* Video camera * 1. What is a CCD camera?
CCD is ChargeCoupledDevice (charge-coupled device) stands, it is a semiconductor imaging device, which has high sensitivity, anti-glare, distortion, small size, long life, anti-vibration and so on.
2.CCD camera work Photo object image after being Shot Focus to the CCD chip, CCD light intensity according to the corresponding proportion of the charge accumulation, the accumulation of charge in all pixels in the video sequence under the control of the relocation point by point, after filtering, amplification processing, the formation of the video signal output. Video signal connected to Monitors Or the TV's video inputs can see the same image with the original video image.
3. Resolution of the choice Assess the level of the camera resolution is a resolution of the target, in units of line pairs, ie, after imaging can identify the number of black and white lines on. Commonly used in black and white cameras generally 380-600 resolution, color for the 330-480, the greater its value the more clear image. General Monitoring Occasions, with about 400 lines in black and white camera is enough to meet requirements. For health care, image processing and other special occasions, with 600 line camera to get a clearer picture.
4. Imaging sensitivity Usually the minimum illumination requirements of the environment that the camera sensitivity, black and white camera's sensitivity is about 0.02-0.5Lux (lux), color camera more than in 1Lux. 0.1Lux surveillance camera for the general situation; at night use or when ambient light is weak, recommended 0.02Lux camera. Used in conjunction with near infrared light, they must use low-light video camera.
In addition the sensitivity of camera with lens related, 0.97Lux/F0.75 equivalent 2.5Lux/F1.2 equivalent 3.4Lux/F1.
Reference environment illumination: Summer sun 100000Lux cloudy outdoor 10000Lux
Television studio 1000Lux 60W lamp 60cm away from the desktop 300Lux
Indoor fluorescent 100Lux evening indoor 10Lux
20cm Department candlelight 10-15Lux night lights 0.1Lux
5. Electronic shutter Electronic shutter time 1/50-1/100000 seconds, the camera's electronic shutter is set to automatic electronic shutter normal way, can automatically adjust light and dark environment, the shutter time, get a clear image. Some cameras allow the user to manually adjust the shutter time, to accommodate special applications.
6. External synchronization with external trigger
External synchronization is different from video devices use the same sync signal to ensure synchronization of the video signal, it can ensure the output of different devices, the video signal has the same frame, the line beginning and ending time. To achieve external synchronization, the camera needs to enter a composite sync signal (C-sync) or composite video signals. External synchronization can not guarantee that users get full from the specified time frame continuous one, to achieve this feature, you must use some special features of the camera with external trigger.
7. Spectral Response Characteristics CCD device from the silicon material, sensitive to the near infrared spectral response can be extended to about 1.0um. The response peak green (550nm), the distribution curve as shown on the right. Night covert surveillance, you can use near-infrared light illumination, were seeing clear the environment, it can be clearly on the monitor image. As the CCD sensor surface with a layer of UV-absorbing transparent electrode, so CCD is not sensitive to the ultraviolet. Color camera's imaging unit on the red, green, blue three-color filter, so you color camera on the infrared and ultraviolet are not sensitive.
8.CCD chip size
CCD imaging common size of 1 / 2 ", 1 / 3" and so on, the smaller the size of the camera image size can be done with less. The same optical lens, the image size larger field of view angle. Image plane size of the chip specification