Split and Merge

• one possible segmentation algorithm
• Algorithm:
  Step 1 - SPLIT
  Recursively splits an image region (which starts out as the entire image) by dividing it into quarters. Feature vectors are computed for each block.
  • If the four blocks are judged to be similar, they are grouped back together and the process ends.
  • If not, each of the blocks are recursively divided and analyzed using the same procedure.
    
    

  Step 2 - MERGE
  When we are finished, there will be many different sized blocks, each of which has a homogeneous texture according to our model. However, the arbitrary division of the image into rectangles (called a ``quad-tree'' decomposition) might have accidentally split up regions of homogeneous texture. The merge step, then, tries to fix this by looking at adjacent regions that were not compared to each other during the split phase, and merging them if they are similar.

• The resulting regions will not be rectangular, but hopefully they will give a satisfactory result.