Abstract— In this paper we present a feature-extracting image sensor targeted to wireless image sensor networks. The image sensor was designed and fabricated on a 3D integrated 0.18 m silicon-on-insulator CMOS process. The image sensor can simultaneously capture an intensity image and extract image features, which include temporal illumination differentiations and contours. By taking advantage of massively parallel, vertical connectivity, the image sensor can perform more analog computations at higher speed and higher communication efficiency. The top layer is covered by photodiodes and the pixel fill factor is 95%.