基于像素电荷补偿的超宽动态范围CMOS图像传感器研究

项目名称： 基于像素电荷补偿的超宽动态范围CMOS图像传感器研究

项目编号： No.61274023

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 无线电电子学、电信技术

项目作者： 常玉春

作者单位： 吉林大学

项目金额： 91万元

中文摘要： CMOS图像传感器应用广泛，但其动态范围较小，不能满足记录自然场景的需求。目前提高其动态范围的方法存在着牺牲成像速度和质量、电路架构复杂、提升效果有限等缺点。本项目创新地提出利用像素电荷补偿的方法来得到超宽动态范围的CMOS图像传感器，特色是通过像素中加入一个附加的光电二极管，弱光时反偏，强光时自动转换为正偏，从而实现电荷补偿，使得像素输出电压在弱光下与光强成线性，强光下变成与光强对数成正比，达到提高图像传感器动态范围的目的。该方案受工艺影响小，弱光下响应速度快，信噪比高，强光下信号不饱和，动态范围提升明显。像素结构简单，无需采用复杂电路及额外时序来判断入射光的强弱。处理电路及系统方案采用传统积分式结构，技术成熟可靠。目标是所研究的图像传感器在30fps下动态范围将接近或超过160dB。本项目的研究将能够比较完美地解决CMOS图像传感器动态范围的问题，具有重要的科学意义和应用价值。

中文关键词： CMOS；图像传感器；宽动态范围；电荷补偿；

英文摘要： There are plenty of applications for CMOS image sensors. However, the dynamic range of CMOS image sensor is too narrow to meet the requirement of recording natural scene. Currently, there are a lot of methods to improve the dynamic range; however, most of them have drawbacks, such as deteriorating image quality and recording speed, complicated circuits building blocks, and limited effects on dynamic range, etc. In this proposal, pixel charge compensation method has been introduced to achieve ultra-wide dynamic range CMOS image sensors, creatively. The feature is by inserting another supplementary photodiode in the pixel, which is reverse biasing under weak incident light and is converted automatically to forward biasing when the incident light is strong. This conversion makes it possible to compensate charge to the capacitor of the pixel, to obtain the aim of improving the dynamic range, because the output voltage of the pixels is proportional to the light intensity at weak condition and is proportional to the logarithm of the light intensity under high illumination condition. This strategy has little influence with the process variation. The transient response is very fast at low light level with high signal-to-noise ratio. Under high light level, the output signal doesn't show any saturation phenomenon. There

英文关键词： CMOS；Image Sensor；High Dynamic Range；Charge Compensation；