基于通用三原色信道的四原色图像颜色表示方法

Representing four-primary-color image based on three-primary-color channels

本文针对当前多原色宽色域成像系统的图像信号无法在现有标准三原色信道传输、以及多原色宽色域显示系统没有多原色图像源的问题,提出了一种基于通用三原色信道的四原色图像颜色表示方法。由四原色构成的四边形被分解为两个三角形,位于每个三角形内的复合色光可以由三原色进行唯一地表达。若四原色成像系统摄取的彩色像素位于由红绿蓝三原色构成的三角形内,该像素将按照标准YUV格式进行编码,形成YUV序列;若四原色成像系统摄取的彩色像素不位于由红绿蓝三原色构成的三角形内,该像素将采用非标准YUV格式进行编码,也形成YUV序列。标准YUV格式与非标准YUV格式的区别使得解码器能够盲识别彩色像素来自红绿蓝三原色还是来自其他三原色,从而使得宽色域视频显示系统使用相应的三原色进行正确显示。实验结果表明:本文提出的图像编码方法可以完全利用标准三原色信道传输四原色图像信号,解码器可以100%正确识别YUV信号的三原色来源。作者利用JPEG图像压缩算法测试YUV序列,相较于RGB三原色系统下的标准YUV序列,非红绿蓝三原色下的YUV序列压缩率提升0.07~5.99,色域覆盖率远远超过Pointer色域,更加接近人眼可视色域。

To overcome the problem that images captured by the current imaging system with the multi-primary-color image sensor cannot be transmitted under the three-primary-color channel,as well as the wide color gamut display system using multi-primary color filters or backlight does not have multi-primary-color image contents,this paper presents a method transmitting four-primary-color images only with the data amount of the YUV format.The quadrilateral constituted by four-primary colors is decomposed into two triangles so that one can represent a composite color uniquely using the corresponding three-primary colors.If a composite color lies in the RGB triangle,it can be encoded according to the standard YUV format.Otherwise,it can be encoded in a non-standard YUV format.The difference between standard YUV format and non-standard YUV format enables the decoder to blindly identify the source of the YUV data stream.In this way,the display can render the color in question using three corresponding primaries.The experimental results show that the proposed image coding method can completely deliver the four-primary-color image signals using the YUV data amount.Decoder can identify the source of the YUV data stream absolutely.Using JPEG compression algorithm to test the YUV sequence,the compression ratio is increased by 0.07~0.59 compared to the RGB three-primary-color system.The gamut coverage far exceeds the Pointer gamut,even is closer to the visible gamut of the human eye.