The function of light source in machine vision are as follows:
1. Illuminate the object and improve the brightness
2. Get good result for image processing
3. Avoid the interference of ambient light,to ensure the stability of the image
4. Used as measuring tool or object of reference
Light source is one of the most crucial part in machine vision, it greatly affects the whole system. A good lighting design can get good image, improve the resolution of the system and simplify the software operation. Otherwise, a lot of problems will occur.
A suitable light source can separate the object information from background well in the image, making image processing easier and improving the accuracy and reliability of the system
A good image should have the following conditions
1. The contrast of object and background is very clear
2. The background is uniform and easy for image processing
3. The color information is true, moderate brightness and exposure
The upper images are relatively unideal, because bad contrast makes it hard to separate the object information from background, bad uniformity leads much difculty to nd a global gray differentiation criterion, and bad consistency results in incomplete object extraction. While the lower images are easy for processing and stable as well.