Camera is also known as camera or CCD (Charge Coupled Device) that is charge coupled device. Strictly speaking, camera is a general term for camera and lens, while in fact, most of the cameras and lenses are purchased separately, the user according to the size of the target object and the distance between the camera and the object, through the calculation to get the focal length of the lens, so each user needs a lens is based on the actual situation, do not think that there is already a lens on the camera (head).
The main sensing component of the camera is the CCD, which has high sensitivity, small distortion, long life, anti-vibration, anti-magnetic field, small size, no residual shadow, etc., the CCD is an electrically coupled device (Charge Couple Device) for short, which can change the light into a charge and can be stored and transferred, but also can be stored out of the charge so that the voltage changes, so it is the ideal camera component. Therefore, it is an ideal camera element. It is a new type of device that replaces the camera tube sensor.
The working principle of the CCD is: the photographed object reflects the light, spread to the lens, the lens focuses on the CCD chip, the CCD according to the intensity of the light accumulates the corresponding charge, by the periodic discharge, resulting in the production of a picture of a picture of the electrical signals, filtering, amplification, through the camera's output terminals output a standard composite video signal. This standard video signal with home video recorders, VCD players, home video cameras, the video output is the same, so you can also record or receive a TV set to watch.
CCD camera selection and classification CCD chip is like the human retina, is the core of the camera. China does not yet have the ability to manufacture, most of the cameras on the market are used in Japan SONY, SHARP, Panasonic, LG and other companies to produce the chip, South Korea also has the ability to produce, but the quality is a little inferior. Because of the chip produced by different levels of production, each manufacturer to obtain different ways and other reasons, resulting in CCD acquisition effect is also very different. At the time of purchase, you can take the following methods of detection: turn on the power, connect the video cable to the monitor, close the lens aperture, see if the image is completely black when there are bright spots, the screen snowflake big or not, these are the detection of the CCD chip is the most simple and direct method, and does not require other specialized instruments. Then you can open the aperture, look at a still life, if it is a color camera, it is best to ingest a brightly colored object, to see whether the image on the monitor is off-color, distorted, color or gray scale is smooth. A good CCD can well restore the color of the scene, so that the object looks clear and natural; while the image of the defective product will have a color deviation phenomenon, even if the face of a piece of white paper, the image will show blue or red. Individual CCD due to the dust of the production plant, CCD target surface will have impurities, in general, the impurities will not affect the image, but in low light or microscopic camera, fine dust will also cause adverse consequences, if used for such work, must be carefully selected.
1, according to the imaging color division Color camera: applicable to the scene of fine discrimination, such as identification of clothing or the color of the scene. Black-and-white cameras: for poorly lit areas and areas where lighting can not be installed at night, only to monitor the location or movement of the scene, black-and-white cameras can be used.
2, according to the resolution of sensitivity and other divisions Image pixels in the 380,000 or less for the general type, especially 250,000 pixels (512 * 492), the resolution of 400 lines of the most common products. The high resolution type with more than 380,000 pixels.
3, divided by the size of the CCD target CCD chip has been developed in a variety of sizes: most of the chips used 1/3 and 1/4. In the purchase of the camera, especially for the camera angle has a more stringent requirements of the time, the size of the CCD target, the CCD and the lens with the situation will have a direct impact on the size of the field of view angle and the clarity of the image. 1 inches - the target size of the width of 12.7mm * 9.5mm high. 1 inch - target surface size is wide 12.7mm * high 9.6mm, diagonal 16mm. 2/3 inch - target surface size is wide 8.8mm * high 6.6mm, diagonal 11mm. 1/2 inch - target surface size is wide 6.4mm * high 4.8mm, diagonal 8mm. 1/3 inch - target surface size is wide 4.8mm * high 3.6mm, diagonal 6mm. 1/4 inch - target surface size is wide 3.2mm * high 3.6mm, diagonal 6mm. Target surface size is 3.2mm wide * 2.4mm high, diagonal 4mm.
4, according to the scanning system PAL system. NTSC system. China's use of interlaced (PAL) system (black and white for CCIR), the standard is 625 lines, 50 fields, only medical or other specialized areas to use some non-standard system. In Japan, the standard is NTSC, 525 lines and 60 fields (EIA in black and white).
5, according to the power supply 110VAC (NTSC is mostly such), 220VAC, 24VAC, 12VDC or 9VDC (miniature cameras are mostly such).
6, according to the synchronization method is divided into internal synchronization: the synchronization signal generated by the camera within the synchronization signal generation circuit to complete the operation. External synchronization: the use of an external synchronization signal generator, the synchronization signal into the camera's external synchronization input. Power synchronization (linear lock, line lock): with the camera AC power to complete the vertical push synchronization. External VD Sync: Input the VD sync pulse from the camera's signal cable to complete the external VD sync. Multi-camera external synchronization: Fixed external synchronization of multiple cameras, so that each camera can operate under the same conditions, due to the synchronization of the cameras, so that even if one of the cameras converted to other scenes, the synchronization of the camera's picture will not be distorted.
7, in accordance with the degree of division, CCD is divided into:
Ordinary type of illumination required for normal operation 1 ~ 3LUX
Moonlight type of illumination required for normal operation 0.1LUX or so
Starlight type of illumination required for normal operation 0.01LUX or less
Infrared type of illumination using infrared lamps, in the absence of light can also be Imaging
8, according to the appearance: organic plate type, pinhole type, hemispherical type.