts how the simplified exemplary system may further assign raw touchpad data to two different hands (left hand (2202) including F0L through F4L, and right hand (2204) including FOR through F4R) of the same user, based on the assumption that the range of possible hand angles for the same user is limited by the user's anatomy, in accordance with one embodiment of the invention. According to the previously discussed multi-touch protocol, the touch angle of a touch point may also be determined along the long touch side defined as follows. That is, usually a finger will touch in a roughly oval pattern with the long axis of the oval, i.e. the long touch side, corresponding to the touch angle a of a touch point. For example, based on human anatomical considerations, the angle a between the touch point directions D4L, D2R and the associated respective palm line vertical direction (2220, 2230) will generally be in the range of [0, 90] degrees. The palm line vertical direction (2220, 2230) is substantially perpendicular to associated palm lines left and right (1322, 2222) respectively. In this example, palm line vertical direction (2220) may be associated with finger F4L through touch point (2224) and palm line vertical direction (2230) may be associated with finger F2R through touch point (2234) Alternatively or additionally, in one embodiment, the system may also partition the touchpad area (for example, split the touchpad area into a left half and a right half) and assign some or all of the touch pad data from the left half to the user's left hand, and assign some of all of the touch pad data from the right side of the touchpad to the user's right hand.

Angle based finger matching algorithms:

Figure 23 depicts a first simplified exemplary example of angle based finger matching algorithms, in accordance with one embodiment of the invention. Angle based methods may be used to match raw touchpad data with specific user fingers. These alternative, angle- based, finger matching algorithms may be implemented as follows. First, perform or do a best fit between the touchpad data and the biomechanical and/or anatomical model of the user's hand, and second, use this best fit biomechanical and/or anatomical model of the user's hand, to find a point substantially along a mid-line (2310) of middle finger F2. Here, for example, one may have mid-line of middle finger F2 pass through the center of the palm, e.g. palm center point, (x_c, y_c) or other point on the palm (any palm center point (x_center, ycenter) may be used so long as it is inside a region bounded by the five metacarpophalangeal joints (xri, yri)). The coordinates of the palm center point may be calculated based on the finger model, and known finger positions.

Continuing the above algorithm with the second step, find (e.g. calculate) the finger root (metacarpophalangeal joint) coordinates (x_r0, y_ro)■■■ (^xr_4,yr₄) and calculate the angle a_ri of finger root "i" to palm center:

OL_ri ^Q.tCinZ^' iXyi X enter > !^"> 'i V center -

The angle calculated by atan2 has a range within about -π to +π. Third, sort the a_ro, a_n..a_r4 in ascending or descending order.

Figure 24 depicts a second simplified exemplary example of angle based finger matching algorithms, in accordance with one embodiment of the invention. Continuing the above algorithm with the fourth step, find all fingertip coordinates (x_o, yo), (xi, y i)... (x4, y₄) and calculate the fingertip angle % to palm center (xc, yc) = (^center■_> ycenter), where a_t = atan2 (xi— x_center_> yi ^~ ycenter) - Next, sort ¾ in the same order as the ¾. Then, match the corresponding finger to the associated angle, as per Figure 24. The advantage of this approach is that one does not need to perform coordinate rotation to match the fingers.

Instead, the atan2 calculations may be done by computationally faster methods, even by table lookup methods, as needed. Iterative or best fit embodiments.

In some embodiments, particularly when the raw touchpad data is cluttered or otherwise confusing, the hand and finger analysis software discussed above may operate by an iterative process. For example, the software may make tentative assignments between the raw touchpad data and one possible set of fingertip, finger root, or palm touch points on the previously discussed biomechanical and/or anatomical model of the human hand (here the user's hand), and score the results according to how close the raw touchpad data, either before or after various possible transformations, may fit with a known hand configuration. The software may then explore other possible hand configurations and transformations, and then select or choose the hand configuration and/or transformation (e.g. rotations, translocations, missing fingers, and the like) that produces the highest overall score. The software will then use the highest scoring hand configuration and orientation model for virtual hand display purposes.

Optional Imaging.

In some embodiments, to improve accuracy (that is to replace standard human hand biomechanical and/or anatomical model default parameters with actual user calibration parameters), it will be useful to acquire an image of the user's hands, and to employ various image processing and analysis techniques to analyze this image of the user's one or more hands to better estimate the relative length of the various bones of the user's hands. Indeed, in the event that the user has lost one or more fingers, the system may then use this information to make corresponding changes in its biomechanical and/or anatomical model of the human hand. In other words, the model may include calibration information associated with an image of at least a portion of the hand of the user.

Figure 14 depicts how the simplified exemplary user's hand or hands may be photographed by the device's camera or other camera, and this image information may be used to refine the default parameters of the biomechanical and/or anatomical model of the user's hand, in accordance with one embodiment of the invention. In acquiring such images, often it is useful to have the system provide a standardized background, such as a series of distance markings, grid, graph paper, and the like (1400) in order to better calibrate the image of the hand and correct for image distortions. This standardized background may additionally include various color, shades of gray, and resolution test targets as well. The background may be conveniently provided by, for example, electronically providing one or more background image sheets (e.g. a jpeg, png, pdf or other image file) for printing on the user's printer.

In one embodiment, the user may put each hand on background (1400), and take a photo of the hand(s) (1402) with either the computerized device's camera or other camera. This image may then be analyzed, preferably by an image analysis program. The background image will help correct for any image distortions caused by different camera angles, and the like. The user hand image analysis may be done onboard the user's handheld computerized device, but it need not be. In an alternative embodiment, the user may upload one or more images of the hand taken by any imaging device to an external image analyzer, such as a remote internet server. In either event, the image analyzer will analyze the user's skin or hand outline appearance (1404), deduce the most probable lengths one or more bones of the user's hand, such as the user's various finger and thumb bones, and send this data or other data to correct the default biomechanical and/or anatomical model of the user's hand(s) back to the user's computerized device, such as for example during calibration step 906 referenced in Figure 9 above.

Alternatively, at least with more sophisticated and possibly next-generation touchpads capable of providing position details for a large number of contact points, the user may calibration the touchpad by firmly pressing a portion or all of the user's hand on the touchpad, and allowing a highly capable touchpad to in turn precisely render the resulting handprint. A compute program may then analyze the touchpad-derived handprint, extract parameters such as finger joint positions, probable finger and hand bone lengths, and the like and derive the same information as previously discussed for the photographic calibration step above. In other words, the model includes calibration information in accordance with pressing a portion of the hand of the user on the touchpad.

Alternatives or supplements to the touchpad.

In an alternative embodiment, information on the user's finger placement may be obtained using optical methods. Thus in an alternative embodiment, the touchpad sensor may be an optical method such as one or more cameras. These camera(s) may keep track of the user's hand and finger positions, and this data may then be fed into the biomechanical and/or anatomical model of the human hand(s) to compute a graphical representation of at least the user's fingers as described previously.

Real time video updating In another embodiment, image information may also be used to refine the biomechanical and/or anatomical model of the user(s) hands in real time while the user is using the touchpad.

Figure 15 depicts how an exemplary device camera (1500) may be used to obtain a partial image of the user's hand (1506) while using the device's touchpad (1508), and this information also used to update and refine the biomechanical and/or anatomical model of the user's hand, in accordance with one embodiment of the invention. The rear mounted device camera (1500), which often will have a very limited field of view at close range (1502), may nonetheless be used to obtain a real time video image of a portion or part (1504) of the user's hand (1506) while the user is using a rear mounted touch pad (1508) using a touch pad mounted on the back of the computerized device (1510). At the same time, touch pad data gives the position of the user's index finger (1512) as a strong touch pad signal, and the position of the user's middle finger (1514) as a weaker touch pad signal (1514).

Note that although the portion of the hand (1504) that may be directly visualized by video camera (1500) does not include any image information at all pertaining to the position of the user's fingers, the image information (1504) does provide a useful series of further constraints upon the biomechanical and/or anatomical model of the user's hands. Thus, the partial hand image information, in conjunction with the touch pad data (1512), (1514), and optionally with a refined biomechanical and/or anatomical model of this user's hand (if available) obtained in Figure 14, above, may improve the accuracy of the depiction of the user's hand and fingers.

