Bayer滤波型彩色空间相机的调制传递函数检测方法  

Modulation Transfer Function Detection Method of Bayer Filter Color Space Camera

作　　者：王煜皓 樊元朋 魏磊[1] Wang Yuhao;Fan Yuanpeng;Wei Lei(Institute of Frontier and Interdisciplinary Science,Shandong University,Qingdao 266237,Shandong,China)

机构地区：[1]山东大学前沿交叉科学青岛研究院,山东青岛266237

出　　处：《光学学报》2024年第19期354-363,共10页Acta Optica Sinica

基　　金：山东省自然科学基金青年项目(ZR2022QF077);光电测量与智能感知中关村开放实验室与北京控制工程研究所空间光电测量与感知实验室开放基金(LabSOMP-2022-08)。

摘　　要：为解决Bayer滤波型彩色空间相机调制传递函数(MTF)检测困难的问题,对计算方法和检测方式进行改进。提出一种先对三基色颜色分量单独进行MTF检测,再根据光源的定标结果加权得到彩色图像测试结果的方法,解决了由插值造成的像质进一步退化,且可能会使空间频率提前截止的问题。通过对边缘检测和边缘扩展函数数据处理两个关键步骤的改进,对刃边法进行了优化。首先,利用抵抗噪声能力强的Canny算子进行图像边缘拟合,并利用自适应滤波函数和最大类间方差法对Canny算子进行改进,解决了噪声影响刃边拟合精度的问题;然后,提出一种基于非均匀快速傅里叶变换的边缘扩展函数处理方法,降低了平滑数据带来的误差,提高了均匀化处理精度;最后,完成了某型号Bayer滤波型彩色空间相机的MTF测量实验。仿真和实验结果表明,所提出的解决方案能够实现Bayer滤波型彩色空间相机MTF的高精度检测。Objective When modulation transfer function(MTF)detection for Bayer filter color spatial cameras with low modulation transfer function is conducted,the spatial frequency cutoff will occur,and the complete MTF curve at zero to Nyquist frequency cannot be obtained.Meanwhile,edge detection and edge spread function processing are the two most important steps in edging methods.The ISO 12233 method employs the centroid method for edge detection,which is greatly affected by noise.Canny operators have low sensitivity to noise and are widely adopted in image edge detection.However,they have some limitations in edge detection in MTF tests.Additionally,the ISO 12233 method requires the sampling rate of the edge spread function to be as integer as possible.Otherwise,the edge spread function curve will not be smooth and continuous,and will not accurately represent the edge spread function distribution of the actual image.Moreover,since the subsequent differential and FFT processing will amplify ESF data fluctuations,it is necessary to homogenize ESF data.However,the present homogenization method will introduce new errors which cannot be ignored,resulting in insufficient accuracy of the algorithm.Methods To meet the requirements of Bayer filter color cameras for high-precision MTF measurement,we improve the calculation algorithm and detection method.The MTF detection of three primary color components is proposed,and the color image test results are obtained by weighting according to the calibration results of the light source.Additionally,the edge method is optimized by improving the two key steps of edge detection and edge extension function data processing.Firstly,the image edge fitting is carried out by employing the Canny operator with strong noise resistance.When the Canny operator is utilized for edge detection in MTF tests,the selection of scale parameters and threshold parameters of non-maximum suppression in the Gaussian filter is essential.Meanwhile,the Canny operator is improved by employing an adaptive filter funct

关 键 词：调制传递函数 刃边法 Bayer滤波型彩色相机 

分 类 号：O439[机械工程—光学工程]