CCD Security Camera
A CCD security camera consists of a CCD array (one or three), and control circuits for gathering and transferring the image information.
A lens gathers and focuses light on the CCD array.
A housing provides protection from the elements and a way to mount the camera. Some cameras have the ability to move (pan-tilt-zoom, or PTZ) under control of an operator.
CCD Cameras for security are generally one component of a more extensive Closed Circuit Television system (CCTV). The CCTV system is not broadcast, instead it is used to monitor specific locations, or in distance learning situations.
The first CCTV system was built in 1942 to observe the launch of V2 rockets.
Security Camera Housing and Mounting
Cameras may be purchased in a variety of housings which allow for mounting, and also for hiding the camera. Security camera housings may be a dome shape, angled ceiling mounts, flush ceiling mounts, Kleenex boxes, smoke detectors (that work), teddy bears and many more.
Security Camera Lenses
The lens gathers and focuses light onto the image sensor(s). The quality of the lens can affect the quality of the image. Lenses
can be fixed focal length, or they can zoom to capture greater detail, under the control of an operator. A pin-hole lens is one that provides a very wide-angle view. The advantage to this type of lens is that you can cover a large area (like a parking lot). The disadvantage is there is very little detail.
The output of a security camera is generally composite video, S-video, Internet Protocol (this would be an IP camera), or possibly a memory stick or other type of removable solid state memory).
- Composite video is a single wire output containing either monochrome (black and white) or color video which can be connected directly to a display device like a television set or LCD screen that accepts this video input, as well as connected to a recording unit (tape or DVR). In North America, the composite video would conform to the NTSC television standard.
- The advantage to composite video is that only a single wire is needed to transport the video to a recorder or monitoring station. The signal can be run for a fairly long distance before degradation occurs.
- S-Video is a form of video where the brightness information and the color information are carried on two separate wires. The advantage to S-video is a higher quality image. Disadvantage is two wires are necessary to carry the signal.
- Internet Protocol cameras (IP camera). This type of camera converts the image to a digital stream and has a built in circuit to enable it to be connect to a network, and then accessed using a web browser or other network means.
- With removable solid-state memory, the memory device can be removed and then viewed on a computer. The disadvantages of this are you can’t see what is going on in real time.
CCD Sensor Resolution
Resolution relates directly to the amount of detail that can be captured with the camera. With modern digital cameras,
resolution is measured in pixels – the more pixels the more detail can be captured.
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