结合小波自适应阈值与双边滤波的图像降噪

针对传统硬阈值函数不连续,造成图像重构后出现Pseudo-Gibbs现象,软阈值函数因估计小波系数与原小波系数之间存在恒定偏差,影响重构精度,提出一种改进的小波阈值函数以及自适应阈值。该阈值函数有效克服二者局限性,改进的自适应阈值抑制传统阈值对有效信号造成的过度扼杀。提出改进的双边滤波器与小波阈值结合方案,最大限度保护图像目标边缘和细节特征。仿真结果表明,改进算法提高了峰值信噪比,获得了良好的图像降噪效果。

Image noise reduction combining wavelet adaptive threshold and bilateral filtering

Aiming at the discontinuity of traditional hard threshold function,the phenomenon of Pseudo-Gibbs appears after image reconstruction,and the soft threshold function has a constant deviation between the estimated wavelet coefficients and the original wavelet coefficients,which affects the reconstruction accuracy,an improved wavelet threshold function and adaptive threshold were proposed.The proposed threshold function effectively overcame the limitations of both.The improved adaptive threshold suppressed over-strangulation of the valid signal caused by the traditional threshold.An improved bilateral filter combined with wavelet threshold was proposed to maximize the image edge and detail features.Simulation results show that the improved algorithm can improve the peak signal-to-noise ratio and obtain good image noise reduction effects.