How important is the light source in the imaging system of an image measuring instrument!

The imaging optical path quality of the image measuring instrument refers to the imaging quality under the influence of the optical lens and lens mounting system used by the imaging probe. The application of the light source has a powerful auxiliary effect on data collection, and the light source control is very important for the measurement effect of the image measuring instrument. Good light source design can not only reduce the requirements of image processing algorithms, but also improve the accuracy and efficiency of the system. However, not all parts can be measured with the same light source. The role of the light source: illuminate the target parts and increase the brightness; form an imaging effect that is conducive to image processing, reduce the complexity of the system and the requirements of image processing algorithms; overcome the interference of ambient light, ensure image stability, and improve system accuracy and efficiency.

The light source in the imager usually includes three types, namely surface light, contour light and coaxial light. According to the classification and application of the light source, it can be divided into: Illumination angle: Coaxial light: used to measure high reflectivity parts, the circular multi-angle programmable light source can easily realize the measurement of deep holes and thickness cross-sections; Surface light: located with the camera On the same side, it is mainly used to measure the surface size of objects, blind holes and bosses; profile light: through hole measurement and profile measurement, called bottom light, usually more commonly used. Low-angle ring light: used for plastic parts appearance defect detection, bottle mouth defect detection and hardware edge positioning, etc.; high-brightness bar light source: mainly used for character reading of electronic components, destructive testing of large-format products, and large-format Appearance test of printed products; Weak light source of ring-shaped low-angle display: used for defect detection on workpiece surface, OCR recognition of plastic surface and recognition of capacitive characters, etc.; Dome light source: cylindrical surface inspection, surface irregularity defect inspection and appearance Electronic component defect inspection; Linear light source: Mainly used for PCB circuit board measurement and large format accuracy measurement. In appearance inspection technology, both image measurement system and defect detection system rely on image acquisition, and image acquisition requires a suitable lighting system. Different light sources act on different parts and different inspection positions. In the inspection process of the image measuring instrument, the light source should be used flexibly to prepare to obtain accurate inspection data.