Zonal DCT Coding
Toggle between masks to see how many DCT coefficients survive and how the reconstruction looks.
All presets operate on 8×8 blocks of the demo image.
DCT transformed image (log scale)
Bright spots mark coefficients that survive the quantization matrix.
Inverse DCT transformed image
Reconstructed demo image using the zonal mask.
Frequency quantization matrix
Higher numbers preserve more energy for the corresponding frequency. Zeros fully discard a coefficient.
Entropy
SNR
PSNR