An Image Depth Extractable CMOS Image Sensor with a Variable Bit-resolution Infrared Pixel

Abstract

A variable bit-resolution CMOS image sensor(CIS) for an image depth extraction is discussed. In order to implement an image depth extraction, CIS pixel matrixes with RGB and Infrared (IR) color filters are used. Further, the single-slope ADC inside of CIS has a variable bit-resolution performance to compensate the light density between RGB and IR. For example, RGB signal has an 8-bit resolution, while IR signal has an 12-bit resolution. The proposed CIS has 4 different bit resolutions for IR pixel, such as 12-bit, 10-bit, 8-bit and 6-bit. The proposed ADC has a maximum resolution of 12-bit with the architecture of two-step single-slope (TS SS) type. The proposed image depth extractrable CIS has a 100 MHz clock, and it has been designed with 0.18 mu m CIS technology.