Question

I need to convert a image (square) into a quadtree, in the ‘usual’ way – slice it in four, check if there’s only one color into each piece; if yes: close the node, else: repeat;

Anyone know an opensource program to it?

Preferably in Java, but I can use any language.

Thanks.

Answer 1

I imagine you could easily write a program that does it for you in OpenCV. Provided you already have some data structure to hold the actual tree, the main function would look something like this (I’ve written it for gray images, but it’s only the test that needs repeating three times for color):

void divideAndConquer(Mat im, QuadTree &tree, int parent){
  if(parent<0) 
    return;
  double min,max;
  minMaxLoc(im,&min,&max);
  if(max-min<0.01)
    tree.addNode(parent,closed);
  else{
    tree.addNode(parent,open);
    Mat im0=Mat(im,Range(0,image.rows/2-1),Range(0,image.cols/2-1));
    Mat im1=Mat(im,Range(image.rows/2,image.rows),Range(0,image.cols/2-1));
    Mat im2=Mat(im,Range(0,image.rows/2-1),Range(image.cols/2,image.cols));
    Mat im3=Mat(im,Range(image.rows/2,image.rows),Range(image.cols/2-1,image.cols));
    divideAndConquer(im0, tree, parent/4);
    divideAndConquer(im1, tree, parent/4+1);
    divideAndConquer(im2, tree, parent/4+2);
    divideAndConquer(im3, tree, parent/4+3);
  }
}