GBDX

ENVI® Spectral Subspace Background Statistics

This task removes anomalous pixels and can be used prior to calculating background statistics. When the true background is better characterized with subspace background, the spectral detection methods achieve greater target-to-background separation. This can potentially improve detection results, particularly in scenes that contain a lot of clutter or man-made objects.

GBDX Registered Name: ENVI_SpectralSubspaceBackgroundStatistics

Provider: Harris Geospatial Solutions

Inputs

The following table lists all ENVI_SpectralSubspaceBackgroundStatistics inputs.
Mandatory (optional) settings are listed as Required = True (Required = False).

Name Required Default Valid Values Description
file_types False N/A string GBDX Option. Comma seperated list of permitted file type extensions. Use this to filter input files -- Value Type: STRING[*]
input_raster True N/A See ENVIRASTER input type Specify a raster for computing subspace background statistics. -- Value Type: ENVIRASTER
input_raster_format False N/A See ENVIRASTER input type Provide the format of the image, for example: landsat-8. -- Value Type: STRING
input_raster_band_grouping False N/A See ENVIRASTER input type Provide the name of the band grouping to be used in the task, ie - panchromatic. -- Value Type: STRING
input_raster_filename False N/A See ENVIRASTER input type Provide the explicit relative raster filename that ENVI will open. This overrides any file lookup in the task runner. -- Value Type: STRING
input_raster_raw_output False False See ENVIRASTER input type Provide True to output an ENVI Binary instead of a tif. -- Value Type: STRING
threshold False 0.9 string Specify the fraction of the background to use for calculating the subspace background statistics. The data type is floating-point. The allowable range is 0.500 to 1.000 (the entire image). -- Value Type: DOUBLE -- Default Value: 0.9

Outputs

The following table lists all ENVI_SpectralSubspaceBackgroundStatistics outputs.
Mandatory (optional) settings are listed as Required = True (Required = False).

Name Required Default Valid Values Description
task_meta_data False N/A directory GBDX Option. Output location for task meta data such as execution log and output JSON
mean False N/A string The mean of the subspace background, one for each input bands. -- Value Type: DOUBLEARRAY
covariance False N/A string This is the covariance matrix of the subspace background, returned as a double-precision array `[number of bands, number of classes]. -- Value Type: DOUBLEARRAY
eigenvalues False N/A string The eigenvalues of the subspace background. -- Value Type: DOUBLEARRAY

Output structure

Background

For additional background information on this task please refer to the Harris Geospatial ENVI documentation and
ENVI® Spectral Subspace Background Statistics.

Contact

If you have any questions or issues with this task, please contact gbdx-support@digitalglobe.com.