JP2016110299A - Coordination detection system, coordination detection method, information processing apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load for detecting the coordinates of a position when an indicator is shielded.SOLUTION: When light from an electronic pen is shielded by a shielding body 14 such as a finger and then the shielding is ended, a coordination detection system calculates a distance between a shielding start position and a shielding end position. When the distance is short (shorter than a predetermined threshold) as with a locus a, the coordination detection system performs simple interpolation with a straight line, and when the distance is long (equal to or longer than the predetermined threshold) as with a locus b, switches interpolation processing to perform interpolation with a least square method.SELECTED DRAWING: Figure 17

Description

  The present invention relates to a coordinate detection system, a coordinate detection method, an information processing apparatus, and a program.

  Coordinate input devices such as touch panels are widely used. With such a coordinate input device, position coordinates, which are position information on a coordinate input surface designated by a user with a pointer, are input to a computer to control the computer or to write characters or figures. Can do.

  In addition, the coordinate input device includes an optical coordinate input device that optically detects position coordinates. The optical coordinate input device detects position coordinates based on detection of light from an indicator. There are a light detection type coordinate input device and a light blocking type coordinate input device in which position coordinates are detected based on light blocking by an indicator.

  That is, for example, Patent Document 1 describes a coordinate input system that inputs position coordinates to a computer using a light detection type coordinate input device. In this coordinate input system, a pointer (indicator) located on a touch panel as a coordinate input surface is photographed by digital cameras arranged at a plurality of locations around the coordinate input surface, and image frames acquired by the respective digital cameras are acquired. The position coordinates where the pointer is in contact are detected by triangulation. Here, as the pointer, both an active pointer (a pointer having a light emitting function: for example, an electronic pen) and a passive pointer (a pointer having no light emitting function: for example, a finger) can be used.

  Further, Patent Document 2 describes a coordinate input system that inputs position coordinates to a computer using a light blocking type coordinate input device. This coordinate input system includes a light emitting / receiving unit having a fan-shaped light emitting surface arranged at two locations around the coordinate input surface, and a retroreflecting unit arranged around the coordinate input surface. Then, when light emitted from each light emitting / receiving unit to the coordinate input surface, reflected by the retroreflecting unit, and returned to each light receiving / emitting unit is blocked by the indicator that contacts the coordinate input surface, each light receiving / emitting unit The position coordinates of the indicator are detected by triangulation from the distance between the parts and the angle formed between each light receiving / emitting part and the blocked light path obtained from the received light intensity distribution in each light receiving / emitting part.

  However, the coordinate input system having such an optical coordinate input device detects the position coordinates of the indicator based on the outputs of the light detection units (light sensors) arranged at a plurality of locations around the coordinate input surface. Therefore, when the indicator is hidden behind a finger or the like as viewed from the light detection unit (hereinafter, this state is referred to as shielding), the position coordinates cannot be detected.

  In order to prevent this, in the interactive input system described in Patent Document 1, when light from one pointer to the digital camera is shielded by another pointer, the position coordinates tracked using a prediction filter such as a Kalman filter Is used as a position coordinate missing due to shielding.

However, tracking using such a prediction filter has a problem that a load due to processing for detecting position coordinates is increased.
The present invention has been made to solve such a problem, and an object thereof is to reduce a load caused by a process for detecting a position coordinate when the pointer is shielded.

  The present invention is a coordinate detection system for detecting the position coordinates of the indicator on the display surface based on the outputs from the light detection units arranged at a plurality of locations around the display surface for displaying information, Based on an output from the light detection unit, shielding determination means for determining whether or not the indicator is shielded, and shielding start for detecting a position coordinate of the indicator when shielding of the indicator starts. A position detecting unit, a shielding end position detecting unit for detecting a position coordinate of the indicator when the shielding of the indicator is over, and interpolation of a position coordinate between the shielding start position and the shielding end position. A coordinate interpolation means having a plurality of types of interpolation processing, a shielding distance detecting means for detecting a shielding distance between the shielding start position and the shielding end position, and a shielding distance detected by the shielding distance detecting means. According , Having a switching means for switching a plurality of interpolation process in the coordinate interpolation means, a coordinate detection system.

  ADVANTAGE OF THE INVENTION According to this invention, the load by the process for detecting the position coordinate when a pointer is shielded can be reduced.

