Home Security Cameras
There are many things to consider when selecting the right home security cameras for your application. But when you are faced with a low light application there is one spec that you need to pay very close attention to.
Low Light Cameras
This is known as the camera Lux rating or Minimum illumination rating. Based on this you will be able to determine weather a home security camera can perform well in low light application or not. Lux is the lumen (one candela per radian of a solid angle) per square meter. The closer to zero the Lux rating the better the security camera will perform in a low light application.
For example night vision home security cameras which are aided by infrared beams that are invisible to the human eye, have a Lux or minimum illumination rating of 0 meaning the camera can see in complete darkness with no light required. Most monochrome or black and white home security cameras have a lower Lux rating than color security cameras therefore they perform better in low light situation.
However in recent months advancements in color camera technology have improved low light performance of some color cameras which are known as day night security cameras. It must be noted that these home security cameras will automatically switch to a black and white picture at night for optimum performance in a low light situation and switch back to color once the light level is adequate.
Resolution
Camera resolution is one of the most important specs to consider when purchasing a security camera or home security camera systems. Having the right camera resolution could make the difference in identifying a person committing a crime and apprehending them or letting them walk away.
The resolution of the home security camera is indicated by the number of horizontal TV lines that make up a picture. Each individual horizontal TV line is made of a number of pixels and the total number of these lines makes up the full picture you see on your screen. Does that mean that the more lines of resolution per picture the better the clarity of the overall picture will be? That is absolutely true if and only if the rest of the equipment that your system consists of has equal or better resolution than your home security camera.
For example: You could purchase a high resolution color home security camera that has 480 lines resolution, a monitor with 500 line resolution and a time lapse security recorder with 300 line resolution. The end result will be a picture that looks great on the monitor when you are viewing it live but not so great when you playback anything that has been recorded. Why was the quality of the playback picture so poor when it looked so good live? Well, your live picture was clear because the monitor had 500 line resolution which surpassed the 480 line resolution that the security camera was putting out, so there will be no loss in resolution on live picture. However the recorder that was purchased was only 300 line resolution causing all of your recording to be done at 300 line resolution instead of 480 line security camera resolution.
As you can see the home security camera resolution is not the only factor that determines the resolution you will get as the end result. When choosing a home security camera system, you must consider the resolution of each individual component comprising your home security camera system so you can select components with similar resolution.
Analog vs Digital Cameras
Video Cassette Recorders use 1/2" tapes to store video information, while Digital Video Recorders use hard drives, thereby storing information digitally. DVR's have surpassed VCR's in sales due to superior features.
This is true because, except for the alarm mode, VCRs offer no quick way to search through the information recorded by home security cameras. The tape must be fast forwarded or rewound sequentially. Also, VCRs store information in an analog format, making further manipulation of the image impossible. Furthermore, the quality of video recorded with VCRs is always lower than the source. These drawbacks are not true of home security cameras with DVRs.
The limitations regarding DVRs have also lessened as home security cameras evolve. What once was a major drawback of home security cameras - the size of the hard drive - has increased substantially. Capacities of over 1000 gigabytes (1 TB) are easily available on modern home security cameras. It is difficult to estimate how much a hard drive will store without first knowing the type of compression that is being used and without first selecting the image quality. Advanced compression ratios which provide a quality image with a relatively small file size, such as MPEG-4, are now standard on DVRs. These qualities have made DVRs the logical choice when deciding on home security cameras.
Digital Video Recording Systems
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