How to choose the right industrial camera
June 23, 2022
How to choose the right industrial camera
Compared with ordinary camera cameras, industrial cameras have higher advantages in image stability, anti-interference ability and data transmission. They are a core part of a machine vision system. The overall performance of an industrial camera determines the performance of a machine vision system. Stablize. Every industrial camera has many parameters for customers to choose from, and there are many models for reference, so how can we better choose an industrial camera when it comes to camera selection? Parameters to pay attention to when choosing a camera:
1. Types of industrial cameras
For static detection or general low-speed detection, priority is given to area scan cameras, and for special applications such as large-format high-speed motion or roller motion, consider using line scan cameras. According to the detection speed, the frame rate of the selected camera must be greater than the speed of the object movement, and it must be completed within the exposure and transmission time of the camera.
2. Industrial camera resolution
The pixel accuracy of the camera must be higher than the accuracy required by the system in order to have practical measurement significance. The improvement of sub-pixel accuracy does not have much impact in actual measurement, and cannot fundamentally solve the problem of insufficient accuracy. Generally speaking, if conditions permit, we will ask to increase the resolution of the camera by an order of magnitude or increase the pixel accuracy of the camera by an order of magnitude.
3. Industrial camera frame rate
The frame rate of the camera determines the measurement efficiency of the device. For example, if the frame rate of the camera is 30FPS, it can shoot up to 30 times per second. And if the speed of the camera is 120FPS, if the algorithm is fast enough, it can detect up to 120 products per second.
Generally speaking, the lower the resolution of the camera, the higher the frame rate of the same interface, and the higher the resolution, the lower the frame rate. When the resolution is fixed, the frame rate also has its maximum value. That is, if the resolution of the camera is to be fast, and the frame rate of the camera is to be high, then a bus with a larger bandwidth needs to be found, that is, the output interface of the camera.
4. The exposure time of the camera
The minimum exposure time of the camera can determine the speed of movement of the target. Or conversely, the movement speed of the target places a requirement on the minimum exposure time of the camera. Generally speaking, the blur caused by object motion should be an order of magnitude smaller than the measurement accuracy we require, which can reduce its impact on the system. Generally, the fastest exposure time of our industrial cameras can reach tens to more than 100 microseconds. . Such a short exposure time requires relatively large light energy, so it is necessary to select an appropriate light source and light source controller.
5. Color of industrial cameras
Usually in machine vision projects, we choose black and white cameras. Color cameras are only considered when measuring color images. This is because there are many more algorithms for black and white images in machine vision. Color cameras use better quality composite white light.
6. Industrial camera sensor types
If the target is static, in order to save costs, consider using a CMOS camera, while if the target is moving, a CCD camera is preferred. If high-speed acquisition is required, the high-speed here refers to a very high acquisition speed, rather than a very high movement speed, and a CMOS camera can be considered, because the acquisition speed of CMOS will be better than that of CCD. If you need high-quality images, such as size measurement, you can consider CCD. In small-sized sensors, the imaging quality of CCD is still better than CMOS.
7. Industrial camera lens interface
The general camera is C/CS interface, you need to pay attention to the correspondence with the lens. If there are lenses with other interfaces, also consider the camera's interface. However, at present, industrial CCTVs basically use C-mounts. Even industrial cameras with CS-mounts can add a 5mm ring to turn them into C-mounts to adapt to different C-mount industrial lenses.