AOI (Automated Optical Inspection) offline equipment is a common non-destructive testing equipment used to detect surface defects and solder quality of electronic products or components. It works as follows:

1. Preparation: The electronic product or component to be inspected will be placed on the working table of the equipment and fixed.

2. Image Acquisition: The device will use a high-resolution camera or other optical sensor to capture an image of the object to be inspected. The sensor can capture mechanical defects, soldering problems, etc. that are reflected or scattered by light sources of different wavelengths.

3. Image Processing: Using image processing algorithms, the device pre-processes the captured images, such as removing noise, enhancing contrast, etc. It then uses specific image processing algorithms to process the captured images. It then uses specific image processing algorithms to detect potential surface defects or weld quality issues.

4. Defect Detection: The device analyses and compares each pixel in the image according to predefined rules and algorithms to determine if there is a defect or quality issue. Common detections include defective solder joints, misaligned pins, short circuits, missing parts, and so on.

5. Result determination: Depending on the settings of the device, the detection result can be binary (defective/non-defective) or quantitative (defect level). The device will automatically determine the result and record it.

6. Report output: The device can generate corresponding inspection reports, including information on the type, location and number of defects found. These reports can be used for production process optimisation and quality control.

Overall, AOI offline equipment utilises advanced image processing technology and algorithms to efficiently detect surface defects and soldering quality issues in electronic products or assemblies, improving the reliability and efficiency of the production process.