In some embodiments, for amusement or artistic purposes, the user may not wish to have a fully accurate anatomical model of the user's virtual hand displayed on the screen, but may instead prefer a variant, such as a realistic depiction of a "monster hand" with fingers being replaced by claws, fur, or pads, and the like, or of a skeleton hand that shows the underlying biomechanical and/or anatomical estimation of the user's hand bones as per Figure 13.

In one embodiment, the system software may also be configured to render the user's fingers and hands as various hand variants when displayed. Generally, these hand variants will still provide realistic information pertaining to the user's hand and finger placement, but will also provide this information as various user artistic options that often may be customized according to user preference.

Three dimensional multi -touch gesture controls. Commonly, touchpad controls to a computerized system have focused on two dimensional finger gesture controls requiring finger contact on the locally two-dimensional touchpad surface, even if that surface as a whole may be curved or otherwise project into the third dimension to some extent. In contrast, certain aspects of the invention, which may operate using a biomechanical and anatomical model of the human hand, may include a three dimensional gesture component that enables various types of three dimensional multi-touch gesture controls described below. Three dimensional multi-touch gesture controls may be advantageous in applications where the user needs to touch a portion of the touchpad continually, such as for example, when the user holds a handheld computerized device including a touchpad on the backside of the device. The three dimensional multi -touch gesture controls may help the computerized system differentiate touches on touchpad control regions intended as control inputs from touchpad touches used to merely hold the device.

In some embodiments, the three dimensional sensing aspects of the invention may be used to control virtual keyboard data entry to a computerized system by various "lift and tap", or "lift and drag", or "lift and other gesture" type modes for data input. More complex variants can also implement other commands, such as "lift and tap and rotate, e.g. with two fingers", "lift and tap, and enlarge, e.g. with two fingers", and so on.

In one embodiment, the biomechanical and anatomical model of the user's hand may inform the system when one or more user fingers are positioned on the touchpad so as to be above a corresponding control region of the touchpad, such as above a key of a virtual keypad, virtual keyboard, or above a hyperlink, and/or the like, but not yet touching the corresponding control region. Because the model of the hand accurately determines the location of the one or more user fingers even when the user's finger is not touching the surface of the touchpad, the "off-touchpad" finger location may be used for three-dimensional gesture control.

In one embodiment, the control region of the computerized system may be on a touchpad including an integrated display screen located in substantially the same location. For example, integrated touchpads may include both display screen and touchpad built in layers and accessible from the same surface or side of the computerized device and thus located substantially in the same location even though the layers may be separated by small dimensions relative to the touchpad surface length or width. In an alternative embodiment, the control region of the computerized system may be on a separate and/or additional touchpad being located in a location that is different from the location of the display screen as previously described in reference to Figure 8. For example, integrated touchpads may include both display screen and touchpad built in layers and accessible from the same surface or side of the computerized device and thus located substantially in the same location even though the layers may be separated by small dimensions relative to the touchpad surface length or width. In one embodiment, the user moves a finger onto a control region of the touchpad, and this finger is in contact with the touchpad. The computerized system may determine if the user wants to activate that control region, e.g. press the virtual key or control region to generate an input to the computerized system using, for example, a "lift and tap" type control scheme described as follows. When the system does not receive inputs according to the "lift and tap" or "lift and related type" control schemes described below, the initial finger touch, even if touching a control region of the touchpad, may not generate unwanted control inputs enabling the user to continue just safely holding the touchpad.

Figure 26 depicts a simplified exemplary flowchart of a "lift and tap" technique of key entry for controlling an input from a user to the computerized system, in accordance with one embodiment of the invention. Figure 26 depicts the "lift and tap" technique includes obtaining (2510) data from a touchpad, the data being associated with the location and movement of a finger and/or hand of the user and not associated with an image of the finger of the user from an image sensor, when the user operates the computerized system using the touchpad. The "lift and tap" technique further includes communicating (2620) the data from the touchpad to the computerized device and analyzing (2630) the data in accordance with a model of a human hand, such as referenced in Figure 9 - Figure 25.

Figures 27A - 27F depict a series of simplified exemplary display screen shots of the "lift and tap" technique of key entry depicted in Figure 26 being used to type the first two letters of a "Hello World" message on the computerized system, in accordance with embodiments of the invention. Figures 27A - 27F were obtained as screen shots or grabs in that respective order from a few seconds of video showing the display screen of a prototype handheld computerized device while the user proceeded to type at touch-typing speed using the "lift and tap" technique referenced in Figure 26. The system has already assigned the touch data from the touchpad to at least one of the multitude of fingers of the model, computed a graphical representation of the at least one finger of the user, in accordance with the model, and now displays the graphical representation of the fingers (Fl, F2, F3) and hand (2701) of the user on a display screen (2700) of the computerized system. Note that hand (2701) including fingers (Fl , F2, F3) is displayed clearly as a virtual, i.e. computer-generated, hand because the palm includes square edges, the fingers include straight sides, and the joints between the fingers and the palm are not continuous.

Referring simultaneously to Figure 26, Figure 27A, and Figure 27D, in one embodiment, the system (optionally) determines (2640), in accordance with the touchpad data and the model of the human hand, that at least one user finger (Fl, F2, F3) is initially touching, or is in contact with, the region of the touchpad corresponding to a virtual key (2702, 2703, 2705, 2725) or other control region.

In one embodiment, when the system first detects that a particular user finger initially touches or is in contact with a virtual key or other control region, the system may optionally generate a graphical representation associated with the control region being touched on display screen (2700) of the computerized system. For example, Figures 27A - 27F further depict the system is generating and displaying on display screen (2700) a graphical representation of a virtual keyboard including a multitude of virtual keys, including virtual keys (2702, 2703, 2705, 2725), corresponding to control regions on the touchpad.

In one embodiment, the system may then change the appearance of the graphical

representation of the touched virtual key or other control region to show or indicate the control region is being initial touched thus providing confirmative feedback to the user. For example, the change of the display image of the touched virtual key may be shown as a change of size, color, shape, slight displacement of the position of the control region image, slight change in display type such as distortion of the control region image, flashing, and/or the like. For example, Figure 27A depicts virtual keys (2702, 2703, 2705), which are being initially touched by respective user fingers (Fl, F2, F3) are temporarily displayed including a slightly larger size and a slightly bolder upper border than the remaining untouched keys.

Referring simultaneously to Figure 26, Figure 27B, and Figure 27E, in one embodiment, the user may next lift the at least one user finger, e.g. graphically represented by finger F2 in Figure 27B, and finger F3 in Figure 27E, and the system determines if the now missing in touch contact or lifted finger is most likely positioned above the same previously touched virtual key or other control region on the touchpad. In some embodiments, the system will use the biomechanical and anatomical model of the user's hand to make the above determination. In other words, the system determines (2650), using the model that at least one finger of the user, e.g. graphically represented by finger F2 in Figure 27B, and finger F3 in Figure 27E, is positioned above but not touching the control region of the touchpad, e.g. graphically represented by virtual key Ή" in Figure 27B, and virtual key "E" in Figure 27E. The model may be used to determine, for example, that although the touchpad may no longer directly sense that the user's finger is in contact with that particular virtual key or other control region, nonetheless the finger is positioned directly above the control region, in accordance with touch data from other regions of the user's hand and/or fingers and the constraints of the model of the human hand.

It is understood that even if the user initially positions his or her hand and associated fingers in contact with the touchpad such that the at least one finger, e.g. graphically represented by finger F2 in Figure 27B, and finger F3 in Figure 27E, does not initially contact the control region, then the system may still properly determine what control region is positioned directly below the at least one finger not in contact with the control region. In other words, step 2640 described earlier may be an optional step in some embodiments because the model may determine the fingertip locations even with the at least one finger not initially in contact with the touchpad but hovering over the control region using the constraints of model of the human hand.

Still referring simultaneously to Figure 26, Figure 27B, and Figure 27E, in one embodiment, the system may temporarily - for example, a first time interval between 0.05 and 5 or even 10 seconds, change the appearance of the graphical representation of the virtual key or other control region the at least one finger is hovering over. In other words, when the at least one finger is positioned above but not touching the first control region, the system may display the graphical representation of the control region with a different appearance than the prior appearance of the control region. The difference in the graphical representation may be an enlargement of the represented virtual key or other control region, as shown at (2720) and (2730), or the difference may be another visual change such as a change of size, color, shape, slight displacement of the position of the control region image, slight change in display type such as distortion of the control region image, flashing, and/or the like.

