GB2522250A

GB2522250A - Touch device detection

Info

Publication number: GB2522250A
Application number: GB1400903.9A
Authority: GB
Inventors: Andrew Oakley
Original assignee: Promethean Ltd
Current assignee: Promethean Ltd
Priority date: 2014-01-20
Filing date: 2014-01-20
Publication date: 2015-07-22
Also published as: GB201400903D0

Abstract

A contact detection apparatus comprises an interactive surface arranged to detect a contact point; an interface responsive to the detection of a contact point and adapted to determine whether the contact point is a pen event or a touch event and a processor for processing data associated with the contact point on the basis of the determination. A pen event is a contact carried out by an active pen device that is able to communicate with the interface, preferably through a communication back-channel. The interface may include pen detection circuitry to detect a pen and preferably includes circuitry for wirelessly transmitting an interrogation signal responsive to the detection of a contact point and the wireless detection is enabled to detect a wireless signal transmitted by the pen in response to receiving the pen interrogation signal. A touch event is carried out by a finger, thumb or passive pen or stylus. The data associated with the contact point may be marked with a pen event flag or a touch event flag based on the determination of a contact being a pen event or a touch event. The invention is said to improve the functionality of interactive surfaces such as electronic whiteboards.

Description

I

TOUCH DEVICE DETECTION

BACKGROUND TO THE INVENTION

Field of the Invention

The present invent ion is concerned with touch input detection s..2tCflS and the adaptation of such systems to allow for the detection of devices providing pen inputs. The invent ion particularly provides for distinct ion between the identification of a contact point provided by a touch input and a contact point provided by a pen input

Description of the Related Art

in the foliowinq description the expressions touch' and peri' are used to refer to two different tynes of technoloay for providing a contact point at cuiiii teractive suriace. ifl a touch system a contact point may be provided by an object such as a finger, or a aevice such as a stylus. In a pen system a contact may be provided by an object termed a pen device or a pointing device, which can interact with the system by means other than simply providing a contact point.

Interactive systems incorporating touch arid/or pen technology are welL-known in the art.

An exemplary touch system is illustrated in FIG. 1(a) The exemplary system comprises an interactive surface 10, a touch data processor 12, and a computer 14, A touch contact on the interactive surface provided by a finger of a hand 11 is detected arid data associated with tha.t touch contact pcint provided as DATA in a data stream to the touch data processor 12. The touch data processor 12 processes the data in accordance with known techniques, before forwarding the processed data to the computer 14 for further processing in accordance with known techniques.

Touch systems typically rely on detecting a contact point at the disoiav surface provided by a touch such as a finger contact. Typically touch detection systems have a number of disadvantages in cornpar.i son to a system which is arranged to detect a device such as a pen.

In a system arranged to detect a pen t is possIble to distinguish between and identify multiple contact points.

because a contact point may be mapped to a unique pen.

In a system arranged to detect a pen it is possible to distinguish between a contact point on a surface and a hover contact point above the surface, because a contact point may he determined to he at the disolav surface or proximate to the display surface., In a system arranged to detect a pen it is possible to provide automatic switching of modes through. the provision of buttons on the pen device.

Systems which are adapted to provide for detection of both touch inputs and pens can potentially provide the advantages of both systems in a sinale system. However such a system ma:)' tyDcaiy require a user to manually se,iect a menu in order to switch between touch and pen modes.

It is an aim of the present invention to provide an actaptatioi to a touch detection system to improve the functonanty offered.

SUMMARY OF THE INVENTION

There is provided.n interface for a contact detection apparatus for use with an. interactive surface, wherein the interface is adapted to be responsive to the detection of a contact point on said interactive surface, the interface is adapted to determine whether the-contact point Is associated with a touch event and/or a pen event; and the interface is adapted to forward the data associated with the contact point S to a processor for processing following said determination, [here is disclosed a contact detection apparatus, comprisincp an interactive surf ace arranged to detect a contact point thereon; an interface responsive to detection of a contact point, and for determining whether the contact point is associated with a touch event or a pen-event; and a processor for processing the data associated with the contact point following said determination.

The contact detection apparatus may comprise a communication back-channel, wherein the apparatus is adapted to determine the contact point as a pen event or a touch event using the back-channel.

The processor may be adapted to process the data as touch data if it is determined that the contact point is associated with a touch event.

The processor may he adapted to process the data as teri data if it is determined that the contact point is associated with a pen event.

The interface may include pen detection circuitry for detecting a pen. The pen -detection circuitry may include a wireless detection circuitry for detecting a wireless signal from a pen. The pen detection circuitry may include circuitry for wirelessly transmitting an interrogation signal responsive to detection of a contact point, wherein the wireless detection is enabled to detect a wireless signal responsive to the pen interrogation signal..

There is disclosed a method in a contact detection system for detecting a contact point on an inteüctiiéiürfáce the method including determining, responsive to detection of a contact point, whether the contact point is provided by a pen S input, and further processing the data in accordance with that determination.

The method may further comprise suspending processing of the data as touch data during said determination.

The method may further comprise processing the data as touch data if it is determined that the contact point is not provided by a pen input.

The data may be adapted to indicate whether it is touch data.

The data received from the contact point may be appended with a flag indicating that the data is touch data.

The method may further comprise processing the data as pen data if it is determined that the contact point is provided by a pen input. The data may be adapted to indicate it is pen data. The data may be appended with a flag indicating that the data is pen data.

The method may further comprise detecting a wireless signal from a pen. The method may further courise wirelessly transmitting an interrogation signal responsive to detection of a contact point, and enabling the wireless detection to detect a wireless signal responsive to the pen interrogation signal.

There is provided a method in a touch detection system for detecting a touch contact point on a surface, the method further including determining, responsive to detection of a contact point, whether the contact point is provided by a pen input, and further processing the data in accordance with that determination -The method may further comprise suspending processing of the data as touch data during said determii.atiori. There is S thus provided an interrupt technique for a touch detection system. An existing touch detection system may be adapted to provide art augmented interface which determines whether contact data is provided by a touch input or a pen input whilst touch processing is suspended or interrupted The method may further comprise processing the data as ouch uaa t it Is uetezmihea LnCt the conact point is not provided by a pen input. The data may be adapted to indicate whether it is touch data. The data received from the contact point may he appended with a flag indicating that the data is touch data. Thus once a determination is made, the interrupted normal or default touch input processing may be proceeded with, or additional pen. input processing may be enabled.

