>  Docs Center  >  ENVI API  >  ENVIFlatFieldCorrectionTask

ENVI

ENVIFlatFieldCorrectionTask

ENVIFlatFieldCorrectionTask

This task performs Flat Field correction to normalize images to an area of known flat reflectance. This is particularly effective for reducing hyperspectral data to relative reflectance.The average spectrum from a region of interest (ROI) can be used as the reference spectrum, which is then divided into the spectrum for each pixel of the image.

Example


; Start the application
e = ENVI()
 
; Open an input file
File = Filepath('qb_boulder_msi', Subdir=['data'], $
  Root_Dir=e.Root_Dir)
Raster = e.OpenRaster(File)
 
; Open ROIs
fileName = Filepath('qb_boulder_roi.xml', SUBDIR=['data'], $
  ROOT_DIR=e.Root_Dir)
rois = e.OpenRoi(fileName)
 
; Calculate ROI statistics
TaskStats = ENVITask('ROIStatistics')
TaskStats.INPUT_RASTER = Raster
 
; Specify the ROI for Water. We assume that water pixels 
; have flat spectra.
TaskStats.INPUT_ROI = rois[2]
 
; Run the task
TaskStats.Execute
 
; Get the task from the catalog of ENVITasks
Task = ENVITask('FlatFieldCorrection')
 
; Define inputs
Task.INPUT_RASTER = Raster
Task.MEAN = TaskStats.MEAN
 
; Run the task
Task.Execute
 
; Get the collection of data objects currently available in the Data Manager
DataColl = e.Data
 
; Add the output to the Data Manager
DataColl.Add, Task.OUTPUT_RASTER
 
; Display the result
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)

Syntax


Result = ENVITask('FlatFieldCorrection')

Input properties (Set, Get): INPUT_RASTER, MEAN, OUTPUT_RASTER_URI

Output properties (Get only): 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.

Methods


This task inherits the following methods from ENVITask:

AddParameter

Execute

Parameter

ParameterNames

RemoveParameter

Properties


This task inherits the following properties from ENVITask:

COMMUTE_ON_DOWNSAMPLE

COMMUTE_ON_SUBSET

DESCRIPTION

DISPLAY_NAME

NAME

REVISION

TAGS

This task also contains the following properties:

INPUT_RASTER (required)

Specify a raster on which to perform flat field correction.

MEAN (required)

Specify an array of floating-point values to divide into each band. The array size must be equal to the number of bands in the raster. To perform proper Flat Field correction, these mean values should be computed from a set of pixels of known flat spectral response.

OUTPUT_RASTER

This is a reference to the output raster of filetype ENVI.

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 property, or set it to an exclamation symbol (!), a temporary file will be created.

Version History


ENVI 5.5, Service Pack 1

Introduced

API Version


3.3

See Also


ENVITask, ENVITask::Parameter, ENVIDarkSubtractionCorrectionTask, ENVIIARReflectanceCorrectionTask, ENVIQUACTask



© 2019 Harris Geospatial Solutions, Inc. |  Legal
My Account    |    Store    |    Contact Us