Solid state image sensing device for analog-averaging and sub-sampling of image signals at a variable sub-sampling rate and method of driving the same

Abstract

Provided are a CMOS image sensor (CIS) type image sensing device for averaging and sub-sampling analog image signals at a variable sub-sampling rate and a method of driving the same. The image sensing device includes: a two-dimensional active pixel sensor (APS) array including pixels arranged in rows and columns; an averaging unit averages reset signals and image signals alternately generated from each of pixels corresponding to odd- numbered and even-numbered rows and columns in based on a predetermined sub-sampling rate in a sub-sampling mode by repeating a method of accumulating, averaging, (and dumping) the reset signals and the image signals, and generating a comparison signal corresponding to a difference between the average of the reset signals and the average of the image signals; and a conventional digital signal output circuit that generates digital signals corresponding to the sub-sampled (averaged) image signals generated from the pixels represented by the comparison signal. The CIS type image sensing device can analog-average image signals output from pixels at a variable sub-sampling rate and carry out a sub-sampling operations for moving pictures, without increasing chip size.