LIU Yi, CHEN Yan, GUI Zhi-guo
（Science and Technology on Electronic Test & Measurement Laboratory, North University of China, Taiyuan 030051, China）
Abstract： The gradient image is always sensitive to noise in image detail enhancement. To overcome this shortage, an improved detail enhancement algorithm based on difference curvature and contrast field is proposed. Firstly, the difference curvature is utilized to determine the amplification coefficient instead of the gradient. This new amplification function of the difference curvature takes more neighboring points into account, it is therefore not sensitive to noise. Secondly, the contrast field is nonlinearly amplified according to the new amplification coefficient. And then, with the enhanced contrast field, we construct the energy functional. Finally, the enhanced image is reconstructed by the variational method. Experimental results of standard testing image and industrial X-ray image show that the proposed algorithm can perform well on increasing contrast and sharpening edges of images while suppressing noise at the same time.
Key words： image enhancement; contrast field; difference curvature; variational enhancement scheme
CLD number： TN911.73 Document code： A
Article ID： 1674-8042（2016）03-0247-08 doi： 10.3969/j.issn.1674-8042.2016.03.007
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一种改进的基于差分曲率和对比度场的细节增强算法
刘 祎， 陈 燕， 桂志国
（中北大学 电子测试技术重点实验室， 山西 太原 030051）
摘 要： 针对图像细节增强过程中梯度对噪声敏感的缺点， 本文提出了一种改进的基于差分曲率和对比度场的细节增强算法。首先， 该算法利用差分曲率代替梯度值决定系数的放大倍数， 以差分曲率作为自变量的放大系数函数考虑了更多的邻域像素， 从而克服了图像梯度对噪声敏感的缺点； 然后， 利用该放大系数非线性地放大对比度场， 并构造能量泛函； 最后， 通过变分方法得到增强后的图像。标准测试图像和工业X射线图像的实验结果表明， 本文提出的算法在有效增强图像对比度的同时， 能够较好地抑制噪声。
关键词： 图像增强； 对比度场； 差分曲率； 变分增强方法
引用格式： LIU Yi, CHEN Yan, GUI Zhi-guo. An improved detail enhancement algorithm based on difference curvature and contrast field. Journal of Measurement Science and Instrumentation, 2016, 7(3)： 247-254. ［doi： 10.3969／j.issn.1674-8042.2016.03.007］
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