About motion detection - Security Center 5.8

Security Center Administrator Guide 5.8

series
Security Center 5.8
revised_modified
2020-08-17

Motion detection is the feature that watches for changes in a series of video images. The definition of what constitutes motion in a video can be based on highly sophisticated criteria.

There are two types of motion detection:
Software motion detection
Motion detection is executed by the Archiver on the video stream set for recording, and motion events are generated by Security Center.
Hardware motion detection
Motion detection is executed by the video unit, and motion events are generated by the unit and sent to Security Center.
Supported capabilities differ between the two types as shown in the following table:
Capability Software Hardware
Configuring motion detection settings Config Tool Unit's proprietary configuration tool1
Motion search task in Security Desk2 Yes Limited support3
Shows motion indicators (green bars) in the timeline Yes See our Supported Device List4
Multiple motion detection zones Yes Camera-specific5
Requires additional server resources Yes No
Auto calibration of sensitivity6 Yes No
IMPORTANT:
  1. To ease configuration of hardware motion detection, motion blocks derived from software motion detection are shown in Config Tool.
  2. The Motion search task does not support cameras using H.265 (HEVC) streams.
  3. Only Axis cameras with legacy motion detection are supported.
  4. For cameras with hardware motion detection, the green bars only indicate the presence of motion in the timeline (0% or 100%). For Axis cameras with legacy motion detection, the green bars also indicate the amount of motion as a percentage.
  5. Not all units support multiple motion detection zones. If you switch motion detection from Archiver to Unit, existing zone configurations not supported by the unit are lost.
  6. The unit and Archiver might interpret sensitivity differently, so testing your motion zones in Config Tool might not accurately reflect the unit's behavior.

To configure motion detection, you must specify areas of the video image, motion sensitivity, and a schedule for when to apply motion detection settings. Every camera has a default motion detection configuration based on the Always schedule. The default motion detection configuration can be modified but not deleted.

When an H.264 stream is selected as the recording stream, the Advanced settings button becomes available. Clicking this button opens the H.264 advanced motion detection settings dialog box which you can use to refine the motion detection settings.

Motion block

A motion block is when motion is detected inside one of the blocks you configure on the video image. There is positive motion in a video image when the area covered by the block detects motion in two consecutive video frames. The number of motion blocks detected represents the amount of motion. A motion block is represented by a semi-transparent green square overlay on the video image.

Positive motion detection

Seeing motion blocks on the video does not necessarily mean that the system will generate a motion related event. It might be noise. To determine when motion started (Motion on event) and stopped (Motion off event), adjust the Sensitivity, Consecutive frame hits, Motion on threshold, and the Motion off threshold parameters to achieve the best results in the specific environment.

Best practices for configuring motion detection

The main purpose for using motion detection is to minimize storage requirements, search times, and retrieval times by reducing the amount of video recordings that must be saved. However, configuration of motion detection must be done carefully and on an individual camera basis. When configuring motion detection, consider the following:
  • It is preferable to have sensitive settings that might trigger false motion events, than missing expected recordings when settings are not sensitive enough.
  • All motion settings are stored in the Directory database, so make sure to back up your database when changes are made.
  • Motion detection is the most basic video analytic capability. Due to possible false motion events, it should not be used to trigger alarms in critical situations, for example in replacement to a specialized intrusion detection system.
  • If you set the Time to record before an event parameter to a high value, it increases the memory (RAM) resources required by the Archiver. This reduces the camera count allowed on the Archiver. Cameras with a higher resolution have the same effect on the memory resources.
When configuring software motion detection:
  • It is always possible to use MJPEG streams.
  • It is possible to use MPEG-4 streams.
  • It is also possible to use H.264 streams, but because of the notion of profiles, some cameras must be configured through the additional H.264 advanced motion detection settings dialog box.
For pre-configuration instructions or any additional configuration steps required to enable motion detection in Security Center for specific video units, see the Security Center Video Unit Configuration Guide.