It is a figure which shows the whole structure of the coordinate detection system to which this invention is applied. It is a figure for demonstrating the hardware constitutions of the computer in FIG. It is a figure for demonstrating the outline | summary of the function of the coordinate detection system of the premise of the coordinate detection system which concerns on embodiment of this invention. It is a flowchart which shows the outline | summary of operation | movement of the system shown in FIG. It is a figure for demonstrating the coordinate detection process in FIG. It is a flowchart which shows the frame determination process in FIG. It is a flowchart which shows the 1st example of the shielding determination process in FIG. It is a figure for demonstrating the position coordinate corresponding to 1 stroke in FIG. It is a figure for demonstrating the case where shielding cannot be detected in the 1st example of the shielding determination process shown in FIG. It is a flowchart which shows the 2nd example of the shielding determination process in FIG. It is a flowchart which shows the 1st example of the coordinate interpolation process in FIG. It is a flowchart which shows the 2nd example of the coordinate interpolation process in FIG. It is a figure for demonstrating the marking in FIG. It is a figure for demonstrating the locus | trajectory and interruption | blocking area | region of an electronic pen. It is a figure for demonstrating the outline | summary of the function of the coordinate detection system which concerns on embodiment of this invention. It is a flowchart which shows the outline | summary of operation | movement of the system shown in FIG. It is a figure for demonstrating the interpolation process in the coordinate detection system which concerns on embodiment of this invention, and the interpolation process in the coordinate detection system of the premise. It is a figure for demonstrating switching of the interpolation process in the coordinate detection system which concerns on embodiment of this invention. It is a flowchart which shows the 1st example of the shielding determination process in the coordinate detection system which concerns on embodiment of this invention. It is a flowchart which shows the 1st example of the coordinate interpolation process in the coordinate detection system which concerns on embodiment of this invention. It is a flowchart which shows the 2nd example of the coordinate interpolation process in the coordinate detection system which concerns on embodiment of this invention. It is a flowchart which shows the 2nd example of the shielding determination process in the coordinate detection system which concerns on embodiment of this invention. It is a flowchart which shows the 3rd example of the coordinate interpolation process in the coordinate detection system which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
<Overall configuration of coordinate detection system>
FIG. 1 is a diagram showing an overall configuration of a coordinate detection system to which the present invention is applied.

  The coordinate detection system 500 includes an electronic pen 13 as an indicator having a light emitting function, an electronic board 200, a computer 100 as an information processing apparatus, and a PC (Personal Computer) 300 as an additional element. Here, the electronic pen 13 and the electronic board 200 constitute a photodetection type coordinate input device.

  The electronic board 200 includes a coordinate input surface and a panel surface 201 as a display surface for displaying information, and light receiving sensors 11a to 11d as light detection units (in the case where any one or more are shown, they are simply referred to as the light receiving sensor 11). ing. The light receiving sensors 11 a to 11 d are arranged outside the square of the board surface 201 as a plurality of locations around the board surface 201. However, this is an example of an arrangement form, and may be increased or decreased depending on the number of electronic pens 13 that are detection targets of positions (position coordinates) in contact with the board surface 201.

  The light receiving sensor 11 is configured by combining a plurality of light receiving element groups arranged one-dimensionally or two-dimensionally and an imaging optical system, and the output is processed by the computer 100 to receive light intensity distribution (subject image) in the light receiving element group. ) Is used to obtain the position coordinates on the board surface 201 instructed by the electronic pen 13.

  Outside the four edges of the board surface 201, peripheral light emitting units 12a to 12d for illuminating the surface of the board surface 201 so that the illuminance on the surface of the board surface 201 is uniform are arranged. The peripheral light emitting units 12a to 12d are operated when a passive pointer such as a finger is used as an indicator. In the following description, a case where the electronic pen 13 that is an active pointer is used as an indicator will be described.

  A PC 300 is connected to the computer 100, and the computer 100 can display an image output from the PC 300 by a display device such as a liquid crystal display built in the board surface 201.

  An application corresponding to the coordinate detection system is installed in the computer 100, and the application detects a position coordinate on the board surface 201 touched by the user with the electronic pen 13 based on a signal from the light receiving sensor 11. Then, the application analyzes the gesture based on the position coordinates and controls the computer 100.

  The application can display an operation menu on the panel 201. For example, when the user touches a menu for drawing a line and then draws a figure on the board surface 201 with the electronic pen 13, the computer 100 analyzes the position coordinates with which the electronic pen 13 is in contact in real time, Create coordinates.

  The computer 100 connects the time-series coordinates to create a line and displays it on the panel surface 201. In the figure, since the user moves the pointing tool along the shape of a triangle, the computer 100 records a series of coordinates as one stroke (triangle). Then, it is combined with an image (here, sun and mountain) displayed on the display device 301 of the PC 300 and displayed on the board surface 201.

  As described above, even when the electronic board 200 does not have a touch panel function, by using the application, the user can perform various operations only by touching the panel surface 201 of the electronic board 200 with the electronic pen 13.

