Image compression using the Iteration-Tuned and Aligned Dictionary

We present a new, block-based image codec based on sparse representations using a learned, structured dictionary called the Iteration Tuned and Aligned Dictionary (ITAD). The question of selecting the number of atoms used in the representation of each image block is addressed with a new, global (image-wide), rate-distortion-based sparsity selection criterion. We show experimentally that our codec outperforms JPEG2000 in both quantitative evaluations (by 0.9 dB to 4 dB) and qualitative evaluations.