GBDX

ENVI® RX Anomaly Detection

This task uses the Reed-Xiaoli Detector (RXD) algorithm to identify the spectral or color differences between a region to test and its neighboring pixels or the entire dataset.

GBDX Registered Name: ENVI_RXAnomalyDetection
Provider: Harris Geospatial Solutions

Imagery Examples

Before: WorldView 2 image after AOP correction

Before: WorldView 2 image after AOP correction

After: WorldView 2 image after ENVI_RXAnomalyDetection where areas of bright white show detection of anomaly

After: WorldView 2 image after ENVI_RXAnomalyDetection where areas of bright white show detection of anomaly

Quickstart

This is a workflow example for basic processing.

# Quickstart Example running the task name.

# Initialize the Environment.
from os.path import join, split
from gbdxtools import Interface
gbdx = Interface()

tasks = []
output_location = 'ENVI/RXAnomalyDetection'

cat_id = '105001000672E000'

# Image Auto ordering task parameters
order = gbdx.Task("Auto_Ordering")
order.inputs.cat_id = cat_id
order.impersonation_allowed = True
order.persist = True
order.timeout = 36000
tasks += [order]

# Image AOP task parameters
aop = gbdx.Task("AOP_Strip_Processor")
aop.inputs.data = order.outputs.s3_location.value
aop.inputs.bands = 'MS'
aop.inputs.enable_dra = False
aop.outputs.data.persist = True
aop.outputs.data.persist_location = output_location+'/aop'
aop.timeout = 36000
tasks += [aop]

# Clump the classification
envi_rx = gbdx.Task("ENVI_RXAnomalyDetection")
envi_rx.inputs.input_raster = aop.outputs.data.value
envi_rx.inputs.mean_calculation_method = 'Local'
envi_rx.inputs.kernel_size = '15'
envi_rx.inputs.anomaly_detection_method = 'RXD-UTD'
tasks += [envi_rx]

workflow = gbdx.Workflow(tasks)
workflow.savedata(
    envi_rx.outputs.output_raster_uri, location=output_location
)

workflow.execute()

Inputs

The following table lists all ENVI_RXAnomalyDetection 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 anomaly detection. -- 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
suppress_vegetation False false string Set this property to true to suppress vegetation anomalies in the RXD results. The options are true or false (default). -- Value Type: BOOLEAN -- Default Value: false
mean_calculation_method False "global" string Specify one of the values from the CHOICE_LIST, indicating which mean calculation method to use. Global: Derive the mean spectrum from the full dataset, Local: Derive the mean spectrum from the KERNEL_SIZE around a given pixel. -- Value Type: STRING -- Default Value: "Global"
anomaly_detection_method False "rxd" string Specify one of the values from the CHOICE_LIST, indicating which method to use. RXD: Standard RXD algorithm, UTD: Uniform Target Detector algorithm, RXD-UTD: Hybrid of the RXD and UTD algorithms. -- Value Type: STRING -- Default Value: "RXD"
kernel_size False 9 string Specify the kernel size in pixels, around a given pixel that will be used to create a mean spectrum. Use an odd number. The minimum value is 3, and the maximum value is (number of columns - 1) less than (number of rows - 1). Specify KERNEL_SIZE only when using the 'Local' option for MEAN_CALCULATION_METHOD. -- Value Type: UINT -- Default Value: 9
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_RXAnomalyDetection 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® RX Anomaly Detection.

Contact

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

ENVI® RX Anomaly Detection

This task uses the Reed-Xiaoli Detector (RXD) algorithm to identify the spectral or color differences between a region to test and its neighboring pixels or the entire dataset.

GBDX Registered Name: ENVI_RXAnomalyDetection
Provider: Harris Geospatial Solutions