This task performs a simple atmospheric correction by subtracting a user-specified digital number (DN) from each band to account for atmospheric scattering (haze).
This example uses the minimum DN value of each band as input to dark subtraction.
; Start the application
e = ENVI()
; Open an input file
File = Filepath('qb_boulder_msi', Subdir=['data'], $
Raster = e.OpenRaster(File)
; Process a spatial subset
Subset = ENVISubsetRaster(Raster, Sub_Rect=[600,200,799,399])
; Calculate basic statistics
Stats = ENVIRasterStatistics(Subset)
; Get the task from the catalog of ENVITasks
Task = ENVITask('DarkSubtractionCorrection')
; Define inputs
Task.INPUT_RASTER = Subset
Task.VALUES = Stats.Min
; Define outputs
Task.OUTPUT_RASTER_URI = e.GetTemporaryFilename()
; Run the task
; Get the collection of data objects currently available in the Data Manager
DataColl = e.Data
; Add the output to the Data Manager
; Display the result
View1 = e.GetView()
Layer1 = View1.CreateLayer(Task.Output_Raster)
Result = ENVITask('DarkSubtractionCorrection')
Input properties (Set, Get): IGNORE_VALIDATE, INPUT_RASTER, OUTPUT_RASTER_URI, VALUES
Output properties (Get only): DESCRIPTION, NAME, OUTPUT_RASTER
Properties marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Properties marked as "Get" are those whose values you can retrieve but not set.
This task inherits the following methods from ENVITask:
This property describes the task.
This property is now deprecated and has no effect on task behavior. All task property values are validated when they are set, and they throw an error with bad input.
Specify a raster on which to perform dark subtraction correction.
This property contains the name of the task.
This is a reference to the output raster of filetype ENVI.
Specify a string with the fully qualified filename and path of the output raster. If you do not specify this property, the output raster is only temporary. Once the raster has no remaining references, ENVI deletes the temporary file.
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.