A Wide-Dynamic-Range CMOS Image Sensor Based on Multiple Short Exposure-Time Readout With Multiple-Resolution Column-Parallel ADC

Abstract

A wide-dynamic-range CMOS image sensor based on synthesis of one long and multiple short exposure-time signals is proposed. A high-speed, high-resolution column-parallel integration type analog-to-digital converter (ADC) with a nonlinear slope is crucial for this purpose. A prototype wide-dynamic-range CMOS image sensor that captures one long and three short exposure-time signals has been developed using 0.25-m 1-poly 4-metal CMOS image sensor technology. The dynamic range of the prototype sensor is expanded by a factor of 121.5, compared with the case of a single long exposure time. The maximum DNL of the ADC is 0.3 least significant bits (LSB) for the single-resolution mode and 0.7 LSB for the multiresolution mode.Index Terms-CMOS image sensor, multiple-exposure, multiresolution analog-to-digital converter (ADC), wide dynamic range.

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