Coherent illumination for touch point identification

A method comprising:

• receiving a series of first images that includes a monitored object illuminated by a coherent light source, wherein each of the first images includes a time of capture;
• comparing values of corresponding pixels of two images of the series of first images to identify touch pixels, wherein each touch pixel changes in value between the two images, and the change is greater than a threshold;
• and
• upon identifying a spatial pattern of touch pixels that corresponds to a pointing end of a pointing object, providing at least one of:
• i) a touch location of the pointing end relative to the monitored object, wherein the touch location is based on the spatial pattern of touch pixels, or the time of capture of the two images that produced the spatial pattern.

A non-transitory computer readable medium storing instructions causing a processor to:

• compare pixels of a first pair of images of a series of images of an item illuminated by coherent illumination to identify touch pixels, wherein a difference in value of each touch pixel between the two images is greater than a threshold;
• identify and store a first pattern of touch pixels that corresponds to a pointing end of a pointing object;
• compare pixels of a second pair of images of the series of images;
• identify and store a second pattern of touch pixels that corresponds to the pointing end of the pointing object.