LOW POWER IMAGE SENSOR ADJUSTING REFERENCE VOLTAGE AUTOMATICALLY AND OPTICAL POINTING DEVICE COMPRISING THE SAME

摘要

A low power image sensor sensing light from an object and outputting an image signal includes: an image sensing unit which senses light from an object, converts the light into an electric signal, and outputs the electric signal; a comparing unit which receives an electric signal from the image sensor, compares a voltage level of the electric signal with a reference voltage, and outputs an image signal as an lbit signal per pixel; and an effective image adjuster which compares bit value distribution of an image signal output from the comparator with a preset effective range, and adjusts the effective image to output an effective image. Further, an optical pointing device includes: an image sensor which senses light from an object and outputs an image signal; and a motion computing unit which receives the image signal and compares before and after images to calculate a motion vector, wherein the motion computing unit includes: a temporary storage unit to temporarily store image data output from the image sensor; a comparator to compare the image data output from the image sensor with the image data stored in the temporary storage unit; a direction selector to calculate a motion vector from a value output from the comparator; a controller to control operation of the motion computing unit.