ENVILabelEntropyTextureRaster

This function constructs an ENVIRaster from a source raster where a first-order entropy texture has been computed on a the label bands of a rank-strength-texture raster.

ENVI performs the following steps to create an ENVILabelEntropyTextureRaster:

It creates a Label image, which is described in Rank-Strength-Texture Algorithm Background.
It computes first-order entropy on the Label image, using the steps described in Process for Computing Texture Metrics.

The result is a virtual raster, which has some additional considerations with regard to methods and properties. See Virtual Rasters for more information, including how they differ from ENVITasks.

The equivalent task is LabelEntropyTextureTask.

Example

; Start the application

e = ENVI()

; Select a multispectral input file

file = FILEPATH('qb_boulder_msi', $

ROOT_DIR=e.ROOT_DIR, SUBDIRECTORY = ['data'])

raster = e.OpenRaster(file)

; Compute label entropy

image = ENVILabelEntropyTextureRaster(raster, [3,3])

; Display each band of the label entropy image in a separate view

view1 = e.GetView()

layer1 = view1.CreateLayer(image, BANDS=[0], $

NAME='Label entropy for band 1')

view2 = e.CreateView()

layer2 = view2.CreateLayer(image, BANDS=[1], $

NAME='Label entropy for band 2')

view3 = e.CreateView()

layer3 = view3.CreateLayer(image, BANDS=[2], $

NAME='Label entropy for band 3')

view4 = e.CreateView()

layer4 = view4.CreateLayer(image, BANDS=[3], $

NAME='Label entropy for band 4')

; Create a geographic and zoom link for all views

view1.GeoLink, /LINK_ALL, /ZOOM_LINK

Syntax

ENVIRaster = ENVILabelEntropyTextureRaster(Input_Raster, Kernel_Size, ERROR=variable)

Return Value

This routine returns a reference to an ENVIRaster.

Arguments

Input_Raster

Specify the input ENVIRaster. This routine accepts images with any number of bands.

Kernel_Size

Specify a two-element array [n,m] as the kernel size, where n is the number of columns and m is the number of rows. The values must be odd and at least 3, for example [3,3].

Methods

This virtual raster inherits methods and properties from ENVIRaster; however the following methods will override the ENVIRaster methods:

Dehydrate

Hydrate

Keywords

ERROR (optional)

Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.

When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.

See Manage Errors for more information on error handling in ENVI programming.

NAME

Specify a string that identifies the raster.

Version History

ENVI 5.4

Introduced

API Version

4.2