High-Resolution Scanners
Optical quality inspection is an established field, but assume one needs to produce a 1,500 by 1,000 mm panel that can have various types of defects in the size range of a few micrometers: who is going to inspect that? Obviously, we require an automatic inspection system that can inspect large objects with a high resolution in a reasonable amount of time.
We offer such an inspection systems, based on standard industrial vision components and sophisticated algorithms to compensate for mechanical and optical inaccuracies.
Standard Components
A standard megapixel camera, a macroscopic zoom lens, and flashed LED illumination define the core of our scanners. Both the mechanical and the optical inaccuracies are compensated for using state-of-the-art image processing algorithms, e.g. for illumination correction and image stitching. This enables us to provide a low-cost solution for a challenging task.
Defect Statistics and Validation
The main challenge however is not only to deliver a large high-resolution image
but to detect the defects on the fly and deliver error statistics for the whole panel and the different defect types. In addition to providing error-density maps, optimization routines are used to estimate the regions of lowest error density in case that only certain parts of the workpiece may be used.
One of the most serious problems with these kinds of applications is validation. Therefore, we have developed techniques that allow to find correspondences between the images taken with our scanner and other more sophisticated imaging techniques like the scanning electron microscope.
Sample Images
- Sample scanner images (for illustration purpose only): fabric (left), 50 euro bill (middle), leather (right). Images recorded with 4 micrometer per pixel.
