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ratiox stsdas.hst_calib.foc.focphot



ratiox -- Divide images so that relative DE corrections can be performed.


ratiox input denominator output


This task performs simple division of two (or more) files. The difference between this program and other image arithmetic tasks is that this task checks labels, and therefore, should be used for calculations involving relative detector efficiency (DE). This task also adjusts the image section of the denominator image and, if necessary, of the input image (i.e., if the denominator is too small), in order to avoid explicitly setting the image sections. The values of the SAMPBEG and LINEBEG keywords are used when adjusting the sections.


input [file name template]
The input image used as the numerator. This can be a single file, or a list of files.
denominator [file name]
The input image used as the denominator. This can be either a source nonuniform map, or the normalized image generated by dqenormx if the relative DE correction is being applied to a science image. In the latter case, the optical relay (OPTCRLY) and wavelength (WAVELEN) keywords are checked, both in the input and denominator files, and a warning is issued if these keyword values conflict.

In any case, the pixel format (PXFORMT) of the images should be compatible to prevent a zoomed image from being combined with a normal image. A fatal error occurs if the pixel formats conflict.

output [file name template]
List of file names in which to store output from ratiox. If the input file was a source nonuniform map (i.e., if the CALTYPE is set to "SOURCE_NON_UNIFORM"), the output file will have CALTYPE set to "SOURCE_NORMALIZED".


1. Divide a section of the image "in1" by the corresponding area of the image "in2". For example, if "in1" has SAMPBEG = 257, LINEBEG = 257 while "in2" has SAMPBEG = 1, LINEBEG = 1, the section "in2[266:276,296:306]" is used. .

fo> ratiox("in1[10:20,40:50]", "in2" ,"out")



This task was written by David Giaretta.


sourcegenx, dqenormx

Type "help focphot option=sysdoc" for a higher-level description of the focgeom package.

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