JPEG-Based Image Coding Algorithm at Low Bit Rates with Down-Sampling and Interpolation

The JPEG standard is the most commonly employed lossy compression method for still continuous-tone images due to its high effectiveness and low computational complexity. However, the visually disturbing blocking artifacts generates when image is compressed at low bit rates. JPEG-based image coding algorithm has shown that employing down-sampling to a low resolution before JPEG and subsequently interpolating the decompressed image to the original resolution can improve the overall PSNR performance. In this paper, the all phase discrete cosine transform (APDCT) filter which can be used as antialiasing low-pass filter is designed. And two interpolation methods, cubic interpolation and APDCT interpolation are proposed for further performance improvement. The experimental results presented clearly exhibit an improvement over existing approaches in terms of PSNR and visual quality while keeping low computational complexity.