An effective bilinear interpolation-based iterative chroma subsampling method for color images

Kuo-Liang Chung, Szu-Ni Chen

Abstract: Prior to encoding a color image, such as the RGB full-color image IRGB, the Bayer color filter array (CFA) image IBayer, or the digital time delay integration CFA image IDTDI, performing chroma subsampling on the converted chroma image is a necessary step. Previously, several chroma subsampling methods were developed for IRGB, IBayer, and IDTDI independently. In this paper, we propose an effective bilinear interpolation-based iterative chroma subsampling method for the considered three image types simultaneously, achieving better reconstructed images. Based on the considered three types of images collected from the Kodak, IMAX, and SCI (screen content images), the comprehensive experimental results demonstrated that under the versatile video coding (VVC) platform, our chroma subsampling method achieves the best quality and quality-bitrate tradeoff of the reconstructed color images when compared with the existing chroma subsampling methods.