Search for line-crossing

Last modified: Thursday February 08, 2024.

With video security systems, it is common to want to find when an object (a person, or vehicle, for example) crosses a defined line within field of view of your cameras. With Alta Video, searching for when an object crosses a defined line has been made simple, by using the machine learning built into the system.

Setting line-crossing configurations on Pan-Tilt-Zoom (PTZ) cameras can produce unexpected results if the view is moved, as the position of the line remains static as the camera view changes.

See How Alta Video detects line-crossing events for information on the requirements for Alta Video to be able to detect a line-crossing event.

Task — Search for objects crossing lines

  1. Open Tools Tools > Search Search.
  2. Click the Line crossingLine crossing
  3. Select the type of object you want to find.
    You can select Any object, Person, or Vehicle.
  4. Depending on your chosen object selection, select further characteristics for your search.
    For Person search, select Only this color, or Ignore this color for upper and lower body clothing.
    For Vehicle search, choose All types or Only this type. For Only this type, choose one or more from 2 wheeled, Small/Medium vehicle, Large vehicle, or Unknown type. In addition, select Only this color, or Ignore this color for the vehicle.

    For deployments that have LPR configured, you can also enable license plate matching in the search.

    For license plate matching, you can select Any plate, Exact match, Matches groups, Starts with, Ends with, or Includes characters.

    You can also choose to exclude all license plates in a chosen License plate group from appearing in the search.

    You can also Use an image in your search.
  5. When you have defined what you are looking for, click Next.
      1. Use Search to help find the required cameras in the list.
      2. Click Site and device groups icon to filter cameras by site name, device group name, and device name, or click Labels icon to filter by label.
      3. If you have predefined them, use Camera presets to simplify adding the same groups of cameras to multiple rules.
  6. Draw a line across the part of the camera view that you want to use as the line crossing.
  7. By default, this line is a 2-way crossing; the system will detect traffic crossing in either direction. To only search for objects crossing the line on one direction, click the direction to disable (the circle arrow turns white when disabled).
    Line crossing direction enabled — Line crossing direction enabled.
    Line crossing direction disabled — Line crossing direction disabled.
  8. Select the time period to search from the predefined options, or specify your required times and dates.
  9. Click Search.

    The results from your search are displayed, based on the perceived (by Alta Video) accuracy against your selected search criteria.
    Where Alta Video considers results to be very similar, those results are collapsed together. To view the collapsed results, click Collapsed resultsCollapsed results to view each result in the sequence.

  10. Hover over a thumbnail to view a short video replay of the event, or click PlayPlay clip to view the clip in a larger window.

    To exclude an object from the search, right-click the thumbnail and select Hide this & similar results.

  11. When you discover the object of interest, click Add button Add to selected clips button.
  12. Optionally, click Create a rule buttonCreate a rule to define a rule with the same parameters as your search.
    1. Type a name for the rule.
    2. Click Create.
    3. Specify the When settings to apply to this rule.
    4. Click Next.
    5. Select your required actions. Select from:
      • Pop-up — when triggered, pops up a notification on the Alta Video user interface that includes a thumbnail view of the camera view that triggered the rule. The Pop-up can be expanded to show more detail and allow further actions to be taken by your operators.
      • Email — when triggered, an email message is sent to the defined user or group of users.

      Alarms are only shown to operators that have access to the cameras that trigger the rule.

    6. Choose if you require your operators to acknowledge the rule when it is triggered.
    7. Click Done.
  13. After you have identified a few clips that relate to the object you are looking for, click Similarity search buttonSimilarity to further refine the search results.

    The more relevant clips you add to the similarity search, the better your search results will be.

Task — Select List options

  1. Click List options List options.
  2. To display more results, enable Show low matched results.
  3. To display similar results collapsed into a single results spot, enable Collapse similar results.
  4. Click Done.