Why JPEG compression processes image by 8x8 blocks?
compression, dct, jpeg
Solution
8 X 8 was chosen after numerous experiments with other sizes.
The conclusions of experiments are: 1. Any matrices of sizes greater than 8 X 8 are harder to do mathematical operations (like transforms etc..) or not supported by hardware or take longer time. 2. Any matrices of sizes less than 8 X 8 dont have enough information to continue along with the pipeline. It results in bad quality of the compressed image.
Problem
Why JPEG compression processes image by 8x8 blocks instead of applying Discrete Cosine Transform to the whole image?