| Many modern CCTV installations use motion detection | | | | of camera placement and motion detection |
| to record video footage onto a Digital Video | | | | configuration. Place cameras to maximise the view of |
| Recorder(DVR). The technology is very useful | | | | important pathways and entrances that intruders will |
| reducing the amount of video images you need to | | | | use to access your property. Minimize the number |
| record, it can be even used to alert you in real time to | | | | motion detection regions by selecting small areas that |
| any potential intruders. However, as much as motion | | | | must be crossed to access your property. |
| detection can be a real benefit it can be a real problem | | | | Be aware that motion detection works by monitoring |
| if setup incorrectly. At best you'll end up recording | | | | changes in image pixel light intensity, so any significant |
| random video sequences which will quickly eat up your | | | | changes in light intensity in a motion detection region will |
| DVR storage capacity. At worst you'll miss an intruder | | | | trigger a motion event. This can often create |
| break into your property because the motion detection | | | | unforeseen problems when the motion detector is |
| isn't configured properly. | | | | triggered by reflections, shadows or even car |
| Setting up your motion detection camera depends on | | | | headlights. |
| whether the motion detection software is built into the | | | | You will normally have another two main settings, one |
| camera itself, or you are using the in built software on | | | | for motion sensitivity and the other for noise sensitivity. |
| the DVR. As an example, many network cameras | | | | Motion sensitivity, is based upon the number of image |
| that communicate over I.P. networks have built in | | | | pixels in your defined region that will trigger a motion |
| software to provide a variety of functions including | | | | event. It's useful because you can prioritise the size of |
| motion detection. If you've bought a camera that just | | | | the object you want to detect. For example, you can |
| sends a video signal over a wired/wireless network, | | | | detect someone entering through a door by placing a |
| you'll need to utilise the motion detection software on | | | | human sized region at the door opening and setting the |
| your DVR. The DVR itself can be a stand-alone box | | | | motion sensitivity so at least half to two thirds of the |
| or a home P.C. | | | | region must be in motion to activate the trigger. On |
| The easiest to configure out of all these options is the | | | | some cameras you'll even have the option to define |
| networked camera because you can access it from | | | | how long a motion has to be active in order to fire the |
| any P.C. on the same network. Furthermore, each | | | | trigger. Now, instead of just knowing when someone is |
| camera is individually configured and self reliant (if one | | | | entering a door, you can monitor if someone is waiting |
| camera stops working it doesn't affect the rest). A | | | | outside your front door, effectively creating a front |
| network camera can also be used to record images | | | | door bell. |
| to a DVR and send/email images to a remote server. | | | | The noise sensitivity is there to filter out any noise in |
| This means that if your DVR fails you will still get | | | | the image and is based upon the signal to noise ratio |
| copies of your images either through email or on | | | | of the camera.The signal to noise ratio is the ratio |
| another remote P.C. Cameras that use the motion | | | | between the strength of the camera signal and the |
| detection on the DVR are reliant on a single piece of | | | | noise present in that signal. This varies between |
| software to run all cameras, if that fails then no | | | | cameras, but is more important in low lighting conditions |
| images will be recorded. Furthermore, if the DVR itself | | | | when the camera amplifies the weak camera signal. In |
| fails then no images can be recorded. | | | | this case the ratio of noise present in the signal is |
| Which ever configuration you choose the principle of | | | | increased, seen as white fuzzy noise in the camera |
| setting up motion detection is generally the same. First, | | | | image. Why is this important to motion detection? Well, |
| for each camera you'll need to set up an area(s) in the | | | | because motion is detected by the number of |
| image whereby motion is to be detected. Many | | | | changing pixel intensities in a given region and that also |
| interfaces use an image overlay of small squares | | | | includes noise. If you have a lot of noise in the image, |
| regions that can be selected and de-selected. | | | | this will effect the performance of your motion |
| Selecting a square means motion will be monitored | | | | detector and you'll need to adjust the noise sensitivity |
| from that image region and vice-versa. It's important to | | | | accordingly. For this reason, it's important to calibrate |
| consider which areas you select for detection. Think | | | | your camera both in daylight and night time conditions. |
| about the circumstances when you actually want to | | | | Many cameras will allow you to have separate |
| record images. For example, pointing your camera into | | | | settings for low light conditions. If you need your |
| a busy communal area will generate a lot of motion | | | | camera to work in very low light, then either you need |
| recordings, it's often advisable in these circumstances | | | | a camera with a low light lux rating, or use an infra-red |
| to limit your motion regions to points of access to the | | | | camera. |
| room, i.e. doorways and windows. Outdoor cameras | | | | Although setting up motion detection on your CCTV |
| can often be more problematic:cameras pointing out | | | | system may seem time consuming, it can have a huge |
| onto the street can capture passers-by, tree's moving | | | | effect on the performance of your system. If done |
| in the wind can trigger detection and even rain on the | | | | properly, you will be able to monitor the daily activity in |
| lense can appear as motion. In truth, the solution to | | | | and around the home without the inconvenience of |
| overcoming most of these problems is a combination | | | | trawling through endless empty images! |