Octagonal CMOS Image Sensor with Strobed RGB LED Illumination for Wireless Capsule Endoscopy

This paper proposes a novel, octagonal shaped CMOS image sensor (CIS) array for use in tandem with colored LED illumination and a corresponding, innovative pixel scanning method. The octagonal shape of the pixel array allows the CIS to make near-optimal use of silicon real estate by matching the perimeter of the pixel array to the focal plane area of lenses used in Wireless Capsule Endoscopies (WCE). Providing illumination by sequencing different-colored LEDs allows the system to reuse the same pixels to capture different colors at different times, thus removing the need for manufacturing a Color Filter Array (CFA) and effectively trading temporal for spatial resolution. The system was designed with AMS 0.35 mu m 2P4M CMOS technology. The simulated system consumes 1.06 mW from a 2.5 V supply at 2.217 frames/sec operation.