This task returns a high pass kernel of a specified size for use with convolution filtering. ENVI’s high pass kernel consists of a high central value, surrounded by negative weights. The default kernel size is 3x3.

Example

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; Start the application

e = ENVI()

; Get the task from the catalog of ENVITasks

Task = ENVITask('HighPassKernel')

; Define outputs

Task.KERNEL_SIZE = [3,5]

; Run the task

Task.Execute

; Print the resulting 3x5 kernel

print, Task.OUTPUT_KERNEL

IDL prints:

-1.00000     -1.00000     -1.00000

-1.00000     -1.00000     -1.00000

-1.00000      14.0000     -1.00000

  -1.00000     -1.00000     -1.00000

  -1.00000     -1.00000     -1.00000

Syntax

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Result = ENVITask('LowPassKernel')

Input properties (Set, Get): KERNEL_SIZE

Output properties (Get only): OUTPUT_KERNEL

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

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This task inherits the following methods from ENVITask:

AddParameter

Execute

Parameter

ParameterNames

RemoveParameter

Properties

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KERNEL_SIZE (optional)

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 default kernel size is [3,3].

OUTPUT_KERNEL

This is the low pass kernel output.

Version History

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ENVI 5.3

Introduced

API Version

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4.2

See Also

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ENVITask, DirectionalFilter Task, DirectionalKernel Task, HighPassFilter Task, LaplacianFilter Task, LaplacianKernel Task, LowPassFilter Task, LowPassKernel Task, MedianFilter Task, RasterConvolution Task, SobelFilter Task, RobertsFilter Task