The Bayer color filter array (CFA) pattern has been widely used in modern digital color cameras, and the captured image is called the Bayer CFA image IBayer. Chroma downsampling is a necessary and important step in the coding system. In this paper, a novel and optimal luma modification-based chroma downsampling (LMCD) method is proposed for IBayer. For each converted 2 x 2 YUV block, the downsampled (U, V)-pair and the modified luma values by the proposed LMCD method can be optimally determined, and the optimal variant of our LMCD method associated with the two modified luma values has the best quality among all sixteen variants of LMCD. Based on the Kodak and IMAX datasets, on the High Efficiency Video Coding (HEVC) platform HM-16.18, the Versatile Video Coding (VVC) platform VTM-8.0, and the Joint Photographic Experts Group (JPEG) platform, the comprehensive experimental data showed the substantial quality and quality-bitrate tradeoff merits of the reconstructed images by our optimal LMCD method relative to the traditional and state-of-the-art chroma downsampling methods.

中文翻译：

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针对拜耳滤色镜阵列图像的基于新颖且最佳亮度修改的色度下采样


拜耳滤色器阵列（CFA）图案已广泛应用于现代数码彩色相机中，捕获的图像称为拜耳CFA图像IBayer。色度下采样是编码系统中必要且重要的步骤。本文为 IBayer 提出了一种新颖且最优的基于亮度修改的色度下采样（LMCD）方法。对于每个转换的 2 x 2 YUV 块，可以通过所提出的 LMCD 方法最佳地确定下采样（U，V）对和修改后的亮度值，并且我们的 LMCD 方法与两个修改后的亮度值相关的最佳变体具有LMCD 所有 16 种变体中质量最好的。基于柯达和IMAX数据集，在高效视频编码（HEVC）平台HM-16.18、多功能视频编码（VVC）平台VTM-8.0、联合图像专家组（JPEG）平台上综合实验数据显示相对于传统和最先进的色度下采样方法，通过我们的最佳 LMCD 方法重建图像的实质质量和质量比特率权衡优点。