GBDX

ENVI® Forward ICA Transform

This task performs an independent component analysis (ICA) procedure to transform a set of mixed, random signals into components that are mutually independent.

GBDX Registered Name: ENVI_ForwardICATransform
Provider: Harris Geospatial Solutions

Inputs

The following table lists all ENVI_ForwardICATransform 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 on which to perform an ICA transform. -- 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
coefficient False 1.0 string Specify the coefficient to use. Specify COEFFICIENT only when using the 'LogCosh' or 'Gaussian' option for CONTRAST_FUNCTION. -- Value Type: FLOAT -- Default Value: 1.0
maximum_iterations False 100 string Specify the maximum number of iterations to perform for IC optimization using a fixed-point algorithm. The minimum value is 100, and the maximum value is 32767. More iterations will help find more optimal components; however, each iteration adds to processing time depending on the CUP and system load. -- Value Type: INT -- Default Value: 100
maximum_stabilization_iterations False 100 string Specify the maximum number of iterations to perform for IC optimization using a stabilized fixed-point algorithm. When estimating one IC, the fixed-point algorithm runs first. If the algorithm does not converge after the maximum number of iterations, the stabilized fixed-point algorithm runs to improve convergence. The minimum value is 0 and the maximum value is 32767. Enabling stabilization and increasing stabilization iterations will help find more optimal components; however, each iteration adds to processing time depending on the CUP and system load. -- Value Type: UINT -- Default Value: 100
change_threshold False 9.999999747378752e-05 string Specify a floating-point value used to optimize independent component (IC) analysis. If the change of the IC is less than this value, then the IC iteration stops. The allowable range is 0.00000001 to 0.1. Increasing the value increases the speed of convergence but may provide a less optimal solution. -- Value Type: FLOAT -- Default Value: 9.999999747378752e-05
sort_output False true string Set this property to sort output ICA bands by decreasing spatial coherence. -- Value Type: BOOLEAN -- Default Value: true
contrast_function False "logcosh" string Specify the contrast function. -- Value Type: STRING -- Default Value: "LogCosh"
sampling_percent False 10.0 string Specify a floating-point percentage (0 to 100) for sub-sampling the data when calculating the IC transform. Sub-sampling reduces the IC sample size to fit into memory and increases computation speed. The default setting of 100 does not change the data. For example, a sampling percentage of 50 will use every other pixel in the statistics calculations and the IC sample. Setting this value too low could lose features of interest, as those pixels may be discarded. -- Value Type: DOUBLE -- Default Value: 10.0
output_raster_uri_filename False N/A string Specify a string with the fully-qualified path and filename for OUTPUT_RASTER. -- Value Type: STRING

Outputs

The following table lists all ENVI_ForwardICATransform 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
output_raster_uri True N/A directory Output for OUTPUT_RASTER. -- Value Type: ENVIURI

Output structure

The output_raster_uri file will be written to the specified S3 Customer Account Location.

Background

For additional background information on this task please refer to the Harris Geospatial ENVI documentation and
ENVI® Forward ICATransform.

Contact

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

ENVI® Forward ICA Transform

This task performs an independent component analysis (ICA) procedure to transform a set of mixed, random signals into components that are mutually independent.

GBDX Registered Name: ENVI_ForwardICATransform
Provider: Harris Geospatial Solutions