<Hardware configuration of computer>
FIG. 2 is a diagram for explaining the hardware configuration of the computer 100 in FIG. The computer 100 is a commercially available information processing apparatus or an information processing apparatus developed for a coordinate detection system.

  The computer 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an SSD (Solid) connected electrically via a bus line 118 such as an address bus or a data bus. State Drive) 104, network controller 105, external storage controller 106, capture device 111, GPU (Graphics Processing Unit) 112, and sensor controller 114.

  The CPU 101 executes an application and controls the entire coordinate detection system 500. The ROM 102 stores a program such as an IPL (Initial Program Loader) that is mainly executed by the CPU 101 at the time of startup. The RAM 103 serves as a work area when the CPU 101 executes an application. The SSD 104 is a nonvolatile memory that stores an application 119 for the coordinate detection system and various data. The network controller 105 performs processing based on a communication protocol when communicating with a server or the like via a network. The network is a LAN (Local Area Network) or a WAN (Wide Area Network such as the Internet) to which a plurality of LANs are connected.

  The external storage controller 106 performs writing / reading with respect to the removable external memory 117. The external memory 117 is, for example, a USB (Universal Serial Bus) memory, an SD (Secure Digital) card, or the like. The capture device 111 captures (captures) the video displayed on the display device 301 by the PC 300. The GPU 112 is a processor dedicated to drawing that calculates the pixel value of each pixel of the electronic board 200. The display controller 113 outputs the image created by the GPU 112 to the electronic board 200.

  The light receiving sensor 11 is connected to the sensor controller 114, and the light receiving output of the light receiving sensor 11 is sampled at a predetermined cycle (for example, 10 ms) to detect the light receiving direction. Then, the position coordinates of the electronic pen 13 are detected by triangulation based on the light receiving direction detected from the light receiving outputs of the two adjacent light receiving sensors 11.

  When the electronic pen controller 116 receives the pressing signal from the electronic pen 13, the computer 100 can detect whether or not the tip of the electronic pen 13 is pressed. As a communication means between the electronic pen controller 116 and the electronic pen 13, it is possible to use radio waves, sound waves, light having a wavelength different from that of light for coordinate detection, or the like.

  The application 119 for the coordinate detection system may be distributed while being stored in the external memory 117, or may be downloaded from a server (not shown) via the network controller 105. The application 119 may be in a compressed state or an executable format.

<Function of Coordinate Detection System on the Premise of the Present Invention>
FIG. 3 is a diagram for explaining an overview of functions of a coordinate detection system (hereinafter referred to as a premise system) that is a premise of a coordinate detection system (hereinafter referred to as the present system) according to an embodiment of the present invention.

  The reason for explaining the premise system before explaining this system is that the occlusion determination unit 123 among the coordinate detection unit 121, the frame determination unit 122, the occlusion determination unit 123, and the coordinate interpolation unit 124 that constitutes the premise system. This is because the coordinate interpolation unit 124 is improved.

  As shown in the figure, in the premise system, a coordinate detection unit 121 to which outputs of the light receiving sensors 11a and 11b are input, a frame determination unit 122 to which outputs of the coordinate detection unit 121 are input, and outputs of the frame determination unit 122 are input. A shielding determination unit 123 and a coordinate interpolation unit 124 to which an output of the shielding determination unit 123 is input are provided. Each of these units is a functional block realized by the application 119 in FIG.

  The coordinate detection unit 121 calculates the position coordinates of the electronic pen 13 by triangulation based on the outputs of the light receiving sensors 11a and 11b. The frame determination unit 122 determines the frame number of the image based on the output of the coordinate detection unit 121. The shielding determination unit 123 determines whether the light from the electronic pen 13 is blocked by the shielding object (for example, a finger) 14 based on the output of the frame determination unit 122. The coordinate interpolation unit 124 calculates a position coordinate between the position coordinate of the electronic pen 13 when shielding is started and the position coordinate of the electronic pen 13 when shielding is ended based on the output of the shielding determination unit 123. Interpolate.

  Details of these units will be described later. As described above, since the present system is an improvement of the shielding determination unit 123 and the coordinate interpolation unit 124 in the premise system, the coordinate determination unit and the coordinate interpolation unit will be described after describing the premise system. .

<Operation of prerequisite system>
FIG. 4 is a flowchart showing an outline of the operation of the system shown in FIG.
First light receiving sensor 11a, the image _O L than 11b, to obtain the _{O R} (Step S1). Then calculates the feature amount of the image _O L, _{O R} (step S2). That is, for example, the pen light emission area is cut out by labeling, and the center of gravity of the light emission area and the number of labels are calculated as feature amounts.

