The image of the object to be photographed through the lens focus to the CCD chip, the CCD according to the intensity of the light accumulation of the corresponding proportion of the charge, each pixel accumulation of charge in the video under the control of the timing, point by point outward, after filtering, amplification, the formation of the video signal output. The video signal is connected to the video input of the monitor or TV set to see the same video image as the original image.
First, the classification of CCD cameras
A division in accordance with the imaging color
CCD cameras are divided into color cameras and black and white cameras according to the imaging color. In addition to different chromaticity processing, other principles are basically the same. The main optical system, photoelectric conversion system, signal processing system. One of the photoelectric conversion system is the core of the camera.
Natural image through the optical lens imaging in the camera light target surface, color camera optical system using coherent color separation prisms or special strip filters will be divided into red, green, blue light signal, photoelectric conversion system through the camera tube or CCD components using television scanning method to convert the light image signals into time-varying video electrical signals, and then amplified, processed, coding and Become a full TV signal.
Second, according to the resolution
According to the resolution is divided into about 250,000 pixels, corresponding to the color 330 lines / black and white 400 lines of the low-grade type; 250,000 to 380,000 pixels, corresponding to the color 420 lines / black and white 500 lines of the mid-range type; 380,000 pixels or more, corresponding to the color greater than or equal to the 460 lines of the high-grade type of black and white more than 570 lines.
Three according to the camera sensitivity
In accordance with the sensitivity can be divided into the lowest illuminance 1 to 3lux of the ordinary type; 0.1lux or so of the moonlight type; 0.01lux below the starlight type as well as in principle, can be 0Lux, the use of infrared light source imaging of the infrared illumination type.
Four in accordance with the CCD target size division
Camera camera device (CCD) size is divided into 1 inch, 1/2 inch, 1/3 inch, 1/4 inch and so on. Among them, 1/3 inch and 1/2 inch are the most common.
CCD Size
Horizontal (mm)
Vertical (mm)
Diagonal (mm)
1 inch
12.7
9.6
16
2/3 inch
8.8
6.6
11
1/2-inch
6.4
4.8
8
1/3-inch
4.8
3.6
6
1/4-inch
3.6
2.4
4
1/5-inch CCD cameras are under development and will occupy a certain percentage of the market in the future. Generally speaking, the large CCD chip, its corresponding pixel area is also larger, receiving the light taken by the area increases, will inevitably increase the pixel output charge, sensitivity rises, in low-light conditions have a better ability to shoot, easy to make the overall quality of the camera to improve, the image is obviously fine and natural detail. The smaller the focal plane of the optical system to focus the image, the more details are lost in the imaging process, the image obtained after magnification of the fine detail of the transition may be a sudden change in the phenomenon, it seems unnatural. In addition, smaller CCDs with more pixels and higher resolution also result in a smaller light-sensitive area for individual pixels, with the possibility of underexposure. The smaller the area of a single pixel, the lower its light-sensitive performance, the lower the signal-to-noise ratio, and the narrower the dynamic range. The information on each pixel tends to mix with that of pixels in its vicinity (in electronics this concept is called chromatic brightness interference).
Second, the CCD sensor technology trends
CCD is the core device of the camera, so its performance will directly affect the quality of the camera, and the development of CCD is the basis of the camera update.
CCD sensors have two kinds, the first is a special CCD sensors, such as infrared CCD chip (infrared focal plane array device), high-sensitivity back-illuminated and electronic bombardment CCD, EBCCD, etc., in addition to a large target surface, such as the 2048 × 2048, 4096 × 4096 visible CCD sensors, a wide range of spectral range (ultraviolet → visible → near infrared →). 3-5μm mid-infrared light → 8-14um far-infrared light) focal plane array sensors. Currently there are commercialized products, and widely used in various fields. The second is a general-purpose or consumer CCD sensors, in many ways there is greater progress, the general direction is to improve the overall performance of the CCD camera.
A CCD sensor image size to the integrated, lightweight direction of development.
Because the manufacture of CCD sensors silicon and processing costs are very high, so it is hoped that a 6.5-inch wafer photolithography out of more CCD sensor chip; due to advances in photolithography, so in still maintain the characteristics of a very high sensitivity, the size of CCD sensors to the direction of the development of 1/2-inch, 1/3-inch, 1/4-inch, 1/5-inch. In 1993, 1/2 inch CCD sensors accounted for 5% of the total output; 1/4 inch CCD sensors accounted for 10% of the total output; 1/3 inch CCD sensors accounted for 85% of the total output. In 1997, in the total output than in 1993 increased by more than 200% of the case, 1/2-inch CCD sensors are still a great development, has accounted for 15% of the total output (1/2-inch due to the larger target surface is still many occasions need, especially in the field of scientific research); 1/4-inch CCD sensing accounted for 60% of the total output. That is to say, 1/2 inch larger target size CCD sensors still have a lot of growth. 1/4 inch CCD sensor production than 1/3 inch CCD sensors, accounting for the proportion of the total production in the reduction.
Two CCD sensors to a high number of pixels, multi-format development
A variety of CCD sensors in the reduction of the image plane size, but the number of pixels in the increase, has been from the early 512 (H) × 596 (V) to the development of 795 (H) × 596 (V), and even appeared more than one million pixels of the CCD sensor. In order to improve the horizontal and vertical direction of the resolution, has been from the usual interlaced scanning to progressive scanning format development.
Three reduce the operating voltage of the CCD sensor, reduce power consumption
In the initial development of CCD cameras have +24V, +22V, +17V and +5V, etc., the current general for the +12V. with the application of PC cameras and network image transmission, and gradually to the +12V and +5V two main operating voltages.
⑷ improve the manufacturing efficiency of CCD cameras
In order to reduce the manufacturing cost of CCD cameras, high-speed automated production, manufacturers to pursue compact structure, dedicated to the miniaturization of the CCD camera, that is, by Dip On Board (DOB) over the tin plate process to improve the Chip On Board (COB) board connected to IC chip Chip-on-board (COB) IC chip connection on the board. So far, it has realized the Multi Chip Module (MCM) multi-chip integrated modular manufacturing technology for multi-layer boards.
Five CCD camera digital
In the manufacture of CCD cameras, from the previous Analog analog system to gradually realize the DSP digital processing, can be achieved with the help of electronic computers and specialized software systems to the CCD camera, especially for color CCD camera quantitative adjustment of various parameters, can ensure that the optimization of the performance indicators of the CCD camera Consistency and quantitative modification of parameters under special conditions of use.
Three, CCD camera technical performance, characteristics and progress
A Hyper-D high dynamic range CCD camera
CCD camera is a photodetector used to simulate the human eye. However, when the human eye is observing the target, the minimum illumination at which the target can be seen is 1 Lux, and when the target illumination reaches 3×105 Lux, which is the dynamic range of the human eye, this camera is known as the Hyper-D CCD camera.
Two from the analog Analog CCD camera to the DSP digital processing CCD camera direction
The use of DSP technology, can make the CCD camera in the digital detection and digital computing technology can effectively achieve intelligent backlight background compensation; can automatically track the white balance, that is, can be detected and tracked under any conditions "white", and digital computing processing function to reproduce the original scene color.
Beijing Xinzhiheng Technology Co., Ltd Professional camera manufacturer Tel 010-82872655