The method may further comprise processing the data. as pen data if it is determined that the contact point is provided by a pen input. The data may be adapted to indicate it is pen data. The data received from the contact point may be appended with a flag indicating that the data is pen data.

Thus a modified data stream is provided which identifies whether a contact event is caused by a pen input or a touch input, without the touch system having knowledge of the pen, or undergoing any modification to its normal operation.

The. also provides a touch detection apparatus, comprising nterface for receiving data associated with a contact point, wherein the interface is adapted to determine, on receipt of data, whether the contact point is provided by a touch input or a pen input.

The touch detection apparatus further comprises circuitry for processing said data, wherein the data is passed to circuitry for processing said data by the interf ace.

The interf ace may include circuitry for determining if a contact point is provided by a pen input.

The circuitry for processing data associated with touch inputs may be adapted to process data associated with pen inputs. The circuitry may be a computer.

BRIEF DESCRIPTION OP ThE FIGURES

The present invention is now described by way of reference to the accompanying figures, in which: FIG. 1(a) illustrates a typical touch detection apparatus; PIG 1(b) illustrates a modified touch detection apparatus in accordance with the invention; FIG. 2 illustrates a schematic of an arrangement of a touch detection apparatus adapted to detect a contact point provided by a pen; PIG. 3 illustrates a process for controlling the schematic apparatus of Pta. 2; FIGS * 4(a) and 4(b) illustrate an exemplary system implementation of an apparatas for allowing pen detection on an interactive system arranged to detect touch inputs; PIG, 5 illustrates a second alternative exemplary system implementation of a touch detection apparatus adapted to detect a contact point provided by a pen; PIG. 6 illustrates an exemplary implementation of pen circuitry in accordance with PIG 5; FIG. 7 illustrates a schematic of an arrangement of touch detection apparatus adapted to detect a contact point provided byapen; FIG. S illustrates a process for controlling the schematic apparatus of nO. 7; FIG, 9 illustrates a process for controlling the pen apparatus of FIG. 6; FIG. 10 illustrates an exemplary principle of operation of the arrangement of FIG. 6 and FIG. 7; nO. 11 illustrates an exemplary implementation of pen circuitry in accordance with an arrangement; and FIG. 12 illustrates a schematic of an arrangement of touch detection apparatus consistent with the exemplary pen circuit of FIG. U.

DESCRIPTION OF PREFERRED EMBODIMENTS:

The invention is described by way of example and with reference to exemplary arrangements, and particularly in relation to exemplary interactive systems. The invention is not limited to any specific detail or arrangement described herein unless explicitly stated or defined by the accompanying claims. One skilled in the art will appreciate how the described arrangements may be modified, as appropriate, with alternatives.

In the following description reference is made to a touch input. In practice the eerm touch input' is used to refer to any input at an interactive surface of an interactive system provided by any passive input device that allows interaction with programs, buttons and menus. A passive input device may be an input device with no technology housed in it. and that cannot communicate with the interactive system other than to provide a contact point. A passive input device may in1ude, out not oe limited:o, a body pare such as a finger, a stylus cr a pointer. In this corthext a passive input device is a device which cannot interact with the Interactive system other than by providing a contact point on the interactive surface.

A nassive device may also be referred to as an inactive device.

In general a touch input can be detected as a contact input, but cannot be uniquely identified and cannot be identified as being on the interactive surface or proximate the interactive surface.

In the following description reference is also made to a pen input. In practicer the tern pen input' is used to refer to any input at an interactive surface of an interact; -lye system provided by any input device that allows interaction with programs, buttons and menus. Such an active input device may he an input device having technology, such as printed circuitry and/or a battery, housed in it allowing the device to communicate with the interactive system to provide a. more natural interaction with the interactive system. A pen input device can provide additional features such as, but not limited to, detection of the active input device hovering above the interactive surface, pressure sensitive handwriting, and quick tool and functionality access through the inclusion of electrical switch buttons on the active input device. An input device can he any type of device, but typically may be provided by a device which reseffbles and is referred to as a pen device or pointing input. An input device may include but not he limited to, light pens, infrared pens, inductive pens and. capacitive pens, To the extent that such additional operations require an active link with the interactive system beyond simple detect ion of a contact point, a pen device can he considered to provide an active input and be an active input device In the art, pen devices are sometimes referred to as being passive or active devices in dependence on whether they S have internal, power sources for providing their interaction with the interactive system or not. For example, an active pen may he. provided with a battery. This definition is not to be confused with reference to a touch input or a pen input being associated with a passive input device or an active input device. An active input device may be passive' or active in terms of a power sour.cc. Exemolary arrangements may be advantageously implemented i.n conjunction with a pen input provided, by an active pen in order to provide an appropriate transmission which is detected by an appropriate interface of the interactive system. Arrangements as described may be implemented with the pen being provided by either a passive or an active pen, unless the specifics of an arrangementS require an active pen.

Where a pen provides an input in a touchonly system, it may he considered a stylus In general a pen input can be detected as a contact input, and can be at least one of; uniquely identified (identifying the pen amongst a plural ry of pens) ; determined as being on the interactive surface or proximate the interactive surface (such as indicating a hover or pen down state) ; or provide an additional input (such as a switch state) -Arrangements are described herein in the context of touch detection systems, and particularly interactive systems in which an input is detected based on a touch provided by that input. The invention is not limited to any specifics of a touch system unless specifically stated and may be implemented in any touch detection interactive system When a pen device providing a pen input is requ±red to provide a pen input it may he equipped with its own powe.r source, or it may be adapted to uti.lise the energy in another signal of the interact;ive system, such as the energy in an electromagnetic (EM) field1 such as an infra-red (IR) or radio frequency (RF) field1 provided. on an interactive surface for detecting contact points.

When a pen device providing a pen input is adapted to transmit, it may be adapted to transmit continually or only when certain conditions are met, f-or example when the pen contacts the interactive surface (which for example may be facilitated by a pressure switch in the pen nib) The invention is not limited to any orrangement of apen although different types of pen may allow a.dvar.t. ageous features of-the invention to be implemented.

