Algorithm for improving the performance of JPEG image coding

The standard JPEG algorithm is improved by increasing its compression efficiency and reducing block artifacts. The improved algorithm first uses spatial block prediction to reduce spatial redundancy, then uses DCT, quantization, and entropy coding to compress the prediction errors. The spatial block prediction has two modes: DC prediction and plane prediction, each of them followed by a block smoother. Simulation results show that the improved algorithm achieves a bit rate saving of up to 13.7%, compared with the standard JPEG algorithm. It also improves subjective image quality by reducing blocking artifacts.