A new image denoising algorithm for laser active imaging

Aiming at the speckle noise in laser active imaging, a denoising algorithm combining improved wavelet threshold method with non-local mean(NLM) filtering is proposed. Firstly, noise analysis of laser active imaging is performed. Secondly, the speckle noise is converted into additive noise by logarithmic transformation. Thirdly, the image is decomposed into two layers by wavelet transform, then improved wavelet threshold denoising algorithm is used in the high-frequency party of the first layer, and NLM filtering is used in the high-frequency party of the second layer. Finally, the denoised image is obtained via the corresponding inverse transform. Experimental results show that the proposed algorithm has advanced denoising performance and the details of image is well protected, meanwhile, it has good real-time performance.