Editing Touchscreen (section)

===Optical imaging===
Optical touchscreens are a relatively modern development in touchscreen technology, in which two or more [[image sensors]] (such as [[CMOS sensor]]s) are placed around the edges (mostly the corners) of the screen. Infrared backlights are placed in the sensor's field of view on the opposite side of the screen. A touch blocks some lights from the sensors, and the location and size of the touching object can be calculated (see [[Visual hull#In two dimensions|visual hull]]). This technology is growing in popularity due to its scalability, versatility, and affordability for larger touchscreens.