Welcome to the CST FAQs site Products and technologies available of the Electro Optical Imaging market vary widely in feature and performance. If you've ever been confused about claims of low lux and day/night performance, this page may help you to evaluate two products side by side. Most of the contents has been provided by our engineers and technicians. However, we would very much appreciate, and strongly encourage, contributions by anybody – you don't have to be an expert to have a valuable contribution to make!
Please look around the site – and enjoy! Index A-Z Automatic Gain Control (AGC) is used to provide a stronger picture by amplifying the video signal. As the light reduces, AGC cuts in incrementally, and thereby stretches as much as possible from the signal.The down side of this is that in boosting the signal, it also has the effect of boosting any noise on the signal.
So in order to provide a level playing feel and check the inherent sensitivity of a camera, (and the true resolution of the resulting picture). ^TOP The camera monitors the levels of black in the image expands the contrast between light and dark in the scene.If the image would become shrouded by fog or lens glare, picture contrast will be enhanced by the camera automatically. ^TOP The camera monitors the sharpness of the picture. If the picture would become fuzzy e.g. due to fully opened lens
iris the camera enhances the sharpness automatically. ^TOP Back light compensation is programmable to operate over various areas of the picture. Combined with the very
dynamic range of the camera it provides the best possible pictures in back light situations. ^TOP Bore site retention gives an indication on the alignment of the CCD on the optical axis of the lens. The camera will only ensure optical track on the target, if the sensor is positioned 100% in the centre of the optic. All CST cameras are provided with 100% bore site retention. ^TOP One of the major causes of deteriorating of viewing quality with a telephoto lens is chromatic aberration (color blur). The degree of refraction of light changes according to the color (wavelength). The degree of such refraction is called ”dispersion”. The focal length of a lens varies slightly according to color, generating a red or purple blur along the outline of the image. Normally, a combination of two or more types of optical lenses with different dispersion properties are used to compensate for one another and reduce color blur. Nevertheless, this blurring cannot be compeletely eliminated even when using high quality optical glasses. ED (EXTRA LOW DISPERSION) glass is the key to eliminating color blur and because of its extra low dispersion qualities we are able to almost eliminate color blur. The elimination dramatically improves resolution and contrast resulting in images rendering outstanding colors and shapes and detail. ^TOP CST employs air-cooling of the CCD in order to transfer the heat off the sensor to the outer sections of the camera house. Cooling is performed by means of a high-speed fane integrated into the large cooling surface of the camera housing. Compared to other cooling techniques air-cooling is very efficient and clean without the appearance of any side effects, such as the formation of condense water or alike. The number of white pixels on the image is effectively reduced and the signal-to-noise ratio increased. CST air-cooled cameras provide excellent operation in wide temperature ranges, 24-hour surveillance (in colour and B/W) and as imager in optical systems without iris. ^TOP
Infra red light is the spectrum of a light beyond 700nm which a camera can "see" buth the human eye cannot. Extra Infra-red illumination is used to help cameras see in the dark where high levels of lighting are unavailable or unwanted, although there is always an element of IR light conventional light sources. An IR
pass filter cuts out visible light and allows the infra-red light to pass through. An IR cut filter does exactly the oppostie by cutting out the IR light and using only visible light. ^TOP What was considered good low light performance five years ago, may not be so good now. Low Light Cameras can be colour, or mono, though generally it is easier to achieve good mono pictures in low light levels than it is in colour ones. Resolution Resolution refers to how detailed a picture the camera can see. The measurement is horizontal TV lines; the higher the resolution the better the picture. Normal CCTV picture is around 350 to 400 TVL; CST camera colour pictures are 540 TVL and 570 TVL for b/w pictures. ^TOP Indication for the lowest level at which a camera can produce 100 IRE and 50 IRE video signals with AGC on and off. ^TOP Noise increases with the operation temperature of the CCD. The higher the temperature, the more the image is blurred by noise. CST cameras have an high signal-to-noise ratio obtained through the employment of air-cooling of the CCD and A-grade DSP processors. ^TOP The conventional type of twin camera is a camera which provides both a colour and mono function. These types automatically switch from colour to mono when a certain level of darkness is reached. As oposed to them, the extreme light sensitivity of CST twin cameras allows for continuous operation in colour mode during darkness. For the user, who needs to recognize more details in the image manual switch to mono is reserved. Through the switch image resolution is increased from 540 TVL to 570 TVL. CST twin cameras can be used as replacement for earlier dual sensor cameras which were consists of a colour camera and 1Gen intensified cameras. Excellent light sensitivity in monochrome mode does easily meet the performance of 1Gen intensified cameras. ^ TOP
The automatic white balance function controls the color temperature from 3.000K to 10.000K. ^ TOP
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