Inter-Layer Prediction of Color in High Dynamic Range Image Scalable Compression
Abstract of Inter-Layer Prediction of Color in High Dynamic Range Image Scalable Compression
Inter-Layer Prediction of Color in High Dynamic Range Image Scalable Compression
This Inter-Layer Prediction of Color in High Dynamic Range Image Scalable Compression.Two color representations are studied. In a first encoding scheme, the HDR image is represented in the classical Y’CbCr format. In addition, a second scheme is proposed using a colorspace based on the CIE u’v’ uniform chromaticity scale diagram. Our experiments highlight several advantages of using a CIE u’v’-based colorspace for the compression of HDR content, especially in a scalable context. In particular, this article deals with the scalable compression of HDR images or videos from a LDR base layer.
As regards the representation of color, the use of Y’CbCr colorspaces prevails in the compression of digital images and videos.
It has several advantages such as the reduction of the redundancy between RGB color components. The separation of an image data into a luma and two chroma channels also enables the down-sampling of the chroma signal for which the human visual system is less sensitive.
Conclusion
In the context of the scalable compression of HDR content with a LDR base layer, we have developed a new inter-layer prediction method specifically for the chromatic components. Our method is based on a model linking the colors in the HDR layer to those in the LDR layer. In particular, it follows the general assumption that the hues of the colors in an HDR image were preserved in the LDR version. In addition, the model uses a single parameter to adjust the saturations of the HDR colors in the prediction.
