Video surveillance camera is the core equipment and other equipment for video monitoring project may not use the camera is a must, but from the appearance, monitoring camera can be divided into QiangJi, camera, video intelligent ball hemisphere, from the function of infrared cameras, points can be divided into the camera, infrared seek, high-speed ball, medium-speed ball, constant speed, ordinary camera, others are low illumination, dynamic division, etc. Current monitoring camera is mainly used as SONY and sharp chip camera. Surveillance cameras are currently developing, the high-definition television line of mainstream or 420, but 480 line and the camera is becoming more and more get the above model of engineering.
In the society as monitoring system is widely used for kinds of cameras (brand, type and increasingly numerous models). As the monitoring project design installation contractor, so many kinds of cameras, the system designer and purchasing manager, is a test. How to correctly, to ensure that the system selects camera best effect, the system of the lowest cost? The problem with many design engineers and purchasing manager.
Perhaps, in this article, the difficulties for the engineers help and inspiration. In order to well on this question, let's start with some basic knowledge about CCD camera! :
A CCD camera, classification
1 and in imaging colour
Color kinescope: applicable to discern, such as the details of the scenery scenery of clothes or discern color.
Black and white video: not enough resynchronized region and night cannot install lighting equipment, in the region of the position or only monitoring objects move, can choose the black and white video camera.
2, resolution and sensitivity
Image pixels in 38 million for the plain below, especially to 25 million pixels (512 *), resolution for 400 492 line of products, the most common.
Image pixels in 38 million above the high resolution.
3, by cameras into shape
Cameras are mainly divided according to appearance: gun type camera, pinhole cameras, video and ball type.
4, according to the size of the target surface CCD
1 inch wide screen size - 1.27 mm * for high 9.6 mm, 16mm diagonals.
2/3 inches wide screen size - to 8.8 mm *, 11mm diagonal high 6.6 mm.
1 1/2 inch wide screen size - is 6.4 mm * 480 mm, high 8mm diagonals.
1/3 inches wide screen size for - 4.8 mm * 360 mm, 6mm diagonal high.
1/4 inches wide screen size - for 3.2 mm * high 2.4 mm, 4mm diagonals.
By scanning formats, divided
PAL.
NTSC system.
Six, in power supplies
220VAC, PAL system.
24VAC.
12VDC, domestic cameras are such.
7, synchronous way
With cameras synchronization: synchronization signal circuit of synchronizing signal to complete the operation.
The synchronous: use a synchronous signal generator, the camera external synchronizing signal into synchronous input.
Power synchronous (linear lock, lock) : use camera competition AC power complete vertical push synchronization.
The DVD synchronous: the camera signal cable on the DVD synchronous pulse input complete DVD synchronization.
Many cameras to external synchronous: more cameras, make each fixed external synchronous camera can be in the same conditions for the camera, so if one synchronization, a camera to other objects, the picture is not synchronized camera.

Second, a CCD camera main technical indices of color
(1) the CCD camera, i.e., the size of the target surface. Now, 1/3 inches has became popular, 1/4 inch has commercialized.
(2) the CCD pixels, the image resolution pixels, the higher, more and more clear to 25 million and 38 million pixels, 38 million pixels delimitation of high-definition cameras.
(3) level of resolution. Color is typical of the camera in the resolution to 500 TV line between 320, on the market to 420TVL and 480TVL two resolution dominant.
(4) minimum illumination, also known as sensitivity. The moonlight and increased sensitivity high grade stars can work in a dark camera on general conditions, camera, 2 ~ 3lux belong to the lowest, the average illuminance 1lux now is popular, the most common camera.
(5) scanning formats. Have PAL and NTSC system.
(6) camera power. Communication is 220V and 110V, 24V dc 12V 9V or for.
The signal-to-noise ratio (7). Typical values for 46db, if 50db, image with small noise, but the image quality is good, If 60db, image quality, not the noise.
(8) video output. For more than 1Vp - p, 75 Ω, adopts BNC connectors.
(9) lens installation. Have C and CS mode, the difference between them is different from photosensitive distance.

Third, the camera chooses experiences
In the application of monitoring system, camera, it is very crucial chosen directly determine the whole monitoring system of image effects. Below, we talk about the camera chooses various occasions, for your reference.
Camera chooses according to two major factors: one is the camera use environment (applications), One of the main parameters of the camera is relevant.
A) camera applications - type selection of cameras
Currently, the camera phyletic and applications are also different. Applications of type selection decisions, video camera, we must choose correct understanding of this camera installations, determine the installation. Currently, the camera installed applications mainly has: office buildings, hotels, factories, bank, prisons, etc. General is divided into indoor and outdoor use.
Our monitor installation with hotel is illustrated the camera. According to the current practice, hotel, the application of monitoring system in front of cameras installation position mainly has: the lobby, elevator, corridor corridor, parking lot, etc.

Installation location monitoring camera chooses type selection demand characteristics
Parking monitoring range, dynamic big integration camera
Or gun type of camera + electric zoom camera built-in zoom lens, suitable for dynamic range of occasions, but on site installation and debugging, and details and simple.
Lobby, dynamic range monitoring camera big
Elevator control scope, light stable flying camera fixed position of elevator's installation, install small-sized hemisphere stenosis caused by customers, camera, can both elevator entropion and image monitoring results
Building corridor, light scope of monitoring camera relatively stable explosion-proof hemisphere of the hotel, such as low condole top gun type camera, lifting common eye damage of corridor is to decorate the effect. Absorb top, can install hemisphere camera and monitor overall consideration corridor, installation, commissioning and simple

2) camera chooses parameters
After that, we selected camera type for application environment should determine the specific parameters, and video camera model selection. Generally speaking, the main parameters of the camera is: the minimum illumination, clarity, and for reference. Parameters,
Definition: on the market 330TVL camera 480TVL - the majority, according to the current application, most commonly used 420TVL camera, high-definition cameras 480TVL application second,
The minimum illumination: the minimum illuminance is normal work of camera around the minimum requirement of environment. Therefore it is an important parameter selection of the camera.
Our monitor, for example, or hotel on camera parameters using analysis:

Installation position control parameters selection type selection camera
Parking requirements high-definition, environmental change brightness camera
Night and day type of camera image or gun + electrical zoom lens
520TVL high definition, built-in camera lens aperture, suitable for automatic brightness changes
Lobby monitoring range, dynamic big integration camera
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Elevator control scope of fixed, light stability, big small Angle camera hemisphere
Elevator installed a light inside, so little change, we choose luminosity 0.01-1LUX illumination camera, 420 line, configuration 3.6 mm wide-angle lens
Building corridor, light scope of monitoring camera relatively stable hemispheres
Install lamplight hallway, therefore there inside, we choose luminosity 0.01-1LUX illumination camera, 420 line, configuration 8mm wide-angle lens

3) various types of video applications

Following are some of the most appropriate type of camera applications for monitoring system design engineer:

Type of camera applications
1 hemisphere camera elevator, has changed the indoor ceiling light applications
2 most suitable for camera installed indoors monitoring of dynamic range, also suit to install outdoor surveillance range medium occasions (if within the radius of outdoor surveillance 60m)
3 gun type of camera can be installed in any situation inside, but not too small for monitoring or install range
4 underwater camera applicable to use underwater installation
5 day type camera suitable environment changes greatly occasions, such as indoor lighting weaker during the night, the brightness of the normal occasions