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ENVI

ENVIDimensionalityExpansionRasterTask

ENVIDimensionalityExpansionRasterTask

This task expands the number of bands in a raster. Dimensionality expansion is a mathematical technique to increase multispectral data dimensionality in a nonlinear fashion so that standard hyperspectral linear methods can perform better at both pure-and mixed-pixel detection and classification. These hyperspectral methods include Orthogonal Subspace Projection (OSP), Constrained Energy Minimization (CEM), Matched Filter (MF), and Adaptive Coherence Estimator (ACE). The additional bands are created by computing the square roots, natural logs, auto-correlations (squares), and cross-correlations of the input bands.

The virtual raster associated with this task is ENVIDimensionalityExpansionRaster.

References

Chang, C.-I., J.-M. Liu, H. Ren, C.-M. Chung, C.-W. Yang, and D.-J. Ma. "Generalized Constrained Energy Minimization Approach to Subpixel Target Detection for Multispectral Imagery." Optical Engineering 39, No. 5 (2000): 1275-1281.

Heinz, D. "Constrained Least Squares Approaches to Target Detection and Image Classification for Remotely Sensed Images." Ph.D. dissertation. University of Maryland Baltimore County (2001).

Heinz, D., and C.-I. Chang. "Fully Constrained Least Squares Linear Spectral Mixture Analysis Method for Material Quantification in Hyperspectral Imagery." IEEE Transactions on Geoscience and Remote Sensing 39, No. 3 (2001): 529-545.

Heinz, D., and C.-I. Chang. "Unsupervised Fully Constrained Least Squares Linear Spectral Mixture Analysis Method for Multispectral Imagery." Proceedings of IGARSS 2000: 1681-1683.

Example


This example creates and adds 18 new bands to a four-band multispectral raster. After the image is displayed in the view, open the Data Manager to see the additional bands.

; 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)
 
; Get the task from the catalog of ENVITasks
Task = ENVITask('DimensionalityExpansionRaster')
 
; Define inputs
Task.INPUT_RASTER = Raster
 
; Run the task
Task.Execute
 
; Add the output to the Data Manager
e.Data.Add, Task.OUTPUT_RASTER
 
; Display the result
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)

Syntax


Result = ENVITask('DimensionalityExpansionRaster')

Input properties (Set, Get): INPUT_RASTER, 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 the input ENVIRaster. This task accepts an image with any number of bands, although it is best used with multispectral imagery.

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 to export the associated OUTPUT_RASTER.

  • If you set this property to an asterisk symbol (*), the output raster will be virtual and not written to disk.
  • If you do not specify this property, the associated output raster will not be created. To force the creation of a temporary file, set this parameter to an exclamation symbol (!).

Version History


ENVI 5.5, Service Pack 2

Introduced

API Version


3.3

See Also


ENVITask, ENVITask::Parameter, ENVIDimensionalityExpansionRaster, ENVIDimensionalityExpansionSpectralLibraryTask



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