A Guide to Home Security Surveillance Systems
Night Vision PTZ Camera with Built-In Recorder and Motion Tracking
The technology used in home security surveillance systems has changed dramatically over the years. Surveillance systems today have video cameras that are cheaper, smaller, and better. Up until a few years ago video footage was recorded onto VHS tape, but today DVR (digital video recorder) systems record video footage onto a hard drive. The price of home security surveillance system has come down dramatically over the last few years. A home security surveillance system consists of two main parts: the video recording device, and the surveillance cameras.
1. Surveillance Camera Technology
Surveillance cameras either use CMOS or CCD (charge couple device) chips to record video images. CCD surveillance cameras produce better quality video than the cheaper CMOS surveillance cameras. We use inches to measure CCD camera formats, and brighter images are produced by larger CCD chips. A CCD format of 1/4″ or 1/3″ is good enough for most situations.
Resolution of a surveillance camera is specified as the number of TV lines (TVL) produced by the camera. This determines how detailed the video picture quality is. Cameras today typically produce a video resolution between 350-400 TVL. The frame rate of a surveillance camera is the number of separate images that the camera can record per second. Most camera’s can record at 30fps (frames per second), and video below 30fps is not smooth and begins to look jerky.
Black and white surveillance cameras are better in poor lighting conditions than color cameras. A camera’s sensitivity to light is measured in lux. A camera’s light sensitivity must be 0.5 lux or lower to be able to view images at night.
2. Surveillance Camera Lenses
The lens of a surveillance camera should match the CCD format of the camera - 1/3″ lenses should be used with cameras with a 1/3″ CCD format. Most home security surveillance systems have cameras with fixed focal length lenses, which means that the cameras do not have a zoom in/out facility. Motorized zoom cameras are more expensive, and allow you to change the camera’s zoom focal length remotely.
3. Other Surveillance Camera Features
Some surveillance cameras include Infrared (IR) LEDs, which project an infrared light allowing you view video in complete darkness. The range that these camera’s can see in the dark vary, and is typically between 10 to 50 feet. More expensive home security surveillance systems have cameras with a pan, tilt and zoom (PTZ) facility. To be able to pan the camera’s view left and right, tilt the camera’s view up or down, or zoom in and out, the camera must have a PTZ (pan, tilt and zoom) facility.
4. Surveillance Camera Housings
A home security surveillance system can have large, visible cameras, which are cheaper, have larger housings, and can deter criminals by being clearly visible. Hidden (covert) security cameras are quite small, are more expensive, and are usually hidden within other objects, such as a wall clock. Cameras with dome housings are mounted on the underside of ceilings. Dome housings are normally used to house cameras with a PTZ (pan, tilt and zoom) facility. Protective weatherproof security camera housings are used by cameras that need to be protected from the elements. Outdoor surveillance cameras need to be waterproof and to be able to withstand extremes in temperature.
5. Video Surveillance Monitors
Using a standard TV as a video surveillance monitor does not produce the best picture quality. Computer monitors produce better picture quality, and also offer an extended lifespan. If you want to display video from multiple cameras onto a single monitor, then a 15″ monitor should be the minimum size you purchase.
6. Video Surveillance System Recorders
Most home security surveillance systems today record video onto a hard drive and not VHS tape. This has several advantages. Firstly, you do not need to fast-forward or rewind a tape to go to a specific point in a recording – you can immediately go to that specific point in the recoding. Secondly, you can playback an earlier part of any camera recording whilst that camera is still recording.
Motion detection is a handy feature which is incorporated into some home security surveillance systems, which allows you to only record when motion is detected within a certain area. This will reduce the hard drive storage space requirements. VCR systems today are a lot cheaper than DVR systems, and this is the only advantage of buying a VCR system.
7. PC Based DVR Versus Standalone DVR
There are two types of home security surveillance system, PC based DVR systems, and standalone DVR systems. A PC based DVR system is quite cheap, and is run off an existing PC. A PC board must be installed inside the PC, and special software installed on the PC. PC based DVR systems are generally slower, and a lot more unstable when compared against any freestanding DVR system.
The recording on a standard DVR security camera system is done using hardware, and this eliminates software crashes that you sometimes get with the PC based DVR systems. PC based systems generally do not perform as well, and are not as reliable as DVR systems.
8. Considerations when buying a Home Security Surveillance System
Your first consideration is the quality of the video you want to record. This is the resolution of video recordings in TV Lines, as well the video frame rate (smoothness) of the recordings. The second consideration is the number of cameras that you will need for your home security surveillance system. Typically, an entry level system contains four cameras. The size of the hard drive you need for the DVR system is your third consideration. Low-end DVR systems come with 80 gigabyte (GB) hard drives, whilst top-end systems come with a 750GB hard drive.
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