Using Negative Feedback in CMOS Image Sensors to Detect Intra-frame Motion

Abstract

We investigated a negative feedback method for adding functionality to a CMOS image sensor. Our sensor effectively uses the method to set any intermediate voltage into a photodiode capacitance while a pixel circuit is in motion. The negative feedback reset functions as a noise cancellation technique and can obtain intermediate image data during charge accumulation. Using the above features, we achieved duplicated interlaced processing and were able to output frame-difference images without frame buffers. The experimental results obtained with a chip fabricated using a 0.25-μm CMOS process demonstrate that intra-frame motion detection is an effective application of negative feedback resetting.