二维离散小波变换(Mallat快速算法)对图像进行二维离散小波变换, 变换级数大于等于3级,然后进行阈值化处理(阈值约为10左右),再统计系数中0的个数（百分比表示）并进行重构, 最后计算重构图像的峰值信噪比(PSNR).

数据：灰度图像lena.bmp或其它图像, 滤波器系数可以调用matlab中的wfilters函数获得, wfilters函数的使用请在matlab中help wfilters.-Two-dimensional discrete wavelet transform (Mallat fast algorithm) two-dimensional discrete wavelet transform image transformed series is greater than or equal to 3, and then processing thresholding (threshold of about 10 or so), the number of re statistical coefficient 0 ( reconstruct the final calculation of the peak signal-to-noise ratio (PSNR) of the reconstructed image data: the grayscale image lena.bmp or other images, the filter coefficients can call matlab in wfilters function to obtain, wfilters function, expressed as a percentage) in matlab help wfilters.