Choosing a good light source in the industrial visual inspection system can greatly reduce the difficulty of image recognition algorithm processing, and improve the positioning and measurement accuracy of the visual system, thereby improving the stability and comprehensive performance of the visual system. That is, the selection of light source directly affects the success or failure of visual inspection. So let's talk about several commonly used light sources for industrial production visual inspection.
1. Ring light source
The ring light source provides different lighting directions and different color combinations, which can better highlight the three-dimensional data of the product; high-density LED array, high brightness; a variety of compact designs, saving installation space; solving the problem of diagonal lighting and shadows; optional diffuser light guide, light evenly diffused.
Main uses: PCB substrate visual inspection, IC component visual inspection, microscope lighting, LCD calibration, plastic container visual inspection, integrated circuit printing inspection.
2. Dome shadowless light source
LEDs are densely arranged on a circular circuit board. Through the reflection of a special coating, the illumination of the entire image is very uniform. It is most suitable for objects with undulating and shiny surfaces. Even curved metal surfaces can be evenly illuminated. Main uses: packaging bag surface inspection, curved and uneven workpiece inspection, object surface inspection with strong reflective surfaces, etc.
3. Strip light source
Strip light source is the preferred light source for larger square structure objects; the color can be matched and combined freely according to needs; the lighting direction and installation are freely adjustable.
Main uses: metal surface inspection, image scanning, surface crack visual inspection, LCD panel visual inspection, etc.
4. Coaxial light source
Coaxial light sources can solve the shadows caused by uneven product surfaces, thereby reducing interference; some use beam splitter designs to reduce light loss, improve imaging clarity, and evenly illuminate the product surface.
Main Application: This series of light sources are most suitable for products with high reflectivity, such as visual inspection of scratches on the surface of metal materials, glass, film, chips, etc., visual inspection of chip and silicon wafer damage, mark point positioning, and packaging barcode recognition.
5. AOI dedicated light source
Three-color light illumination in different directions highlights the three-dimensional data of solder; additional diffuser guides light to reduce reflection; different direction matching;
Main use: Mainly used for visual inspection of circuit board soldering.
6. Four-sided adjustable light source
The illumination angle and brightness of each illumination surface can be adjusted independently according to the requirements of the object being measured. It has good versatility and is suitable for many occasions. It is the first choice for large-format lighting.
Main applications: solder detection, package damage detection, label detection, barcode recognition, spherical object detection, product positioning recognition.
7. Linear light source
Ultra-high brightness, using cylindrical lens to focus light, mainly used in various automatic production lines for continuous visual inspection occasions.
Main application: dedicated for array camera lighting and AOI.
8. Area light source
Using high-density LED arrays to provide high-intensity backlighting can highlight the appearance and contour characteristics of the product, especially used as a microscope stage. Red and white dual-purpose backlights, red and blue multi-purpose backlights, can be mixed with different colors to meet the multi-color requirements of different objects being measured.
Main uses: measurement of mechanical parts dimensions, visual inspection of electronic components and IC appearance, visual inspection of film stains, visual inspection of transparent product scratches, etc.