Abstract: Motion deblurring is to restore the origin image from motion blurred image using image degenerative prior knowledge.When the Point Spread Function（PSF） associated with motion blur is unknown，estimating parameters of the PSF is necessary for image restoration.In this paper the frequency characteristics of the motion blurred image and PSF are analyzed theoretically in Fourier transform perspective.The validity of the motion parameter estimation algorithm which is based on the PSF’s zero property in frequency domain and the direction property of the blurred image’s twice Fourier transform is proved.According to these properties，a direction estimation method and two methods to estimate the motion distance are proposed.And experiments validate the accuracy of the whole estimation method.

Key words: motion blurring, image restoration, Fourier transform, Point Spread Function（PSF）, parameter estimation

摘要： 运动模糊恢复就是利用运动模糊退化的某种先验知识来重建或恢复原有图像。在运动模糊的点扩散函数未知的情况下，估计运动模糊的点扩散函数是运动模糊恢复的前提和关键。从傅立叶变换的角度对匀速直线运动模糊图像的点扩散函数在频域中的特点做了理论分析，论证了点扩散函数在频域内的零点特性及模糊图像两次傅立叶同态变换后的方向特性，并提出了利用这些特性进行运动模糊方向估计的方法及两种模糊距离的估计方法。实验结果证明了所提出方法的有效性。

关键词: 运动模糊, 图像复原, 傅立叶变换, 点扩散函数, 参数估计