A 180nm CMOS image sensor with on-chip optoelectronic image compression

Abstract

We demonstrate an image sensor which directly acquires images in a compressed format. The sensor uses diffractive optical structures integrated in the CMOS back-end layer stack to compute a low-order 2D spatial Gabor transform on visual scenes. As this computation occurs in the optical domain, the readout back-end uses the transform outputs to implement the subsequent image digitization and compression simultaneously. Implemented in a 180nm logic CMOS process, the image sensor uses a 384×384 array of complementary angle-sensitive pixel pairs, consumes 2mW at a frame rate of 15fps, and achieves a 10:1 compression ratio on test images.