Next, the image O _L, the angle of FIG. 5 using the center of gravity of the O _R theta _L, calculation of the theta _R is (step S3), and using the calculated results, by triangulation, to calculate the position coordinates of the electronic pen 13 (Step S4).

  The processing so far is performed by the coordinate detection unit 121. Thereafter, the frame determination unit 122, the occlusion determination unit 123, and the coordinate interpolation unit 124 sequentially execute the frame determination process (step S5), the occlusion determination process (step S6), and the coordinate interpolation process (step S7), respectively. The contents of these processes will be described later.

<Frame judgment processing in the prerequisite system>
FIG. 6 is a flowchart showing the frame determination process (step S5 in FIG. 4).

First check the image _O L, the frame number N of the _{O R} (step S11). The frame number N is information indicating the number of frames after the activation of the light receiving sensor 11. Next, it is determined whether N is greater than 1 (step S12). As a result of the determination, if N is greater than 1 (step S12: Yes), the process proceeds to the shielding determination flow. If not (step S12: No), the process ends without doing anything.

<First Example of Shielding Determination Process in Premise System>
FIG. 7 is a flowchart showing a first example of the shielding determination process (step S6 in FIG. 4), and FIG. 8 is a diagram for explaining the position coordinates corresponding to one stroke in FIG.

First earlier image _O L calculated in step S2, among the _{O R} number label, compared images _O Ln of frame number _N, the number of labels _{O Rn,} determines different not (step S21). If they are different (step S21: Yes), it is considered that the light receiving sensor with the smaller number of labels is shielded, so it is determined that there is shielding. When the number of labels matches (step S21: No), it is determined that there is no shielding.

  When there is shielding, it is determined whether or not the number of times of shielding so far is 0 (step S22). If the number of occlusions so far is 0 (step S22: Yes), the position coordinates corresponding to one stroke up to the N-1 frame are saved (step S23), the occlusion number is incremented (step S24), and the process is terminated.

  As shown in FIG. 8, one stroke is a collection of individual coordinates corresponding to continuous frames from the start of detection of the position coordinates of the electronic pen to the end of detection. For example, the Chinese character “three” consists of 3 strokes, and if a block occurs at the position coordinate of the point Ps in the figure, the portion surrounded by the rectangle corresponds to one stroke up to the (N−1) frame. Become. Note that the point Pe is a position where the shielding is finished. Hereinafter, the position coordinates where the shielding occurs (position coordinates where the shielding starts) are referred to as “shielding start position”, and the position coordinates where the shielding ends are referred to as the shielding end position.

  Returning to the description of FIG. When the number of occlusions so far is not 0, that is, 1 or more (step S22: No), the occlusion number is incremented (step S25), and the process proceeds to coordinate interpolation processing.

  If there is no shielding (step S21: No), the process proceeds to coordinate interpolation processing. The reason for moving to the coordinate interpolation process even in the case of no shielding is that there is no shielding immediately after the shielding is finished as in the case of no shielding, in which case it is necessary to interpolate the position coordinates of the shielding part from the images before and after shielding. This is because the behavior is different from that of the case without normal shielding.

<When shielding is not detected only by the number of labels in the image>
FIG. 9 is a diagram for explaining a case where the shielding cannot be detected in the first example of the shielding determination process shown in FIG. 7.

As shown in the figure, there are a plurality of electronic pens, and the position coordinates are A and B, respectively. In this case, shield 14a for each, the shielding occurs by 14b, a number of labels image O _L obtained by the light receiving sensor 11a, becomes equal to the number of labels of the image O _R obtained by the light receiving sensor 11b Therefore, in the shielding determination process (step S21) shown in FIG. 7, it is erroneously determined that there is no shielding in spite of the fact that shielding is present.

<Second Example of Shielding Determination Processing in Premise System>
Therefore, the second example of the shielding determination process (step S6 in FIG. 4) enables correct shielding determination even in the case shown in FIG. FIG. 10 is a flowchart illustrating a second example of the shielding determination process.

First, the number of labels of the images _OLn and _ORn of the frame number N calculated in step S2 is compared with the number of contact signals of the electronic pen (the number of electronic pens in contact with the panel surface 201). O _Ln label number ≠ contact signal number of the electronic pen "or" label number ≠ contact signal number of the electronic pen in the image O _Rn "and judges whether or not satisfied (step S31).

  If it is established (step S31: Yes), it is determined that shielding is present, and if it is not established (step S31: No), it is determined that shielding is not performed. Steps S32 to S35 that are branched depending on the determination result are the same as steps S22 to S25 in the first example (FIG. 7) of the shielding determination process.

<First Example of Coordinate Interpolation Processing in Premise System>
FIG. 11 is a flowchart showing a first example of coordinate interpolation processing (step S7 in FIG. 4). This process is executed by the coordinate interpolation unit 124.

