Computer Engineering and Applications ›› 2011, Vol. 47 ›› Issue (29): 192-195.

• 图形、图像、模式识别 • Previous Articles     Next Articles

Method to image denoising by using local similar block means

ZHANG Yong1,2,LAN Yihua1,REN Haozheng1,LI Ming3   

  1. 1.School of Computer Engineering,Huaihai Institute of Technology,Lianyungang,Jiangsu 222005,China
    2.School of Management,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China
    3.Department of Imaging Processing Business,Beijing E-COM Technology CO.,LTD,Beijing 100176,China
  • Received:1900-01-01 Revised:1900-01-01 Online:2011-10-11 Published:2011-10-11

一种利用局部块相似均值去噪的方法

张 勇1,2,兰义华1,任浩征1,李 明3   

  1. 1.淮海工学院 计算机工程学院,江苏 连云港 222005
    2.中国矿业大学 管理学院,江苏 徐州 221116
    3.北京友通上昊科技有限公司 图像处理事业部,北京 100176

Abstract: Non Local Means(NLM) is a state-of-the-art method for image denoising based on a nonlocal weighted mean of image blocks’ similarity.It performs well on Gaussian noisy images.However,local extremal points are prone to yield in smoothing area.By analyzing strengths and weaknesses of NLM’s searching area and similarity function,the reasons of extremal points’ appearance in smoothing area are given.A novel image denoising method based on NLM framework is presented to achieve improved performance.The new method adopts a compact weight set by using a threshold based on image block variation to eliminate irrelevant similar blocks.Compared with the original NLM,the new method is more efficient in keeping smooth in homogeneous areas and boundary maintenance according to the experimental results.

Key words: denoising, non-local means, similar, distance function, searching area, image block

摘要: 非局部平均(NLM)是一种基于图像块之间相似性的加权平均去噪算法,对高斯噪声具有很好的抑制作用,但是在平滑区域的去噪效果并不是很好。从相似块的搜索区域和相似性度量函数两个方面对NLM算法进行了分析,指出其在平滑区域容易产生极值点的原因。提出了一种结合图像块特征的阈值方法,用于消除搜索区域中的无关图像块,提高了图像相似结构的利用率。实验表明,新算法对光滑区域和细微结构的去噪能力要优于NLM算法。

关键词: 去噪, 非局部平均, 相似性, 度量函数, 搜索区域, 图像块