ISIS Application Documentation
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Create a flat-field image for line-scan instruments
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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.
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
The equation for the final single framelet, single band flat field file is:
Average(
PixelInFramelet1, PixelInFramelet2, PixelInFramelet3, ... )
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
Name | Description |
---|---|
FROMLIST | List of input cubes |
TO | Output flat field cube |
EXCLUDE | Output PVL-formatted file of all excluded files and sections of data |
Name | Description |
---|---|
STDEVTOL | This is the maximum standard deviation |
Name | Description |
---|---|
IMAGETYPE | This is the type of camera which took the image. |
Name | Description |
---|---|
NUMLINES | This is the the number of lines to consider when doing statistics |
Name | Description |
---|---|
FRAMELETHEIGHT | This is the height of each framelet in the image. |
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 flat field cube
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 |
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 |
---|
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: |
|
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 |
---|
Line Scan Cubes
This is a typical run for the linescan mode
Parameter Name:
IMAGETYPE This is a typical run for makeflat. files.lis is a list file generated by a "ls *.cub > files.lis" command. The files inside of files.lis are between 20,000 lines and 200,000 lines of data (variable length). The file flat.linescan.cub is the flat-field output given these cubes and the file exclude.txt is a detailed output of what was excluded. |
|
This is a section of one of the inputs listed in files.lis
Parameter Name:
FROMLIST This is the input to makeflat. Notice the vertical lines persistent throughout the image and the dark area on the right-hand side. |
|
This is input that has been calibrated This is the same section of image data as before, except calibrated with the flat-field file that was generated by dividing by the flat field file. The vertical lines and darkness have completely gone away. |
Tracie Sucharski | 2007-06-20 | Original version, Adapted from Isis2 version of makeflat. |
Steven Lambright | 2008-05-13 | Removed references to CubeInfo . |
Steven Lambright | 2008-06-11 | Changed algorithm and added support for framing and push frame cameras. |
Ian Humphrey | 2014-06-23 | Cleaned up spacing in pushframe test Makefile |