Abstract: The present invention relates to a method and system for determining an optical property of a pointer used in an interactive touch system. The interactive device having a touch area; a plurality of emitters on the periphery of the touch area; the emitters emitting an intensity of light into the touch area; a plurality of pointers having a distinct optical property responsive to the light; at least one detector having a field of view of the touch area. The processing structure, in communication with the emitters and the at least one detector, executes instructions from a memory to: transmit an emitter signal to at least one of the emitters initiating emission of light at the first frequency; receive at least one detector signal from the at least one detector; and determine the distinct optical property from the at least one detector signal.

Abstract: The present invention relates to a method and system for determining an optical property of a pointer used in an interactive touch system. The interactive device having a touch area; a plurality of emitters on the periphery of the touch area; the emitters emitting an intensity of light into the touch area; a plurality of pointers having a distinct optical property responsive to the light; at least one detector having a field of view of the touch area. The processing structure, in communication with the emitters and the at least one detector, executes instructions from a memory to: transmit an emitter signal to at least one of the emitters initiating emission of light at the first frequency; receive at least one detector signal from the at least one detector; and determine the distinct optical property from the at least one detector signal.

Abstract: An interactive input system comprises at least one imaging device configured to capture image frames of a region of interest comprising a background and at least one background feature. Processing structure is configured to compare the image frames to determine if the location of the at least one background feature has changed signifying system displacement.

Abstract: An image capture method comprises generating a synchronization signal based on modulated illumination; and synchronizing image frame capture of at least one image sensor using the synchronization signal with the illumination timing of an active pointer within a region of interest in the field of view of the at least one image sensor.

Abstract: An interactive input system comprises at least two imaging assemblies capturing image frames of a region of interest from different vantages, each imaging assembly comprising an image sensor and signal processing circuitry implemented on an application specific integrated circuit (ASIC), image data acquired by the image sensor being pre-processed by the signal processing circuitry; and processing structure processing pre-processed image data output by the imaging assemblies to determine the location of at least one pointer within the region of interest.

Abstract: A method for grouping graphical objects, comprises presenting graphical objects on a display surface and in the event that the graphical objects at least partially overlap, grouping the graphical objects.

Abstract: An interactive input system comprises at least one imaging device configured to capture image frames of a region of interest comprising a background and at least one background feature. Processing structure is configured to compare the image frames to determine if the location of the at least one background feature has changed signifying system displacement.

Abstract: An image capture method comprises generating a synchronization signal based on modulated illumination; and synchronizing image frame capture of at least one image sensor using the synchronization signal with the illumination timing of an active pointer within a region of interest in the field of view of the at least one image sensor.

Abstract: An interactive input system comprises at least two imaging assemblies capturing image frames of a region of interest from different vantages and processing structure processing image frames captured by the imaging assemblies to determine the location of a pointer within the region of interest, wherein each imaging assembly comprises an image sensor and integrated signal processing circuitry.

Abstract: A participant response system (50) comprises at least one host computer (52) and a plurality of remote units (62) communicating wirelessly with the host computer using a radio packet protocol. During communications between the host computer (52) and the remote units (62), data messages from the host computer (52) to be processed by substantially all of the remote units (62) are transmitted to the remote units in general broadcast frames (BF) destined for all of the remote units and data messages from the host computer (52) to be processed by selected ones of the remote units (62) are transmitted to the selected ones of the remote units in message frames destined for those selected ones of the remote units (62) outside of the period of each general broadcast frame. Data messages from remote units (62) destined for the host computer (52) are also transmitted in message frames beyond the period of each general broadcast frame.