关键词: 无抽样方向滤波器组, Contourlet变换, 图像去噪

Abstract: This paper presents a new method of image denoising based on decimation-free directional filter banks.First，all the filters like four-direction，eight-direction and sixteen-direction directional filter banks are revealed by filters’ rotating，skewing and/or scaling.This paper transforms all directional filters in frequency domain to spatial operators，and uses multiscale analysis of Contourlet transform and spatial operators to analyze the input image and get coefficients.At last，the paper chooses the reasonable threshold based on statistic traits of all coefficients.Directional synthesis can be achieved by just simply adding all the subband images.Multiscale synthesis is the same as Contourlet transform.The experimental results indicate that the method avoids false Gibbs visual distortion and is better than the existing denoising algorithms in smoothing noises，preserving image textures and details and improving the SNR of image.

Key words: decimation-free directional filter banks, Contourlet transform, image denoising