This brief presents a 640×480 CMOS image sensor (CIS) with in-circuit bidirectional gamma correction for use in computer vision applications. The conventional gamma correction method can saturate the bright region in an image, leading to the loss of bright image information. Using the proposed bidirectional gamma correction method, which can be implemented with a log-exponential counter, both bright and dark regions in an image can be simultaneously corrected. The transfer function of an 8-bit single-slope analog-to-digital converter can be selected considering either linear or bidirectional gamma curves with three different slope-change points to enhance the visibility in the pseudo-dynamic range. From the prototype sensor, we observed that the visibility of dark images was increased with proper bidirectional gamma curvatures. The CIS was fabricated in a 110 nm CIS process, and the full chip area was 5900 μm × 5240 μm. The total power consumption was 6 mW at a rate of 15 frames per second with an analog, pixel, and digital supply voltage of 3.3 V, 3.3 V, and 1.5 V, respectively.

中文翻译：

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利用双向伽玛曲率技术设计伪宽动态范围CMOS图像传感器


本简介介绍了一款具有电路内双向伽玛校正功能的 640×480 CMOS 图像传感器 (CIS)，适用于计算机视觉应用。传统的伽玛校正方法会使图像中的亮区饱和，导致亮图像信息丢失。使用所提出的双向伽玛校正方法（可以通过对数指数计数器实现），可以同时校正图像中的亮区和暗区。可以根据具有三个不同斜率变化点的线性或双向伽马曲线来选择 8 位单斜率模数转换器的传递函数，以增强伪动态范围内的可视性。从原型传感器中，我们观察到，适当的双向伽玛曲率可以提高暗图像的可见度。 CIS采用110 nm CIS工艺制造，全芯片面积为5900μm×5240μm。在每秒 15 帧的速率下，总功耗为 6 mW，模拟、像素和数字电源电压分别为 3.3 V、3.3 V 和 1.5 V。