An Effective Bicubic Convolution Interpolation-Based Iterative Luma Optimization for Enhancing Quality in Chroma Subsampling

Traditionally, prior to compressing an RGB full-color image, for each converted $2\times 2$ CbCr block $B^{CbCr}$ , chroma subsampling only downsamples but without changing the luma $B^{Y}$ at all. In current research, a special linear interpolation-based, namely COPY-based, subsampling-first modification (CSFLM) study has attempted change enhancing quality of reconstructed image. this paper, fast and effective nonlinear interpolation, bicubic convolution interpolation (BCI), based iterative method CSFLM is proposed. our method, BCI-based distortion function its convex property proof are first provided. Next, on proposed function, pseudoinverse technique applied obtain initial solution, then improve solution. Based five testing image datasets, IMAX, Kodak, SCI (screen content images), CI (classical Video thorough experimental results have demonstrated that newly released Versatile Coding (VVC) platform VTM-12.0, achieves substantial quality, execution-time, quality-bitrate tradeoff improvements when compared with existing state-of-the-art methods.