  First, it is determined whether or not the number of times of occlusion so far is 0 (step S41). If it is 0 (step S41: Yes), the flow shown in FIG. On the other hand, if it is not 0 (step S41: No), it is determined whether or not the shielding is not completed (step S42). When the shielding is not finished (step S42: Yes), the flow shown in this figure is finished.

  When the shielding has been completed (step S42: No), the position coordinates corresponding to one stroke stored when the number of times of shielding is 1 (position coordinates saved in step S23 or S33) and the position coordinates calculated this time Are fitted by the least square method using an nth-order polynomial (step S43), the number of occlusions is set to 0 (step S44), and the flow shown in FIG.

<Second Example of Coordinate Interpolation Processing in Premise System>
FIG. 12 is a flowchart showing a second example of the coordinate interpolation process (step S7 in FIG. 4) in the premise system, and FIG. 13 is a diagram for explaining the marking in FIG.

  The second example of the coordinate interpolation process has a shape in which the stroke cannot be approximated by a polynomial when occlusion occurs, and the line fitted by the first example of the coordinate interpolation process greatly deviates from the locus of the electronic pen. Can also handle cases.

  In such cases, the shielding start position and the shielding end position are often separated. Therefore, if the number of occlusions so far has not been 0 (step S51: No), it is determined whether or not the distance between position coordinates before and after occlusion is longer than a predetermined threshold (step S52). Step S52: Yes), as shown in FIG. 13, the fitted region is marked for a certain time (step S53), and an OK / NG button is displayed.

  When the marked area is accepted by the user, when the user taps the OK button, drawing is performed as marked. On the other hand, when the NG button is tapped, the shielding area (between the shielding start position and the shielding end position) is not drawn, and the user can rewrite again.

  When the distance between the position coordinates before and after the shielding is equal to or less than the predetermined threshold (Step S52: No), fitting is performed in the same manner as in the first example of the coordinate interpolation process (Step S43) (Step S54), and the number of times of shielding. Is set to 0 (step S55), and the flow shown in FIG. After step S53, the shielding count is set to 0 (step S55), and the flow shown in FIG.

  A mode that allows the user to select such a marking, a mode that performs fitting without marking, and a mode that does not perform marking and does not perform fitting can also be configured so that the user can use properly according to the application. .

<Track of electronic pen>
FIG. 14 is a diagram for explaining the trajectory and blocking area of the electronic pen.
As described with reference to FIGS. 11 and 12, in the coordinate interpolation processing in the premise system described so far, as shown in the figure, after the shielding of the electronic pen is completed and the shielding end position is detected, the shielding is performed. Perform region interpolation. The same applies to the case of coordinate interpolation processing in the present system described below. By performing the interpolation after the shielding is completed in this manner, there is an advantage that the accuracy of the interpolated position coordinates is higher than the process of performing the interpolation when the shielding is started.

<Functions of this system>
In the premise method described above, the interpolation between the shielding start position and the shielding end position is performed by the position coordinate calculated by the least square method using an nth-order polynomial. There is a problem that there is a load due to processing. According to the present system, this problem can be solved and the software processing of the interpolation processing can be reduced.

  FIG. 15 is a diagram for explaining an outline of functions of the present system. In this figure, the same reference numerals as those in FIG. 3 are assigned to the same parts as those in FIG. In this system, the shielding determination unit 123 and the coordinate interpolation unit 124 in the premise system are improved to be a shielding determination unit 123a and a coordinate interpolation unit 124a, respectively.

  FIG. 16 is a flowchart showing an outline of the operation of the system shown in FIG. In this figure, the same step numbers (reference numerals) as those in the figure are attached to the same steps as those in FIG. 4 (a flowchart showing an outline of the operation of the prerequisite system).

  As shown in the figure, the contents of the shielding determination process (step S6a) executed by the shielding determination part 123a and the coordinate interpolation process (step S7a) executed by the coordinate interpolation part 124a are different from those in FIG. The other processes are the same as those in FIG.

<Interpolation in this system and interpolation in the premise system>
FIG. 17 is a diagram for explaining the interpolation processing by the coordinate interpolation processing (step S6a) in the present system and the interpolation processing by the coordinate interpolation processing (step S6 in FIG. 4) in the base system. FIG. 18 is a diagram for explaining switching of interpolation processing in the present system.

  As shown in FIG. 17, in the premise system, fitting is performed by a least square method using an nth-order polynomial, and a shielding region between a shielding start position and a shielding end position is interpolated. On the other hand, this system has a simple interpolation function for interpolating the shielding area with a straight line.

