Efficient gamut clipping for color image processing using LHS and YIQ
Efficient gamut clipping for color image processing using LHS and YIQ
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DOI：
10.1117/1.1544479
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发表时间：
2003-03
影响因子：
1.3
通讯作者：
Christopher C. Yang;S. Kwok
中科院分区：
文献类型：
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作者：
Christopher C. Yang;S. Kwok
在彩色图像处理和不同设备中的颜色再现中存在色域外问题。已经对将色域外的颜色转换到输出设备的色域内以进行颜色再现进行了广泛的研究。本文主要研究彩色图像处理中的色域外问题。亮度，色调和饱和度（LHS）和YIQ颜色坐标系进行了研究。提出了用于亮度和饱和度处理以及色域裁剪的有效技术。提出了基于缩放的LHS亮度限幅技术和基于平移的YIQ亮度限幅技术。然而，用于LHS和YIQ两者的饱和限幅的有效技术是缩放和移位的组合。这种有效的技术显著地降低了表示颜色坐标系（RGB）的颜色与处理颜色坐标系（LHS或YIQ）之间的前向和后向变换的复杂性。插图显示RGB、亮度和饱和度裁剪的结果。饱和度裁剪在保持原始图像的色调和对比度方面是最好的。还进行了实验，以衡量所提出的有效技术的效率。实验结果表明，与传统的前后向颜色变换方法相比，该方法的处理时间减少了27%。© 2003年摄影光学仪器工程师协会。
Out-of-gamut problems exist in color image processing and color reproduction in different devices. Extensive research has been done on transforming out-of-gamut colors to the inside of the output device's color gamut for color reproduction. We focus on the out-of- gamut problem in color image processing. Luminance, hue, and satura- tion (LHS) and YIQ color coordinate systems are investigated. Efficient techniques for luminance and saturation processing and gamut clippings are presented. The efficient technique of luminance clipping for LHS is developed based on scaling, and the efficient technique of luminance clipping for YIQ is developed based on shifting. However, the efficient technique of saturation clipping for both LHS and YIQ is a combination of scaling and shifting. Such efficient techniques reduce the complexity of forward and backward transformations between the color representing the color coordinate system (RGB) and the processing color coordinate system (LHS or YIQ) significantly. Illustrations show the result of RGB, luminance, and saturation clippings. Saturation clipping is the best in terms of maintaining the hue and contrast of the original image. Experi- ments are also conducted to measure the efficiency of the proposed efficient techniques. It shows that the processing time is reduced by 27% comparing with the conventional technique using forward and backward color transformations. © 2003 Society of Photo-Optical Instrumentation Engineers.