In another embodiment that might be useful for handicapped individuals, the system may instead produce or generate a sound signal audible to the user instead of, or in addition to, the changed appearance of the graphical representation of the control region when the at least one finger of the user is positioned above but not touching the control region. Note that in Figure 27B the graphical representation of virtual keys (2702, 2705) remains displayed as in Figure 27 A because user fingers (Fl, F3) continue to touch the touchpad in Figure 27B. Referring simultaneously to Figure 26, Figure 27C, and Figure 27F, in one embodiment, when the user lowers the at least one finger (e.g. graphically represented by F2 in Figure 27C, and F3 in Figure 27F) back onto or touching the touchpad in that region of the touchpad that corresponds to the control region (e.g. graphically represented by virtual key Ή" in Figure 27C, and virtual key "E" in Figure 27F). In one embodiment, to prevent false inputs and/or to enable finger re-positioning without command input, the user's finger lowering may optionally be required to happen within a certain time interval or "first period of time" (usually on the order of between 0.01 seconds and 5 or even 10 seconds after the system optionally changes the appearance of that particular key or other control region at the start of step 2650.

In one embodiment, the system may then verify, using the biomechanical and anatomical model of the user's hand, that the user's at least one finger has now "struck" or "tapped" the particular virtual key or other control region. In other words, the system determines (2660) that the at least one finger is subsequently touching the control region in accordance with the data and the model. In one embodiment, the system may record, or register that the appropriate virtual key has been pressed by storing a record of that action in memory. In Figures 27A - 27C the user is inputting a command to the computerized system to type the letter "H". The system recognizes by the lift and tap action of user finger F2 that the user is commanding the system to type the letter "H", and the system generates and displays a corresponding letter "H" (2722) on display screen (2700) to confirm the execution of the command. In Figures 27D - 27F the user is inputting a command to the computerized system to type the letter "E". The system recognizes by the lift and tap action of user finger F3 that the user intends to command the system to type the letter "E", and the system generates and displays a corresponding letter "E" (2732) to confirm the execution of the command. In one embodiment, the system may optionally change the displayed appearance of the graphical representation of the struck or tapped virtual key or other control region, often back to either its original appearance (as depicted in Figure 27C and Figure 27F) or an optional different altered appearance (e.g. a "key struck" appearance) to visually confirm the control region is touched or struck. In one embodiment, the altered appearance may include visual change such as a change of size, color, shape, slight displacement of the position of the control region image, slight change in display type such as distortion of the control region image, flashing, and/or the like. In one embodiment, the optional different altered appearance may be displayed for a short second period of time or time interval, often in the 0.05 to 1 second range, but may extend longer, such as up to 10 seconds. In one

embodiment, alternatively or additionally, the system may also generate an auditory signal that the user's actions have resulted in the pressing of a particular virtual key or other control region. Figure 28 depicts a simplified exemplary flowchart of a "lift and drag" technique of key entry for controlling an input from a user to the computerized system, in accordance with one embodiment of the invention. The above embodiments may be extended to other input techniques, such as "lift and drag". In a "lift and drag" technique, in one embodiment, the control region may include an elongated control region with a length substantially greater than the longitudinal length of the surface region of the user's at least one finger when contacting the touchpad. Such an elongated control region may include a virtual slider (e.g. a virtual linear control region), virtual rectangular or circular rotation (e.g. a virtual control knob) or virtual expansion-contraction control region, and the like. In another embodiment, the control region may include a multitude of file names, images, icons, and the like, so that the user may drag these file names, images, icons and the like via the drag technique to, for example, execute a move and/or copy command on the corresponding files or virtual objects.

In one embodiment, after determining that the at least one finger is subsequently touching (2660) the first control region in accordance with the data and the model and optionally within a certain third time interval (usually on the order of between 0.0 seconds and 5 or even 10 seconds after the user's finger initially contacts the touchpad), the user may move or slide the at least one finger on the elongated control region of the touchpad. The system may then verify, using the biomechanical and anatomical model of the user's hand, that the user is moving or sliding the at least one finger over the elongated virtual key or other control region. In other words, the system determines (2810) that the at least one finger is subsequently touching the first control region in accordance with the data and the model. The system may then store (2820) in memory a record of the moving or sliding of the at least one finger (e.g. register that for example, a slider has been moved, and the like), and then optionally change the appearance of the elongated virtual key or other control region, such as file names, images, icons and the like, to visually confirm the command action was executed (e.g. move a knob on a slider control). In one embodiment, alternatively or additionally, the system may also give an auditory signal that the user's actions have resulted in the actuating of the drag command and associated result. In one embodiment, the user may lift two or more fingers. In other words, the system may determine using the model, that a multitude of fingers of the user are positioned above but not touching the control region of the touchpad. The user may then lower the two or more fingers to the touchpad. In other words, the system may determine that the multitude of fingers are subsequently touching the control region in accordance with the data and the model.

Then in one embodiment, the system may determine a motion of a first finger in relation to a motion of a second finger different than the first finger and assign a command to control the computerized system in accordance with the determined motion. For example the user may either move the two fingers further apart on the touchpad to change the displayed image, e.g. magnify or zoom-in on a displayed image, move the two fingers closer together to zoom-out, or rotate the fingers around a rotation point intermediate between the two fingers to rotate an image. The system may be configured to do corresponding display screen operations under touchpad control where the image on the display screen expands or contracts, or rotates according to the rotation direction of the fingers when the relative motions of the two fingers are assigned to the respective commands. In one embodiment, the system may not require the use of a virtual key or other control regions. Instead, the system may operate as if the entire screen is a control region that may be subject to zoom-in, zoom-out, and/or rotation controlled as described above.

Most existing two dimensional multi-touch gestures may be similarly extended or modified into corresponding three-dimensional counterparts that incorporate the finger lift gesture component described above. Examples of existing multi-touch gestures that may be modified for additional finger lift functionality include various Apple OXS gestures, such as, but not limited to: swipe behind full-screen apps, two-finger scroll, tap to zoom, pinch to zoom, swipe to navigate, open launch pad, show desktop, look up, app expose, rotate, three-finger drag, tap to click, secondary click, notification center, and show web browser tabs.

Certain aspects of the invention may be extended or modified for use with touchpads that are capable of sensing the force exerted by a finger in contact with or touching the touchpad. One example of a force sensing touchpad embodying the invention may use a touch sensing device commercially available from Synaptics Inc., San Jose, California and commonly known as the ForcePad™ family of products. With a force-sensing touchpad, the touchpad not only may determine a finger touch location on the surface of the touchpad, but also may sense and determine how much force per finger is being applied to the surface of the touchpad. In one embodiment, the dimension of force per finger in the touchpad data may be used by the system instead of or in addition to sensing when a finger of the user is lifted off the surface of the touchpad.

Figure 29 depicts a simplified exemplary flowchart of a "lift and tap" technique of key entry modified to use force applied per finger for controlling an input from a user to the computerized system, in accordance with one embodiment of the invention. Figure 29 includes the same features as Figure 26 with the following exceptions. When the system obtains (2910) data from the touchpad, the data may be be additionally associated with the force of a finger and/or hand of the user upon the touchpad.

Referring to Figures 27 A - 27F in one embodiment, the system may display a graphical representation of at least one touch point associated with the force per finger (2743, 2750, 2753, 2765, 2770, 2775) applied upon the surface of the touchpad by the user at the corresponding location on the touchpad where the fingers touch the surface of the touchpad. In one embodiment, the graphical representation of the touch point may be depicted as a solid circle including a diameter associated with the amount of force per finger applied upon the surface of the touchpad. In altemative embodiments, shapes other than a solid circle may be used and/or other display attributes than size may be associated with the force per finger. In one embodiment, the force per finger may be associated with at least one of a size, a color, a position, a shape, or a display type depicted on the display screen. For example, the amount of force per finger may be associated with a flashing type display where the rate of flashing may be associated with the amount of force.