Whilst the description of arrangements refers to

detection of a-wireless signal in order to detect the presence of a pen device, the arrangements may be applicable to any system in which an indication is provided as to whether a contact point is associated with a touch input or a pen input and thus whether a pen device providing pen inputs is present.

Preferably, the system is arranged to detect the presence of a pen device oni.y in contact with th.e touch surfaces and not for example to detect th.e presence of a pen distant from the surface, to avoid. spurious or mistaken detection, On this basis a pen device may only he detected as present when a pen-down' condition is detected. On this basis, a pen detector may preferably only be enabled when a contact point s detected, or the wireless d''ecti.on 01: a signal frnm a pen device may be arranged such that it can cn.iy be detected if the pen is at or near the surface.

However, the invention is not limited to enabling differentiated pen detection circuitry only when a contact point is detected, but the pen detection circuitry may continually look for a pen, and may not be enabled only responsive to a contact point.

The principle of the present invention is illustrated by the arrangement of FIG. 1(b). As illustrated, the arrangement of FIG. 1(a) is adapted to include an interface which provides for an interruption of the contact data processing. Thus the data from the contact surface is provided to an interface 11.

The output of the interface 11 is provided to a data processor 13, which may perform both touch data processing and pointing device data processing. The output of the processor 13 is connected to a computer 14, although in fact the computer 14 may implement the data processing of block 13.

An arrangement which provides for detection of a pen device for providing pen inputs in a touch contact detection system adapted to provide an interruption to determine whether an input is provided by a pen input or a touch input is now described. In this arrangement, for simplicity there is disclosed a technique for determining if a single detected contact is associated with a touch contact or a pen contact.

FIG. 2 illustrates schematically the touch contact system of FIG. 1(b) adapted to distinguish between pen inputs and touch inputs in an interrupt procedure, and an associated flow process is illustrated in FIG. 3.

With reference to nO. 2, there is provided an interface 16 between the interactive surface 10 and the computer 14. The interface 16 comprises a buffer 20, a delay block 22, a register 24, a pen detector 28, and a flag set.

block 26.

A contact point on the interactive surface is detected, and data associated with this contact point, termed DATA, is forwarded on line 3 from the interactive surface 10 to the interface 16. The detection of this contact point is illustrated by step 30 in FIG. 3.

The contact point may be provided by a touch, for example a finger or a stylus or a pen.

S The interf ace 16 receives the data stream from the interactive surface 10, which in practice may comprise receiving coordinate data from the touch surface when coordinate determination circuitry is provided with the surface. This coordinate data may be received on any electrical connection, for example, via a USE connection, but could also be received via a wireless communication network, such as Bluetooth. In the example it is assumed that the touch surface generally provides data associated with a contact point, which includes the coordinates of that contact point, but this is irrelevant to the present invention.

The data stream DATA is received by the buffer 20, and as denoted by step 29 is buffered. Also illustrated in FIG. 2 is a delay block positioned at the output of the buffer 20, and as denoted by step 31 the buffered data is also delayed. In practice, the buffer 20 may perform the delay function, and so an additional delay block 22 may not be required. The steps 29 and 31 of nO. 3 may therefore be implemented as a single buffering/delaying step, as illustrated by reference numeral 32.

The delay is provided to allow for the interrupt of normal contact point processing in the touch system, whilst it is determined whether the contact point is provided by a touch input or a contact input.

The delay associated with the buffering and/or delaying steps provided by blocks 20 and 22 results in a delayed version of the data stream DELAYED DATA being produced on line 5.

In a simple arrangement, in response to detection of a contact point, the interface 16 may search for a wireless signal. The wireless signal may be an RF signal, such as a Bluetooth signal. If a wireless signal is not identified within a certain time limit, for example milliseconds or preferably between 4Oms and 200ms and even more preferably between 6Oms and lOOms, it is assumed that the contact point is associated with a touch event. If a wireless signal is received within the time limit, it is assumed the contact point is associated with a pen event.

With further reference to nO. 2, the pen detector 28 may be enabled by receipt of contact point data, and may be connected to receive the data stream DATA (not shown) simply to identify the presence of data associated with a detected contact point. The pen detector 28 may alternatively be enabled by some control means, such as the computer 14, or may be permanently enabled to detect a wireless signal.

The pen detector 28 is adapted to detect whether a wireless signal is received, as denoted by step 33, following or in tandem with detection of a contact point. A pen providing a contact point is adapted to provide a wireless transmission for detection by the pen detector 28. The pen detector 28 is adapted to detect this wireless transmission.

In dependence on whether a wireless signal is received in combination with detection of a contact point, the pen detector 28 dictates whether the system operates in pen mode or touch mode.

In this arrangement, if a wireless signal is received the system operates in pen mode as denoted by step 37. If a wireless signal is not received the system operates in touch mode, as denoted by step 35. The pen detector 28 sets a signal on its output to indicate a pen (P) or a touch CT), to control the flag set block 26 to set the flag bits of the register 24 in accordance with the mode of operation.

If the pen detector 28 does not detect a wireless signal, then the pen detector 28 sets its output accordingly to the flag set block 26 indicating that no pen is present. This may simply comprise setting its output to 0' or 1' to indicate the system mode (pen or touch) which is followed by the flag set block 26. The setting at the output of the flag set block indicates a touch mode.

If the pen detector 28 does detect a wireless signal, then the pen detector 28 sets its output accordingly to the flag set block 26 indicating that a pen is present. Again this may simply comprise setting its output to 0' or 1'. The setting at the output of the flag set block indicates a pen mode.

On determination of the mode of operation, in step 42 the appropriate flag is set by the flag set block 26. In step 44, the flag set block then controls the register to append the appropriate bits to the current data which is held in the register 24.

As denoted by step 46, the appropriately appended data is then output by the register 24 to the computer 14 on line 7 as the data PEN/TOUCH DATA.

Some latency is associated with the passing of the data to the computer 14, because of the additional processing needed to determine whether the contact is provided by a touch or a pen. Data processing is not performed by the computer 14 until a determination of the input is made, and such processing has a latency determined by the delay of the buffer 20 and/or delay block 22.

The delay provided by the buffer 20 and/or delay block 22 is preferably sufficient to allow the pen detector 28 to 1.5 complete a determination of whether the contact input is a pen input or a touch input. The data stream may he delayed by rt frames where nl or 2 or 3, etc. Preferably the data stream may be delayed by one frame Le. frame delayed.

