Surveillance Cameras

Motion Detection – What it means for you and your security DVR system

Motion Detection is a useful feature found on most security DVR systems today. Whether you’re looking to optimize record times, count objects, utilize advanced search techniques, or trigger certain alarms, motion detection can be one of the most important features in turning your security system from a fancy gadget to a useful management and loss prevention tool.

Generally the DVR you purchase will be set up to record only when it detects motion in the video. Your system does this digitally when it notices differences in the pixels on the screen. Usually your system when it notices these differences will be triggered to start recording a few seconds before the motion, and a few seconds after, this is called pre-alarm and post-alarm recording. Pre alarm and post alarm recording not only saves a lot of hard drive space, it can also make searching for video much faster and easier by eliminating useless video data. DVR systems with Pre and post alarm triggers will also give you an entire event as they will retroactively save video that occured before the system saw motion and will continue to record for a preset amount of time after the motion stops.

Most systems have sensitivity adjustments which will make more or less motion necessary before they start recording and it may take some tweaking to get your system setup properly. This applies to most PC based DVR systems as well as standalone DVR systems and the process can be a bit time consuming, but the benefits of going through the process far outweigh the setup time. After installing your security camera system, spend a few minutes each day looking over recorded video to find what motion events are causing the system to record. Then go through the motion masking features of your DVR system to mask out unwanted triggers. Remember, with pre-alarm and post-alarm recording, you can rest assured you will get the whole event whenever an object or person moves into the motion detection field, so dont be afraid to mask out unwanted motion triggers.

There are different levels of sophistication when it comes to motion detection – typically PC based DVR systems offer more features and enhanced sensitivity settings when compared to Standalone DVRs, but the principles are the same. For more information on this topic, see our article on the differences between PC based DVRs and standalone DVRs.
Most systems will include a grid overlay accessed in the setup menu for each camera. When we turn parts of this grid off we can tell the system to ignore motion in these areas, this is what we call motion masking. Much like masking tape helps a painter avoid painting trim pieces, the DVR uses the motion masking function to avoid triggering a recording condition in unwanted areas.  This can be useful if our camera is detecting a tree blowing in the wind or a ceiling fan or even a monitor or Television. While PC based DVRs usually will have more detailed grids allowing more specific masking, a standalone DVR system may only have 9 squares that make up it’s grid, so choose your DVR based on how precise you are going to want your masking and motion detection to be. Generally the more advanced your DVR system is, the more things we can do with motion detection, like trigger a siren or strobe light, some DVR systems will even send you an email or text message. Keep in mind, you will want your motion to be very accurate in order to use it as a trigger.

We can setup multiple motion detection zones which allow several benefits. We can count the amount of people that pass through a hallway or a point of sale area, count objects on a conveyer belt, or detect when an object passes through one zone but not another indicating theft. We can also setup motion detection zones where there shouldn’t be any motion. When motion is detected the DVR system can sound an alarm notifying users of potential problems.

Regardless of what level of motion detection your system includes, you will find it a useful feature enhancing your surveillance system’s usability and functionality.

About the Author

Alex Underwood is Director of Product Development at CCTVDynamics. He has written dozens of articles on the applications of CCTV cameras and has been involved in the application, installation and development of thousands of security camera systems throughout north america. Alex is working to bring high end security solutions to every American who wishes to protect their property, their families and their businesses.  Find more about Alex and the products he recommends at CCTVDynamics.com.