应用二维小波变换对图像进行去噪。程序image_denoise1.m应用sym5小波对图像进行2层分解，直接用各层的逼近信号表示去噪后的信号。程序image_denoise2.m利用不同的阈值对含噪信号进行去噪，相当于进行两次高频噪声的消除，并且阈值不同。-Application of two-dimensional wavelet transform for image denoising. Application procedures image_denoise1.m image sym5 wavelet decomposition layer 2, the direct use of all floors of the signals that the approximation of the signal after denoising. Image_denoise2.m procedures using different thresholds for denoising noisy signals, which is equivalent to twice the elimination of high-frequency noise, and different thresholds.