1.3 Compression - zeros grouping

Compression algorithm

Zeros grouping

The second part to our image framework is zeros grouping. Just like the JPEG standard, the algorithm utilizesa zig-zag pattern that goes through each DCT matrix and creates a 64-length vector for each matrix. The advantage of the zig-zagpattern is that it groups the resulting vector from low frequencies to high frequencies. Groups of zeros are then replacedwith an ASCII character representing how many zeros are represented within that group.

With this simple framework in place, we are able to model a real world image compression algorithm and focus onimplementing steganography.