skyview.geometry.imagefinder
Class RecursiveImageFinder

java.lang.Object
  skyview.geometry.ImageFinder
      skyview.geometry.imagefinder.RecursiveImageFinder

public class RecursiveImageFinder
extends ImageFinder

This class finds the best images to be used for sampling using a recursive rectangle algorithm.

• The output image is sampled in a rectangular grid with the samples spaced no more than half the image size of the input images.
• For each primary rectangle, the best image of any of the candidate input images for each corner pixel in the rectangle is determined.
  • If the output pixel does not deproject to the celestial sphere (e.g., it may be from an Aitoff projection outside of the region representing data), then the pixel is marked as not physical and no checking against the input images is performed.
  • The corner is projected into each candidate image.
  • If the corner is within the candidate image, this candidate is marked as a candidate if another level of recursion is needed.
  • If the distance from the corner to any of the edges is greater than for any previous input image, then this image is considered the best candidate so far.
  • After all candidate input images are considered the best candidate is returned, or the pixel is marked as not being available on any input image if the output pixel did not project to the interior of any image.
• If all four corners of a rectangle project to the same image (or if all four are non-physical, or not present on an input image), then this value is copied to all pixels within the rectangle.
• Otherwise, if the rectangle can be split then it is split into subrectangles and the check is performed on the sub-rectangles.
• Whenever a best image for a pixel is determined, that result is saved, so that only the 'new' corners in rectangles need to examined.
• When checking the split rectangles, only images that overlapped at least one of the four corners in the previous level are considered.

Constructor Summary

RecursiveImageFinder()

Method Summary

int[]

findImages(Image[] input, Image output) Find the best image for each output pixel.

Methods inherited from class skyview.geometry.ImageFinder

factory

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RecursiveImageFinder

public RecursiveImageFinder()

Method Detail

findImages

public int[] findImages(Image[] input,
                        Image output)

Find the best image for each output pixel.

Specified by:

findImages in class ImageFinder

Parameters:

input - An array of images from which the output image is to be interpolated.

output - An output image to be generated from the input. This method does not change the output image.

Returns:

An index array which for each pixel in the output image gives the best image to sample. Note that this has dimension int[nx*ny] where nx changes most rapidly. The values of the index array can be:

• >= 0: The pixel is best indexed with the given image.
• -1: [internal] The best image for this pixel has not yet been determined.
• -2: This pixel is not on any of the input images.
• -3: This pixel does not represent a physical coordinate.
• -4: [in other methods] this pixel has already been processed.