Video Analytics Events: Region of Interest (ROI)

What is a Region of Interest (ROI)?

Region of Interest is a feature found in cameras with built-in video analytics or 3rd party software products. A ROI allows you to specify special regions on cameras that are used to optimize resources for processing and analyzing video or enable line crossing or perimeter intrusion.

Usually, the initial set-up and any changes in ROI configuration would have to be made by visiting the camera's dedicated web page or the 3rd party software settings.

ROI in Nx Witness

Beginning with the 4.1 release, Nx Witness users will be able to configure 3rd party video analytics from within the Nx Witness desktop client. This includes drawing lines, boxes, polygons, and setting the minimum and maximum size of detected objects. You will no longer need to go to the 3rd party software settings or camera's web page to make such changes.

Currently, this feature is only supported on Hanwha AI cameras using firmware version 1.41.xx or higher. Supported cameras and software are expected to grow, as this feature is available for developers to integrate by using the Metadata SDK.

How to use the ROI in Nx Desktop

To access the ROI configuration settings in the Desktop client, open the context menu on a camera > Camera Settings > Plugins > Analytics. A preview of the selected camera will be available to draw any necessary lines, polygons, or boxes to represent the ROI.

The following options may be available to you depending on the type of analytics provided by the camera or 3rd party software:

General

Performance

• CPU Cores – Number of CPU cores the plugin can use.

Object Detection

• Person Confidence (%) – Confidence level for how accurate the detection of an object should be. A lower number will be less accurate but provide more detections, while a higher number will be more accurate but provide fewer detections.
• Detection Frequency – Frequency at which the object will be detected.

Object Tracking

• Track Reset Timeout (s) – Amount of time an object will be tracked on the feed before it is considered a new object.

Line Crossing

• Line – Create a line that will be used to detect and record how many times people cross it.
• Display on camera – Check this box to overlay the line on the camera feed.
  

  

Area Monitoring

• Area – Create an area that will be used to detect and record people entering the area.
• Display on camera – Check this box to overlay the selected area on the camera feed.
• Detections – Check the box next to an option to activate it: Entrance, Appearance, Loitering, Exit, Disappearance, and Crossing.
• Detection sensitivity (%) – Camera's sensitivity to motion.
• Loitering duration (s) – Minimum amount of time that needs to pass.

Motion Detection

Define the size of the object that will be tracked for motion detection.

• Object size – Set the maximum size of an object with the red box and minimum size with the blue box.

Include Areas

Define the area that will be analyzed for motion detection. Click +Add to create more than one area to be analyzed.

• Include area – Set the maximum size of an object with the red box and minimum size with the blue box.
• Display on camera – Check this box to overlay the selected area on the camera feed.
• Level of detection – Threshold that needs to be passed for changes to be considered motion.
• Sensitivity – Camera's sensitivity to motion.
• Minimum duration(s) – Minimum amount of time that needs to pass.
  

  

Exclude Areas

Define the area that will not be analyzed for motion detection. Click +Add to create more than one area to be ignored.

• Exclude area – Set the maximum size of an object with the red box and minimum size with the blue box.
• Display on camera – Check this box to overlay the selected area on the camera feed.

Tampering Detection

Detect changes to the camera feed due to a physical obstruction or device tampering. Click Enable to activate this option.

• Level of detection – Threshold that needs to be passed for the camera to be considered tampered with.
• Sensitivity – Camera's sensitivity to tampering.
• Minimum duration(s) – Minimum amount of time the detection needs to continue before being notified of the detection.
• Except dark images – Check this box to ignore the limit set for "Minimum duration(s)" when the camera feed is not bright enough.

Defocus Detection

Detect if the camera becomes unfocused. Click Enable to activate this option.

• Level of detection – Threshold that needs to be passed for the camera to be considered out of focus.
• Sensitivity – Camera's sensitivity to loss of focus.
• Minimum duration(s) – Minimum amount of time that needs to pass.

Audio Detection

Detect if the camera's audio level goes above a specified dB. Click Enable to activate this option.

• Level of detection – Minimum dB that needs to be passed.

Note: Some plugins may allow you to choose the primary or secondary stream to be used for analytics.

Questions

If you have any questions related to this topic or you want to share your experience with other community members or our team, please visit and engage in our support community or reach out to your local reseller.