Referring simultaneously to Figure 27A , Figure 27D, and Figure 29, after analyzing (2630) the data in accordance with a model of a human hand, the system may optionally determine (2940) that at least one finger is initially touching the control region using force within a range "A" in accordance with the data and the model. In one embodiment, force range A may include a range of force per finger above about 0.5 newton or about 50 gram weight equivalent units (on the surface of the Earth), corresponding to when the user touches the surface of the touchpad by pressing firmly. In one embodiment, the system may optionally display the graphical representation of the at least one touch point associated with the force per finger (2705, 2765) corresponding to force range A depicted as a solid circle having a relatively large diameter close to the pitch between adj acent virtual control surfaces, i.e. virtual keyboard keys, and/or close to the width of user fingers (F2, F3), respectively. In one embodiment, an audible signal may be generated in addition to or instead of the graphical representation of the touch point when the user's finger is initially touching the first control region using force range A. In one embodiment, an mechanical response may be generated by the system in addition to or instead of the graphical representation of the touch point when the user's finger is initially touching the first control region using force range A. In other words, the computerized system may generate a haptic feedback response from the computerized system to the user when the at least one finger of the user is touching the first control region using the first force.

For example, the mechanical response may include a haptic response such as mechanically shaking or vibrating a portion of the computerized system using a mechanical actuator such that the touchpad is shaken by being mechanically coupled to the shaken portion of the computerized system. In one embodiment, the shaken touchpad may provide haptic feedback to the user's fingers in any combination of the visual, i.e. graphical representation, and/or audible feedback to the user indicating the user's action has been registered by the computerized system. In another embodiment, a different portion of the computerized system than the touchpad may be mechanically shaken or vibrated such a portion of the

computerized system in mechanical contact with the user, e.g. a wearable device, or a device supporting the user such as a chair, seat, backrest, elbow rest and/or the like. Haptic feedback may be useful when audible feedback is undesireable or ineffective, such as in an audibly noisy environment.

Referring simultaneously to Figure 27B , Figure 27E, and Figure 29, in one embodiment, the system may determine (2950), using the model, that at least one finger of the user is touching a control region of the touchpad using a force range "B" different than force range A. In one embodiment, a force per finger from force range A may be greater than a force per finger from force range B. In one embodiment, force range B may include a range of force per finger between zero newton and about 0.5 newton. In one embodiment, the system may change the display of the graphical representation of the at least one touch point associated with the force per finger (2750, 2770) to a different size, color, position, shape, or display type. For example, the touch point associated with the force per finger (2750, 2770) may be depicted on the display screen as a smaller solid circle corresponding to a lighter touch of the user's finger than when the finger was initially touching the control region in Figure 27 A and Figure 27D. In one embodiment, an audible signal may be generated in addition to or instead of the graphical representation of the touch point when the user's finger is touching the control region using force range B. In one embodiment, an mechanical response may be generated by the system in addition to or instead of the graphical representation of the touch point when the user's finger is touching the control region using force range B. In other words, the computerized system may generate a haptic feedback response from the computerized system to the user when the user's finger is touching the control region using force range B.

In the example depicted in Figure 27B and Figure 27E, the finger is still in contact with the surface of the touchpad but with a lighter touch than the initial touch. However, the users lighter touch action may be interpreted by the system in similar fashion as to the earlier embodiments which described the user's finger being lifted completely off the touchpad surface, i.e. force equal to zero newton, the lift in the present embodiment include lifting the finger merely to reduce the force exerted by the finger but not completely lifting the finger off the surface of the touchpad. The lighter force lift technique may take less computational resources, provide faster system speed, and/or better reliability than when the finger is lifted completely off the touchpad surface because the lighter force touch point location of the user's finger is directly available without having to estimate the position of a finger lifted completely off the touchpad surface.

Referring simultaneously to Figure 27C , Figure 27F, and Figure 29, in one embodiment, the system may determine that the at least one finger is subsequently touching the control region using force range A in accordance with the data and the model. In one embodiment, the system may change the display of the graphical representation of the at least one touch point associated with the force per finger (2753, 2775) to a different size, color, position, shape, or display type. For example, the at least one touch point associated with the force per finger (2753, 2775) may be depicted on the display screen as a larger solid circle corresponding once again to a more forceful touch of the user's finger in force range A similar to that when the finger was initially touching the control region in Figure 27A and Figure 27D.

Figure 30 depicts a simplified exemplary flowchart of a modified "lift and tap" technique of key entry modified to use a third force applied per finger for controlling an input from a user to the computerized system, in accordance with one embodiment of the invention. Figure 30 depicts the same features as Figure 29, except Figure 30 depicts the system may determine that the at least one finger is subsequently touching (3060) the control region using a force range "C" in accordance with the data and the model. The third force applied per finger may be within a range of force per finger from force range C. Force range C may include a range of force per finger that is different than both force range A and force range B. Use of three force ranges A, B, and C may further reduce unintended inputs compared to using just two force ranges. In one embodiment, force range C may include a range of force per finger that is greater than force range A, which in turn may be greater than the range of force per finger from force range B. For example, the computerized system may respond to a touchpad input sequence from a finger of a user that includes a medium force A, followed by a small force B, followed by a large force range C similar to what the user may use when typing on mechanically actuated keys. It is understood that other combinations of the three force ranges may be used in sequence to provide an input to the computerized system.

In one embodiment, an audible signal may be generated in addition to or instead of the graphical representation of the touch point when the user's finger is subsequently touching the first control region using the force range A. In one embodiment, an mechanical response may be generated by the system in addition to or instead of the graphical representation of the touch point when the user's finger is subsequently touching the first control region using the force range A. In other words, the computerized system may generate a haptic feedback response from the computerized system to the user when the user's finger is subsequently touching the first control region using the force range A.

The sequence of steps for a user's finger actuating a command area on the touchpad in certain aspects above included the system responding to an optionally stronger force range, followed by a weaker force range, followed by a stronger force range, in that order. It is understood that, in an alternative embodiment, the inverse sequence of force by the user's finger may be used where the system responds to a weak force range (optionally) applied by the user's finger, followed by a stronger force range, followed by a weaker force range, in that order. In either alternative embodiment, the system may recognize and respond to any sequence of a first force range followed by a second force range that is different from the first force range applied by the user's finger to actuate a command area on the touchpad.

Certain aspects of the invention may be extended or modified for use with not only force- sensing touchpads that may directly determine the force exerted by a finger in contact with or touching the touchpad, but also with capacitive sensing touchpads. In one embodiment of the invention, a capacitive sensing touchpad may indirectly determine the force using a contact area included in the data from the touchpad. In contrast, force-sensing touchpads directly determine the force without using a contact area included in the data from the touchpad. Figures 31A - 3 IB respectively depict simplified exemplary side and top views of a portion of the touchpad (3110) using the contact area (3120) resulting from a first force FA, in accordance with one embodiment of the invention. Figures 31A depicts a user's finger (3130) pressing on the touchpad with a force FA using force range A, in accordance with one embodiment of the invention as described above. Force range A deforms the soft tissue of user's finger (3130) between the user's bone and the touchpad surface, which is more rigid than the soft tissue, forming a contact area (3120) at the touch point on the touchpad.

Figures 32A - 32B respectively depict simplified exemplary side and top views of a portion of the touchpad (3110) using the contact area (3220) resulting from a second force FB, in accordance with one embodiment of the invention. Figures 32A depicts user's finger (3130) pressing on the touchpad with a force FB using force range B, which is different than force FA, in accordance with one embodiment of the invention as described above. In one embodiment, force range B may be less than force range A. Therefore, force FB deforms the soft tissue of user's finger (3130) between the user's bone and the touchpad surface to a lesser extent than when force FA is applied, forming a contact area (3220) at the touch point on the touchpad that has smaller area than contact area (3120) as depicted respectively in Figures 32B and 3 IB.

The system may use the contact area data from the touchpad to then indirectly calculate or determine the force range applied by the finger and/or hand against the touchpad. The contact area information requires the soft and/or resilient tissue of the hand to be in contact with the touchpad without the touchpad supplying the force data directly, which for example, precludes the use of a rigid stylus to enter the touchpad data instead of a user's hand. Once the system calculates or determines the finger force range applied to the touchpad, the system may then use the calculated force information in the same embodiments described in reference to Figures 27 A - 30.

Distinguishing between control regions and "holding regions."

