Class BoundaryAverage

  • All Implemented Interfaces:
    Serializable, Component, Processor

    public class BoundaryAverage
    extends Object
    implements Processor
    This class adjusts the 0 point for data taken from multiple images to try to minize edge effects. The alogithm used in this version is as follows:
    1. Find all of the 'edge' pixels in the image and compute the jump over the edge.
      • We determine the edge pixels by looking at the source images of pixels which differ by one in the x or y dimension. We sweep in both directions
      • The jump is simply the change in value between the two pixels.
    2. Add the jump at each edge pixel to the any previous jumps for these two source images. When we finish we have a matrix of the total deltas along the edges shared by each pair of images. We compute the delta's in both directions, so that deltas[a][b] = - deltas[b][a] Also keep track of the number of edge pixels for each pair of images. [Note that many of the candidate images will not have been used in any pixels in the output image. This will simply correspond to empty rows and columsn in the deltas and counts matrices.]
    3. Create an offset array with a NaN offset for each input image.
    4. Find the source image which has the maximum number of pixels in the output image. Make this the base image with an offset of 0.
    5. Consider the source images in two sets: the set for which an offset has been defined, and a set for which it has not. Initially only the base image is in the first set and all others are in the undefined set.
    6. Find the largest entry in the counts matrix where the row corresponds to an image with a defined offset, and the column corresponds to an image with an undefined offset.
    7. Assign an offset to the image associcated with the column such that the total delta along the edge should become 0. Remember that the defined image will change too.
    8. Iterate until all images have an offset defined.
    See Also:
    Serialized Form
    • Constructor Detail

      • BoundaryAverage

        public BoundaryAverage()
    • Method Detail

      • process

        public void process​(Image[] inputs,
                            Image output,
                            int[] source,
                            Sampler samp,
                            DepthSampler dsamp)
        Initialized the de-edger.
        Specified by:
        process in interface Processor
        Parameters:
        inputs - The input images.
        output - The output user image
        source - The index array
        samp - The spatial sampler (not used)
        dsamp - The energy sampler (not used)
      • updateHeader

        public void updateHeader​(nom.tam.fits.Header h)
        Update a FITS header with the processing done here.
        Specified by:
        updateHeader in interface Processor