Solution by means of an artificial vision system for the inspection of defects in sheets of material used in the metallurgical industry.
These films usually have an indefinite or very high length and a great amplitude, by extension they usually have a finish covered by certain layers of material with high reflection.
Based on these premises, a solution is stipulated using a vision system based on linescan technology to confront these animadversions:
- Indefinite length: Acquisition by means of linescan with suitable LineRate and management for encoder signal to manage the speed changes produced in the passage of the element.
- High amplitude: Selection of linescan cameras with horizontal resolution according to the required precision.
- High reflection: Location of lighting with power and location determined to highlight defects without generating unwanted reflections in the field of vision.
- Lateral distortion, high working distance and depth of field: A lens with a low focal length or a very high working distance is required to cover a large field of view. Therefore, we have to look for the optimization between focal distance and working distance. With a low focal length lens we can operate at a shorter working distance, but this causes a lateral distortion that triggers a reduction in accuracy homogeneity. On the other hand, with a lens with a long focal length, it leads to a reduction in depth of field, a factor that does not absorb the difference in height between the different references.
Fulfilling these requirements the system is able to perform a homogeneous inspection focused on obtaining high quality images to identify those parts of the part that have surface defects.