一种新的小波阈值函数在图像去噪中的应用

New wavelet thresholding function in image denoising

为了解决传统的小波阈值函数在图像去噪中存在的一些问题,提出了一种新的阈值函数进行去噪。新的阈值函数和传统的软硬阈值函数相比,它弥补了硬阈值函数不连续的不足之处,同时又保留了与软阈值函数一样的连续性,减小了软阈值函数中存在的恒定偏差。新的阈值函数表达式简单且高阶可导,易于各种数学处理。对图像的仿真实验表明,相比软硬阈值函数和软硬阈值折中函数,该方法具有更好的去噪效果,具有较高的实用价值。

A new thresholding function which is used in image denoising is proposed in this paper to solve the problems existed in the traditional wavelet thresholding functions.Compared with the traditional hard-thresholding function and soft-thresholding function,the new thresholding function overcomes the shortcoming of uncontinuity of hardthresholding function and remains the continuity of soft-thresholding function as well as decreases the invariable dispersion in the soft-thresholding function.The new thresholding function is simple in expression and has a high order derivative,it is suitable to do some kinds of mathematical disposals.The simulation results for image show that this method has better denoising effect and higher practical value than the traditional hard-and soft-thresholding methods and soft and hard thresholding compromised methods.