基于小波变换的图像阈值去噪的改进方法

基于Donoho提出的传统的阈值去噪方法,提出了一种新的阈值函数,并应用于图像的去噪.与Donoho的软阈值和硬阈值函数相比,这种新的阈值函数有更多的优点:可以实现能量自适应去噪;能够保存图像的边缘信息;函数的表达式简单,避免了硬阈值函数的不连续性;相比软阈值和硬阈值函数,新阈值函数更灵活.仿真结果表明,改进后的方法应用于图像去噪,无论是视觉效果还是信噪比都有了改善.

An Improved Approach to Threshold Function De-noising of Image Based on Wavelet Transform

A new threshold function is presented based on the traditional de-noising method put forward by Donoho. The new threshold function has many advantages over Donoho's soft-threshold and hard-threshold functions. This new algorithm is in possession of not only the de-noising ability of the energy-adaptation, but also the capability of protecting edge information of image signal when it is applied to de-noise. It is simple in expression and avoids the discontinuity of hard-threshold function. Besides, the new threshold function is more elastic than the traditional soft-threshold and hard-threshold functions. Simulation results indicate that the de-noising approach with the new threshold function outperforms the traditional soft-threshold function in both visional effects and signal-to-noise ratio.