ISIS Application Documentation
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Create a flat-field image for line-scan instruments
Description
Categories
Groups
Examples
History
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
- Push Frame
- Framing
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
Categories
Parameter Groups
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 |
Statistical Options
| Name | Description |
|---|---|
| STDEVTOL | This is the maximum standard deviation |
Image Options
| Name | Description |
|---|---|
| IMAGETYPE | This is the type of camera which took the image. |
LINESCAN
| Name | Description |
|---|---|
| NUMLINES | This is the the number of lines to consider when doing statistics |
PUSHFRAME
| Name | Description |
|---|---|
| FRAMELETHEIGHT | This is the height of each framelet in the image. |
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 |
Files: TO
Description
Output flat field cube
| Type | cube |
|---|---|
| File Mode | output |
| Pixel Type | real |
Files: EXCLUDE
Description
Output PVL-formatted file of all excluded files and sections of data.
| Type | filename |
|---|---|
| File Mode | output |
| Internal Default | None |
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 |
|---|
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: |
|
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 |
|---|
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 |
|---|
Examples
Example 1
Line Scan Cubes
Description
Command Line
GUI Screenshot
![Line-Scan Run](javascript:popUpNewWindow ("assets/images/linescan_gui.jpg",450, 550)) 
Line-Scan Run
|
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. |
![Line-Scan Input Image](javascript:popUpNewWindow ("assets/images/PSP_004398_1610_RED5_0.raw.crop.jpg",550, 550)) 
Line-Scan Input Image
|
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. |
![Line-Scan Calibrated Image](javascript:popUpNewWindow ("assets/images/PSP_004398_1610_RED5_0.corr.crop.jpg",550, 550)) 
Line-Scan Calibrated Image
|
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. |
History
| 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 |
| U.S. Department of the Interior | U.S. Geological Survey ISIS | Privacy & Disclaimers | Astrogeology Research Program To contact us, please post comments and questions on the USGS Astrogeology Discussion Board To report a bug, or suggest a feature go to: ISIS Github File Modified: 02/24/2025 16:09:13 |