Lighting applications for component contour detection
Ⅰ.Lighting method
For the contour detection of the lighting method is flexible, and there are three lighting methods：back emitting, direct emitting for bright FOV, direct emitting for dark FOV. It can be flexibly selected according to different structure and constraints on site.
Ⅱ．Application analysis Ⅰ.Lighting method
For the contour detection of the lighting method is flexible, and there are three lighting methods：back emitting, direct emitting for bright FOV, direct emitting for dark FOV. It can be flexibly selected according to different structure and constraints on site.
Back emitting
Direct emitting for bright FOV
Direct emitting for dark FOV
Back light
High angle ring light
Low angle ring light
Effective picture for back light
Effective picture for high angle ring light
Effective picture for low angle ring light
Workpiece picture for component contour detection
Through product analysis, the sample is placed in a black mold for testing. The mold is black with low reflectivity, and the product surface is smooth and reflective.Analyze the above three lighting methods:
(1)Back emitting with back light: The advantage is that the contour edge can be highlighted, but the product is placed in a black mold for detection, which will block the camera from light, so this lighting method is not applicable.
(2)Direct emitting for bright FOV: There is a big difference in material and reflectivity between the product and the mold, so we use LOTS high-angle ring light to emit directly, which is close to the lens at a high angle to make the product surface bright, in sharp contrast to the black mold background. Effects are as follows.
Effective picture for high angel ring light
(3)Direct emitting for dark FOV: The advantage of dark field lighting is to eliminate surface reflection, and it’s easy to make the harsh edge bright. The image below is illuminated at low working distance using LOTS low-angle ring light. The white edges contrast well with the black surface.
Effective picture for low angle ring light
(4) Effect for uniformity lighting: For metal or smooth products, the same way to use the direct dark field, can be appropriate to select diffuser or shadowless light which have better uniformity, can improve the effect. The following picture can make the plastic mold background completely disappear, so as to better detect the contour edge.
Effective picture for shadowless light
Ⅲ．Summary 
Ring light with diffuser
Shadowless light
Different lighting methods can present different effects for the same product. In the project, according to the type and characteristics of the product, the structure and limitations of the site, the flexible selection of light source for testing is the accumulation of experience to test the technical strength. LOTS Light Source has been focusing on the independent research and development of machine vision light source over ten years, aiming to create competitive vision solutions for system integrators, equipment manufacturers, large manufacturing enterprises and large processing enterprises.
