5 things to look for in a video security system
5 things to look for in a video security system
Whether you are a first time purchaser of video security or you are looking to replace or upgrade your existing system, there are a number of factors of which you should be aware and consider before you commit to a solution.
Different system components will each offer different features, attributes and prices so it is important to match those factors against your specific requirements. By making an informed decision up front, you stand the best chance of buying the system that you need and achieving what you set out to do.
In this article, I’ve identified the top five critical features that you should look for in a video security system.
We’re all pretty familiar with the concept of megapixels from out daily exposure to television, computer screens and cameras that we find on our phones. We frequently hear terms such as megapixel, high definition and 1080p and we know to equate these with clarity and detail. Well, the same applies to security video cameras. The higher the resolution, the better the image quality… to a point. There is a point of diminishing return on investment where more megapixels doesn't add any further benefit.
Resolution is expressed in terms of the horizontal and vertical number of pixels in the image. In high definition terms, 1920(H) by 1080(V) equals 1080p resolution, where the “p” means progressive scan. This describes the way in which the image is scanned on the screen. If you multiply 1920 by 1080 you get 2073600 pixels which equates to 2 megapixels.
Older style video surveillance systems use Standard Definition recording which roughly matches the old PAL and NTSC video standards. PAL has a vertical line depth of 576 lines, referred to as television lines or TVL. PAL has a resolution of 0.4 megapixels. Standard Definition is typical of the cheap video surveillance systems sold in many electronics stores and on discount web sites. SD resolution should be avoided.
1080p or 2 megapixels is the current sweetheart resolution for day to day video security systems and provides an excellent result for most applications.
Motion detection is a feature of the video security system which enables a timed segment of video to be recorded when either the camera or the recording device, depending on the type of system, detects movement in the field of view. The alternative to motion detection is to leave the video recording all of the time. This consumes more storage space, thereby lessening the amount of time that video can be retained, and may make locating an event in the video footage more difficult.
Some video systems support a combination of constant recording with motion events highlighted as alerts. This provides a convenient option for searching the recorded video for only those events in which you are interested.
The things that you most want to record on your video security system may not be limited to daylight hours. With criminal activity, in particular, the cover of darkness is the favoured environment. It is therefore important that your system can “see in the dark”. This is a feature of the camera and is accomplished in one, or both, of two ways.
Most modern, quality cameras can capture images in low light situations. Light is measure in LUX. This is the illuminance of an area or object as perceived by the human eye. Direct sunlight is regarded as being more than 32000 lux where as a moonless, starlit night is roughly 0.0001 lux. A quality video camera will detect light between 0.01 and 0.001 lux.
Very low lux levels will probably not allow for identification or sufficient detail in many surveillance situations. This is where infra red comes in.
Infra Red is a spectrum of light which is invisible to the human eye. At best, you might notice a dull red glow surrounding an infra red light source. However, IR cameras can use this spectrum to illuminate an area in the field of view and record that as a black and white image. The distance that can be illuminated is a factor of the number of IR LEDs that are built into the camera. Typical mid range cameras can illuminate up to 15 metres with good detail.
Video Storage Units
In the “old days”, video surveillance systems recorded the video stream to VCR tape. For some time now, video security recorders have used the same hard drives that you would find in your computer. For IP networked video systems we refer to the recording devices as Network Video Recorders or NVRs.
The two critical factors which will affect your NVR’s ability to store video are the number of cameras feeding a video stream and the resolution of the video. We’ve already seen in point 1 that 1080p is now the most popular video resolution for general recording. However, 1080p creates some pretty big files. Only recording motion on those cameras where this is possible helps save some disc space and is recommended where practical.
Most NVRs these days will support 4TB disc drives. Some will support more than one and others still will additionally support external networked storage. Generally speaking, disc space is cheap so should not be a factor when considering other necessary features such as resolution.
The NVR itself is quite similar to the home Personal Video Recorder which may be connected to your television. Like the PVR, the NVR will capture and store the video streams from the cameras and allow you to play back those videos at a later time. When the available storage space is full, the NVR will begin to overwrite the oldest video so you don’t have to change discs as you would once have done with a VCR recorder. The more disc space you have, the longer your archive files will be retained.
Most NVR units can now connect to a local network or Internet connection and, through embedded web server software, allow access to live and recorded video through a web browser on the LAN or Internet or by using an app on a mobile phone or tablet.
Remote access to video can be coupled with direct email or TXT notification of events such as movement and enable immediate access to the video stream from anywhere as long as Internet connectivity is available. This feature allows action, such as calling the police or neighbours, to be taken.
Remote access is now an invaluable feature of a video security system and should be a must have for anyone seeking to invest in a new system. Specifically, look for NVR units which support Android and iOS apps.
If you would like further information about security systems or have any questions or comments about my top 5, please feel free to contact me using the “connect” form on this site.