LowPassFilter Task

This task performs low pass filtering. Pixels in the input raster that are masked out or with the data-ignore value set will not be included in the convolution calculations and will be set to the data-ignore value in the output raster.

Example

; Start the application

e = ENVI()

; 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('LowPassFilter')

; Define inputs

Task.INPUT_RASTER = Raster

Task.KERNEL_SIZE = [3,5]

; Run the task

Task.Execute

; Get the collection of data objects currently available in the Data Manager

DataColl = e.Data

; Add the output to the Data Manager

DataColl.Add, Task.OUTPUT_RASTER

; Display the result

View = e.GetView()

Layer = View.CreateLayer(Task.OUTPUT_RASTER)

Syntax

Result = ENVITask('LowPassFilter')

Input parameters (Set, Get): ADD_BACK, DATA_IGNORE_VALUE, INPUT_RASTER, KERNEL_SIZE, OUTPUT_RASTER_URI

Output parameters (Get only): OUTPUT_RASTER

Parameters marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Parameters marked as "Get" are those whose values you can retrieve but not set.

Input Parameters

ADD_BACK (optional)

Specify a filter add-back percentage value between 0.0 and 1.0. A value of 1.0 is equal to 100%.

DATA_IGNORE_VALUE (optional)

Specify a unique data value for pixels in the output raster that have a non-zero pixel state value.

INPUT_RASTER (required)

Specify a raster on which to perform low pass filtering.

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_RASTER_URI (optional)

Specify a string with the fully qualified filename and path of the associated OUTPUT_RASTER.

If you do not specify this parameter, or set it to an exclamation symbol (!), ENVI creates a temporary file.
If you set it to the hash symbol (#), ENVI creates a file in the temporary directory, but this file will not be deleted when ENVI closes.