Although users may, for example, use back mounted touchpads to control their various handheld computerized devices, in some situations, users may simply wish to hold their handheld computerized devices in the same region as the back mounted touchpad, which may create false command inputs when the user inadvertently touches a control region but really intends to merely hold the device by touching the touchpad. In these and related situations, according to one embodiment, the user may designate a portion of the touchpad surface area as being reserved for non-control purposes, e.g. "holding" purposes, hereinafter also referred to as a "non-control" region of the touchpad. In other words, the system enables the user to designate or lock out a portion of the touchpad temporarily as a non-control region for holding the handheld computerized device without controlling an input when the user touches the non-control region.

In one embodiment, the system enables the user to designate some or all of a touchpad as being at least temporarily a non-control region or off limits from a device control perspective by including an actuating button - either real or virtual. Alternatively, in another

embodiment, certain user hand gestures, such as a swipe border gesture followed by a swipe "x" gesture within the border, may be assigned and recognized by the system as temporarily turning off touch control within the portion of the touchpad covered by the border and the swiped "x". The user may then safely hold the handheld computerized device or other device by the non-control region of the touchpad. When the user wishes to return to controlling the computerized device using the non-control regions of the touchpad, the user may then, in one embodiment, actuate a corresponding "restore" (real or virtual) button, or implement an appropriate "restore control" gesture or set of gestures designated to execute the restore control command.

"Push and lift" or "Enter and lift" key actuation.

Figure 35 depicts a simplified exemplary flowchart of a "push and lift" technique of key entry for controlling an input from a user to the computerized system, in accordance with one embodiment of the invention. Figure 33 has the same features as Figure 26 with the following exceptions. Figure 33 depicts that the the computerized system first obtains (3310) data from the touchpad. The data may be associated with the location and timed movement of a finger and/or hand of the user and not associated with an image of the finger of the user from an image sensor, when the user operates the computerized system using the touchpad. After analyzing (2630) the data in accordance with a model of a human hand, the

computerized system determines that at least one finger is initially touching a first control region on the touchpad in accordance with the data and the model. In other words, the user may initially slide, touch, or tap one or more fingers over a key area or control region on the touchpad. The system may use the biomechanical and anatomical model of the human hand to recognize this sliding, touching, or tapping action by the user's finger on the touchpad. In one embodiment, the computerized system may respond by, in turn, changing the visual appearance of the key or control area on the display as described above. Then, the computerized system determines (3350), using the model, that at least one finger of the user is positioned above but not touching a first control region of the touchpad during a predetermined time window. In other words, the key or control region on the touchpad becomes activated or actuated when the system determines, again using the biomechanical and anatomical model of the human hand, that the user has then subsequently lifted their fingers or other portion of their hand from the key or control region of the touchpad.

Figure 34 depicts a simplified exemplary time-line of the "push and lift" technique depicted in Figure 33, in accordance with one embodiment of the invention. The computerized system may use a predefined delay time Td and a predefined time window Tw to provide the system a technique to distinguish between deliberate user control actions, and random signals that might be caused by the user simply holding the device by the input surface area of the touchpad without intending to send control signals. Referring simultaneously to Figures 33 - 34, the computerized system may be configured so that when the system determines (3340) the user initially slides, touches, or taps their fingers or other portions of the hand on a key or control region at time To, there is then only a limited predefined time window, Tw, during or in which the system may determine (3350) that a subsequent lifting of the user's fingers or other portion of their hand is considered to be a deliberate control signal so as to store a record of the lifting of the user's fingers in memory as described in certain aspects previously described.

In one embodiment, time window Tw may initially commence or open at a first delay time Td after the system determines (3340) the initial sliding, touching, or tapping motion of the user's finger or hand over the key or control region on the touchpad at time T₀. Once open, time window Tw may then remain open until a time equal to T₀ + Td + Tw when the time window then closes. In other words, the predetermined time window closes at the sum of the first delay time and window duration time Tw. Once time window Tw closes or after time T₀ + Td + Tw, then if the system determines a finger of the user positioned above but not touching the first control region of the touchpad, then the computerized system may not consider such "finger lift" as a deliberate control signal and may not store a record of such a finger lift.

In one embodiment, the time duration for delay time Td may be between about 0 and 1 seconds after sliding was first detected at To, or in other words, predetermined time window Tw commences after determining that the at least one finger is initially touching the first control region, which is at To. In one embodiment, predetermined time window Tw commences at delay time Td after determining that the at least one finger is initially touching the first control region. In one embodiment, delay time Td includes a range of time equal to or less than 1 second. In one embodiment, the time duration for window duration time Tw may include a range of time between about 0.25 second to 30 seconds.

In alternative embodiments, other values for delay time Td and window duration time Tw may also be possible so long as Td and Tw are chosen so as to enable the computerized system to differentiate between finger lifts intended as inputs versus finger lifts resulting in unintended inputs, such as for example, during finger repositioning merely to better grip or support the touchpad. In other words, determining (3350), using the model, using predetermined time window Tw enables the computerized system to differentiate between an intended input versus an unintended input by the at least one finger when the at least one finger is positioned above but not touching the first control region of the touchpad and when predetermined time window Tw is not open, such as before time T₀ + Td and/or after time T₀ + Td + Tw. Certain aspects described in reference to Figures 33 - 34 may be combined in any combination with certain aspects referenced in Figures 1 - 32B described previously.

"Hover and tap" type key activation.

Figure 35 depicts a simplified exemplary flowchart of a "hover and tap" technique of key entry for controlling an input from a user to the computerized system, in accordance with one embodiment of the invention. Figure 35 depicts features similar to Figure 26 with the following exceptions. The computerized system obtains (3510) data from the touchpad. The data may be associated with the location and movement of a multitude of fingers and/or a hand of the user. But the data is not associated with an image of a first finger of the multitude of fingers from an image sensor, when the user operates the computerized system using the touchpad.

Figures 36A - 36F depict a series of simplified exemplary display screen shots of the "hover and tap" technique of key entry depicted in Figure 35 being used to type and enter the numeral "0" on a prototype computerized system, in accordance with embodiments of the invention. Referring simultaneously to Figures 35 and 36A, after analyzing (2630) the data in accordance with the biomechanical and anatomical model of the human hand, in one embodiment the computerized system may optionally determine (3540) that first finger Fl is initially touching a control region on the touchpad, in accordance with the data and the model. For example, the system displays a graphical representation of virtual touch-point (3610) of finger Fl, touching between virtual keys "9" and/or "0" (3620, 3630) respectively. In one embodiment, the computerized system may generate a special graphical representation of the control region when first finger F 1 is initially touching a control region on the touchpad. However, in certain aspects depicted in Figures 36A because touch-point (3610) of finger Fl is in an intermediate position between keys, the keys are still displayed normally. The graphical representation of finger 1 is near both the number keys "9" and "0" on the virtual keyboard, but is not yet hovering over either number key, so neither number key is highlighted.

Referring simultaneously to Figures 35 and 36B, in one embodiment, the computerized system may determine (3550), using the model and the data from the touchpad, that finger Fl of the user is positioned above but not touching, hereinafter also referred to as "hovering", a control region such as virtual key "9" of the touchpad, which in one embodiment may in turn cause the system to display the control region or virtual key "9" in a highlighted fashion as described previously. The biomechanical and anatomical model of the human hand may be used to determine when a user's finger is likely hovering above a key or other control area, which when detected may cause the computerized system to highlight the graphical representation of the displayed control area for virtual key "9" (3625).

The computerized system may predict (3545) the location of finger F l in accordance with the analyzed data and the location of at least another finger of the multitude of fingers, such as for example finger F2 different than finger F l and/or hand (2701). The touch-point data from finger F2 and/or hand (2701), which is touching the touchpad, is used with the biomechanical and anatomical model of the human hand by the computerized system to predict the location of finger F l even when direct real-time finger Fl touch-point location data is absent because finger Fl is hovering above the touchpad without making touch contact with the touchpad. For example, it is noted that the position of finger F2 fully obscures the display of the numeral "6" on virtual key "6" (3630), while the position of finger F3 only partially obscures the display of the numeral "4" on virtual key "4" (3635). In some embodiments, the prediction (3545) step may precede determining when a finger hovers step (3550), while in alternative embodiments the prediction (3545) step may come after determining when a finger hovers step (3550) Referring to Figure 36C, because the user does not wish to type the number "9", the user continues to move his Finger 1 hover location still above but not touching the touchpad towards the location of control region key "0". It is noted that finger F2 and F3 are still touching the touchpad but at slightly different positions than in Figure 36B. Now in Figure 36C the position of finger F2 only partially obscures the display of the numeral "6" on virtual key "6" (3650) because finger F2 has moved slightly upwards with respect to the figure. Similarly, the position of finger F3 has moved slightly upwards to fully obscures the display of the numeral "4" on virtual key "4" (3655). The changed positions of the touch-points of fingers F2 and F3 are used to predict the new real time position of still hovering finger F l . Thus the computerized system in transition briefly enlarges or highlights the displayed graphical representation of both the previous key "9" (3640) and key "0" (3645).

