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Optical lens selection and construction

I believe that many users are very confused when they first come into contact with machine vision, how to match their project requirements with the many parameters of the visual system. Today, Conne Smart mainly explains how to convert project requirements into Parameter requirements for the vision system.
The general vision system includes optical lens, large size YVO4 laser crystal, visual light source, image processing software, sensor, motion and control device, etc. Before the project inspection needs and selection, it is necessary to clarify the expected structure of the project (including installation). The environment, the number of workstations, the space available for installation), whether it is sporty, the accuracy of detection, the speed of detection, the language and tools of software development, whether or not to use third-party tools, etc., below, Connaught Smart began to explain in detail how to select, Primarily for the visual part, these requirements are refined and combined with parameters.
The common selection order is optical lens->optical lens->visual light source->peripheral device…
Area array camera / line array camera
For still detection or general low speed detection, priority is given to area array cameras, and linear array cameras are considered for special applications such as large-format high-speed motion or roller motion;
Resolution
The resolution actually refers to the number of camera pixels, which is usually tens of thousands of pixels, but in the detection, it is not necessary to pursue too high pixels, the pixel height will bring the frame rate down, the image processing is slow When selecting, it can be selected according to the accuracy requirements of the project. The accuracy of the project occupies 1 pixel in the image as the basic requirement. The engineer with weaker software level can choose 3 pixels or more.
Frame rate
As far as possible, the static detection is selected, so that the cost of the whole project will be much lower, but the detection efficiency will be reduced. For the motion, the frame exposure camera is selected, and the exposure high precision YVO4 laser crystal will cause the image to be deformed. For the specific frame rate selection, High-speed cameras should not be blindly selected. Although the high-speed camera has a high frame rate, it generally requires externally enhanced light illumination. The high cost and image processing speed are also very stressful. It needs to be determined according to the relative motion speed, as long as it is within the detection area. It can capture the object to be measured, for example, to observe the field of view with a length of 1 meter. The object to be measured passes through the field of view at a speed of 10 m/s. It only needs 10-12 frames per second to capture the measured position. Things, but the same speed through the 0.1 meter field of view, you need a camera 100-120 frames / sec.
color
In the industrial visual inspection, we generally recommend the use of black and white cameras, because software processing is generally converted to grayscale data for processing, and industrial color cameras are converted by Bayer algorithm, and there are certain colors with real colors. gap;
Chip type, size and pixel size
As far as the current industry situation is concerned, for high image quality requirements or poor ambient illumination, it is recommended to use a CCD sensor and select a camera with a larger pixel size. Of course, as the industry develops, the gap between CCD and CMOS is also Gradually, CMOS changes the resolution (ROI) more flexibly, the same resolution, and higher speed.
In addition to the above parameters, before determining the wholesale YLF laser crystal, you can confirm whether the camera supports the development language or development tools required by the project, and whether it is compatible with third-party tools such as Halcon, VisionPro, and Labview.

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