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 properties (Set, Get): ADD_BACK, DATA_IGNORE_VALUE, INPUT_RASTER, KERNEL_SIZE, OUTPUT_RASTER_URI

Output properties (Get only): OUTPUT_RASTER

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:

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

This is a reference to the output raster of filetype ENVI.

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 property, or set it to an exclamation symbol (!), a temporary file will be created.

Version History


ENVI 5.3

Introduced

ENVI 5.6

Added DATA_IGNORE_VALUE property

API Version


4.3

See Also


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