A new mixed noise filtering method for laser image

Laser image often contains mixed noise mainly including salt and pepper noise and Gaussian noise. Not only the quality of laser image is made deteriorated but also the important details of laser image are flooded by it. A new mixed noise filtering method for laser image is proposed in this paper to filter out mixed noise effectively meanwhile ensure laser image details clear and completed. In the first space, salt and pepper noise in laser image is filtered out in spatial domain. A Novel Adaptive Switching Median (NASM) filter based on local salt and pepper noise density which determines filter window of every salt and pepper noise point adaptively is introduced here. Secondly, image is transferred to wavelet domain to filter out Gaussian noise. Local Adaptive BayesShrink Threshold (LABT) wavelet denoising on basis of Gaussian Mixture Model (GMM) is used in this step where wavelet coefficients are modeled by GMM and LABT is used for adjusting the threshold adaptively which utilizes local relevant characters of sub band wavelet coefficients. Experimental results show that new method can remove mixed noise effectively meanwhile protect details of laser image well thus getting better filtering performance compared with other filters for laser image.