Quadtree decomposition (Encoding) and Decoding of RGB Image

Quadtree decomposition (Encoding) and Decoding of RGB Image of size M-by-N-by-3.

Quadtree Decomposition of an RGB Image (M × N × 3)

This method performs Quadtree decomposition on an RGB image of size M × N × 3, using three separate thresholds for the red, green, and blue components.

For any R, G, or B block, if the difference between the maximum and minimum values of the block exceeds its respective threshold, the RGB block is split into four smaller blocks.

In lossy encoding, the mean values of the R, G, and B components are assigned to the corresponding RGB block. If the image size is not a power of 2, it is padded to ensure division continues down to a block size of 1 × 1.

Thresholds

Thresholds are specified as values between 0 and 1 (0 for lossless encoding).

• If the image is of type uint8, the threshold is multiplied by 255 to determine the actual threshold.
• If the image is of type uint16, the threshold is multiplied by 65535 to determine the actual threshold.

🔹 No toolbox is required.

main.m

A test program for Quadtree decomposition (encoding) and decoding of an RGB image.

Reference

📖 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, Vol. 1, No. 3, pp. 263–283, Nov. 2007.