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ENVI

Spatial Filtering

Spatial Filtering

Use the Spatial Filtering panel to filter the detection overlays produced by the Rule Thresholding panel. The THOR Viewer is displayed along with the existing detection overlays.

  1. To continue in a workflow without performing spatial filtering, select the Do not perform spatial filtering option.
  2. Select one or more layers in the Select Layers to be Filtered list that the filter will apply to. You can apply one set of filtering parameters to certain layers and another set of parameters to other layers by utilizing this list.
  3. Spatial filtering consists of clumping and/or sieving. If both clumping and sieving are selected, clumping occurs first, then sieving. Select the Clump Results and/or Sieve Results options to indicate whether each will be performed.
  4. Clumping groups nearby isolated detections into one cohesive blob. The larger the Clump operator size parameter, the further apart the isolated detections that will be grouped.

    Sieving removes detections that are smaller than the Min Blob Size or larger than the Max Blob Size. The Pixel Neighbor Scheme determines how blob sizes are calculated. By default, all eight neighboring pixels are considered as part of the blob. Alternatively, only four neighboring pixels may be considered for blob grouping.

  5. Click Apply Filter to preview the filtered results. Click Flicker Results to better see the changes. This will alternate the original, non-filtered detection overlay with the filtered overlay.



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