基于自适应移动窗口的CMOS图像非均匀性校正

Adaptive Moving Window-Based Non-Uniformity Correction of CMOS Image

为保证航天遥感相机互补金属氧化物半导体(CMOS)图像传感器非均匀性校正的实时性,降低图像的光响应非均匀度(PRNU),根据COMS图像传感器的结构特点,提出了一种基于自适应移动窗口的COMS图像非均匀性校正方法。首先,从工程应用角度出发,采用可移动变步长窗口对图像进行分块,使同一窗口内的多列像元共用一组校正参数。然后,针对现有方法中线性拟合校正精度不足的问题,基于COMS传感器的非线性响应特性用最小二乘法对响应曲线进行二阶拟合。实验结果表明,本方法既能提升COMS图像的质量,又能减少硬件系统的校正参数量。用本方法校正后的图像PRNU小于1%,相比线性拟合校正,本方法的校正参数量减少了23.7%。

To ensure the real-time performance of the nonuniformity correction of the complementary metal-oxidesemiconductor(CMOS)image sensor in aerospace remote sensing cameras and reduce the photo response nonuniformity(PRNU)of the image,according to the structural characteristics of the CMOS image sensor,a CMOS image non-uniformity correction method based on an adaptive moving window is proposed in this study.First,from the perspective of engineering applications,a movable variable-step window is used to block the image so that multiple columns of pixels in the same window shared a set of correction parameters.Then,to solve the problem of insufficient linear fitting correction accuracy in existing methods,based on the nonlinear response characteristics of the CMOS sensor,the response curve is second-ordered by the least squares method.Experimental results show that the method can not only improve the quality of CMOS images but also reduce the number of correction parameters of the hardware system.The PRNU of the image corrected by the method is less than 1%.Compared with the linear fitting correction method,the number of correction parameters of the method is reduced by 23.7%.