During the delay; the pen interface 16 determines whether the object on the surface is a pen. This may be done in a nurcber of ways and the above described technique represents an exemplary way of achieving this.

The data DELAYED DATA provided to the register 24:is the data for which the mode of operation is determined for the flag setting.

The received data provided on line 7 by the register 24 may then he adapted to append flag bits.

FIGS. 4(a) and 4(b) show a first example apparatus for providing pen detection functionality to a touch input detection system in accordance with the exemplary interface 16 of FIGS 2. It should be noted that this is an exemplary apparatus, and does not limit the scope of the invention.

In addition, in the following example implementations, specifics of touch detection systems are set out, hut these are only examples for illustratIng the invention.

FIG. 4(a) illustrates a view onto the display surface, and FIG, 4(b) illustrates a corresponding side view of the arrangement of FIG, 4(a).

With reference to FIGS. 4 (a) and 4(b) , reference numeral 10 generally illustrates the interactive surface of FIG, 2. It is assumed that the interactive surface has touch detection capabil. i.ty. The interactive surface may he of any construction known in the art such as electromagnetic, resistive or infrared.

In FIG, 4 (a) , the interactive surface 10 is a surface of an interactive whiteboard (IWS) provided with bezel technology for detecting contact inputs, and ordinarily associating such contact inputs with a touch input. The IWS of FIG. 4(a) is provided with a vertical IR emitter bezel array 70a, a horizontal In emitter bezel array 70b, a vertical In detector bezel array 70c, and a horizontal IR detector bezel array 70d.

The implementation of bezel technology to allow detection of a contact point on an interactive surface is well-known in the art and is not shown in detail in FIG. 4(a).

As also illustrated in nO. 4(a), the system is provided with a USS port. 54 for a touch detection system (not shown), although in a further embodiment this connection could be provided by wireless technology, such as Bluetooth. The implementation of a touch detection system to allow for detection of a contact point on a bezel system will be well-known to one skilled in the art and will not be described in detail in this embodiment. The use of a bezel system and bezel technology is merely exemplary.

In accordance with the illustrated exemplary arrangement, the system is additionally provided with an augmentation interface 52, which has aUSS input port 58 which is connected by a cable 56 to the USB port 54 of the touch sydtem. The augmentation interface 52 additionally is provided with a U8B port 60 for connection to a computer. The augmentation interface 52 provides the additional electronic circuitry needed to provide for the identification of pen in accordance with the foregoing described exemplary arrangement, and is connected to the existing board and touch detection circuitry.

Although in FIG. 4(a) a wired connection is illustrated between U8B port 54 and 1388 port 58, this is merely exemplary and the potts may be wireless ports providing a wireless connection. Similarly 1338 port 60 may be a wireless port.

To implement the detection of a pen 68, the augmentation interface 52 is preferably provided with an ZR transceiver 62 to provide for communication with the pen 58.

With reference to tO. 4(a) and nO 4(b), the augmentation interface 52 is preferably mounted with respect to the interactive display surface to allow an IR transceiver 62 to illuminate the interactive display surface with ZR. The IR illumination field 66 produced by the ZR transceiver 62 is additional to and separate from any ZR transmission/reception associated with the bezel technology for detecting touch inputs. This ZR illumination field 66 is additionally provided to allow, in accordance with this described embodiment, detection of a pen device. The location of the augmentation interface 52 may be chosen to allow the IR illumination field 66 to be optimised for the interactive surface. In the described example, the interface including the IR transmitters is located at the centre of the top edge of the interactive whiteboard, although a person skilled in the art will recognise that the interface including the IR transmitters could be located in other positions.

The field of view of the ZR transceiver 62 across the interactive surface is preferably limited to a region proximate to thesurface, so thata.

surface is not illuminated by the IR transceiver. This may be achieved by the design or orientation of the ZR transceiver, which is outside the scope of the present invention, or by the provision of a plate or housing 64 (as shown in nO. 4(b)) in front of the ZR transceiver 62 which limits its optical field.

As illustrated in the example of nO. 4(b), the Ilk transceiver 62 provides a collimated ZR illumination field 66, having a restricted field of view angle. The collimated ZR illumination field 66 will typically extend at least 1cm from the IWB surface and ideally less than 10cm from the IWE surface. The anqie of the field of view will be implementation dependent. The restriction of the I?. illumination field in this way supports an exemplary implementation of the foregoing arrangements.

S As illustrated in FIG. 4(b), pen SBa indicates a pen located outside the IR illumination field 65, signifying a touch mode of operation, as the pen is not detected. With the pen inside the IR illumination field 66, as indicated by EBb.

a pen mode of oneration is determined as the pen is detected by the augmentation interface 52, This is because the pen 68 is preferably adapted to be enabled or activated by the energy of the IR illumination field 65, so that the pen 68 is unable to transmit unless it is located within the

1W, illumination field 65,

When a wireless connection Is established between a pen 68 and the augmentation interface 52, establishing a pen tointerface connection, the system switches to pen'mode. When the pen moves away from the surface, the IR connection is broken and the system reverts back to touch mode.

In an embodiment, the presence of the pen may only be detected if the pen is depressed on the display surface, closing a switch provided at the nib.

It should be noted that; this arrangement is not limited to any specific pen configuration. The pen 58 may he an active pen which constantly transmits a wireless signal. The pen 68 preferably may transmit a wireless signal only when it is energised to do so by reception of IR energy which is received within the IT liumination field 66. The pen 68 may more preferably transmit a wireless signal only Shen it is energised to do so by reception of IR energy within the 1W illumination field 66, and further only then at some cert.ain time interval, for example by pulse transmissions, or in reply to a request from a pen detect block with...n the augmentation interface 52, which transmits a request when data is received to indicate a contact point has been detected.

The pen 68 may more preferably be adapted to transmit only in response to a request, and the pen may be adapted only S to detect a request when the pen is located within the IR illumination field 66. Thus the pen may start transmitting as soon as it is energised by the IR illumination field 66, or only start transmitting when it is energised by the IR illumination field 66 and receives an interrogation signal from the augmentation interface 52 or when a pen tip switch is activated by contact with the surface. The system may also be designed so that the native IR flux from the scanning bezel touch system can be detected by the pen and supplement or replace the interrogation signal provided by the IR transmitter of the interface 52 as a trigger for the pen to signal its presence.

