Xinsheng IntelligentWritings50 questions about industrial cameras (4)

　　31: What is the role of the network communication device in the smart industrial camera?

　　The network communication device is an important part of the smart camera, which mainly completes the communication tasks of control information and image data. Smart cameras generally have built-in Ethernet communication devices and support a variety of standard network and bus protocols, so that multiple smart cameras form a larger machine vision system.

　　32: From which aspects to compare several interfaces of industrial cameras?

　　The following is a comparison of several interfaces of industrial cameras:

　　33: What should be paid attention to when choosing an industrial camera?

　　1. Decide whether to choose CCD or CMOS camera according to different applications. CCD industrial cameras are mainly used in image extraction of moving objects, such as mounters. Of course, with the development of CMOS technology, many mounters are also choosing CMOS industrial cameras. . CCD industrial cameras are generally used in visual automatic inspection schemes or industries. CMOS industrial cameras are more and more widely used due to their low cost and low power consumption.

　　2. The choice of resolution, first consider the accuracy of the object to be observed or measured, and select the resolution according to the accuracy. Secondly, look at the output of the industrial camera. If it is posture observation or machine software analysis and identification, high resolution is helpful; if it is VGA output or USB output, it depends on the resolution of the display, and the resolution of the industrial camera. No matter how high it is, the display resolution is not enough, and it is meaningless; it is also helpful to use the memory card or camera function, and the high resolution of the industrial camera is also helpful.

　　3. Matching with the lens, the sensor chip size needs to be less than or equal to the lens size, and the C or CS mount should also be matched (or add a transfer interface);

　　4. Selection of camera frame number. When the measured object has motion requirements, an industrial camera with a high frame number should be selected. But generally speaking, the higher the resolution, the lower the number of frames;

　　34: How to set the "Auto Gain Control" function in the industrial camera?

　　There is a video amplifier in the industrial camera that amplifies the signal from the CCD to a usable level. Its amplification is the gain, which is equivalent to having a higher sensitivity. However, in the bright light environment, the amplifier will be overloaded and the video signal will be distorted. When the switch is ON, the lens iris is fully opened in low light conditions, and the gain is automatically increased for a clear image. When the switch is OFF, a natural and low-noise image can be obtained at low brightness.

　　35: How to choose a frame grabber?

　　When purchasing and using a frame grabber, two key factors to consider are: hardware reliability and software support. All other things being equal, a complex card with more devices will dissipate more heat than a card with fewer devices. A good design will use more ASIC (Application-specific integrated circuits) and programmable devices to reduce the number of electronic devices and achieve higher functions. You can also choose a card with fewer useless features to cut down on unnecessary hassles. Overvoltage protection is an important indicator of reliability. Approaching high voltage will generate a strong surge in the video cable. Adding an overvoltage protection circuit to the video input end and I/O port can protect the capture card from high voltage breakdown caused by electromagnetic interference in the industrial environment. When choosing a capture card, you must also consider whether the software to be selected for this vision system is compatible with the capture card, whether it is easy to use, and whether the software requires payment.

　　36: What are the advantages of high-speed industrial cameras compared with general industrial cameras?

　　1. High-speed real-time uncompressed image recording, real-time display, and set speed echo;

　　2. The system adopts the recording method of directly writing the data to the hard disk, which solves the problem of short recording time in the traditional memory recording method, and also solves the traditional acquisition;

　　The system transmission speed is limited by the PCI bus bandwidth;

　　3. Guarantee 100% frame loss, which solves the problems of traditional memory recording methods that are easy to lose frames and lack of power-off protection;

　　4. The system works independently, hardly occupies computer resources, and has high reliability;

　　5. One system can support multiple boards and cameras, and track and record multiple targets at the same time;

　　6. Support the superposition and fusion of various external signals;

　　7. Support a variety of image formats, with a variety of software and hardware external trigger functions;

　　8. The software interface is simple, which is convenient for secondary development and real-time processing.

　　37: What are the categories of infrared cameras?

　　Infrared cameras mainly include near-infrared cameras, short-wave infrared cameras, high-speed infrared cameras, medium-wave infrared cameras, and DSP-based long-wave infrared cameras.

　　38: How to improve the sensitivity of industrial cameras?

　　The sensitivity of the industrial camera can be achieved by setting the following functions of the industrial camera:

　　Technology to improve the sensitivity of industrial cameras

　　name

　　Features

　　Technical points

　　Bining function

　　Increased sensitivity, reduced resolution, and increased frame rate: suitable for occasions with weak light intensity and low resolution requirements

　　Provide frame, row, and column synchronization signals, set the merging circuit or merging software

　　image enhancement

　　Significantly enhances low-light images for low-light situations

　　Brighten images with an image intensifier

　　AR Coating Technology

　　Reduce the reflectivity of incident light to 0 and maximize the use of incident light

　　Coating the anti-reflection film on the surface of the photosensitive chip, using the principle of light refraction to improve the transmittance of light

　　Illuminated CCD

　　Enhance the sensitivity of the imaging device, suitable for low-light situations

　　Thinning the thickness of the imaging device, the light is incident from the back of the photosensitive chip

　　Micro lens

　　Improve pixel sensitivity, reduce pixel noise, increase effective fill factor

　　Add a microlens to the photosensitive pixel

　　In-chip multiplication

　　Increase the number of carriers and improve the responsivity of the camera

　　On-chip charge energy multiplication through multiplication registers to excite more carriers

　　Time Delay Integral (TDI)

　　Improve camera responsiveness with multiple exposures

　　The exposure time of an N-level TDI CCD is N times that of a single-stage CCD, so the responsivity of the CCD is correspondingly increased by N times.

　　39: What is the white balance of an industrial camera?

　　White balance is a technology used in color cameras. White balance is the balance of red, green and blue components so that the camera can reflect the true color of the actual scene. Since the output of the three RGB components of the photosensitive element is unbalanced under different lighting conditions, the color distortion of the image will be caused, and the color of the image will be bluish or reddish. Therefore, white balance is required to restore the color of the image. Usually the camera completes the white balance can be divided into two ways: automatic and manual white balance, in addition, white balance can also be achieved through software.

　　40: How to improve the photosensitive uniformity of the camera?

　　Technology to improve camera photosensitive uniformity

　　name

　　Features

　　Technical points

　　Flat field correction

　　Overcome lighting inhomogeneities and inconsistencies in lens center and edge response

　　By collecting dark field and both and bright field images, the gain and offset of each pixel are calculated, and each point in the image is corrected separately

　　Non-uniform correction

　　Eliminate the uneven responsivity of each pixel, improve image quality, and improve image measurement accuracy

　　Measure and store the responsivity of each pixel, set the correction circuit or correction software, and use the correction circuit or correction software to correct the non-uniformity error