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ENVI

THOR Target Detection

THOR Target Detection

The Target Detection workflow is used to locate objects within an image that match the signatures of in-scene regions. THOR uses a variety of target detection algorithms to search for targets. After the targets are detected, the workflow will guide you through combining the rule images from each target detection algorithm into a single detection overlay for each target.

Selecting One Input file


  1. From the Toolbox, select THOR > THOR Target Detection > THOR Target Detection Process Single File. The File Selection dialog appears.
  2. Select an input file and click Next.
  3. Perform atmospheric correction.
  4. Select target signatures.
  5. Select background signatures.
  6. Reduce dataset dimensionality and select bands.
  7. Perform signature matching.
  8. Perform rule thresholding. When you proceed to the next step, THOR creates a rule threshold file in your default output directory called rootname_rule_thresh.dat. At this point, you can quit your workflow session. When you return, select THOR > THOR Target Detection > THOR Target Detection Resume Rule Thresholding Previous Results from the ENVI menu bar. Click Select Rule Thresh File and restore the file rootname_rule_thresh.dat. Review the Target Detection results, and click Next to continue with rule thresholding.
  9. Perform spatial filtering.
  10. Export targets.

Selecting Multiple Input Files


  1. From the Toolbox, select THOR > THOR Target Detection > THOR Target Detection Process Multiple Files. The File Selection dialog appears.
  2. Click Add. The File Selection dialog appears.
  3. Click Open > New File. A file selection dialog appears.
  4. Use the Ctrl or Shift key to select multiple input files. They must all have the same number of bands. Click Open.
  5. In the File Selection dialog, use the Ctrl or Shift key to select all the files you want to open. Click OK. The THOR File Selection dialog lists all available input files.
  6. Click Select Output Path and select a directory for the Target Detection output files.
  7. You can choose to process a subset of spectral bands by clicking one of the following buttons in the File Selection panel:
    • Graphically: The THOR Spectral Subsetting dialog appears.
    • By List: The File Spectral Subset dialog appears.
  8. You can optionally perform destriping, spectral binning, and/or spectral smoothing.
  9. Click Next. The Batch Parameters dialog appears.
  10. Select the options to apply to all of your input files. These include atmospheric correction, target selection, dimensionality reduction, the number of M of N rule images, spatial filtering, and target export.
  11. Click Next.
  12. Perform rule thresholding. Click Next, then Finish.

Reviewing Results

  1. From the Toolbox, select THOR > THOR Target Detection > THOR Target Detection Review Batch Target Detection Results. A File Selection panel appears.
  2. Click Select Database File and select the .dbase file that was generated in your output folder after you ran the Target Detection workflow. The Database Summary section lists the details of your workflow.
  3. Review the Target Detection results, and perform rule thresholding again if needed to achieve the desired results.

Related Topics


Target Detection Wizard



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