For power efficiency, the pen 68 may detect a diffused or coherent IR illumination field 66 near to the surface provided by the Itt transceiver 62 of the augmentation interface 52, and then signal its presence to a pen detector located in the augmentation interface 52 using the energy provided by the Itt illumination field 66. The pen may do so asynchronously, or the pen may wait for a synchronisation beacon emitted by the augmentation interface 52 before transmitting (i.e. respond to an interrogation signal). In such an arrangement, the pen 68 preferably only wirelessly signals its presence to the augmentation interface 52 when a touch contact has been detected at the interactive surface 10, rather than the pen continually signalling its presence.

The Itt connection between the pen 68 and the augmentation interface 52 may also act as a communications charnel for flagging the tip and side switch activation of the pen. The pen may simply transmit a code to the pen detect block of the augmentation interface 52 which identifies the tip or switch state.

The IR connection between the pen 68 and the pen detector oi the augmentation interface 52 may also act as a pen identification for systems with more than one pen. Without such information the system will not he able to identify the specific individual pen amongst multiple pens. The pen may simply transmit a code to the pen detect block which identifies the pen. This additional pen identity information may be provided in any of the arrangements.

tn examples the pen identity i.s associated with a transmission frequency, and thus multiple pens can be identified in a system which allows discrimination detection between signals of different frequencies.

It may be necessary to use a different wavelength of IR for the bac.kchannel communication system with the pen (where IR is used for the backchannel) * to avoid interfering with the touch sensing system of the bezel technology. The imp].ementation of the IR, including the relevant frequency of the IR, is an implementation detail, in a more preferable etrbodiment the hackchannel is RF from the pen to the controller in order to avoid potential interference from the IP. of the bezel technology.

Adaptations will provide for advantageous or preferable techniques for establishing the wireless connection between the pen and the pen detect block.

In accordance with the arrangements as described above; there is provided the ability to distinguish between a touch and. a pen providing a contact point is provided by ii. terruotina the normal touch process to determine whether there is a touch Input or a pen input. However tuis technique as described does not provide for aientifyng mu.Ltipie contact 2! points as being associated with one of multiple pens unless the identity of a pen is represented by its signal frequency.

With reference to FIG. 5, a second example apparatus is illustrated in which a plurality of co-located ZR transceivers (three in the example illustrated) 302a, 302b, 302c, located in the augmentation interface 52 which is placed in the centre of either an upper or lower horizontal edge of an interactive whiteboard (IWE).

The three transceivers 302a, 302b, 302c each have a respective emitter/transmitter as well as a respective detector associated therewith, The emitters of the transceivers are angled such that they direct radiation across the surface so that a photodiode detector located within a tracked pen placed on the surface will receive maximum incident IR flux at different bearings from the three emitters. Thus with each emitter of the three transceivers emitting 114 signals, a photodetector of a pen placed on the surface will receive an ZR signal from up to three emitters.

Reference numeral 404 denotes an exemplary position on the surface at which a contact point may be provided by a pen.

In the example shown, using a line parallel to the top horizontal edge of the IWE as a t0s reference, the peak ZR signal from the first emitter will lie along a line at Q° from the top horizontal edge of the niB denoted by reference numeral 402a, the peak IR signal from the second emitter will be along a line at an angle of Q0 from the reference 402a (straight down), denoted by reference numeral 402b. The peak ZR signal from the third emitter at 030 from the peak ZR signal of the second emitter (denoted by reference number 402b) denoted by reference numeral 402c.

The line 402c is additionally at an angle Q° from the reference provided by the top edge of the IWS.

In this embodiment, angles Q01)0 Q30 and 040 range between 0° and 600, and more preferably 60°, 300, 30° and 60° respectively. The beam width of the transmitters means that the transmitted signals from the three emitters will overlap ensuring there are no areas on the surface that do not receive a minimum level of lit signal required for the system to workS In accordance with the described embodiment, the three emitters of the transceivers 302a, 302b, 302c may be modulated by three different excitation frequencies, f1, 4 and f3. The emitters of the transceivers are preferably controlled to transmit for a short duration when instructed to do so by a controller associated with a pen interrogator. The purpose of the pen interrogator is to determine whether a pen is close to the surface. The emitters provide a collimated zone of lit across the surface, such as the zone 66 of PIG. 4, requiring pens to be within this zone to be able to detect an interrogation signal. This zone will typically extend at least 1cm from the flJB surface and ideally less than 10cm from the IWB surface, In accordance with this arrangement a pen is adapted to include a photodiode detector for detecting the lit transmissions from the emitter of one or more of the transceivers 302a, 302b, 302c. The pen is further adapted to include circuitry to process the received signal as discussed below.

An example implementation of circuitry within a pen in accordance with this arrangement is shown in FIG, 6. The pen includes a photodetector 410, an amplifier 412, multiple filters 414a to 414c, multiple demodulators 416a to 416c, multiple analogue-to-digital converters 4l8a to 418c, a coder 420, and a transmitter 422. 2.3

An adaptation of the augmentation. inter face 52 in accordance with this arrangement is illustrated in FIG, 7.

FIGG 8 and FIG. 9 illustrate the methods performed in the pen of FIG. 6 and the interface of FIG. 7 in accordance with this example. The example is now further explained with reference to FIG, 6 to FIG, 9.

The augmentation interface 52 includes emitters 440a, 440b, 440c; modulators 442a, 44Th, 442c; an interrogator 430; a receiver 444; a control block 48; a positioned determinaon blocK 446; a compardor 448; a flag set block 449; a register 447; a comparator 445; a look-up table 443; a buffer 20; and a delay block 22.

The interrogator 430 is adapted to transmit an interrogation signal. The Interrogator 430 may be triggered as described above, for example in response to a signal from the buffer 20 as denoted by dashed line 432 or in response to a signal from the computer 14 as denoted by dashed line 434.

in the event that a pen is present. the woken up' by the interrogation signal. in general, as denoted in step 450, a contact is detected, and an interrogation signal is transmitted in step 452.

As denoted by stan 470 of FIG. 9, resoonsive to detection of the interrogation signal a pen wakes up' and in step 472 its circuitry is enabled, The interrogator block 430 additionally provides a control signal on line 436 to an emitter controller 438.