Referring to Figure 36D, the user continues to move his Finger 1 so that it is now hovering over the desired control area of key "0" on the touchpad, and the computerized system continues to predict the real time location of still hovering finger Fl using for example the new real time locations of fingers F2 and F3, which are still touching the touchpad at locations slightly different than those depicted in Figure 36C. Then in one embodiment, the graphical representation of key "0" (3660) is enlarged or otherwise highlighted by the system.

Referring simultaneously to Figures 35 and 36E, in one embodiment, the computerized system determines (3560) that finger F l is subsequently touching the control region key "0" on the touchpad in accordance with the data and the model. The user is now actuating the desired key "0" by touching the corresponding "key 0" region of the touch pad. Note that the system is indicating a virtual key "strike" by altering the appearance of the graphical representation as a enlarged or highlighted region of virtual key "0" 3665, and that additionally the system now registers or stores in memory and displays the number "0" (3670) on the top of the screen. Referring to Figure 36E, the action of tapping or pressing the control region of key "0" action is now fully complete and the graphical representation of virtual key "0" (3675) is displayed as at the start in Figure 36A in original state.

The user actuating a key or other control area by hovering and then pressing or tapping a key or control area is, from a human factors standpoint, easy for the user to learn and use because the user need merely tap his finger on a hover-highlighted key or control area in order to then actuate the corresponding virtual key or control area. One advantage of this approach is that that the user does not have to do a separate tap and lift motion to inform the system about his interest in actuating a particular key. Rather, when the user's finger hovers above a given virtual key, but does not actually touch it, the system will enlarge or otherwise highlight the key by predicting the location of the user's hovering finger without having to first touch the touchpad at the desired control region location. As a result, the hovering finger can more easily "hover-slide" onto a particular virtual key of interest, as depicted by the user both hovering and sliding between the key "9" and the key "0" locations in Figures 36B - 36D. Thus the user may experience a more natural keyboard typing experience, although the motions and positions of the fingers are otherwise different since the touchpad may be obscured from direct user view. Certain aspects described in reference to Figures 35 - 36F may be combined in any combination with certain aspects referenced in Figures 1 - 34 described previously.

Tracking a position of a portion of the user's hand and/or finger using a virtual keyboard

In some embodiments, the position and orientation of the virtual keyboard can be set to track the position and orientation of a portion of the user's hand and/or finger as the user operates the touchpad. In this situation, although the virtual keyboard generation software may optionally still perform a certain amount of time averaging of the position and orientation of the portion of the user's hand and fingers, this time averaging may be relatively short, on the average of less than a tenth of a second to a few seconds, or even not at all, in some examples. Making the time averaging either very short or zero enables the system to essentially annotate the image of the moving virtual hand and fingers with corresponding virtual keys displayed in a display screen of the computerized system. In an embodiment, and as will be discussed in detail below, these keys may be assigned to the different fingers of the user in accordance with a standard QUERTY format, or other keyboard formats.

In some embodiments, when the user moves his or her hand around the touch pad, a portion of the virtual hand and/or the virtual finger may be within immediate striking range of the various virtual keys, thus enabling the user to start typing immediately regardless of the orientation of the user's hand relative to the touchpad or the device display screen.

Controlling a control region on a display screen of a computerized system

In accordance with at least some embodiments, the computerized system may assign touch data pertaining to a position of a portion of the hand of the user when the user operates the touchpad to at least one of a multitude of fingers of the model of the human hand and compute a graphical representation of the user's fingers in accordance with the model. In some embodiments, the computerized system may be configured to identify a set of virtual keys to be associated with each of the user's virtual (i.e., graphical representation of) fingers. The assignment of the set of virtual keys to a user's virtual finger may be performed in various ways. In one example, each virtual finger may be associated with a pre-defined set of keys. For example, each virtual finger may be associated with a group of keys that the user is familiar with, such as based on a QUERTY keyboard configuration. Here, for example, the left hand index finger may be associated with the keys 'R', 'F', 'V, 'Τ', Ό', 'Β', which may be the same set of keys that this finger would be expected to strike if the finger were operating a real QUERTY keyboard. Similarly the right hand middle finger may be associated with the keys T, and 'K' and other QUERTY keys that the right hand middle finger would be expected to strike if this finger were operating a real QUERTY keyboard. While the above discussion relates to mapping keys arranged in a QUERTY configuration to the different fingers of the user, it should be appreciated that other finger-key mapping schemes may also be implemented, in other embodiments. For example, other methods to assign keys to specific fingers of the user's virtual hand may be used such as numeric keypad schemes, alternative non-QUERTY keyboard schemes, such as Dvorak, Colemak, as well as various variants of the QUERTY keyboard technique.

In some embodiments, the computerized system may be configured to generate a control region comprising the set of virtual keys and display the control region in a first position of the display screen of the computerized system. In an embodiment, the control region may display the set of virtual keys associated with the fingers of the user. When a user's finger that is in contact with the touchpad moves, the computerized system may be configured to update the position of the set of virtual keys associated with the movement of that particular user' s finger on the touchpad, on the display screen. In an alternate embodiment, the control region may also display a graphical representation of the user's fingers and the different sets of virtual keys associated with each finger, on the display screen. In such an embodiment, when the user's finger that is in contact with the touchpad moves, the computerized system may be configured to update the position of the virtual finger, as well as the group of virtual keys associated with the virtual finger in the control region in accordance with the movement of the user's finger on the touchpad.

As an example, using a QUERTY keyboard arrangement as discussed above, if the user's right index finger moves on the touchpad, the virtual keys 'U', 'J', 'M' as well as Ύ', Ή', and 'N' associated with the user's right index finger displayed in the control region may also move. In some examples, the user's right index finger may be appropriately positioned in the control region to strike these keys.

In some examples, resting keys (i.e. keys, such as Ά', 'S ', 'D', 'F' (left hand) and 'J', 'K', 'L', and ';' (right hand) that a relaxed user's hand would normally contact on a QUERTY keyboard when not pressing a key may also move when the fingertip of the user's finger moves. As described herein, 'resting keys' may refer to the set of keys on a QUERTY keyboard that the user's fingers may typically rest on when not typing. Thus, in some embodiments, the resting keys may move in addition to the movement of the set of virtual keys that are associated with this particular finger that would normally be expected to be struck by the user's finger.

Thus, using the above technique, the computerized system may be configured to position the user's virtual fingers and the corresponding sets of virtual keys associated with the virtual fingers to be located anywhere in the display screen according to the hardware limitations of the touchpad and the display screen.

In some embodiments, when the user lifts his fingertip from the surface of the touchpad (i.e., the user's finger is positioned above but not touching the touchpad), the keys associated with this finger are both frozen or fixed into position, as well as set to an 'enabled' configuration. In an example, the 'enabled' keys may be displayed by visually highlighting these keys on the display screen. For example, the 'enabled' keys may be highlighted by showing these keys as brighter, or more enlarged, or in a different color, and so on.

In some embodiments, the touchpad may include pressure sensitive sensors that are capable of sensing the pressure of a touch of a portion of the hand of the user on the touchpad. In such an embodiment, the computerized system may obtain touch data pertaining to the amount of pressure applied by the user when the user operates the touchpad. Based on the obtained touch data, the computerized system may determine whether to enable a virtual key associated with the user's finger by visually highlighting the virtual key. For example, the computerized system may 'enable' a virtual key associated with the user's virtual finger in the control region if the obtained touch data pertaining to the amount of pressure applied by the user indicates that the pressure is within a pre-determined threshold value. In some embodiments, this pre-determined pressure threshold value may be specified by the user of the computerized system. In certain embodiments, when the user places the tip of the lifted finger back on to an enabled virtual key of an associated group of enabled virtual keys (i.e., when the user's finger subsequently touches the touchpad), then that particular key is selected (i.e. considered pressed). This feature thus enables a user to move his or her hand freely on the touchpad surface, while still allowing the user to type using conventional typing techniques.

