ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

Chapter 14
Image analysis and display
This chapter serves as an introduction to the variety of image and cube analysis, and display
routines in CIA.
They are categorised as:
• General analysis routines that perform some type of statistical or photometric analysis:
xsnr, xradial, flux sum, xphot.
• CVF image analysis routines: cvf display.
• Image analysis routines that only operate on 2D images: xdisp.
• Cube analysis routines that operate on a cube, yielding temporal and spatial information
on a pixel: xselect frame, show frame, xsubcube, xcube, x3d, xv temp, xv raster,
xmovie.
• Image display routines that just display images or images from cubes: tviso and xv sscd.
• Image overlaying routines: isocont, x isocont.
• Finally routines to aid you to produce postscript output: xcontour, ps color, white,
black, ps open, ps print.
14.1 General analysis routines
These routines are xsnr for S/N estimation, xradial for determining the energy radial profile
and flux sum for estimating the flux from a point source.
14.1.1 Estimating S/N in a cube or image
Estimating S/N in a CAM image is a useful indicator of the strength of source detection or the
quality of a calibration.
xsnr is a widget based program that is used to interactively choose noise and signal regions
in an image. The image could be the MOSAIC (.RASTER in a raster PDS) or an EXPOSURE
(.IMAGE in all PDSs). As an example we can take the fifth EXPOSURE from a CVF PDS.
CIA> xsnr, cvf_pds.image(*,*,4)
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