Responsive to the control signal on line 436, which indicates that the ixiterrogator block 430 has transmitted tF.e interrogation signal, the control block 438 seleotively enables the emitters 440a, 440b, 440c as denoted by step 454.

Each of the emitters 440a, 440b, 440c is associated with a respect qe modulation signal. at a frequency f, £2, provided by modulators 442a, 442b, 442c. Thus each emitter emits a signal with a respective modulation.

When a woken up? pen is within a detection zone, the photodiode detector 410 within the pen detects an incident l.R signal from one or more of the plurality of emitters of transceivers 302a, 302b, 202c as denoted by ster 474, The signal will be a composite of the multiple modulation frequencies associated with the different emitters.

After amplification in an amplifier 412 as denoted by step 476, the signals pass into separate band pass filters 412a, ll2b, 412c (equal to the number of: emitters) for filtering a.s denoted by steps 478. They are then demodulated by respective demodulatos 41a, 414h, 414c, in step 480 to provide a 190 voltage proportional to the incident IR signal on each of a plurality of channels. Tr.te number of channels corresponds to the number of emitters.

The analogue to digital (A-fl) converter in each channel? 418a, 418b, 418c, typically within a microprocessor, then measures the plurality of DC voltages and digitises the signals, as denoted by step 482, This information is then output to the coding block 420 and used by the codin block 420 to code a.backchannel transmission as denoted by step 484.

The output of the coding block is providing to a transmitter 422 for transmission in step 486.

The transmission from the pen could be usinc an IR emitter in the pen as the transmitter 422, transmitting coded information to an IF. detector, preferably co-located with the interroqator controller. The pen transmitter 422 may typically he thstructed by a pen microcontroller to transmit after the pen ha.s successfully received an interrogation signal.

Alternatively, the hutckchannel could use an RF link? for example Eluetooth Low Energy' to relay the pen data packet.

with the transmitter 422 being suitably adapted, Regardless of the backchannel physical layer? the pen data packet will typically consist of a pen identifier data, amplItude data for the received IR interrogator signal, and data to indicate the status of pen flag buttons (tip switch and barrel. switch) The receive block 444 of the interface 16 receives the wireless signal transmitted by the pen. This wireless signal is provided to a unit 446 which determines an aporoximate or coarse location of the pen based on the received signal.

Alternatively the received signal may include the approximate location.

The amplitude of the signal. received is different in each detector 416a1 41Gb. 416c for different pen bearin2s. and different pen distances from the detectors. The three vectors of tne signals recerved n tne respective detectors allow a coarse. oearmng to be cai.cui.ated to approximately locate tne position of the pen on the surface generating the wireless signal..

FIG 10 illustrates diagrammatically the amplitude of the signals received in a pen by each of the detectors 416a, 41Gb, 416c, from which it can be determined an approximate location the pen. in general the signal received in each detector can be used to provide a coarse approximation of locationS A principle of operation in accordance with an example arrangement is now further described. It is assumed that a pen may be positioned on the interactive surface providing contact points at locations 307a, 307b, 307c, and i 7d respectively.

Reference numeral 380 of FIG 10 illustrates the amplitude of the signals received by the IR detectors with the pen in position 30Th. The decoder 416 receives a signal having an amplitude as denoted by reference numeral 3B6 the decoder 416 receives signal having an amplitude as denoted by reference numeral 388, and the decoder 416 receives a signal having an amplitude as denoted by reference numeral 390.

Reference numeral 382 of PIG. 10 illustrates the amplitude of the signal received by the detector of a pen 307b. The decoder 416a receives a signal having a decoder 41Gb receive a signal having an amplitude as denoted by reference numeral 394, and the decoder 416c receives a signal having an amplitude as denoted by reference numeral 396.

Reference numeral 384 of FIG. 10 illustrates the amplitude of the signals received by. the detectors of a pen in position 307c. The decoder 416a receives a signal having an amplitude as denoted by reference numeral 393, the decoder 416b receives a signal having an amplitude as denoted by reference numeral 395, and the decoder 416c receives a signal having an amplitude as denoted by reference numeral 397.

Reference numeral 381 of FIG. 10 illustrates the amplitude of the signals received by the detectors of a pen in position 307d. The decoder 416a receives a signal having an amplitude as denoted by reference numeral 387, the decoder 41Gb receives a signal having an amplitude as denoted by reference numeral 389, and the decoder 416 receives a signal having an amplitude as denoted by reference numeral 391.

Thus there is described above a technique for the pen to coarsely calculate its location.

In a step 456 the interf ace 16 determihes if a response is received in the receiver 444 responsive to the transmitted signals from the emitters 410a, 41Mb, 410c.

If no wireless signal is received, then the system is determined to be in touch mode as indicated by step 457.

If a wireless signal is received, then as denoted by step 458 a determination is made by the block 446 as to the approximate location of the pen, or the approximate location determined by the pen (for example using the technique of FIG. 10) is determined. In step 460 this coarse location is compared with an accurate location of the contactS.in block If, as denoted by step 462, it is determined that the two locations do not match, then the mode is set as touch mode in step 457.

If in step 452 it is determined that the two locations do match, then in step 464 the mode is set as pen mode. in view of the approximate or coarse nature of one of these values, the match may be successful if the positions are within a certain distance of each other.

After the mode is set in steps 457 or 464, the process may proceed to steps 42, 44, 46 as before.

The position determination block 446 provided in the interface 16 receives the coarse location of the pen, or may use the received amplitude data representing the strength of the signal incident at the pen to calculate a coarse hearing for the pen. This may be used to remove ambiguity when a number of devices (pen or touch) are presented. simultaneously to the IWB surface and within the interrogator detection zone as described above.

Once a pen is being accurately tracked by ti-ic touch system, a more accurate bearing can be calculated and this can be comoared with the coarse bearing provided by the IR interrogator system, A calibration correction table can be built up, as the pen is moved over the surface, and stored in nor. volatiie memory. With prolonged use the accuracy of the coarse location system steadily improves as the ay*<tern learns' from the accurate touch coordinate, hearing calculation.

