摘要
构造了一个与Donoho提出的硬阈值函数相当的基于邻域相关性的新型阈值函数,其表达式简单易于计算,且连续高阶可导。新的阈值函数克服了硬阈值函数不连续的缺点,还克服了软阈值函数中估计小波系数与含噪小波系数间存在恒定偏差的缺陷。同时新的阈值函数还有效地利用了小波系数的成串性,即在小波系数的估计计算中考虑了邻域小波系数的大小。仿真结果表明,在去噪图像视觉效果和峰值信噪比两个方面,提出的去噪法优于已有的各种门限去噪法。
A novel thresholding function with neighbor dependency was proposed, which was similar to hard thresholding function presented by Donoho. The proposed thresholding function that was simple and continuous had a high order derivative. The new function overcomed the discontinuous shortcoming of the hard thresholding function and the disadvantage of soft thresholding function, which was the invariable dispersion between the estimated wavelet coefficients and the wavelet coefficients contaminated by noise. At the same time, the clustering characteristics of wavelet coefficients were utilized effectively in new function. That was, the neighboring wavelet coefficients were incorporated into the estimation of wavelet coefficients. Simulation results showed that the proposed denoising algorithm had better visual effect and PSNR performance than many exiting thresholding methods.
出处
《武汉理工大学学报》
EI
CAS
CSCD
北大核心
2007年第1期78-81,共4页
Journal of Wuhan University of Technology
基金
高等学校博士学科点专项科研基金(20050290010)
关键词
小滤变换
阈值函数
邻域小波系数
峰值信噪比
wavelet transform
thresholding function
neighbor wavelet coefficients
PSNR
