Xinsheng IntelligentIndustry NewsWhat is CCD?

CCD (Charge Coupled Device), a charge coupled device, is a special semiconductor, and now people are used to using CCD as a synonym for image sensors.

CCD is the mainstream technology of today's image sensors, and it is also the most mature and widely used visible light image sensor, with its wide spectral response, large dynamic range, high sensitivity and geometric accuracy, low noise, high resolution, and easy digital processing. With the advantages of being connected with a computer, the application field is constantly expanding, and it has also been widely used in industrial measurement and control.

1. Characteristics of CCD

1. High resolution (High Resolution): The size of the image point is m-level, which can sense and recognize fine objects and improve the image quality. The current 1/9 inch, the number of pixels has increased from more than 100,000 in the initial stage to tens of millions of pixels, and there will be an urgent need to increase in the future.

2. Low noise (Low Noise) and high sensitivity: CCD has very low readout noise and dark current noise, so it has a relatively high signal-to-noise ratio (SNR), and has high sensitivity of 0.0003, 0.00056LUX and even 0LUX low luminosity The incident light of CCD can also be detected, and its signal will not be masked by noise, so the application of CCD is basically not limited by climate.

3. Wide dynamic range (High Dynamic Range): The dynamic range of the digitally processed CCD signal can reach 400%, and the professional level can reach 600%. It can be applied to both strong light and weak light to improve the use range of the system environment. It does not cause signal contrast phenomenon due to large differences in brightness.

4. Good linearity curve (Linearity): There is a good proportional relationship between the intensity of the incident light source and the size of the output signal, which can well reflect the level of detail of the captured image and reduce the cost of signal compensation processing.

5. High Quantum Efficiency: Very weak incident light illumination can be recorded. If combined with the influence intensifier tube and light projector, even the distant scene in the dark night can be photographed.

6. Large Field of View: Using semiconductor technology, large-area D wafers can be manufactured. At present, 35mm wafers with the same size as traditional film have been used in digital cameras, becoming a key component to replace professional optical cameras. .

7. Wide spectral response: from 0.4 to 1.1 μm, it can detect light in a wide wavelength range, increase the flexibility of the system, and expand the application field of the system; according to different applications, color filters or composite color filters are required;

8. Low image distortion: Using CCD sensor, its image processing will not have distortion, so that the original object surface information can be faithfully reflected;

9. Small size and light weight: CCD has the characteristics of small size and light weight, and is widely used;

10. Low energy consumption, not affected by strong electromagnetic fields;

11. Good charge transfer efficiency: This efficiency coefficient affects the signal-to-noise ratio and resolution. If the charge transfer efficiency is not good, the image will become blurred;

12. It can be produced in large quantities, with stable quality, firmness, not easy to age, easy to use and easy to maintain. Some burned-out CCD pixels can self-recover after a period of live work.

Second, the application of CCD in the field of industrial inspection

1. It can be used to measure the geometric quantity of the object. Geometric parameters including: length, width, liquid level, area, etc. can be measured with CCD sensor technology. In addition, CCD technology can also be used in many other occasions such as multi-dimensional detection and inspection of the size, shape, trademark position and direction of the packaging.

2. Online pattern recognition. Such as identifying the distributed discrete objects or products conveyed along the automated production line, detecting the presence or absence of parts, equipping the robot as a vision system, and whether the equipment installation meets the requirements and the location is accurate, etc.

3. Automatic detection of object surface. In industrial production, the surface condition is an important factor for the quality of the object. Using CCD technology to detect the surface condition of the object with high precision can not only omit the moving parts in the previous optical mechanism scanning method, but also have high detection chromaticity and small system structure. It can automatically display or record the surface state of the detected object. Therefore, it can be used in industrial production to detect surface defects of metal plates, plastics, glass, textiles and other items.

4. Process inspection. Because CCD has high-speed readout capability, it can also be used for detection in the processing industry. For example, position determination in machine tool processing is an indispensable part of closed-loop control. The application of CCD technology can realize high-precision real-time control of the position of processing equipment.