Each detail image is first denoised with ridgelet threshold method, and then decomposed with wavelet. 对细节图像进行脊波阈值去噪处理，然后再进行单层小波分解。
The high frequency signal can be decomposed, and the frequency field can be divided into tinier ones with the emerging of wavelet packets. 摘要小波包的方法能对高频信号进行小波分解，给出了频域带更精细的划分。