  Then, when the distance between the shielding start position and the shielding end position (hereinafter referred to as the shielding distance) is short (less than a predetermined threshold value) as in the locus a of the electronic pen in FIG. 18, linear interpolation is performed. When the shielding distance is long (when it is equal to or greater than a predetermined threshold) as in the electronic pen locus b in FIG. 18, the interpolation processing is switched so as to perform the same interpolation as in the conventional system. That is, a plurality of types of interpolation processing are switched according to the length of the shielding distance.

<First example of shielding determination process in this system>
FIG. 19 is a flowchart illustrating a first example of the shielding determination process in the present system.

  In this figure, steps S61, S62, S63, S65, and S67 are the same as steps S21, S22, S23, S24, and S25 in the first example (FIG. 7) of the shielding determination process in the premise system.

  The difference from the premise system is that when there is no shielding (step S61: No), the current position coordinates are stored as the shielding end position (step S66), the shielding is present (step S61: Yes), and the number of times of shielding is When it is 0 (step S62: Yes), the current position coordinates are stored as the shielding start position (step S64). That is, the shielding determination unit 123a functions as a shielding determination unit, a shielding start position detection unit, and a shielding end position detection unit according to the present invention. In step S66, the position is stored as the shielding end position even if it is not in the middle of shielding. However, in this case, there is no problem because it is not used in the coordinate interpolation process described later.

<First example of coordinate interpolation processing in this system>
FIG. 20 is a flowchart showing a first example of coordinate interpolation processing in the present system. This coordinate interpolation process is executed after step S66 or S67 in the first example (FIG. 17) of the shielding determination process in the present system.

  In this figure, steps S71, S72, S75, and S77 are the same as steps 41, S42, S43, and S44 in the first example (FIG. 11) of the coordinate interpolation process in the premise system. That is, it can be said that the first example of the coordinate interpolation process in the present system is obtained by adding steps S73, S74, and S76 to the first example of the coordinate interpolation process in the base system.

The following processing is executed by adding these steps.
When the number of times of shielding is 0 (step S71: Yes) and shielding is completed (step S72: No), the shielding distance is calculated from the shielding start position and shielding end position (step S73). At this time, the shielding determination unit 123a functions as a shielding distance detection unit. The shielding start position and the shielding end position are obtained by the first example of the shielding determination process in the present system.

  Next, it is determined whether or not the shielding distance is greater than or equal to a threshold distance (threshold) (step S74). If the shielding distance is greater than or equal to the threshold distance (step S74: Yes), the same interpolation processing as that of the prerequisite system is performed (step S75). If the shielding distance is less than the threshold distance (step S74: No), the shielding start position and shielding end. Simple interpolation is performed to connect the positions with straight lines (step S76). That is, the interpolation process shown in FIG. 18 is switched. At this time, the coordinate interpolation unit 124a also functions as a switching unit.

<Second example of coordinate interpolation processing in this system>
As described above, in the first example of the coordinate interpolation process in this system, the interpolation process is switched according to the shielding distance. In the second example of the coordinate interpolation processing in this system, the interpolation processing is switched according to the shielding distance and the shielding time. This coordinate interpolation process is also executed after step S66 or S67 in the first shielding determination process (FIG. 17) in this system.

  FIG. 21 is a flowchart showing a second example of coordinate interpolation processing in the present system. In this figure, steps S81, S82, S83, S85, S86, S87, and S88 are respectively steps 71, S72, S73, S74, S75, S76 in the first example of coordinate interpolation processing (FIG. 20) in this system. Same as S77.

  That is, it can be said that the second coordinate interpolation process in the present system is obtained by inserting step S84 between steps S73 and S74 in the first coordinate interpolation process in the present system.

  In step S84, reference is first made to the number of times of occlusion (the number of frames in the occlusion period). The number of times of shielding is a value incremented in step S65 or S67 in the first example (FIG. 19) of shielding determination processing in the present system, and is proportional to the length of shielding time. That is, the shielding determination unit 123a functions as a shielding time detection unit. Then, when the shielding time is equal to or greater than a predetermined threshold, the smaller parameter of the two parameters having different values is selected as the threshold distance, and when the shielding time is less than the predetermined threshold, The parameter with the larger value is selected as the threshold distance.

  In subsequent steps S85 to S87, the threshold distance selected in step S84 is compared with the shielding distance calculated in step S83, and the interpolation processing is switched according to the magnitude relationship.

  That is, more appropriate interpolation processing can be switched by considering not only the shielding distance but also the shielding time. That is, for example, when the shielding distance is short and the shielding time is long and it is better not to simply interpolate with a straight line, or when the shielding distance is long and the shielding time is short, and it is not necessary to strictly interpolate. it can. In these cases, the load of software processing can be reduced by performing appropriate interpolation processing. Note that although two threshold distances are switched here, three or more threshold distances may be switched.

