LaplacianKernel Task
This task returns a Laplacian kernel for use with convolution filtering. A Laplacian kernel consists of a high central value surrounded by negative weights in the north-south and east-west directions, with zero values at the kernel corners.
Example
; Start the application
e = ENVI(/HEADLESS)
; 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('LaplacianKernel')
; Define inputs
Task.KERNEL_SIZE = [3,5]
; Run the task
Task.Execute
; Print the resulting kernel
Print, Task.OUTPUT_KERNEL
IDL prints:
0.000000 -1.00000 0.000000
-1.00000 -2.00000 -1.00000
-2.00000 14.0000 -2.00000
-1.00000 -2.00000 -1.00000
0.000000 -1.00000 0.000000
Syntax
Result = ENVITask('LaplacianKernel')
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:
Properties
This task inherits the following properties from ENVITask:
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 Laplacian kernel output.
Version History
|
ENVI 5.3 |
Introduced |
API Version
4.2
See Also
ENVITask, DirectionalFilter Task, DirectionalKernel Task, GaussianHighPassKernel Task, GaussianHighPassFilter Task, GaussianLowPassKernel Task, GaussianLowPassFilter Task, HighPassFilter Task, HighPassKernel Task, LaplacianFilter Task, LowPassFilter Task, LowPassKernel Task, MedianFilter Task, RasterConvolution Task, SobelFilter Task, RobertsFilter Task