I've got a situation where I've got some large images (maybe on the order of 4000 pixels square - though many are not square) which have had crops made from them which are quite a bit smaller. 1200 pixels wide and 600 high is one fairly common example.
These crops were taken from the original, and with a reduced pixel count (that 1200x600 might represent a 3000x1500 pixel rectangle in the original image). Is there a reasonably robust and not-too-slow technique to extract the pixel coordinates representing the crop, given the two images? (I think in all cases that matter, the size reduction was the same in both height direction and width direction. Also, in all cases that matter, the crop was reduced in size, not magnified.) I am also interested in verifying that the coordinates are correct, but I expect that that can be done by creating a fresh crop using the coordinates and dimensions and comparing that with the original crop. (I don't think fourier transforms would get me where I need to be. I wonder if some sort of wavelet variation might?) Any clues appreciated... (executable code, if you have it,, would be great, but this seems too specialized for that to be a likely possibility). Thanks, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
