基于改进中值滤波和提升小波变换的阈值去噪方法研究

摘要

Images taken actually always have low signal-noise ratio (SNR) ,large noise density and mixed noise ,however ,most existing algorithms can only remove a single noise .Aiming at the mixed noise containing impulse noise and Gaussian noise ,an efficient algorithm for mixed noise removal in image was proposed , including space impulse noise removal and wavelet Gaussian noise removal .In the process of de-noising ,an impulse noise detection algorithm based on median filter was given to filter impulse ,and at the same time a lifting wavelet trans-form for image was applied to remove Gaussian noise .Simulation result shows when (ρ,σ)=(0 .4 ,20) ,the peak SNR(PSNR) is 34 .002 1 and the mean absolute error( MAE) is 2 .365 3 .%对于实际拍摄的一些图像信噪比低，噪声密度大，且含有混合噪声，而现有算法大多只能去除单一噪声的问题。针对混合噪声中含有的脉冲噪声和高斯噪声，提出基于改进中值滤波和提升小波变换去噪相结合的方法。去噪过程中，使用中值滤波器提取脉冲噪声并采用中值滤波算法滤波后，构造提升小波，采用改进阈值函数提升小波阈值去噪方法去除高斯噪声。实验结果表明，当噪声值（ρ，σ）＝（0．4，20）时，采用本文去噪方法，峰值信噪比（PSNR）为34．0021，平均绝对误差（MAE）为2．3653。