ISIS Documentation

hiccdstitch

Stitch together multiple HiRISE CCD images

This program combines images from multiple HiRISE CCDs into a single output image file. The output file can be considered to be a special type of mosaic in which the different CCD images are placed next to each other in positions that correspond to detector numbers. The input files must each contain both channels of a single detector, which are the files produced by the "histitch" program. CCD images with lower CCD numbers are placed into the output file to the left of CCD images with higher CCD numbers. By default the CCD images are placed into the output file from left to right, i.e., in order of increasing CCD number. This order can be changed with the MosaicOrder keyword in the "shiftdef" file.

Images are inserted at locations corresponding to the relative offsets of the detectors. In most cases, pixel replication is used when processing an input image so that it matches the scale of the image with the lowest summing mode. However, if any of the input images were observed with a summing mode of 3, then pixel replication is used for all images to match the scale that would have been obtained with a summing mode of 1. No resampling of input pixel values is done.

In many cases, adjacent images do not line up vertically due to observing conditions and other factors. The SHIFTDEF parameter allows the user to apply arbitrary offsets in lines to any or all the input images so they align properly.

It has been determined that summing modes add an additional delay to imaging due to pre-cycling of the detector electronics. Typically, images have an additional 180 * (summing mode - 1) lines delay in the actual imaging of the target. These lines are unbinned, not subject to the summing mode applied during imaging. This is not an issue if all images being stitched by this application are the same summing mode. If images with different summing modes are acquired in the same observation, then this offset is automatically applied to the images with differing summing modes. This will result in adding lines of offset to some images and increasing the number of lines in the resulting output image.

The input files may contain multiple bands but all input files must contain the same number of bands. This is useful for creating color products where the input files are compatable with the constraints of this application.

Categories

History

Jim Torson2005-06-24 Original version
Kris Becker2006-03-02 Eliminated the requirement that all CCDs be adjacent. As a side effect, 24 pixels on the left edge of the adjacent CCDs are no longer clipped but are layed on top of the last 24 pixels on the right side of preceding CCDs.
Kris Becker2006-03-31 Added the SHIFTDEF parameter that allows for offsets to be provided for any CCD. Also added the PLACEMENT parameter that writes the line and sample coordinate of each CCD in the output TO file.
Kris Becker2006-09-27 Added recently discovered time delay as a function of summing modes. This adds lines of offset to images with higher summing modes. These lines are unbinned but are subject to the smallest occuring summing mode in that the offsets are reduced by the number of offsets divided by the minimum summing mode.
Kris Becker2006-11-27 Modified to allow a single CCD image file as input to hiccdstitch. Previously, two or more CCDs image files were required. With this change only one need be provided (to expedite pipeline processing).
Tracie Sucharski2007-03-13 Modified to allow user to determine the order the ccd's are laid down through the use of the MosaicOrder keyword in the shiftdef file. Also added option to replicate pixels by nearestNeighbor, Bilinear or cubicConvolution. Also deleted ChannelNumber and CpmmNumber keywords so that output image cannot be projected.
Kris Becker2007-07-31 Modified to allow for stitching of multiband cubes. This will allow users to create color products as long all files have the same number of bands.
Steven Lambright2008-05-13 Removed references to CubeInfo