中文说明：图像的小波去噪，给灰度图像加上一定量的高斯噪声，再采用小波变换的方法去噪，计算去噪前后图像的PSNR。
English Description：
The wavelet de-noising of the image, add a certain amount of Gaussian noise to the gray image, and then use the wavelet transform method to de-noising, and calculate the PSNR of the image before and after denoising.