Intelligent video analytics –IVA – is something of a buzzword at present. Devices support on-board IVA, VMS and NVRs boast IVA on their spec sheets and dedicated IVA applications abound. Some are genuinely analytics-based functions, but more often than not you’ll find that what is on offer is basically video motion detection. Interestingly, Mobotix bills its MxActivitySensor function as intelligent video motion detection, but it offers a lot more than this description suggests. Now the functionality has undergone something of an update to enhance performance in the field.
In an age of video analytics and smart detection, many consider VMD (video motion detection) to be something of a dirty word. There are reasons to consider VMD as a somewhat unreliable technology. In the past, many manufacturers added motion detection functions that simply reacted to contrast change. These detected movements within the viewed scene as motion. They also detected lights turning on or off as motion. The sun passing behind a cloud or reemerging was detected as motion. Foliage moving in a breeze was detected, as were ripples on water or relections from glass on stationary vehicles or buildings. If there was a contrast change, it was typically detected as motion!
Video motion detection which did not include any degree of logical discriminations inevitably caused numerous nuisance activations. In many cases the best way to improve performance was to disable the VMD function.
As with any technology, there were also some very good implementations of VMD. These were stable, reliable and effective. The difference between these and the contrast-based detection engines was that they applied discriminations. Filters relating to object size, speed, direction, shape, etc., were all used to good effect. Today a number of manufacturers do offer VMD with discriminations, and most refer to this as IVA.
Does it matter whether Mobotix refers to MxActivitySensor as intelligent VMD or IVA? Well, we think it does as it tempers expectations and frankly is a little more honest as to how the technology is working.
MxActivitySensor is an integral part of the firmware of Mobotix devices released in the last three or so years. It’s a software-based motion analysis tool with applied discriminations for detecting movement of people and objects in the image area. The selected area can either be the full image or a custom-defined area of interest.
MxActivitySensor delivers consistently reliable results, even in applications with large amounts of external interference. The camera distinguishes between movements of vehicles, people or objects that trigger an alarm and innocuous movements that are not relevant for alarms, such as changes in illumination, heavy rain or objects or trees swaying in the wind.
Along with directional discrimination, the latest version – MxActivitySensor 2.0 – has been enhanced with 3D motion detection. This adds a higher degree of perspective-based discrimination and ensures that innocuous sources of motion, such as animals, flying birds, wind-borne debris, etc., do not generate alarm conditions.
An example which demonstrates the use of 3D motion detection is the monitoring of a flat roof on a site’s building. With MxActivitySensor 2.0’s 3D motion detection deployed, an intruder would trigger an alarm if they gained access to the roof area. However, non-threatening motion, such as birds on the roof, would not create an event condition.
Similarly, persons detected at a perimeter fence would generate a detection alert, triggering an alarm, whereas activity caused by animals would be flagged as innocuous and no alarm would be created.
MxActivitySensor looks at an entire object rather than portions of an object. This ensures that partial motion – such as foliage or tree branches moving due to environmental conditions – are ignored. This process also eliminates false activations due to adverse weather conditions such as rain and snow, or global scene changes caused due to illumination differences such as lights being switched on or off, or clouds obscuring the sun or moon.
MxActivitySensor 2.0, which is available in the current firmware version (4.4.2.34 or later), is quick and simple to configure. In principle, it is only necessary to define the desired image areas, the directions of movement that trigger an alarm and – importantly with 3D motion detection – the image size of targets with a consideration for perspective.
Defining the latter is simplified as the software simply requires the identification of potential target sizes to be established, via drawn bounding boxes, in the foreground and background areas of the protected region.
This allows the software to automatically add violation discriminations for potential target size whilst also enabling adjustments to address perspective. This ensures that just as a bird flying close to the camera will not be identified as an intruder, also an intruder in the distance will not be dismissed as innocuous activity such as a small animal.
The MxActivitySensor software detects objects or people crossing the defined image area or continuously moving toward or away from the camera.
MxActivitySensor additionally has a degree of inherent reliability to a degree that it will detect people who enter or leave a protected space, but not those who remain within it but stand up from sitting, turn around, pick up or put down items, etc..
MxActivitySensor 2.0 also offers the option to set specific directions of movement within the image area (up, down, left or right) as discriminations, thus ensuring that only relevant events will trigger an alarm. This way, it is possible to capture movements going against the direction of traffic on a one way street or a violation of flow at entry or exit points, for example.
When triggered, the software executes individually selectable follow-up actions. Once MxActivitySensor 2.0 has detected a movement, the captured video is stored and the user has the option to make an audio announcement over the integral speaker on the camera, or use the camera to make an alarm notification phone call or an image transfer via FTP or e-mail.
In addition, the Mobotix App for mobile devices can provide an acoustic or visual alarm, access to the live image from the camera, and can instigate two-way communication with the camera over the Internet from anywhere in the world.
In most applications the configuration process is both quick and simple, and if an image area is not defined, the entire camera image is automatically used. The features inherent in MxActivitySensor 2.0 will immediately reduce the number of false alarms generated by motion detection.
MxActivitySensor 2.0 is a free-of-charge feature with no need for additional licensing or fees.