Image-Compression

Overview

• Implementation of JPEG Image Compression algorithm with Lloyds-Max quantizer in MATLAB.
• Implemented and tested on Xilinx Artix-7 FPGA.

Block Diagram

LLOYDS-MAX ALGORITHM

• Aim- Minimize data loss.
• Assume that the number M of quantizer levels and the pdf fU (u) are given.

1. Choose an arbitrary initial set of M representation points a1 < a2 < ··· < aM.
2. For each j;1 ≤ j ≤ M−1, set bj = 1/2 (aj+1 + aj ).
3. For each j;1 ≤ j ≤ M, set aj equal to the conditional mean of U given U ∈ (bj−1, bj ] (where b0 and bM are taken to be −∞ and +∞ respectively).
4. Repeat steps (2) and (3) until further improvement in MSE is negligible; then stop.

• The MSE decreases (or remains the same) for each execution of step (2) and step (3).
• Since the MSE is nonnegative, it approaches some limit.
• Thus if the algorithm terminates when the MSE improvement is less than some given ε > 0, then the algorithm must terminate after a finite number of iterations.

Results