基于色调不变的彩色图像增强

Color Image Enhancement Based on Hue Invariability

色调是反映彩色图像中色彩信息的重要参数,为了在进行图像效果增强的同时保持色调不变,通常的做法是先把图像从RGB转化到HIS色彩空间,然后在保持H变量(色调)不变的情况下,进行I(亮度)的增强。但是这种方法由于需要进行色彩空间的相互转化,大大增加了计算量。通过对简化HIS模型的分析,提出了一种直接对R、G、B分量进行处理的彩色图像增强方法。该方法可以运用已有灰度图增强算法进行彩色图像的增强,由于不需要进行色彩空间的转化,大大减少了计算量,可用于实时性要求高的场合。实验结果表明,该方案使彩色图像的增强效果明显,运行效率高。

Hue is an important attribute of color information. Hue invariability is very important to color image enhancement. Normally, people transform the color space of image from RGB to HIS, then enhance the variable I （intensity） only. Because of the transformation between RGB and HIS is very complex, the program will compute for a long time. Therefor a new method of color image enhancement is proposed. After analyzing the simplified model of HIS, it is found that the hue will keep invariant if the R,G ,B multiplies or adds same number. So we can generalize the enhancement scheme for grey scale images to color images without transformation of color space. This paper also discusses the gamut problem and its solution. The gamut problem will lead to distortion of color. The method proposed by this article keeps off the transformation between RGB and HIS, so it can obviously simplify the computation. It is very useful in real-time situation. Experiment results have shown that the proposed method works well in enhancing color image, and it＇ s efficient.