图像清晰度评价是实现数字图像自动调焦的关键,而调焦图像降噪直接影响着图像评价的准确性。为有效抑制调焦图像中存在的两类主要噪声,结合椒盐噪声和高斯噪声特点,综合采用十字中值滤波法和维纳滤波法实现了图像降噪。实验结果表明,相比于单一降噪方法,综合方法不仅能最大程度地降低两类噪声,而且能较好地保护图像细节,可作为自动调焦成像系统图像预处理的主要方法。

The articulation evaluation is one factor for the automatic focusing of digital images, and the noise suppression of automatic focusing image directly affects the accuracy of image evaluation. To suppress the two main noises of salt/pepper noise and Gaussian noise, the method integrating cross median filtering and Wiener filtering is adopted. The results show that compared with the single noise suppression method, this integrated approach not only can decrease the two kinds of noises smoothly, but also can protect the image details. The proposed method can be used as image preprocessing for the automatic focusing imaging system.