What should I do if I encounter the problem of detection accuracy in the process of operating machine vision inspection?

With the development of the automation industry, the application of machine vision technology has been very extensive. However, in some machine vision inspection projects, many customers have encountered the problem of detection accuracy. For example, to detect the external dimensions, inner and outer diameters of processed parts, the accuracy is required to be 10um. At present, many configurations choose 5 million cameras, which can theoretically achieve an accuracy of 10um. However, the accuracy of the actual customer test is far less than the requirement of 10um, and it is very good to be able to do 30um. The main reasons for the large error are as follows:

1. Selection of industrial cameras:

Many customers choose CMOS cameras for cost reasons, and when shooting the edges of objects, the contrast of the edge contours is poor, and the noise is also large, which brings large errors to the software measurement. CCD-sensor cameras are generally recommended.

2. Selection of camera lens:

Because many mechanical parts have height differences, there is a large depth of field. However, because of the angle of view factor, it is difficult to shoot the inner wall of the parts, etc., which makes it difficult to find the most real and accurate edge contour during software processing, which puts forward higher requirements for the image processing algorithm.

3. Selection of light source:

Many customers will choose a common backlight. When the detection accuracy is not high, the backlight has a price advantage. Under the premise of high requirements, the principle of backlight is to use light to produce uniform and soft light through the diffuse reflector, and the light generated at a certain point will diverge to any angle in space. When detecting round and cylindrical objects, diffraction occurs at the edges of the object to be measured. At the same time, the brightness change of the light source also has a great impact on the brightness and darkness in the image.

Chengdu Xinxiwang Automation is a professional machine vision expert, specializing in providing machine vision complete system solutions for all walks of life, welcome to call: 028-62705808