comparison toolboxes/FullBNT-1.0.7/KPMtools/rectintSparse.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function [overlap, normoverlap] = rectintSparse(A,B)
+%
+% A(i,:) = [x y w h]
+% B(j,:) = [x y w h]
+% overlap(i,j) = area of intersection
+% normoverla(i,j)
+%
+% Same as built-in rectint, but uses less memory.
+% Use rectintSparseC for a faster version.
+%
+
+leftA = A(:,1);
+bottomA = A(:,2);
+rightA = leftA + A(:,3);
+topA = bottomA + A(:,4);
+
+leftB = B(:,1)';
+bottomB = B(:,2)';
+rightB = leftB + B(:,3)';
+topB = bottomB + B(:,4)';
+
+numRectA = size(A,1);
+numRectB = size(B,1);
+
+%out = rectintSparseLoopC(leftA, rightA, topA, bottomA, leftB, rightB, topB, bottomB);
+
+nnz = ceil(0.2*numRectA*numRectB); % guess of number of non-zeroes
+overlap = sparse([], [], [], numRectA, numRectB, nnz);
+normoverlap = sparse([], [], [], numRectA, numRectB, nnz);
+for j=1:numRectB
+  for i=1:numRectA
+    tmp = (max(0, min(rightA(i), rightB(j)) - max(leftA(i), leftB(j)) ) ) .* ...
+	(max(0, min(topA(i), topB(j)) - max(bottomA(i), bottomB(j)) ) );
+    if tmp>0
+      overlap(i,j) = tmp;
+      areaA = (rightA(i)-leftA(i))*(topA(i)-bottomA(i));
+      areaB = (rightB(j)-leftB(j))*(topB(j)-bottomB(j));
+      normoverlap(i,j) = min(tmp/areaA, tmp/areaB);
+    end
+    %fprintf('j=%d, i=%d, overlap=%5.3f, norm=%5.3f\n',...
+    %	    j, i, overlap(i,j), normoverlap(i,j));
+  end
+end
+
+
+if 0
+N = size(bboxDense01,2); % 1000;
+rect = bboxToRect(bboxDense01)';
+A = rect(1:2,:);
+B = rect(1:N,:);
+
+tic; out1 = rectint(A, B); toc
+tic; out2 = rectintSparse(A, B); toc
+tic; out3 = rectintSparseC(A, B); toc
+tic; out4 = rectintC(A, B); toc
+assert(approxeq(out1, out2))
+assert(approxeq(out1, full(out3)))
+assert(approxeq(out1, out4))
+end