摘要
提出了一种新的阈值函数,它高阶可导,便于各种数学运算。与硬阈值函数相比,它在阈值点处是连续的;相比于软阈值函数,减小了估计小波系数存在时的恒定偏差,更好地保留了图像边缘等局部特征。选用平移不变小波变换,结合新提出的阈值函数,给出了一种新的去噪方法。仿真实验结果证明了此方法的优越性。
A new thresholding function is proposed, which has the similar function with the traditional thresholding function except high-order derivative. It is continuous at the threshold compared with the hard thresholding function and it can reduce constant bias between the original wavelet coefficient and the estimated wavelet coefficients compared with the soft thresholding function, so the new function can remain the image edges better. Translation-invariant wavelet transform and the new thresholding function can give a new method for removing the Gaussian white noise. The result of the experiment shows the excellent perfomance of the proposed method.
出处
《光学技术》
CAS
CSCD
北大核心
2009年第6期819-821,824,共4页
Optical Technique
关键词
信息光学
小波变换
阈值
阈值函数
information optics
wavelet transform
thresholding
thresholding function
