调制传递函数在遥感图像复原中的应用

针对空间推扫型全色TDICCD 相机在获取、传输和存储图像的过程中引入模糊和噪声导致图像质量下降的问题，提出了一种基于调制传递函数（MTF）的。感图像复原方法。文中的复原方法是通过图像的MTF 恢复出点扩展函数（PSF），并将其作为退化函数进行图像复原。通过在MTF 提取前对局部图像用同态滤波算法进行增强处理，加强MTF 提取的抗噪声能力，并使用二次复原的方法避免直接加入增强滤波器导致的MTF 误差。使用均值、对比度及边缘强度等指标对。感图像复原结果进行评价。实验结果表明:复原后图像灰度均值提高45%，平均梯度和边缘强度分别是复原前的3.5和1.75 倍，各项评价指标均优于原始图像，并且MTF 所包含面积MTFA 明显增加，该图像复原算法对提高空间TDICCD 相机图像质量有一定的参考意义。

Application of MTF in remote sensing image restoration

In order to solve the quality problem of remote sensing image degradation which is caused by fuzzy and noise in the process of push-broom full-color TDICCD space camera acquisition, transmission, and storage image, a new remote sensing image restoration method based on modulation transfer function (MTF) was proposed. The method in this paper restored point-spread function PSF by MTF, and took it as degradation model for image restoration. The ability of noise resisting of MTF extraction was raised in this paper via enhancing the local image by homomorphic filter algorithm before MTF extraction. Then by using the two times restoration method, MTF error which is caused by adding enhancement filter directly was avoided. Finally, the effect of remote sensing image restoration was evaluated by mean, contrast and edge strength. In experiments, the recovered image grayscale average increases 45%, average gradient is 3.5 times and the edge strength is 1.75 times greater than the values before restoration. And the area which is contained by MTF curves increases. The experimental results show that all above evaluation indexes are better than the original image. In conclusion, the image restoration algorithm of space TDICCD camera has certain reference significance in improving image quality.