【摘要】 针对4f系统输出图像做复原处理时要比平常情况更注重保护图像细节,提出一种小波域自适应窗口调整平滑降噪方法,对系统图像中的随机噪声进行平滑去噪。该方法利用小波分解后高频子图像中图像细节的方向性分别确定平滑窗口的方向,再利用小波变换的能量集中性优点调整窗口大小,实现自适应调整窗口形状,并用调整后的窗口对系统输出图像进行平滑去噪,抑制其中的随机噪声。理论分析和实际光学系统图像实验表明,该方法有明显的抑制随机噪声效果,并且对图像细节有较好的保护,峰-峰信噪比则有2dB左右的提高,视觉效果平滑,适合4f系统这类要求一定精度且本身有低通效果的场合。更多还原

【Abstract】 Due to the features of limited frequency band and existing noise for the output images of the conventional 4f information optics system,it is required to protect the image detail regions much better when restoring the images.Based on the classic AWM method,an adaptive window smoothing method which can adaptively adjust the shape of the smoothing window in wavelet domain is proposed to remove the random noise in the system output images.The method utilizes the direction of the high pass sub-images decomposed by wavelets to determine the direction of the smoothing window,and adjusts the size of the smoothing window based on the advantage of energy concentration characteristics of sub-images in wavelet domain to adjust the shape of the window adaptively.The output image of the 4f system is smoothed with the adjusted windows.The theoretical analysis and experiments show that the method can de-noise the image in visual sensation and protect the image detail well,while PSNR is improved about 2 dB.It is suitable for the cases which require a certain image precision and has low pass characters,such as the 4f optic system.更多还原