An improved no-search fractal image coding method based on a modified gray-level transform

In this paper, we propose a fast no-search fractal image coding algorithm based on a modified gray-level transform. To improve the possibility of successful matching for a range block and a domain block, we introduce a modified gray-level transform with more transform parameters than proposed by Tong and Pi to encode the blocks. Then, we suggest a no-search fractal image coding method using two gray-level transforms, one for the large blocks and the other for the small blocks based on the quadtree partition scheme, to speed up the encoding time and improve the quality of the reconstructed images.