How do video cameras work

Security camera with motion detection

How a surveillance camera works with motion detection: A current IP camera combines classic camera components such as lens and image sensor with advanced software that takes video surveillance to a new level in a compact format. Sophisticated algorithms continually analyze the captured image. They use them to do work that in analog times still required the permanent involvement of people. The basis for a large number of intelligent image analyzes is Motion detection.

How does a surveillance camera with motion detection work

Functions like the are based on the motion detection of a surveillance camera Proximity and intruder alarms or also the People counting. In all of these applications, it is essential that the camera detects changes in the image content. To do this, the software analyzes the contrast ratios. If neighboring image pixels change relatively quickly in a certain pattern, this is typical for a moving object. What sounds simple is actually an engineering masterpiece. Because the pixel-perfect analysis has to be in Real time happen, nothing must be missed, but false alarms must not be constantly triggered. With a simple motion detector that just turns on the light, the Motion detection therefore not much in common.

In surveillance, motion detection is a relief wherever motion is not allowed at all or is only allowed to a limited extent or where there is a need for increased attention. If, for example, nobody is allowed to be in a shop after work, an appropriately equipped camera that records the possible entry points is sufficient for efficient monitoring. If someone enters the shop, this triggers different actions depending on the configuration and equipment:

  • The camera sends a message to the owner or a surveillance center over the network. A large overlay on the surveillance monitor and the automatic change to the live view mode of the camera are also possible.
  • A permanent video recording is saved. This can be stored on a memory card in the camera, an external recording device such as a network video recorder or a NAS. The cloud can also serve as a storage location for a video stream or evidence.
  • An acoustic alarm sounds, a warning announcement or the lighting is switched on.

Combinations with others are also conceivable Smart features. For example, if someone approaches a restricted area, a warning is issued via a loudspeaker at a certain minimum distance. If he enters the restricted area anyway, further actions follow.

The advantages of a Security camera with motion detection are economical in several ways. If only relevant events are recorded, this reduces the space required on memory cards or hard drives. In addition, selective recording and transmission only load the network when necessary. Especially when using a WiFi camera or a large number of surveillance cameras, this pays off. But you don't have to worry that the recording would be incomplete because it is only started with a movement. A good security camera continuously keeps the last few seconds in memory and discards this data regularly. In the event of a movement, the seconds just before are guaranteed to still exist and you will not miss the first actions of an intruder.

In addition to the savings in technical infrastructure, artificial intelligence also reduces the need for human working time. In the professional field, motion detection helps to save personnel costs, private individuals do not miss any movement even if they do not have the camera image in view themselves. Thanks to the notifications via the Internet, you don't even have to be on site to be informed immediately.

Configuration options

The application scenarios for motion detection are innumerable because the function offers a wide range of customization options:

  • The time of detection can be set to days of the week and times.
  • In terms of space, the motion detection does not necessarily have to analyze the entire camera image, but can be limited to different zones of almost any size within the surveillance area. To define it, you simply mark the corresponding parts of the image with the mouse.
  • With the sensitivity control it is very easy to reduce unwanted alarms to a minimum. Settings are typically possible in the form of a percentage ("0-100") or in fixed steps ("low - medium - high").

The fundamental challenge of the configuration is to distinguish security-relevant movements from other movements that are not a threat. When monitoring a garden or a front door, for example, it is inevitable that birds or stray cats will also move through the camera image or that the wind will move leaves and flowers. In particular, the motion detection of an outdoor camera would be almost permanently in the alarm state without fine tuning if it reported every movement.

It is impossible to formulate a general rule as to which settings should be selected, because the local conditions are too different. When determining the image section to be analyzed, one should consider what the attack routes of intruders are and only mark these areas. Burglars break into doors and pry open windows. To do this, they have to move doors and window frames in very specific areas of the image. Animals normally do not initiate such movements. The movement of tree tops in the wind can also simply be excluded by not including the trees in the detection.

The more precisely you define the image section, the higher the sensitivity setting can be without causing an excessive number of false alarms. With the highest sensitivity, even the smallest image changes are sufficient for motion detection. With a little trial and error you can find the optimal setting.

Cameras without motion detection

Almost every current IP camera has one integrated motion detection. This means that the camera carries out the image analysis independently and no additional software is required. Older cameras or models without smart features do not necessarily have to be replaced if you want to benefit from the new functions. One option for retrofitting is to purchase a compatible network video or hybrid recorder. The recorder then analyzes the transmitted images. Programs that master image analysis are also available for the PC, e.g. B. the iVMS-4200 client software by Hikvision. Some manufacturers of NAS systems also offer special firmware or extensions for image analysis.

Everyone can benefit from the advantages of a surveillance camera with motion detection: The camera no longer only delivers videos, but becomes an intelligent surveillance assistant that does its job reliably and cost-effectively.