目的:寻找一种更精确有效的医学图像局部对比度增强方法,解决磁共振图像中常出现的局部对比度不足问题.方法:在对已有算法研究的基础上,提出了新算法.新算法的特点是:形态学运算采用了非对偶运算,对比度扩展运算采用加法运算代替乘法运算.为避免灰度偏差,提出了条件归一方法.结果:用实用磁共振图像和模拟实验对新算法进行了测试.新算法在精度、运算速度及对噪声的敏感性方面都优于已有同类算法.结论:利用形态学非对偶运算能够以更精确的方式实现局部对比度增强,灰度级偏差可以通过归一化方法消除.%AIM: To find a more efficient and accurate method for medical image enhancement to resolve the problem of low local contrast, which often appears in magnetic resonance (MR) images.METHODS: Based on the investigation into the previous methods, a new algorithm was presented. The main features were as follows: Non-dual was used in the morphological operations and addition instead of multiplication was used in the contrast stretching operations. To avoid some gray-level bias, the method of normalized gray-level under condition was proposed.RESULTS: The new algorithm was tested by real MR images and simulated experiments. Compared with the previous method, the new method is more accurate, faster and less sensitive to noise.CONCLUSION: Non-dual morphological operations can achieve local contrast enhancement in a more accurate way, and the gray level bias can be eliminated by normalization.
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