Detecting Ambient Light Levels in a Vision System

Abstract

The detection of ambient light on an optical touch-sensitive device is disclosed. For example, one disclosed embodiment comprises capturing an image of at least a portion of a display screen with a camera located within the display device, and determined if ambient light in the image is at an acceptable level for display screen operation. Then, a visual representation is displayed representing whether the ambient light level is acceptable for display screen operation.

1 . A method of detecting ambient light in an optical touch-sensitive display device, the optical touch-sensitive display device comprising a display screen, an illuminant and an image sensor, the method comprising:
 capturing an image of at least a portion of the display screen with the image sensor;   determining whether an ambient light level in the image is at an acceptable level for optical touch-detection system operation; and   displaying a visual representation of whether the ambient light level is acceptable for display screen optical touch-detection system operation.   
     
     
         2 . The method of  claim 1 , wherein the visual representation of whether the ambient light level is acceptable for optical touch-detection system operation is updated in real-time. 
     
     
         3 . The method of  claim 1 , wherein the visual representation comprises a map of relative ambient light intensities across the display screen. 
     
     
         4 . The method of  claim 3 , wherein the visual representation is color-coded, and wherein a color in the visual representation represents a relative ambient light level. 
     
     
         5 . The method of  claim 1 , further comprising providing a visual indicator of a direction to move the display device to correct for an unacceptable ambient light level. 
     
     
         6 . The method of  claim 5 , wherein a direction to move the display device is determined by determining a plurality of gradients of ambient intensities on the display screen, and generating a directional vector from the gradients. 
     
     
         7 - 15 . (canceled) 
     
     
         16 . An optical touch-sensitive device, comprising:
 a display screen having a touch surface and a backside;   an image sensor configured to capture an image of the backside of the screen;   an illuminant configured to illuminate the backside of the screen; and   a controller configured to:
 operate the illuminant to illuminate the backside of the display screen; 
 operate the image sensor to capture an image of the display screen; 
 determine an ambient light level in the image; and 
 display a visual representation of whether the ambient light level is acceptable for optical touch-detection system operation. 
   
     
     
         17 . The device of  claim 16 , wherein the visual representation comprises a map of ambient light intensity levels on the display screen. 
     
     
         18 . The device of  claim 16 , wherein the controller is configured to update the visual representation in real-time. 
     
     
         19 . The device of  claim 16 , wherein the visual representation comprises an indicator of a direction to move the display device to reduce the ambient light level. 
     
     
         20 . The device of  claim 19 , wherein the controller is configured to determine the direction to move the display device by determining a plurality of gradients of ambient intensities on the display screen, and determining a directional vector from the gradients.