Correction of Touch Screen Camera Geometry

A method comprising:

• forming one or more calibration patterns on a touch screen by producing corresponding visible light patterns on the touch screen;
• capturing the one or more calibration patterns by a group of infrared cameras configured to take images of objects contacting the touch screen;
• and automatically:
• producing an image of the touch screen by taking with each one of the group of infrared cameras a set of plural images of the calibration patterns or a portion thereof when a sheet of white or reflective material is arbitrarily placed on the touch screen to emphasize the one or more calibration patterns produced by the touch screen to the group of infrared cameras;
• determining geometric distortions of the images with relation to the formed one or more calibration patterns;
• and
• calculating calibration parameters configured to enable computational compensation of the determined geometric distortions;
• the method further comprising storing the calibration parameters;
• wherein the forming of the one or more calibration patterns and the producing of the image of the touch screen collectively comprises at least one of:
• forming an infrared light component of a corresponding shape of the one or more calibration patterns;
• and
• taking the images of the calibration patterns on visible light wavelengths.

An apparatus comprising:

• a touch screen configured to display images and comprising plurality of infrared cameras configured to take images of objects contacting the touch screen;
• a display configured to form on the touch screen at least one calibration pattern that is visible to the cameras;
• a processor configured to automatically:
• cause producing an image of the touch screen by taking with each one of the plurality of infrared cameras a set of plural images of the calibration pattern or one or more portions thereof when a sheet of white or reflective material is arbitrarily placed on the touch screen to emphasize the one or more calibration patterns produced by the touch screen to the group of infrared cameras;
• determine geometric distortions of the images with relation to the formed calibration pattern;
• and
• calculate calibration parameters configured to enable computational compensation of the determined geometric distortions;
• the processor being further configured to store the calibration parameters;
• wherein the apparatus is further characterized by at least one of:
• the display being capable of forming an infrared light component associated with the calibration pattern;
• the plurality of infrared cameras being further capable of capturing visible light pattern;
• and
• the display being capable of forming an infrared light component associated with the calibration pattern and the plurality of infrared cameras being capable of capturing visible light pattern.

A computer readable memory medium comprising computer executable program code which when executed by a processor causes an apparatus to perform:

• forming one or more calibration patterns on a touch screen by producing corresponding visible light patterns on the touch screen;
• capturing the one or more calibration patterns by a group of infrared cameras configured to take images of objects contacting the touch screen;
• and automatically:
• producing an image of the touch screen by taking with each one of the group of infrared cameras a set of plural images of the calibration patterns or a portion thereof when a sheet of white or reflective material is arbitrarily placed on the touch screen to emphasize the one or more calibration patterns produced by the touch screen to the group of infrared cameras;
• determining geometric distortions of the images with relation to the formed one or more calibration patterns;
• and
• calculating calibration parameters configured to enable computational compensation of the determined geometric distortions;
• the computer readable memory medium comprising computer executable program code which when executed by a processor causes an apparatus to further store the calibration parameters;
• wherein the forming of the one or more calibration patterns and the producing of the image of the touch screen collectively comprises at least one of:
• forming an infrared light component of a corresponding shape of the one or more calibration patterns;
• and
• taking the images of the calibration patterns also on visible light wavelengths.