两通道按列输出CMOS图像的非均匀性及校正方法

为确保航空遥感图像产品相对辐射质量,提出了一种对两通道按列输出CMOS(互补金属氧化物半导体)图像的非均匀性进行校正的方法。以美国仙童公司CMOS探测器CIS2521F为例,通过实验室积分球观测试验研究了暗电流噪声、平均灰度、两通道输出等因素造成的图像非均匀性;然后,基于实验室积分球观测数据,采用两点线性法,校正了由按列放大输出导致的列状条带噪声;接着,通过优化拼接线附近图像灰度差异统计结果,校正了两通道响应不一致造成的图像辐射差异。试验表明,单通道图像非均匀校正使积分球观测图像的平均非均匀度量值由4.4下降至2.4,两通道图像非均匀校正消除了两通道图像的目视差异。原始航空遥感图像经过非均匀性校正后,图像灰度均匀,能够满足遥感图像判读要求。

Nonuniformity of CMOS image with double channels and column readout and its correction

The CMOS image nonuniformity and its correction methods were researched to improve the relative radiation quality of aerial remote sensing image products. Taking the new CMOS image sensor CIS2521F as an example, the nonuniformity characteristics affected by dark current noise, average gay and double channel readout were researched through the experiments of the integrating sphere observation. Then, the two-point linear correction method based on the observation data was used to remove the column strip noise related to column amplifiers. Finally, a correction method based on the statistical gay difference near the mosaic seam was used to wipe off the mosaic phenomenon related to double channel readout. Experimental results indicate that the nonuniformity of the sphere image has changed from 4.4 into 2.4 after single channel correction, and the manual interpretation difference is disappeared after double channel correction. The remote sensing image after correction is uniformity and satisfies the interpretation requirement.