Imaging in ChIPS

Miller, Joseph

The Chandra Interactive Plotting System (ChIPS) included in CIAO 4.2 allows users to incorporate and manipulate images in their plots. ChIPS uses the Visualization Toolkit (VTK) backend to provide basic imaging support, which includes displaying images in pseudocolor or RGBA true color, adjusting the translucency of images, and several ways to threshold images. Because ChIPS treats images as generic plot objects, users have the ability to enhance them with annotations and place curves and contours directly onto the image. ChIPS image support provides a mechanism to adjust the image display resolution as necessary to provide high quality publication ready output.

Beyond basic imaging, ChIPS includes the ability to recognize and incorporate WCS metadata into plots. Coming with CIAO 4.3, ChIPS accurately calculates the intersections of world coordinate grids and plot axes, ensuring that these elements distort correctly with a tangent plane projection. Multiple images overlays are handled by reprojecting the overlayed images onto the reference image's coordinate system. New zooming and panning functions, and existing limits commands, use the WCS information from the image overlays to update the axes to reflect the new field of view being displayed.

Although ChIPS already provides a number of user interactive commands, additional interactive capabilities are being considered for future releases. New interfaces, including dialog boxes to adjust properties of ChIPS objects, and the ability to select and manipulate objects directly, are being explored to provide users easier means of updating and adjusting their visualizations. Enhanced interactive interfaces alongside the ability to script ChIPS in Python provide a more capable and user-friendly system.

Support of the development of ChIPS is provided by National Aeronautics and Space Administration through the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics and Space Administration under contract NAS8-03060.

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