Dear Customer,
this article will tell you some important precautions before you choose suitable industrial camera, it is useful and helpful for you
how to choose industrial cameras
1. An analog camera or a digital camera?
The analog camera must have a digital capture card. The resolution of the standard analog camera is very low, and the frame rate is also fixed. This should be selected according to actual needs. In addition, what the analog camera collects is an analog signal, which is converted into a digital signal by a digital acquisition card for transmission and storage. Analog signals may be distorted due to electromagnetic interference from other equipment in the factory (such as motors or high-voltage cables). As the noise level increases, the dynamic range (ratio of the original signal to noise) of the analog camera will decrease. The dynamic range determines how much information can be transferred from the camera to the computer. What the digital camera collects is a digital signal, and the digital signal is not affected by electrical noise. Therefore, the digital camera has a higher dynamic range and can transmit more accurate signals to the computer.
2. Camera resolution
Choose the size of the camera resolution according to the needs of the system, the following is an application case to analyze.
Application case: Suppose the surface scratch of an object is detected, the size of the object required to be photographed is 10*8mm, and the required detection accuracy is 0.01mm. First, suppose that the field of view we want to shoot is 12*10mm, then the minimum resolution of the camera should be selected at: (12/0.01)*(10/0.01)=1200*1000, which is about 1.2 million pixel camera, that is to say If one pixel corresponds to a detected defect, then the minimum resolution must be no less than 1.2 million pixels, but 1.3 million pixels are common on the market, so in general, 1.3 million pixels are used. But the actual problem is that if a pixel corresponds to a defect, then such a system must be extremely unstable, because any interfering pixel may be mistaken for a defect, so in order to improve the accuracy and stability of the system, the most It is easy to take a defect area of more than 3 to 4 pixels, so the camera we choose is more than 1.3 million by 3, that is, the minimum should not be less than 3 million pixels. Usually a 3 million pixel camera is the best (I have seen The most people hold sub-pixels and say that they want to achieve sub-pixels of a few tenths, so they don’t need such a high-resolution camera. For example, they say that if 0.1 pixels are achieved, one defect corresponds to 0.1 pixels. The size is calculated by the number of pixels. How can the area of 0.1 pixels be expressed? These people use sub-pixels to fool people, which often shows that they have no common sense). In other words, we are only used for measurement, then using the sub-pixel algorithm, a 1.3-megapixel camera can basically meet the demand, but sometimes because of the impact of edge definition, when extracting the edge, it is randomly offset by one pixel. Then the accuracy is greatly affected. Therefore, if we choose a 3 million camera, we can also allow the extracted edge to deviate by about 3 pixels, which guarantees the accuracy of the measurement.
3. CCD&&CMOS
If the object to be photographed is moving, and the object to be processed is also an object moving in real time, of course, it is most appropriate to choose a camera with a CCD chip. But CMOS cameras produced by some manufacturers can also be used as CCDs if they use frame exposure. Also, if the speed of the object movement is very slow, within the camera exposure time range we set, the distance of the object movement is very small, and the pixel size is within one or two pixels, then it is also appropriate to choose a CMOS camera. Because within the exposure time, the deviation of one or two pixels is not visible to the human eye (if it is not used for measurement), but if the deviation of more than 2 pixels, the image taken by the object will have smear, so you cannot choose CMOS The camera is out.
4. Color && black and white
If what we are dealing with is related to the color of the image, then of course we should use a color camera. Otherwise, it is recommended that you use black and white, because a black and white camera with the same resolution has higher accuracy than color, especially when looking at the edge of the image. Better results.
5. Transmission interface
Choose a camera with USB, 1394, Camerlink, 100M/Gigabit network interface according to the transmission distance, stability, and data size (bandwidth) of the transmission.
6. Frame rate
According to the speed to be detected, the frame rate of the camera must be greater than or equal to the detection speed. If it is equal to, the time you process the image must be fast, and it must be completed within the exposure and transmission time of the camera.
7. Line array && area array
When the detection accuracy is very high and the resolution of the area scan camera cannot meet the requirements, of course the line scan camera is an inevitable choice.
8. CCD target surface
The size of the target surface will affect the length of the lens focal length. Under the same viewing angle, the larger the target surface size, the longer the focal length. When choosing a camera, especially when there are strict requirements on the shooting angle, the size of the CCD target surface and the cooperation between the CCD and the lens will directly affect the size of the field of view and the clarity of the image. Therefore, when choosing the CCD size, it is necessary to choose the focal length and field of view of the lens. Generally speaking, the CCD target surface should be selected in conjunction with the physical installation space to determine whether the working distance of the lens is within the installation space. The size of the lens is required. Must be greater than or equal to the size of the camera's target surface.
Finally Vehviscam manufacture limited official website Vehviscam ( support 10 languages) provide various kinds of industrial camera lens for USB industrial cameras, welcome to view online and find interesting models for your cameras well
