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ISIS Application Documentation

makeflat

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Create a flat-field image for line-scan instruments

Overview Parameters Example 1

Description

This program creates flat-field images for line scan, push frame, and framing instruments. All input cubes should have the same number of samples; any images in the list that do not have the same number of samples as the first image will not be used. The names of the cube files used to create the flat-field image must be entered using an ASCII file (FROMLIST) with one filename per line (any line beginning with a '#' or '//' is treated as a comment). The specific equation for each camera type is below.

  • Line Scan

    • A frame is a NUMLINES line section of data. The equation for the final single line, single band, flat field file is:
    Sum( Sum(FrameColumn) / Average(Frame) * ValidPixels(FrameColumn) ) / TotalColumnValidPixels

  • Push Frame

    • The equation for the final single framelet, single band flat field file is:
    Average( PixelInFramelet1, PixelInFramelet2, PixelInFramelet3, ... )

  • Framing

    • The equation for the final single framelet, single band flat field file is:
    Average( PixelInCube1, PixelInCube2, PixelInCube3, ... )

Warning: This program creates potentially large temporary files

Categories

History

Tracie Sucharski2007-06-20 Original version, Adapted from Isis2 version of makeflat.
Steven Lambright2008-05-13 Removed references to CubeInfo .
Steven Lambright2008-06-11 Changed algorithm and added support for framing and push frame cameras.
Ian Humphrey2014-06-23 Cleaned up spacing in pushframe test Makefile
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File Modified: 02/21/2025 19:28:12
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Files: FROMLIST

Description

Use this parameter to select the file which contains a list of cube filenames to be used to create the flat file.

Type filename
File Mode input
Filter *.lis
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Files: TO

Description

Output flat field cube

Type cube
File Mode output
Pixel Type real
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Files: EXCLUDE

Description

Output PVL-formatted file of all excluded files and sections of data.

Type filename
File Mode output
Internal Default None
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Statistical Options: STDEVTOL

Description

For a framing camera, this is the maximum standard deviation of each image. For a push frame camera, this is the maximum standard deviation of each framelet. For a line scan camera, this is the maximum standard deviation of NUMLINES lines. Data that exceeds this standard deviation will be ignored.

Type double
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Image Options: IMAGETYPE

Description

Line scan cameras collect a cube a single line of data at a time. Push frame cameras collect multiple lines of cube data at once. Framing cameras collect an entire cube of data at once.

Type string
Default LINESCAN
Option List:
Option Brief Description
LINESCANLine scan camera Line scan cameras collect a cube a single line of data at a time. This option makes the flat field a single line of data.

Exclusions

  • FRAMELETHEIGHT

Inclusions

  • NUMLINES
PUSHFRAMEPush frame camera Push frame cameras take multiple lines of cube data at once. This option makes the flat field a single framelet of data.

Exclusions

  • NUMLINES

Inclusions

  • FRAMELETHEIGHT
FRAMINGFraming camera Framing cameras collect an entire cube of data at once. This option makes the flat field the size of one of the input images.

Exclusions

  • NUMLINES
  • FRAMELETHEIGHT
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LINESCAN: NUMLINES

Description

A single line often does not have enough data in it to perform good tolerance calculations. The tolerance calculations will be performed on this many lines as a time, and if found to be invalid, this many lines will be excluded from the output flat file calculations at a time.

Type integer
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PUSHFRAME: FRAMELETHEIGHT

Description

Push frame images consist of framelets. The framelet size needs to be known in order to make a flat field file for a push frame camera.

Type integer
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