在高斯类点扩函数退化图像复原的研究中，提出了一种基于降晰图像频谱特征改进的APEX 图像复原算法。该算法采用APEX 算法的基本原理，根据图像频谱信息特征，对点扩散函数(PSF)估计过程进行了改进，采用加权最小二乘算法拟合出降晰图像频谱主方向，采用图像频谱主方向上的数据进行PSF 估计，以利用更多的有效数据，从而减少PSF 的估计误差。针对模拟和实际采集的降晰图像进行实验，采用主观视觉和峰值信噪比进行评价。实验结果表明，改进的算法较使用非主频谱方向上的频谱数据的复原算法在复原效果上有一定的提高。

During the course of the image restoration degenerated by the Gauss (G) class Point Spread Function (PSF), an improved image restoration algorithm is proposed based on frequency spectrum characteristic of the blur image. According to the frequency spectrum information, the algorithm improves the course of estimation PSF by utilizing the basic principle of the APEX method. The main direction of the frequency spectrum of the blur image is fitted by the weighted least squares algorithm. The PSF is estimated by using the main direction data of frequency spectrum of the blur image, so more available data will be obtained for the PSF estimation, which reduces the error of the PSF estimation. The method is tested by the simulated blur image and the captured real blur image, and it is evaluated by the subjective vision and the Peak Signal-to-noise Ratio (PSNR). The experiment results indicate that, compared with the method using the frequency-spectrum data of non-main direction data, the improved method ameliorates the restoration effect of the blur image.