MixtureTunedMatchedFilter Task
This task performs a mixture tuned matched filter (MTMF) supervised classification.
Example
This example performs the following steps:
- Opens an AVIRIS hyperspectral image subset.
- Runs a forward minimum noise transform (MNF) to reduce noise in the data.
- Defines three regions of interest (ROIs), each containing nine pixels of a common material.
- Retrieves the spectra from the ROIs and uses their means as endmembers for mixture tuned matched filtering (MTMF).
- Runs the MTMF task, which performs matched filtering and adds an infeasibility image to the results. The infeasibility image is used to reduce the number of false positives that are sometimes found when using matched filtering.
- Displays the result. To see all of the bands, open the Data Manager. ENVI creates three MF Score images (one for each ROI) and three Infeasibility images.
; Start the application
e = ENVI()
; Open an input file
File = Filepath('AVIRISReflectanceSubset.dat', $
SUBDIR=['data', 'hyperspectral'], $
ROOT_DIR=e.Root_Dir)
Raster = e.OpenRaster(File)
; First run a Forward MNF on the data
Task = ENVITask('ForwardMNFTransform')
Task.INPUT_RASTER = Raster
Task.Execute
; Use the first 25 MNF bands to run a matched filter
Subset = ENVISubsetRaster(Task.OUTPUT_RASTER, BANDS=LINDGEN(25))
; Define three ROIs, each containing 9 pixels of a common material.
nSpectra = 9d
roi1 = ENVIROI(NAME='Green Field')
pixelAddr1 = [[77,182],[78,182],[79,182], $
[77,183],[78,183],[79,183], $
[77,184],[78,184],[79,184]]
roi1.AddPixels, pixelAddr1, SPATIALREF=Subset.SPATIALREF
roi2 = ENVIROI(NAME='Soil')
pixelAddr2 = [[386,285],[387,285],[388,285], $
[386,286],[387,286],[388,286], $
[386,287],[387,287],[388,287]]
roi2.AddPixels, pixelAddr2, SPATIALREF=Subset.SPATIALREF
roi3 = ENVIROI(NAME='Ground')
pixelAddr3 = [[296,326],[297,326],[298,326], $
[296,327],[297,327],[298,327], $
[296,328],[297,328],[298,328]]
roi3.AddPixels, pixelAddr3, SPATIALREF=Subset.SPATIALREF
; Retrieve the spectra from the ROIs and use their mean as
; endmembers for the Mixture Tuned Matched Filter task
spectra1 = Subset.GetData(ROI=roi1)
mean1 = Total(spectra1,1) / nSpectra
spectra2 = Subset.Getdata(ROI=roi2)
mean2 = Total(spectra2,1) / nSpectra
spectra3 = Subset.GetData(ROI=roi3)
mean3 = Total(spectra3,1) / nSpectra
endmembers = [[mean1],[mean2],[mean3]]
; Get the task from the catalog of ENVITasks
Task = ENVITask('MixtureTunedMatchedFilter')
Task.INPUT_RASTER = Subset
Task.ENDMEMBERS = endmembers
Task.NAMES = ['Green Field', 'Soil', 'Ground']
; Run the task
Task.Execute
; Get the data collection
dataColl = e.Data
; Add the output to the data collection
dataColl.Add, Task.OUTPUT_RASTER
; Display the result
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)
Syntax
Result = ENVITask('MixtureTunedMatchedFilter')
Input properties (Set, Get): BACKGROUND_THRESHOLD, ENDMEMBERS, INPUT_RASTER, NAMES, OUTPUT_RASTER_URI, USE_SUBSPACE_BACKGROUND
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:
Properties
This task inherits the following properties from ENVITask:
This task also contains the following properties:
BACKGROUND_THRESHOLD (optional)
Specify the background threshold to use when calculating statistics using the subspace background. The default value is 0.9.
ENDMEMBERS (required)
Specify an array that is [number of bands, number of classes].
INPUT_RASTER (required)
Specify a raster on which to perform the matched filter classification.
NAMES (optional)
This is an array of endmember names.
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.
USE_SUBSPACE_BACKGROUND (optional)
Specify whether to use the subspace background in statistics calculation. The default value is true.
Version History
|
ENVI 5.5 |
Introduced |
API Version
4.2