A method and apparatus for using TFT transistors or MIS capacitors as light-sensing elements in charge mapping arrays. A bias stress may be applied to a plurality of pixels in a charge map array. As a result, charge carriers may be trapped in each of the plurality of pixels responsive to the bias stress, which may be observed as a value shift such as a threshold voltage VT shift. Light may then be transmitted toward the plurality of pixels in the charge map array causing some of the pixels to absorb the light. The trapped charge carriers are released in the pixels that absorbed the light and not released in the pixels that did not absorb the light. The value shift in each of the pixels can be compared to determine which of the pixels absorbed the light.