Quadtree decomposition (Encoding) and Decoding of RGB Image

Quadtree decomposition of RGB image of size M-by-N-by-3. Three thresholds for red,green and blue components are used. For any R or G or B block if the maximum value of the block elements minus the minimum value of the block elements is greater than its respective threshold then the RGB block is split into 4 blocks. For lossy encoding (individual) mean value R,G,B are assign to RGB block. Image is padded if its size is not power of 2, so that image can be divided until block of size 1.

Thresholds are specified as a value between 0 and 1 (0 for lossless encoding). If Image is of type uint8 then threshold value is multiplied by 255, if Image is of type uint16 then threshold value is multiplied by 65535, to determine the actual threshold. No toolbox required.

main.m
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Test program for Quadtree decomposition (Encoding) and Decoding of RGB image

reference
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Murtaza Khan and Yoshio Ohno, "A hybrid image compression technique using quadtree decomposition and parametric line fitting for synthetic images". Advances in Computer Science and Engineering, 1 (3), pp. 263-283, Nov. 2007.