Additionally, by freezing or fixing virtual key positions when a user's finger lifts the touchpad, the user can precisely strike a virtual key according to the standard relative position of that key on a standard keyboard. Thus, the disclosed technique enables the user to leverage off of a user's long standing 'muscle memory' of relative key positions on a standard keyboard.

Figure 37 depicts a simplified exemplary flowchart of a method 3700 for controlling a control region on a display screen of a computerized system, in accordance with an embodiment of the invention. The method includes obtaining, using the computerized system, first data from a touchpad, the first data being associated with a position of a portion of the hand of a user when the user operates the computerized system using the touchpad at 3702. In an example, the first data is not associated with an image of a finger of the user from an image sensor. The method then includes transmitting the first data from the touchpad to the computerized device at 3704. In an embodiment, the touchpad may be located in a location that is different from the location of the display screen. In some examples, at 3706, the method may include analyzing the first data in accordance with a model of a human hand and assigning the first data to at least one of a plurality of fingers of the model. At 3708, the method may include computing a graphical representation of a first finger of the portion of the hand of the user on the touchpad in accordance with the model of the human hand.

In certain embodiments, at 3710, the method may include identifying a first set of virtual keys to be associated with the first finger. At 3712, the method may include generating a control region comprising the first set of virtual keys. In an embodiment, the control region may include the first set of virtual keys associated with the first finger of the user. In some embodiments, at 3714, the method may include displaying the control region in a first position on the display screen in accordance with the position of the first finger. Additional details of the manner in which the method of Figure 37 may be implemented are discussed in detail in Figures 38 and 39 below.

Figures 38A-38F depict a series of simplified exemplary illustrations, 3800, 3802, 3804, 3806, 3807 and 3810 of controlling a control region displayed in a display screen of a handheld computerized device by a user operating a touchpad, in accordance with embodiments of the invention. In one embodiment, the control region displays different sets of keys associated with different fingers of the user's hand as the user proceeds to type at touch-typing speed using, for example, the 'lift and tap' technique discussed in Figure 26. It may be noted that at this point, the system has already assigned the touch data from the touchpad to at least one of the multitude of fingers of the model and has computed a graphical representation of the at least one finger of the user, in accordance with the model.

Referring now to Figure 38 A, in one embodiment, the system determines (in accordance with the touchpad data and the model of the human hand discussed in Figure 37) that the four fingers (Fl, F2, F3, F4) of the user's right hand 3804 are contacting the touchpad on the back side of the computerized device display, but neither the fingers nor the thumb of the user's left hand 3806, nor the thumb of the user's right hand 3804, are yet contacting the touchpad. Based on the obtained touchpad data, the system may then identify different sets of keys to be associated with each of the virtual fingers (Fl, F2, F3, F4) of the user's hand. In an embodiment, the system may then generate a control region comprising a set of virtual keys to be associated with a finger (Fl, F2, F3, F4) of the user's hand. In certain embodiments, the system may then display the control region in a first position in the display screen 3802. In the example depicted in Figure 38A, the virtual keys (Ύ', Ή', 'Ν') and ('U', 'J', 'Μ') associated with the finger Fl may comprise a first control region. Similarly, the virtual keys (T, 'K', ',') associated with the finger F2 may comprise a second control region, the virtual keys (Ό', 'L', '.') associated with the finger F3 may comprise a third control region and so on. In one example, the letters corresponding to the sets of keys associated with the fingers (Fl, F2, F3, F4) are shown as being positioned near or close to or on top of the user's fingers.

Referring now to Figure 38B, the system (in accordance with the touchpad data and the model of the human hand) may determine that the four fingers of the user's left hand 3806 are also now touching the touchpad on the back side of the computerized device, and the system therefore generates and displays a control region in the display screen 3802 comprising the virtual representation of the four fingers of the user's left hand and the sets of different keys associated with each of the four fingers of the user's left hand, on the display screen 3802. In the example depicted in Figure 38B, the sets of virtual keys associated with each hand may be separated and rotated. The example illustrated in Figure 38B further indicates that the user has raised the little finger of the right hand 3804 above the touchpad, causing the letters ('Ρ', ';' and V) normally associated with the right little finger to become highlighted.

Figure 38C illustrates all four fingers of each hand of the user touching the touchpad. In this situation, system may not highlight any of the keys associated with the user's fingers and may depict them in their normal sizes, thus allowing the user to freely move his hands while operating the touchpad. In some situations, the system may not highlight a particular key (e.g., 'P') associated with the user's finger if the system determines that the user's finger is kept raised (without subsequently touching the touchpad) for a period of time that is greater than a pre-determined time out period (e.g., 0-30 seconds) or if the user's finger touches the outside of the highlighted area associated with the particular virtual key.

In Figure 38D, the user has raised the little finger of the left hand 3806 above the keyboard, causing the keys, 'Q, 'A' and 'Z', associated with this finger to become activated. In the illustrated example, the letters, 'Q', Ά', 'Ζ,' are shown as activated by highlighting and /or enlarging these letters. In an embodiment, the letters, 'Q', Ά', 'Ζ,' may be fixed (i.e., frozen) into position so that the user can precisely strike any one of these keys according to the standard relative positions of those keys on the display screen.

In Figure 38E, the user has just pressed the location on the touchpad that corresponds to the location of the key 'A' on the display screen with the tip of his left little finger. In an embodiment, the system may then be configured to depict the newly entered letter 'A' at a position (e.g., the top) 3809 of the computerized device screen, as well as start to shrink the enlarged highlighted letters ('Q', Ά', 'Ζ') since the tip of the left little finger is now in contact with the touchpad again.

In Figure 38F, since the tip of the left middle finger is again in contact with the surface of the touchpad, the system no longer highlights the keys, 'Q', 'A' and 'Z', and depicts them in their normal sizes. In certain embodiments, the system may be configured to store the letter 'A' just typed by the user in system memory, as well as shows the letter as being displayed (e.g., 3809) in the display screen 3802.

Figures 39A-38F depict a series of simplified exemplary illustrations, 3900, 3902, 3904, 3906, 3908 and 3910 of controlling a control region displayed in a display screen of a handheld computerized device by a user operating a touchpad, in accordance with another embodiment of the invention. In the illustrated embodiment, the touchpad is detached from its normal position on the back of the handheld computerized device and positioned in front of the handheld computerized device. It is to be appreciated that by placing the touchpad in front of the device, a user may simultaneously observe the position of his hands and fingers, as well as the corresponding motions of his virtual hand and fingers and the action of the pressed virtual keys on the display screen of the handheld computerized device.

Figure 39A is an exemplary illustration of a user detaching the touchpad 3901 from its normal location on the back of the computerized device to reposition the touchpad to the front of the computerized device. As discussed above, by re-positioning the touchpad to the front of the device, the user may simultaneously observe both the actions of the user's real fingers on the touchpad as well as the corresponding actions of the user's virtual hand in the display screen.

Figure 39B is an exemplary illustration of a user touching the detached touchpad 3901 near the bottom of the touchpad using the four fingers of the user's right hand. In some examples, the user's thumb may not actually touch the touchpad. However, the system, based on the model of the user's hand, may determine the position of the user's thumb and display the user's virtual thumb in a corresponding location of the display screen. In an embodiment, the system may be configured to display the user's virtual thumb in an alternate color on the display screen. The alternate color may enable the user to recognize that this part of the user's hand is not touching the touchpad. Thus, in some embodiments, the system may be configured to display a more realistic virtual hand of the user by displaying portions of the user's hand that are not touching the touchpad. In addition, by displaying portions of the user's hand that are not touching the touchpad on the display screen, the user's left hand may be visually distinguished from the user's right hand.

