This task performs a simple atmospheric correction by subtracting a value from each band to account for atmospheric scattering (haze). The digital number (DN) to subtract from each band can be either the band minimum, an average based upon an region of interest (ROI), or a specific value. If the user does not provide an ROI or array of values, the band minimum is used.
Example
This example subtracts the band minimum DN value of each band.
e = ENVI()
File = Filepath('qb_boulder_msi', Subdir=['data'], $
Root_Dir=e.Root_Dir)
Raster = e.OpenRaster(File)
Task = ENVITask('DarkSubtractionCorrection')
Task.INPUT_RASTER = Raster
Task.Execute
DataColl = e.Data
DataColl.Add, Task.OUTPUT_RASTER
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)
Syntax
Result = ENVITask('DarkSubtractionCorrection')
Input parameters (Set, Get): INPUT_RASTER, OUTPUT_RASTER_URI, VALUES, ROI
Output parameters (Get only): OUTPUT_RASTER
Parameters marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Parameters marked as "Get" are those whose values you can retrieve but not set.
Input Parameters
INPUT_RASTER (required)
Specify a raster on which to perform dark subtraction correction.
ROI (optional)
Specify an ROI of dark regions which contain the average value to subtract from each band.
OUTPUT_RASTER_URI (optional)
Specify a string with the fully qualified filename and path of the associated OUTPUT_RASTER.
- If you do not specify this parameter, or set it to an exclamation symbol (!), ENVI creates a temporary file.
- If you set it to the hash symbol (#), ENVI creates a file in the temporary directory, but this file will not be deleted when ENVI closes.
VALUES (required)
Specify a digital number (DN) value or array of DN values to subtract from each band. The number of elements in the array must match the number of bands.
Output Parameters
OUTPUT_RASTER
This is a reference to the output raster of filetype ENVI.
Methods
Execute
Parameter
ParameterNames
Properties
DESCRIPTION
DISPLAY_NAME
NAME
REVISION
TAGS
Version History
ENVI 5.2 |
Introduced |
ENVI 6.1 |
Added the ROI keyword and default band minimum.
|
See Also
ENVITask, ENVISubsetRaster, FlatFieldCorrection Task, IARReflectanceCorrection Task, QUAC Task, Masking Support in ENVITasks