This task returns a low pass kernel of a specified size, for use with convolution filtering. ENVI’s low pass filter contains the same weights in each kernel element. The default kernel size is 3x3.

Example


; Start the application
e = ENVI(/HEADLESS)
 
; Get the task from the catalog of ENVITasks
Task = ENVITask('LowPassKernel')
 
; Define outputs
Task.KERNEL_SIZE = [3,5]
 
; Run the task
Task.Execute
 
; Print the resulting 3x5 kernel
print, Task.OUTPUT_KERNEL

IDL prints:

0.0666667    0.0666667    0.0666667
0.0666667    0.0666667    0.0666667
0.0666667    0.0666667    0.0666667
 0.0666667    0.0666667    0.0666667
 0.0666667    0.0666667    0.0666667

Syntax


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


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:

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


ENVI 5.3

Introduced

API Version


4.3

See Also


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