激光主动成像制导图像去噪算法研究

摘要

快速有效地对所获图像进行去噪是提高激光主动成像制导精度的关键一步.针对成像中的散斑噪声,提出了一种改进的小波阈值与基于积分图像的非局部均值滤波相结合的去噪算法.首先对激光主动成像图像进行噪声分析;然后通过对数变换将乘性噪声转换为加性噪声;而后将含噪图像进行两层小波分解,在第一层高频部分运用改进的小波阈值法,在第二层高频部分运用基于积分图像的非局部均值滤波算法进行去噪;最后进行相应的逆变换得到去噪图像.理论分析和实验结果证明,该算法能有效去除噪声,较好地保证了图像细节,并且满足激光主动成像制导对图像去噪实时性的要求.%Fast and effective image denoising is critical for improving the accuracy of laser active imaging guidance.Focusing on the speckle noise in imaging,a denoising algorithm based on the combination of improved wavelet threshold denoising algorithm and integral image based non-local means filtering is proposed.Firstly,noise analysis of laser active imaging is performed.Secondly,speckle noise is converted from multiplicative noise to additive noise by logarithmic transform.Then,the image is decomposed into two layers by wavelet transform:the improved wavelet threshold denoising algorithm is used for the high-frequency part of the first layer,and non-local means filtering is used for the high-frequency part of the second layer.Finally,inverse transforms are carried out and the denoised intensity image is obtained.Theoretical analysis and experimental results show that the proposed algorithm has fine denoising performance and the details of image are well protected.Meanwhile,the proposed algorithm meets the requirements of laser active imaging guidance for real-time image denoising.