Threshold de-noising method for mixed noise based on improved median filter and lifting wavelet transform

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 transform for image was applied to remove Gaussian noise. Simulation result shows when (，)=(0.4, 20), the peak SNR(PSNR) is 34.002 1 and the mean absolute error( MAE) is 2.365 3.