<Second example of shielding determination processing in this system>
FIG. 22 is a flowchart illustrating a second example of the shielding determination process in the present system. In this figure, steps S91, S92, S93, S94, S96, S97, and S98 are respectively steps 61, S63, S64, S65, S66, and S67 in the first example of the shielding determination process in this system (FIG. 19). The same.

  That is, it can be said that the 2nd example of the shielding determination process in this system inserts step S95 between step S62 and S65 in the 1st example of the shielding determination process in this system.

  In step S95, when there is occlusion (step S91: Yes) and the occlusion count is 0 (step S92: Yes), the number of frames corresponding to one stroke up to N-1 frames is stored. That is, the number of frames is counted even when no occlusion occurs (one stroke is appropriate for the counting period), and when the occlusion occurs, the number of frames for the last one stroke is stored.

<Third example of coordinate interpolation processing in this system>
In a third example of coordinate interpolation processing in this system, the interpolation method is switched according to the shielding distance and the movement acceleration of the electronic pen before and after the shielding.

  FIG. 23 is a flowchart showing a third example of coordinate interpolation processing in the present system. This coordinate interpolation process is executed after step S97 or S98 in the second example (FIG. 22) of the shielding determination process in the present system.

  In this figure, steps S101, S102, S103, S106, S107, S108, and S109 are steps S81, S82, S83, S85, S86, S87, respectively, in the second example of coordinate interpolation processing in this system (FIG. 21). Same as S88.

  That is, it can be said that the third example of coordinate interpolation processing in this system is provided with steps S104 and S105 instead of step S84 in the second example of coordinate interpolation processing in this system.

  In step S104, first, the moving speed of the electronic pen during the shielding period is calculated from the shielding distance and the number of shielding times. Here, the shielding distance is the value calculated in step S103. The shielding count is a value incremented in step S96 or S98 in the second example (FIG. 22) of the shielding determination process in the present system, and is proportional to the length of the shielding time. At this time, the coordinate interpolation unit 124a functions as a first speed calculation unit.

  In step S104, the length of one stroke is calculated from the position coordinates of one stroke stored in step S93 in the second shielding determination process (FIG. 20) in the system, and the length and the step 94 are stored. The moving speed of the electronic pen before shielding is calculated from the number of frames for one stroke. At this time, the coordinate interpolation unit 124a functions as a second speed calculation unit.

  In step S105, first, it is determined whether the vehicle is accelerating or decelerating by comparing the moving speed before shielding calculated in step S104 with the moving speed of the shielding period. At this time, the coordinate interpolation unit 124a functions as an acceleration detection unit. When the vehicle is decelerating, the parameter with the smaller value of the two parameters with different values is selected as the threshold distance. When the vehicle is accelerating, the parameter with the larger value is selected as the threshold. Select as distance.

  In subsequent steps S106 to S108, the threshold distance selected in step S105 is compared with the shielding distance calculated in step S103, and the interpolation process is switched according to the magnitude relationship.

  That is, more appropriate interpolation processing can be switched by considering not only the shielding distance but also whether the vehicle is accelerating or decelerating in the shielding region. That is, for example, if the vehicle is decelerating even if the shielding distance is short, a strict interpolation process can be executed. Note that although two threshold distances are switched here, three or more threshold distances may be switched.

As described above in detail, the coordinate detection system according to the embodiment of the present invention has the following features (1) to (5).
(1) Since the shielding area is interpolated after the shielding end position of the electronic pen is detected, the accuracy of the position coordinates is higher than the process of predicting and interpolating when shielding is started.
(2) When the shielding distance is short, the load of the interpolation process can be reduced by switching to a simple interpolation process.
(3) More appropriate interpolation processing can be switched by considering not only the shielding distance but also the shielding time.
(4) More appropriate interpolation processing can be switched by considering not only the shielding distance but also whether the vehicle is accelerating or decelerating in the shielding region.
(5) By providing a mode in which the user can select parameters to be used (threshold distance, etc.), an optimal switching method can be selected in accordance with the user's application such as the importance of the conference.

  In addition, although this system demonstrated above uses the electronic pen which has a light emission function as an indicator, the indicator which does not have a light emission function like a finger | toe can also be used. The present system relates to a coordinate detection system having a light detection type coordinate input device, but the present invention can also be applied to a coordinate detection system having a light input type coordinate input device. In this case, in step S2 in FIG. 4, the blocking area is cut out by labeling, and the center of gravity of the light emitting area and the number of labels are calculated as feature amounts. Further, by providing an acceleration sensor in the electronic pen and transmitting its output to the electronic pen controller 116, it can also be used for acceleration calculation in the third example of coordinate interpolation processing (FIG. 23).

