Hokkaido University Feedback Pixel

Hokkaido University team publishes yet another paper on feedback resetting of the pixel. This time the feedback reset is used to obtain picture smoothing. Here is the abstract of the paper:

CMOS Image Sensor Using Negative-Feedback Resetting to Obtain Variably Smoothed Images
Masayuki IKEBE and Keita SAITO

The authors are with the Graduate School of Information Science and Technology, Hokkaido University, Sapporo-shi, 060-0814 Japan.

We designed a CMOS image sensor capable of capturing variably smoothed images. This sensor uses a negative-feedback technique to set photodiode (PD) capacitance in the pixel circuit to any intermediate voltage during charge accumulation and it provides a neighboring-pixel operation by using their average value when resetting the PD capacitance. Smoothing-filter coefficients are changed by adjusting timing of the pixel-readout and neighboring-pixels operations. The performance of the proposed sensor was evaluated by SPICE simulation and numerical analysis.