Motion detection is an extremely useful feature that can significantly reduce storage requirements by recording only when movement is sensed. There are various methods that security camera manufacturers use to implement motion detection with the most common being video motion detection. It starts with configuring the DVR, security camera or analytics software to highlight one or more areas within the camera’s field of view that should be monitored for changes between successive images. Advanced features include the ability to configure multiple video motion zones and individually configure thresholds. Some security cameras and DVRs allow for configurable pre and post motion times using a memory buffer. For example: Mobotix cameras can be set to record 5 seconds *before* motion is detected and 5 seconds *after* the event allowing for a full story to be captured.

Video Motion Triggered by a bird (click to enlarge)

Motion detection can be used to trigger a number of different events including recording, notification (via email or console) and external alarms such as bells, lights or even phone calls.

Mobotix takes motion detection one step further by including a Passive Infrared (PIR) sensor on some models. Similar to motion sensor used with alarm systems, the PIR sensor detects heat in motion and can often detect motion that might have been outside the camera’s field of view. The sensitivity of the PIR sensor can be adjusted and events triggered by the senor are clearly identified on captured video. Mobotix cameras are able to evaluate video motions zones up to 30 times per second and configure two sets of video motion windows that can trigger different events. For example: record all motion in a parking lot but only alert staff when motion is detected at a door.

When configuring motion detection, avoid areas that includes things such as blowing trees, areas subject to frequent light changes (vehicle headlights) and reflections. False-positives can never be eliminated, only minimized as illustrated by the bird flying through video motion box 4 in the image. The image was captured using a Mobotix VGA camera with a D43 lens and the camera was set to highlight triggered video motion zones in red.