Detection Areas

You can assign what we call “Detection Areas” to your image. Those areas are polygons that define the region in the image where the detector will be applied.

Please note that this feature is not meant for super precise image clipping, but rather a way to broadly say which region the detector should look into, because for performance reasons we apply some geometry simplification when uploading them to the platform.

To set detection areas for an image, click the ‘…’ menu next to your image and open the ‘Info’ popup. There will be a ‘Detection Areas’ line with a manage button that you can click.

This will open the image view screen, with already opened the detection areas tool and the detection areas panel.

Detection Areas Panel

This panel allows you to control whether detection areas are displayed (the checkbox), influence how they are shown (either a pin at the center of the shape, or the full shape drawn on the image), and navigate between them with the < and > buttons. Navigating between the detection areas will automatically zoom the map to the location of the detection area.

Clicking on the dot … menu will reveal options to upload or download your detection areas as GeoJSON, and provide the option to Delete all detection areas and revert to the default (the full footprint of the image) for detection.

Detection Areas Tool

From the Detection Areas Tool, you can select one of three options

Edit Detection Areas

This tool allows you to select existing detection areas and modify their shape, move them, and delete them. See the section on polygon editing tools above for more info.

Draw a new Detection Area

This tool allows you to draw a new shape to create a detection area. Detection areas determine where detections will be made on your image when running your detector. Areas outside of detection areas will not be considered by the detector. Left-click on the image to start drawing an area, click again to place points, and double-click to finish the drawing.

Upload Detection Areas

You can drag and drop a file onto the dialog, or click to select one from your computer. The uploaded file should be a GeoJSON file containing a FeatureCollection of Polygons or MultiPolygons.

There are three main requirements for this file:

Your geometries’ coordinates should be projected in EPSG:4326.
All geometries should be valid. You can check this in QGIS with the Vector → Geometry Tools → Check Validity tool.
Your geometry should cover parts of the image on which it is applied.

Here’s an example of a valid Detection Area file:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Polygon",
        "coordinates": [
          [
            [
              6.573850214481354,
              46.52660109443889
            ],
            [
              6.574483215808868,
              46.52660109443889
            ],
            [
              6.574483215808868,
              46.52700708253873
            ],
            [
              6.573850214481354,
              46.52700708253873
            ],
            [
              6.573850214481354,
              46.52660109443889
            ]
          ]
        ]
      }
    }
  ]
}

Detecting

Detection Areas

Detection Areas Panel

Detection Areas Tool