The technique described above relates to determination of whether an initial contact point is a pen or a touch, and relating a pen input to a contact by location. As referred to in the preceding paragraph, once a contact is determined as a pen input, it can be tracked without having to compare its location. The values provided from the receiver 444 are compared directly in comparator 445 with values of existing contact points stored in a look-up table (LUT), to identify the pen with which the contact is associated. A value can be associated with a particular tracked contact based on its approximation to the values in the LUT.

An arrangement is now described which is a modification of the foregoing arrangement.

In this arrangement, instead of the multiple frequency drive to modulate the plurality of interrogator emitters, the emitters are excited with one frequency and then sequenced in time. The pen may then sample at three different time intervals denoted ti, t2, t3 to obtain three DC levels proportional to the incident energy f or the three different sources.

In this arrangement a plurality of co-located ITt transceivers are again utilised in accordance with the arrangement of FIG. 5.

As discussed above, an interrogation signal may be transmitted to wake up' a pen. However the transmitted signals from the transceivers may also be used as a wake up' signal.

In this arrangement, the emitters do not necessarily transmit in tandem, but instead may transmit in turn in accordance with their time offsets.

To ensure the pen sees the maximum energy to wake it up, the augmentation interface 52 may first activate the emitter which is closest to the detected position provided by the coordinates which information may be provided by the interface signal on line 3 or line 5, followed by the other emitters after a predetermined time associated with their offsets.

The pen on waking, samples for time ti, waits a predetermined time, samples for t2, etc. The sampling process S is used to determine the amplitude of the incident signal arriving during the period ti, t2 and t3.

This simplifies the pen/low power requirements, as it would only require one band pass filter channel.

The tl to t3 duration is dependent upon the frequency and may be in the order of miliseconds.

An adaptation of the pen in accordance with this arrangement is illustrated in nO. 11. The pen includes a receiver 650, an ampiifier 652, a bandpass filter 654, a demodulator 656, an ahalogue-to-digital converter 658, a coder or coding unit 660, and a transmitter 662. It will be apparent that the functional blocks of the pen as illustrated in 110. 11 are consistent with the functional blocks of the pen as illustrated in FIG. 6 above, except in this arrangement there is no requirement to provide multiple channels. A controller denoted by reference numeral 664 within the pen controls the decoding circuitry to decode the received signals for each of the time offsets. The controller 664 may be adapted to process the received signals in accordance with time offsets for a known time offset, based on initial timing mark provided by the first signal from the first emitter.

With reference to PIG. 12 there is illustrated an adaptation to the augmentation interf ace 52 in order to implement this arrangement. This adaptation is shown as an adaptation of the augmentation interface 52 of PIG. 7.

As shown in FIG. 12 the frequency modulation blocks 442a, 442b, 442c of PIG. 7 are replaced by a single frequency modulation block 602 which provides a signal to each of the three emitters 440a, 440b, 440c. Each of the emitters 440a, 440b, 440c, apply a different timing to the signal produced by the signal modulator, but generates signals with the same modulation.

In the arrangement shown in FIGS 12 there is not shown an explicit block for generating an interroQation signal, and in thi.s arrangement it is assumed that the interrocation is province by controlflng one of the emtters 440a, 44Db, and *4Cc, In accordance wnh tins exempiaiy arrangement, the control block 438 is adapted to receive the output of the buffer 20/delay 22, representing the data of the contact point detected. A.s discussed hereinabove, that data will include coordinate information representing the precise location of the contact detected. The control block 438 utilises this coordination information to enable the one of the emitter blocks 440a, 44Db, 44Cc which is determined to he closest to the specific location, the enablement of that emitter block and the generation of its transmit signal acting as a wake up or interrogation signal for the pen. As rioted above, the choice as the first emitter being the emitter closest to the detected contact point maximises the likelihood of the transmitted signal waking up the pen.

As denoted hereinabove, it is unimportant which of the emitters 440a, 44Db, 44Cc, is first enabled, or the sequence of enablement of the emitters. This is because the control block 438 additionally provides a control signal to a reordering block 604, which has knowledge of which. emitter a received wireless signal is received from, such that on receipt of all of the wireless signals the reordering block 604 can reorder the receive signals to he associated, if necessary, the respective time offsets in sequence.

Other than as described, the circuitry of FiG, 12 operates in accordance with the circuitry of FIG 7. The control block 438 additionally receives the signal on line 434 from the computer 14, It wiil also be understood that the circuitry of FIGs 11 and 12 operates generally in accordance with the method processes of flGs. 8 and 9. These Figures are modified as appropriate, with the arrangement of PIG. 12 in particular not requiring the transmission of a dedicated interrogation signal, and requiring the transmission of the signals from the emitters 440a, 440b, 440c to be associated with timing controls provided by the control block 438.

There has beers set out above various exemplary arrangements for implementation of techniques for detecting whether a contact point provided in a touch contact system is provided by a pen. Various aspects of each described arrangement may be implemented in other described arrangements. Therefore aspects of each described arrangement may be mixed.

It will be understood from the foregoing description that in exemplary implementations there is a requirement to carry out an initial determination when a contact point is first detected, and thereafter to track that contact point (including the movement of that contact point) until it is no longer provided. The technique for determining the initial contact point, and the technique for monitoring a determined contact point, may be different. The arrangements describe techniques in which contact points provided by multiple different pens may be detected and tracked, without having to determine a frequency of operation associated with a particular pen.

In a preferred implementation, the augmentation interface 52 (comprising a receiver block) for implementing a preferred whiteboard, although a person skilled in the art will understand that the augmentation interface 52 may be located in any suitable position.

The pen locating signal can be modulated to the interface instead of having to have an independent data backchannel.

In exemplary implementations, the system is adapted such that the buffer, which generally is a data interceptor unit, activates a timer when a contact point is detected. If a backchannel signal from the P"v its transmission having been triggered by the pen tip switch being activated (e.g. preferably signalled over a Bluetooth RP link, is detected within a predetermined time period t of the activation of the timer, the system, switches to pen' mode. As soon as the pen is removed from the surface beyond the touch detection proximity, the system returns to standby mode awaiting a new contact event. If a contact event occurs from a touch' event, the data interceptor unit (buffer) waits for the predetermined time t to see if a pen backchannel signal is received, before allowing the data to exit the buffer as touch' data in the absence of such a bac]cchannel signal. Preferably, in order to achieve good performance and negligible increased latency in touch recognition, t is measured in milliseconds and preferably, is less than 200ms, and even more preferably less than lOOms.

