Electronics Engineering Department, Ewha W. University, Seoul, Korea.
IEEE Trans Image Process. 2011 Feb;20(2):506-12. doi: 10.1109/TIP.2010.2068555. Epub 2010 Aug 26.
The majority of color histogram equalization methods do not yield uniform histogram in gray scale. After converting a color histogram equalized image into gray scale, the contrast of the converted image is worse than that of an 1-D gray scale histogram equalized image. We propose a novel 3-D color histogram equalization method that produces uniform distribution in gray scale histogram by defining a new cumulative probability density function in 3-D color space. Test results with natural and synthetic images are presented to compare and analyze various color histogram equalization algorithms based upon 3-D color histograms. We also present theoretical analysis for nonideal performance of existing methods.
大多数颜色直方图均衡化方法并不能在灰度级上产生均匀的直方图。将颜色直方图均衡化后的图像转换为灰度级后，转换后的图像的对比度比一维灰度级直方图均衡化图像的对比度差。我们提出了一种新的三维颜色直方图均衡化方法，通过在三维颜色空间中定义新的累积概率密度函数，在灰度级直方图中产生均匀分布。使用自然图像和合成图像进行了测试结果，以基于三维颜色直方图比较和分析各种颜色直方图均衡化算法。我们还对现有方法的不理想性能进行了理论分析。
