A 128-pixel CMOS image sensor with integrated analog nonvolatile memory

A 128-pixel complementary metal-oxide-semiconductor (CMOS) image sensor array with analog nonvolatile storage for each pixel has been realized in a 1.5-mu m single-poly standard CMOS/EEPROM technology and successfully tested. The integrated nonvolatile memory allows an offset correction for each sensor element, cancellation of the fixed pattern noise, and compensation of the background illumination. The sensor array can also learn a presented pattern and store it in its analog nonvolatile memory just by "seeing." The stored pattern can be read out directly or, in combination with the optical input, it can be used for pattern recognition or motion detection. The required programming circuitry for the analog memory has been integrated on the same chip.