This task returns a directional kernel for use with convolution filtering.

Example


; Start the application
e = ENVI(/HEADLESS)
 
; Get the task from the catalog of ENVITasks
Task = ENVITask('DirectionalKernel')
 
; Define kernel size
Task.KERNEL_SIZE = [3,5]
 
; Define the angle in degrees
Task.ANGLE = 25.0
 
; Run the task
Task.Execute
 
; Print the resulting kernel
print, Task.OUTPUT_KERNEL

IDL prints:

 -1.32893    -0.422618     0.483689
 -1.32893    -0.422618     0.483689
-0.906308    0.000000     0.906308
-0.483689    0.422618     1.32893
-0.483689    0.422618     1.32893

Syntax


Result = ENVITask('DirectionalKernel')

Input properties (Set, Get): ANGLE, 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


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:

ANGLE (required)

Specify the angle in degrees. The default value is 0.

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 value is [3,3].

OUTPUT_KERNEL

This is the directional kernel output.

Version History


ENVI 5.3

Introduced

API Version


4.3

See Also


ENVITask, DirectionalFilter Task, GaussianHighPassFilter Task, GaussianHighPassKernel Task, GaussianLowPassKernel Task, GaussianLowPassFilter Task, HighPassFilter Task, HighPassKernel Task, LaplacianFilter Task, LaplacianKernel Task, LowPassFilter Task, LowPassKernel Task, MedianFilter Task, RasterConvolution Task, SobelFilter Task, RobertsFilter Task