GramSchmidtPanSharpening Task

This task performs Gram-Schmidt Pan Sharpening using a low-resolution raster and a high-resolution panchromatic raster.

If you process a spatial subset, the resulting image from this ENVITask may differ by approximately 2 percent, compared to one created using the ENVI user interface. The latter uses the full image for resampling, while the ENVITask uses only the subset for processing.

Example

; Start the application

e = ENVI()

; Open an input file

msi_file = Filepath('qb_boulder_msi', Subdir=['data'], $

  Root_Dir=e.Root_Dir)

msi_raster = e.OpenRaster(msi_file)

pan_file = Filepath('qb_boulder_pan', Subdir=['data'], $

  Root_Dir=e.Root_Dir)

pan_raster = e.OpenRaster(pan_file)

; Get the task from the catalog of ENVITasks

Task = ENVITask('GramSchmidtPanSharpening')

; Define inputs

Task.INPUT_LOW_RESOLUTION_RASTER = msi_raster

Task.INPUT_HIGH_RESOLUTION_RASTER = pan_raster

; 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, jump to a specific

; coordinate, and flicker between the

; original and pan-sharpened images

View = e.GetView()

Layer1 = View.CreateLayer(msi_raster)

Layer2 = View.CreateLayer(Task.Output_Raster)

Layer2.QUICK_STRETCH='linear 2%'

Portal = View.CreatePortal()

View.GoToLocation,482221.6000, 4428141.2000, /Map

View.Zoom, 2.0

Portal.Animate, 2.0, /FLICKER

Syntax

Result = ENVITask('GramSchmidtPanSharpening')

Input parameters (Set, Get): INPUT_LOW_RESOLUTION_RASTER, INPUT_HIGH_RESOLUTION_RASTER, OUTPUT_RASTER_URI, RESAMPLING, SENSOR

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

INPUT_HIGH_RESOLUTION_RASTER (required)

Specify a high-resolution panchromatic raster.

INPUT_LOW_RESOLUTION_RASTER (required)

Specify a low-resolution raster.

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.

RESAMPLING (optional)

Specify the resampling method to use when creating the spatial grid:

Nearest Neighbor (default): Uses the nearest pixel without any interpolation.
Bilinear: Performs a linear interpolation using four pixels to resample.
Cubic Convolution: Uses 16 pixels to approximate the sinc function using cubic polynomials to resample the image.

SENSOR (optional)

Specify a lower-case string that indicates the sensor that acquired the high-resolution panchromatic input. If SENSOR is not set, then the task determines if the data has valid sensor information in the metadata. If not, SENSOR is set to Unknown.

See the filterfuncs directory in the ENVI installation path for a list of valid sensor strings. User-defined sensors are also valid as long as they are in this directory. The default path varies by operating system.