In machine vision systems, light sources are not only the basis of imaging quality, but also a key factor affecting detection accuracy and system stability. Especially in complex application scenarios, how to correctly select the appropriate visual light source has become an important issue that must be paid attention to in machine vision systems.
1. Why is the light source so important?
In machine vision detection, the information obtained by the camera depends entirely on the reflected light of the target surface. If the lighting is uneven, the reflection is strong, or there are many interference factors, the image will have problems such as insufficient contrast, blurred edges, and loss of details, which will lead to algorithm recognition failure or misjudgment.
Therefore, a stable and matching light source system can "purify" the image at the source and improve the use effect of the entire system, especially in the following typical scenarios:
Detection of highly reflective metal parts
Extraction of curved surface contours
Identification of mixed packaging of multiple materials
Detection of small defects or foreign objects
2. Principles of light source selection in complex scenarios
Select lighting methods according to the material of the object
For mirror materials or metal surfaces, coaxial light sources or low-angle ring light sources should be used to suppress reflections and strengthen edges;
For curved objects or irregular surfaces, multi-angle, diffuse reflection structure light sources can be used to avoid spot concentration or shadow interference.
Choose color and wavelength based on imaging target
Different colors of light have different penetration and reflection characteristics on materials. For example, red light is suitable for most industrial scenarios, while blue light performs better when detecting small cracks or scratches;
Near-infrared light sources can be considered for special materials or oily scenes to enhance the penetration effect.
Consider the interference tolerance of the external environment
In places where the ambient light is complex and the equipment vibrates frequently, choosing high-quality LED light sources with adjustable brightness and strong anti-interference can effectively improve the stability of the system;
Cooperate with a hood or light source cover structure to further shield interference.
3. Sharing of actual customer cases
On a 3C electronic production line, our customers need to perform online detection of micro cracks on the glass cover of mobile phones. In this scenario, the glass surface is smooth and highly reflective, and the detection requires a resolution of micrometers, which has extremely high imaging requirements.
The pain points are:
Ordinary surface light sources cannot suppress reflections, resulting in strong bright spots in the image;
The cracks are small, irregularly distributed, and the edges are difficult to identify.
The solution is:
We equipped it with a highly uniform linear coaxial light source, supplemented by blue light band imaging. Through precise synchronization with industrial cameras, clear imaging and high contrast are ensured, and the detection accuracy rate is increased to more than 98%. The customer's system has been running stably and reliably so far.
The selection of visual light sources has never been as simple as "buying a bright one", but requires comprehensive consideration based on application, material, precision and on-site environment. A precisely matched light source solution can not only improve image quality, but also solve the uncertainty in identification and detection from the root. As a professional machine vision equipment and overall solution provider, Zhixiang Shijue can provide customers with one-stop selection and supporting services from light sources, cameras to lenses, helping enterprises to easily cope with changing production environments and achieve more efficient and stable intelligent manufacturing.
