CMOS ACTIVE PIXEL SENSOR WITH IMPROVED DYNAMIC RANGE AND METHOD OF OPERATION FOR OBJECT MOTION DETECTION

A CMOS imaging array includes a plurality of individual pixels arranged in rows and columns. Each pixel is constructed the same and includes a photodetector (e.g., photodiode) receiving incident light and generating an output. A first, relatively lower gain, wide dynamic range amplifier circuit is provided responsive to the output of the photodetector. The first circuit is optimized for a linear response to high light level input signals. A second, relatively higher gain, lower dynamic range amplifier circuit is also provided which is responsive to the output of the photodetector. The second circuit is optimized to provide a high signal to noise ratio for low light level input signals. Subtraction of output signals from the amplifier circuits, preferably after gain compensation, can be used to detect moving objects in the scene where the integration times for the two circuits are not the same, e.g., are staggered in time or have a different period.