In the machine vision system, the light source is one of the key components and plays a very important role in the machine vision system. For different inspection objects, different lighting methods must be used to highlight the characteristics of the measured object, and sometimes it may be necessary to take a combination of several methods, and the selection of the best lighting method and light source often requires a lot of experimentation to find.
The light source before machine vision is a type of visual light source, which refers to the light source placed in front of the object to be measured, and is mainly used to detect reflective and uneven surfaces. High-angle lighting is better for printed characters, while low-angle lighting is better for lettering characters.
A brief introduction to the application example of the front light source
The number on the tire protrudes out of the side surface of the tire and is the same color as the background, making it difficult to tell. However, the use of high-angle illumination from the front light source can create a subtle "bulging" effect on the photo, and the numerical number can be clearly revealed.
When detecting the characters on the wheel, the characters in the captured image are in sharp contrast with the background because the text is engraved on the surface of the coating, and the low-angle lighting method is used, which makes it easy to process the images later.
When inspecting the dot print characters on the butter bottle caps on the production line, each dot of the dot matrix characters in the captured image is clearly visible by using the appropriate front light source technology.
The machine vision backlight is placed on the back of the object to be measured, which is mainly used for the contour detection of the object to be measured, the detection of stain defects of transparent bodies, the inspection of liquid crystal text, the size and shape inspection of small electronic components, the appearance and size inspection of bearings, and the appearance and size inspection of semiconductor lead frames.
The backlight also plays a very important role in the machine vision system, for different detection objects, different lighting methods must be used to highlight the characteristics of the measured object, and sometimes it may be necessary to take a combination of several ways, and the best lighting method and the selection of the light source often require a lot of experiments to find.
High-brightness backlight illumination, with the characteristics of highlighting the outline of the object, low calorific value, uniform light, no flicker, etc. Therefore, it can be used for external inspection of electronic components, stain detection of transparencies, etc., inspection of liquid crystal text, SOP and CSP inspection, inspection of the appearance and size of bearings, and appearance and size of semiconductor lead frames.