In some embodiments, the system may be configured to assign a set of virtual keys to be associated with the user's virtual thumb. In this implementation, the user's virtual thumb and its associated virtual keys may also move in accordance with the user's thumb when the user's thumb touches and moves around the touchpad. Figure 39B also displays a control region in a first position in the display screen 3903. In the example depicted in Figure 39B, the keys (Ύ', Ή', 'Ν') associated with the finger Fl may comprise a first virtual region. Similarly, the keys ('U', 'J', 'M') associated with the finger F2 may comprise a second control region, the keys (T, 'K', "') associated with the finger F3 may comprise a third control region, and so on. In one example, the letters corresponding to the sets of keys associated with the fingers (Fl, F2, F3, F4) are shown as being positioned near or close to or on top of the user's fingers. Figure 39C is an exemplary illustration of the user moving his left hand to a different position of the touchpad. In an embodiment, the system may be configured to obtain touchpad data that indicates a position (e.g., a location and/or movement) of a portion of the user's hand and/or the user's fingers on the touchpad. Based on the obtained data, in one embodiment, the system may then be configured to determine an angular position of the portion of the user's hand and/or the user's fingers on the touchpad. The system may then be configured to reposition the control region comprising the user's virtual fingers and its associated virtual keys in accordance with the angular position of the portion of the user's hand and/or the user's fingers on the touchpad.

Figure 39D is an exemplary illustration of a user not yet raising his left middle finger 3907 above the touchpad. However, since the system has not yet received inputs according to the 'lift and tap' technique discussed above, the system has not yet responded by highlighting the virtual keys, E', 'D', 'C associated with this finger.

Figure 39E is an exemplary illustration of the system highlighting (for e.g., by enlarging) the keys 'Ε', 'D', 'C, normally associated with the user's left middle finger on the QUERTY keyboard when the system detects that the user has raised his left middle finger 3907 above the touchpad. It may be observed that the system has also locked in (i.e., frozen or fixed) the position of these keys so that they now do not move (on the display screen) when the user moves this finger or a portion of his hand on the touchpad. Figure 39E also indicates that the user is in the process of starting to bring the tip of his left middle finger 3907 back onto the touchpad in the touchpad position corresponding to the letter Έ'.

In Figure 39F, since the tip of the left middle finger is again in contact with the surface of the touchpad, the system no longer highlights the keys, Έ', 'D' and 'C, and depicts them in their normal sizes. In certain embodiments, the system may be configured to register a particular key (e.g., Έ') struck by the user and store the letter Έ' in system memory, as well display the letter Έ' in a position 3907 in the display screen 3903.

Trademarks: iPAD™ and iPhone™ are trademarks of Apple Inc., Cupertino California. Surface™ is a copyright of Microsoft Corporation.

The above embodiments of the invention are illustrative and not limiting. Various alternatives and equivalents are possible. Although, the invention has been described with reference to a handheld computerized device by way of an example, it is understood that the invention is not limited by the type of computerized device or system wherever the device or system may benefit by differentiating between a user's touch on a touchpad for command input and a user's touch on a touchpad for merely holding the device by the touchpad.

Although, the invention has been described with reference to certain user fingers touching the touchpad by way of an example, it is understood that the invention is not limited by which user fingers are touching the touchpad. Although, the invention has been described with reference to a touchpad located on the back of a handheld device including a display at the front of the device by way of an example, it is understood that the invention is not limited by where the touchpad is located. Although, the invention has been described with reference to a capacitive touchpad used for data entry by way of an example, it is understood that the invention is not limited by the type of input device. Although, the invention has been described with reference to a sequence of strong, weak, strong or medium, small, large force applied by a user's finger used for data entry by way of examples, it is understood that the invention is not limited by those two sequences of forces applied. Other additions, subtractions, or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.

Claims

1. A method of operating a computerized device comprising a front mounted touchscreen, a back mounted touchpad, and at least one processor, said method comprising:

using said at least one processor to receive touch location input from any of said front mounted touchscreen or said back mounted touchpad, and in response to an initialization touch sequence, displaying an image of a semi-persistent button group comprising at least one touch sensitive button at a default location on said front mounted touchscreen;

said semi-persistent button group further comprising an image of at least one touch sensitive button, each said image of at least one touch sensitive button having a touch sensitive button location with respect to said semi-persistent button group;

said semi-persistent button group further continuing to be displayed in an absence of either a front touch or a back touch for a semi-persistent time;

wherein if a front touch or a back touch is detected at a location of said at least one touch sensitive button within said semi-persistent time, then recording that said at least one touch sensitive button has been pressed by a user.

2. The method of claim 1 , where said initialization touch sequence comprises a touch sequence where the touch location input from said front mounted touchscreen matches a location of a back touch on said back mounted touchpad, thereby defining a matching location; and

wherein said default location is set to the location of said matching location.

3. The method of claim 2, wherein during said semi-persistent time, if either said matching location changes, or if only one of a front touch or back touch is detected, then said at least one processor changes the location of said semi-persistent button group according to a present location of either said matching location or said only one of a front touch or back touch.

4. The method of claim 1 , wherein said initialization touch sequence comprises a plurality of rapid taps on said back mounted touchpad; and

wherein said default location is either determined by the location of said plurality of rapid taps on said back mounted touchpad, or where said default location is different from the location of said plurality of rapid taps on said back mounted touchpad.

5. The method of claim 4, wherein said plurality of rapid taps is a double tap within a double tap duration of time.

6. The method of claim 1, wherein said back mounted touchpad comprises either a back mounted touchpad or a back mounted touchscreen, and wherein the dimensions of either of said back mounted touchpad or said back mounted touchscreen are the same as the dimensions of said front mounted touchscreen.

7. The method of claim 1, wherein said semi -persistent button group is a 2D projection of a 3D semi-persistent button group, and said 3D semi-persistent button group configured be rotated in 3D space according to finger swipes according to either of said front touch or back touch.

8. A method of operating a computerized device comprising a front mounted touchscreen, a back mounted touchpad, and at least one processor, said method comprising:

where said initialization touch sequence comprises a touch sequence where the touch location input from said front mounted touchscreen matches a location of a back touch on said back mounted touchpad, thereby defining a matching location;

wherein said default location is set to the location of said matching location;

said semi-persistent button group further comprising an image of at least one touch sensitive button location, each said image of at least one touch sensitive button having a touch sensitive button location with respect to said semi-persistent button group;

said semi-persistent button group further continuing to be displayed in an absence of either a front touch or said back touch for a semi-persistent time;

wherein if a front touch or a back touch is detected at a location of said at least one touch sensitive button location within said semi-persistent time, then recording that said at least one touch sensitive button has been pressed by a user.

9. The method of claim 8, wherein during said semi-persistent time, if either said matching location changes, or if only one of a front touch or back touch is detected, then said at least one processor changes the location of said semi-persistent button group according to a present location of either said matching location or said only one of a front touch or back touch.

10. The method of claim 8, wherein said back mounted touchpad comprises either a back mounted touchpad or a back mounted touchscreen, and wherein the dimensions of either of said back mounted touchpad or said back mounted touchscreen are the same as the dimensions of said front mounted touchscreen.

11. The method of claim 8, wherein said semi-persistent button group is a 2D projection of a 3D semi-persistent button group, and said 3D semi-persistent button group configured be rotated in 3D space according to finger swipes according to either of said front touch or back touch.

12. A method of operating a computerized device comprising a front mounted touchscreen, a back mounted touchpad, and at least one processor, said method comprising:

wherein said initialization touch sequence comprises a plurality of rapid taps on said back mounted touchpad; and

wherein said default location is either determined by a location of said plurality of rapid taps on said back mounted touchpad, or where said default location is different from a location of said plurality of rapid taps on said back mounted touchpad;

said semi-persistent button group further continuing to be displayed in an absence of either a front touch or a back touch for a semi-persistent time; wherein if a front touch or a back touch is detected at a location of said at least one touch sensitive button within said semi-persistent time, then recording that said at least one touch sensitive button has been pressed by a user.

13. The method of claim 12, wherein said back mounted touchpad comprises either a back mounted touchpad or a back mounted touchscreen, and wherein the dimensions of either of said back mounted touchpad or said back mounted touchscreen are the same as the dimensions of said front mounted touchscreen.

14. The method of claim 12, wherein during said semi-persistent time, said at least one processor is configured to change the location of said semi-persistent button group according to a present location of said back touch.

15. The method of claim 12, wherein said semi-persistent button group is a 2D projection of a 3D semi-persistent button group, and said 3D semi-persistent button group configured be rotated in 3D space according to finger swipes according to either of said front touch or back touch.