Video detectors

Motion detectors and appearing/disappearing object detectors

The motion detector used in VOCORD video surveillance systems not only detects motion in the monitored area but also determines the object size, speed, and other parameters.

A distinctive feature of VOCORD motion detector is automatic adaptation to changes of lighting conditions and visual obstruction factors, such as snow or rain. The motion detector has high resolution and is capable of registering objects of size down to 4 pixels.

Therefore, VOCORD motion detector is a perfect choice for outdoor video surveillance systems.

The unique technical specifications of the motion detector are powered by a unique proprietary algorithm by Vocord.

At level 1, for each pixel of the image several static Bayesian models are created and then regularly updated. If the current value of the pixel significantly differs from the previous statistics, it is considered to be a possible motion source.

At level 2, pixels where changes were detected are grouped and analyzed. Then their behavior is classified either as actual motion or as random interference.

The main usages of the appearing/disappearing object detector are

• Detecting objects that appear in the monitored area and stay longer than the specified duration.
• Detecting objects that were present in the monitored area longer than the specified duration and then were removed.

Such detectors are in high demand for detecting terrorist threats in buildings and public locations.

An important feature of appearing/disappearing object detectors is reliable functioning in situations when the monitored object is periodically covered by other objects. For example, a suitcase left in a subway station where people constantly pass by. The underlying algorithms used in appearing/disappearing object detectors are similar to those described above, and they ensure reliable functioning even in such complicated situations.