  DESCRIPTION OF SYMBOLS 100 ... Computer, 201 ... Board surface, 11, 11a-d ... Light receiving sensor, 121 ... Coordinate detection part, 122 ... Frame determination part, 123a ... Occlusion determination part, 124a ... Coordinate interpolation part, 200 ... Electronic board, 500 ... Coordinate detection system.

Special table 2011-522332 gazette JP 2001-265517 A

Claims (8)

A coordinate detection system that detects the position coordinates of the indicator on the display surface based on outputs from light detection units arranged at a plurality of locations around the display surface for displaying information,
Shielding determination means for determining whether or not the indicator is shielded based on an output from the light detection unit;
Shielding start position detecting means for detecting a position coordinate of the indicator when shielding of the indicator starts;
Shielding end position detecting means for detecting a position coordinate of the indicator when shielding of the indicator is over;
Interpolating position coordinates between the shielding start position and the shielding end position, coordinate interpolation means having a plurality of types of interpolation processing,
A shielding distance detecting means for detecting a shielding distance between the shielding start position and the shielding end position;
Switching means for switching a plurality of interpolation processes in the coordinate interpolation means according to the shielding distance detected by the shielding distance detection means;
A coordinate detection system. The coordinate detection system according to claim 1,
A shielding time detecting means for detecting a time from when the shielding starts to when the shielding ends,
The coordinate detection system, wherein the switching means switches the interpolation processing in the coordinate interpolation means according to the shielding distance detected by the shielding distance detection means and the shielding time detected by the shielding time detection means. The coordinate detection system according to claim 1,
Shielding time detecting means for detecting a time from when the shielding starts until the shielding ends, and acceleration detection for detecting an acceleration of the indicator between the shielding start and when the shielding ends. Means,
The coordinate detection system, wherein the switching means switches the interpolation processing in the coordinate interpolation means according to the shielding distance detected by the shielding distance detection means and the acceleration detected by the acceleration detection means. In the coordinate detection system according to claim 3,
First speed calculating means for calculating a speed in a shielding area calculated from the shielding distance detected by the shielding distance detecting means and the shielding time detected by the shielding time detecting means;
Second speed calculating means for calculating a speed in the one stroke calculated from a position coordinate and time of one stroke to the shielding start position;
The coordinate detection system, wherein the acceleration detection means detects the acceleration from the speeds calculated by the first speed calculation means and the second speed calculation means. The coordinate detection system according to any one of claims 1 to 4,
The coordinate interpolating means includes a first interpolation process for interpolating a straight line between the shielding start position and the shielding end position, a one-stroke position coordinate including the shielding start position, and the shielding end position. A second interpolation process for interpolating with position coordinates acquired by multiplication is possible, and the switching means executes the first interpolation process when the shielding distance is less than a predetermined threshold, and the shielding distance is the A coordinate detection system that performs switching so that the second interpolation processing is executed when the threshold value is greater than or equal to a threshold value. A coordinate detection method executed by a coordinate detection system that detects the position coordinates of the indicator on the display surface based on outputs from light detection units arranged at a plurality of locations around the display surface for displaying information There,
A shielding determination step of determining whether or not the indicator is shielded based on an output from the light detection unit;
A shielding start position detecting step for detecting a position coordinate of the indicator when shielding of the indicator starts;
A shielding end position detecting step for detecting a position coordinate of the indicator when the shielding of the indicator is ended;
A shielding distance detecting step for detecting a shielding distance between the shielding start position and the shielding end position;
A coordinate interpolation step having a plurality of types of interpolation processing for interpolating position coordinates between the shielding start position and the shielding end position;
An interpolation control step for switching a plurality of interpolation processes in the coordinate interpolation step according to the shielding distance;
A coordinate detection method. An information processing apparatus for processing information from a coordinate input device having a display surface for displaying information and light detection units arranged at a plurality of locations around the display surface,
Shielding determination means for determining whether or not the indicator is shielded based on an output from the light detection unit;
A shielding start position detection stage for detecting a position coordinate of the indicator when shielding of the indicator starts,
Shielding end position detecting means for detecting a position coordinate of the indicator when shielding of the indicator is over;
Interpolating position coordinates between the shielding start position and the shielding end position, coordinate interpolation means having a plurality of types of interpolation processing,
A shielding distance detecting means for detecting a shielding distance between the shielding start position and the shielding end position;
Switching means for switching a plurality of interpolation processes in the coordinate interpolation means according to the shielding distance detected by the shielding distance detection means;
An information processing apparatus. A program for causing a computer to function as each unit of the information processing apparatus according to claim 7.

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