The above described arrangements illustrate example arrangements of the invention. Details of the arrangements as described in relation to any particular exemplary arrangement may be combined with details of another exemplary arrangement.

In all arrangements, the system may follow an exemplary logic process, in which the system is placed in touch mode or pen mode in dependence on the determination of the type of the first contact detected.

In the event that no data is received from the interactive surfacer the augmentation interface 52 may be in a standby mode of operation, and not operational.

When an object is detected, a data stream may be generated by the interactive surface to the augmentation interface:52, and the augmentation interface 52 leaves the standby mode. The augmentation interface 52 then executes an interrupt process to look for a pen.

It can be noted that a transmission from a pen on the backchannel may be initiated in response to an interrogation signal. However it is not essential to provide an interrogation signal. A pen may, for example, transmit a backchannel signal continuously, or may be adapted to transmit on the backchannel responsive to a pressure switch on its nib being activated responsive to the pen being brought into contact with the display surface.

If no pen is detected, the data is assumed to be associated with a touch, and the system is locked into touch mode until the tracking of the object is lost. If a pen is introduced to the surface while in touch mode, the contact provided by the pen is treated as a touch input. This may prove useful for dual-handed size gestures without the user having to swap from pen to finger in their pen holding hand.

If a finger track is lost, or where multiple finger contacts are detected the last finger track is lost, then the data stream from the interactive surface halts, and the augmentation interface 52 returns to standby mode.

If a pen enters the detection zone, for example the IR bezel detection zone, then a data stream is received by the augmentation interface 52 and the interrogator (where provided) is enabled. Where an interrogator is enabled, the pen responds to the interrogation signal, which response may include a pen identifier, and flag status indicating a button status of the pen. Once a response is received, the interrogator can be disabled. The system then enters pen mode. When a button changes state, the state information is passed through to the computer.

Additional finger contacts may occur while in pen mode, and in an embodiment are determined as an invalid contact points for pen mode, and ignored until/unless the system leaves pen moce and enters touch mode.

in the example given it is assumed that the system operates in either pen mode or touch mode; but in variations the system may operate in both pen and touch node, When in pen mode, in one arrangement the pen must be moved to beyond the field of the interrogator before the system can exit pen mode and revert to touch mode. However in other arramgements, for example where a nib pressure switch is used to excite a backchannel single, the system can revert to touch mode as soon as the pen is removed from the display surface as the nib pressure switch is switched off.

The present invention has keen. described by way of refer.erice to particular examp].es and preferable aspects of: those examples. One skilled in the art wiLl. appreciate that the invention and those examples are not limited to any details given, unless as defined by the appended claims, Various details may be optionally applied in different examples, and various details may he applied alone or in combination to different examples

Claims

Claims 1. An interface for a contact detection apparatus for use with an interactive surface, wherein the interface is adapted to be responsive to the detection of a contact point on said interactive surface, the interface is adapted to determine whether the contact point is associated with a touch event and/or a pen event; and the interface is adapted to forward the data associated with the contact point to a processor for processing following said determination.
2. The interface of claim 1 wherein the contact detection apparatus utilises a communication back-channel, wherein the apparatus is adapted to determine the contact point as a *en event and/or a touch event using the back-char.ne.l.
3. The interface of c1.a.im I. or claim 2 wherein the interface includes pen detection circuitry for detecting a pen.
4, The interface of claim 3 wherein the pen detection circuicry includes wireless detection circuitry for detecting a wireless signal from a pen.
5. The interface of claim 4 wherein the pen detection circuitry includes circuitry for wirelessly transmitting an interrogation signal responsive to detection of a contact point, wherein, the wireless detection is enabled to detect a wireless signal responsive to the pen interrogation signalS
6. A method in a contact detection system for detecting a contacL point on an interactive surfacer the method including determining, responsive to detection of a contact point, whether the contact point is provided by a pen input, and further processing the data in accordance with that determination..
7. The method of-claim 6 further comprising suspending processina of the data as touch data during sa d determinaton..
8. The method of claim 6 or claim 7 further comprising processing the data as touch data if it is determined that the contact point is not provided by a pen input.
9. The method of claim 8 wherein the data is adapted to indicate whether it is touch data.
10. The method of claim 8 or claim S wherein the data received from the contact point is appended with a flag indicating that the data is touch data.
11. The method of claim 6 or claim 7 further comprising processing the data as pen data if it is determined that the contact point is provided by a pen input 12, The method of claim 11 wherein the data is adapted to indicate it is pen data.13. The method of claim 11 or claim 12 wherein the data received from the contact point is appended with a flag indicating that the data is pen data.14. The method of any one of claims 6 to 13 further comprising detecting a wireless signal from a pen.15. The method of claim 14 further comprising wirelessly transmitting an interrogation signal. responsive to detection of a contact point, and enabling the wireless detection to detect a wireless sicmal responsive to the pen interrogation signal - 16. A contact detection apparatus, comprising: an interactive surface arranged to detect a contact point thereon; an interface responsive to detection of a contact point, and for determining whether the contact point is associated with a touch event or a pen event; and a processor for processing the data associated with the contact point following said determination.17. The contact detection apparatus of claim 16 cottçrising a communication back-channel, wherein the apparatus is adapted to determine the contact point as a pen event or a touch event using the back-channel.18. The contact detection apparatus of claim 16 or claim 17 wherein the processor is adapted to process the data as touch data if it is determined that the contact point is associated with a touch event.19. The contact detection apparatus of any one of claims 16 to 18 wherein the processor is adapted to process the data as pen data if it is determined that the contact point is associated with a pen event.20. The contact detection apparatus of any one of claims 16 to 19 wherein the interface includes pen detection circuitry for detecting a pen.21. The contact detection apparatus of claim 20 wherein the pen detection circuitry includes a wireless detection circuitry for detecting a wireless signal from a pen.22. The contact detection apparatus of claim 21 wherein the pen detection vcircuitry includes circuitry for wirelessly transmitting an interrogation signal responsive to detection of a contact point, wherein the wireless detection is enabled to detect a wireless signal responsive to the pen interrogation signal.23. Contact detection apparatus substantially as described or as shown in any one of the Figures.24. A method substantially as described or as shown in any one of the Figures.