Some new features of CCDPACK V4

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CCDPACK version 4

The main new features in CCDPACK version 4 are much improved interactive graphical facilities for image display and registration, and the ability to process data from mosaic cameras much more easily.

This picture shows the interactive image display task IDICURS displaying a group of frames from the INT Wide Field Camera. The data files themselves have not been resampled, but by use of a suitable AST file (constant for all data from that instrument) the CCD alignment and non-linear distortions are taken care of in the display. The image can be zoomed and scrolled, the brightness adjusted, and points from associated position list files added (optionally with automatic centroiding) and removed.

IDICURS screenshot displaying a set of WFC frames

For interactive alignment of images, the PAIRNDF task is provided. It first of all displays a chooser window which allows you to select two images which have a region in common, like this:

PAIRNDF screenshot showing the chooser widget

Selecting one of the tabs on the left or right brings up the corresponding image so you can see the area it covers. Once you have a suitable pair, the aligner window is shown:

PAIRNDF screenshot showing the aligner widget ready to align

You can drag the images around with the mouse until they are aligned, and then mark features in the overlap region. These are centroided on both images when they are identified so you can check the same feature has been located in each. Here is what it looks like when alignment of a pair is complete:

PAIRNDF screenshot showing images aligned in the aligner widget

Like other CCDPACK tasks, PAIRNDF can be used just as well on sets of images from one exposure of a mosaic camera. Here is what the aligner window looks like ready to align a couple of such sets:

PAIRNDF screenshot showing the aligner widget with WFC sets

Once registration has been done the new task DRAWNDF can be used for non-interactive display of the images in their aligned positions. The outlines, the images themselves, or both can be drawn, with a selection of annotations, aligned with previously displayed graphics if required. This example shows the outlines of a set of frames plotted over the mosaic image which was created from them:

DRAWNDF screenshot with outlines plotted over a mosaic

Written by Mark Taylor

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Last modified: 02-Jun-2016
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