SpectralSmoothing Task

This task applies the Savitsky-Golay smoothing filter to smooth noisy spectral signatures.

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('SpectralSmoothing')

; Define inputs

Task.INPUT_RASTER = Raster

; Run the task

Task.Execute

; Add the output to the Data Manager

e.Data.Add, Task.OUTPUT_RASTER

; Display the result

View = e.GetView()

Layer = View.CreateLayer(Task.OUTPUT_RASTER)

Syntax

Result = ENVITask('SpectralSmoothing')

Input parameters (Set, Get): DEGREE_OF_POLY, INPUT_RASTER, ORDER_OF_DERIVATIVE, OUTPUT_RASTER_URI, PIXELS_TO_LEFT, PIXELS_TO_RIGHT

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

DEGREE_OF_POLY (optional)

Specify an integer less than the filter width (sum of PIXELS_TO_LEFT and PIXELS_TO_RIGHT). Typical values are 2 to 4. The default value is 2.

INPUT_RASTER (required)

Specify the raster on which to perform spectral smoothing.

ORDER_OF_DERIVATIVE (optional)

Specify an integer for the smoothed order derivative of the signal. The default value is 0.

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.

PIXELS_TO_LEFT (optional)

Specify the number of pixels to the left of the data point. Larger values produce a smoother result at the expense of flattening sharp peaks. The default value is 1.

PIXELS_TO_RIGHT (optional)

Specify the number of pixels to the right of the data point. Larger values produce a smoother result at the expense of flattening sharp peaks. The default value is 1.