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ISIS Documentation

lromakeflat

Create a flat-field image for line-scan, push-frame, and framing instruments

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:
    Mean Calculation:
    Sum( Sum(FrameColumn) / Average(Frame) * ValidPixels(FrameColumn) ) / TotalColumnValidPixels
    Median Calculation:
    Median(PixelColumn(ValidPixel / Average(Frame)))

  • Push Frame

    • Mean Calculation:
    The equation for the final single framelet, single band flat field file is:
    Average( PixelInFramelet1, PixelInFramelet2, PixelInFramelet3, ... )
    Median Calculation:
    Median(PixelColumn(ValidPixel / Average(Frame)))

  • Framing

    • Mean Calculation:
    The equation for the final single framelet, single band flat field file is:
    Average( PixelInCube1, PixelInCube2, PixelInCube3, ... )
    Median Calculation:
    Median(PixelColumn(ValidPixel / Average(Frame)))

Warning: This program creates potentially large temporary files

Categories

History

Victor Silva2016-09-12 Original version, Adapted from Isis version of makeflat.

Parameters

Files

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

Output prefix of the flat field cube's name
Type cube
File Mode output
Pixel Type real

Output PVL-formatted file of all excluded files and sections of data.
Type filename
File Mode output
Internal Default None

Camera Options

The type of camera that captured the input image.
Type string
Default LINESCAN
Option List:
Option Brief Description
LINESCANLine scan camera Line scan cameras collect an image a single line of data at a time. This option makes the flat field a single line of data.

Exclusions

  • FRAMELETHEIGHT
  • HEIGHT_LINES

Inclusions

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

Exclusions

  • NUMLINES
  • HEIGHT_LINES

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

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

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

Processing Options

If this pre-processing step was not done prior, Makeflat will normalize each pixel by the frame's mean in order to normalize to 1. You can select image dimensions (height and width in pixels) to use when calculating frame mean.
Type string
Default NO
Option List:
Option Brief Description
YES The normalization process will be applied. The normalization process will be applied to each pixel location prior to stacking.

Inclusions

  • WIDTH_PIXELS
  • HEIGHT_LINES
NO The normalization process will not be applied. Each pixel location will not be normalized prior to stacking.

Exclusions

  • WIDTH_PIXELS
  • HEIGHT_LINES

Any pixel column averages beyond this boundary will be excluded. The default value is +- 1 standard deviation. Any pixel column average within this range will be included.
Type double
Default 2

Normalization Options

If value is left at zero, pixels will be normalized using entire width frame of image.
Type integer
Default 0

If LINESCAN, height will always equal 1. If value is left at zero and is not LINESCAN, pixels will be normalized using entire frame height of image.
Type integer
Default 0