Improved threshold function image denoising method

In this paper, an improved threshold function is proposed for the discontinuity problem of hard threshold function and the constant deviation of original wavelet coefficients and estimated coefficients in soft threshold function. This function improves the deficiency of traditional threshold function by introducing control coefficients, and the function have certain flexibility. The experimental results show that the improved wavelet threshold function has a better effect in removing image gaussian noise than traditional threshold function. Moreover, the PSNR(peak signal to noise ratio ) and EPI (edge retention index) values of the image are both improved.