Motion Detection
The motion detection of a network camera is part of the automatic analysis of the video content (VCA, Video Content Analysis / Analytics). Cameras with motion detection evaluate the image content by detecting changes in the contrast ratios of contiguous pixel areas through comparisons. This allows them to distinguish real movements from image disturbances and large objects such as people and vehicles from smaller ones such as animals.
Following detection, the camera triggers one or more reactions that the user has previously defined: The camera can start recording (selective recording), trigger an audible or visual alarm via connected accessories, display a silent alarm on the surveillance monitor, a Contact headquarters or send an email. Other VCAs also work based on motion detection, such as detecting boundary crossings or intruders. Motion detection is not necessarily applied to the entire image content, but only to selected areas. If the surveillance camera itself does not have motion detection, a central recorder (NVR, DVR or hybrid recorder) can take over the intelligent functions. As artificial intelligence (AI) advances, false detections can be reduced to a minimum.
The motion detection of alarm systems usually works differently: External sensors in the form of passive infrared sensors (PIR) or contact sensors report movements to the central unit of the alarm system via cable or radio. The central unit then triggers follow-up actions, which, in addition to the classic loud alarm, can also include notifying the owner via SMS or email, depending on the model.