Implementation of real-time image edge detector based on a bump circuit and active pixels in a CMOS image sensor

This paper presents a hardware-based image edge detector that directly detects edges in an image using CMOS image sensor (CIS) circuitry without any signal processing. The CIS consists of an active pixel sensor (APS) and a bump circuit makes peak current like a bump monitoring the current of the APS. The APS converts illumination density of a photodiode to electric current. The bump circuit creates peak current when a pixel is an edge, compared to the neighboring pixels. The proposed edge detector is implemented using 0.18 μm CMOS technology that provides a 34% fill factor and power dissipation of 0.9 μW per pixel with a 1.8 V power supply. The fabricated chip is a 64 × 64 array that finds edges of an image in real time.