A 0.5V Real-Time Computational CMOS Image Sensor with Programmable Kernel for Always-On Feature Extraction

Abstract

This paper presents a 0.5V computational CMOS image sensor (C2IS) with array-parallel computing capability for always-on feature extraction. By applying the developed pulsed-width modulation (PWM) pixel and switch-current integration (SCI), the in-sensor 8-directional matrix-parallel multiply-accumulate (MAC) operation is realized. Moreover, the analog-domain convolution-on-readout (COR) operation, the programmable 3x3 kernel with 3-bit weights, and the tunable-resolution column-parallel ADC (1b to 8b) are implemented to achieve the real-time feature extraction without use of additional memory. The C2IS prototype has been fabricated and verified to demonstrate the raw and feature images at 480 fps with a power consumption of 77/91 (uW and the resultant FoM of 9.8/11.6 (pJ/pix/frame), respectively.