Artificial intelligence as a future technology in non-destructive X-ray inspection
Artificial intelligence (AI) or machine learning is currently omnipresent everywhere. In addition to prominent examples, like autonomous driving, also the inspection industry is looking into this technology. The R&D driven company VisiConsult X-ray Systems & Solutions GmbH for example, is currently developing an AI platform to detect defects even more reliably and more automated than in the past. X-ray technology is always used in the non-destructive testing (NDT). Unlike optical processes, internal defects like pores, inclusions or geometries can also be tested. Since the digitization period in the last ten years, digital detectors have been used much more heavily instead of analogue film. With this digitization step, the data is available in real time and can be evaluated by computers. Especially in the automotive sector with its high volumes, this is highly relevant. For 20 years, the company has been delivering so-called Automated Defect Recognition (ADR) systems, which detect errors automatically after a human did a component-specific parameterization. Nowadays, production cycles are getting shorter and shorter and the market is calling for faster Ramp-up times. Furthermore, the parts are going to be lighter and more complex, while the quality requirements increase to the same extent. The classic image processing methods of the X-ray specialists require a high positioning accuracy and an extensive component parameterization.
By using artificial intelligence, this effort could be massively reduced predict the specialists from VisiConsult. Initial tests with available AI frameworks already achieved detection rates of up to 90% in a blind study compared to the conventional procedure. “The tests in this area are still in their infancy”, says Lennart Schulenburg, authorized signatory at VisiConsult “since our systems are used to test safety-critical components, extensive tests and qualifications are necessary.” Automation is one of the focus topics of the family business, therefore VisiConsult has concluded a research cooperation with the University of Lübeck in 2017. As part of this cooperation, there are several master and doctoral theses on the subject of AI. “The university of Lübeck is a leader in medical imaging. Since they already investigated heavily in AI, this area is already far ahead of our industry. We are currently transferring this knowledge to our applications”, says Lennart Schulenburg. Due to qualification obstacles, ADR has historically been excluded from high-critical areas such as aviation. Due to the increased quantities in these areas, there is a great interest in qualifying the procedures accordingly. Therefore, VisiConsult is working with a leading aviation group in a European aviation research project to establish ADR as a test method. The use of AI is also being tested in this area. Especially in the field of Automatic Defect Recognition within welds, VisiConsult hopes for a breakthrough with the smart machines.
Crucial for the success of an AI is the number and quality of the underlying image data. “Data is the oil of Industry 4.0” emphasizes Lennart Schulenburg. For this reason, VisiConsult has developed a cloud solution into which cooperation partners can upload evaluated image data. These are anonymized and used to parameterize the AI. The higher the quality of the data, the better the AI can become. VisiConsults error database includes multivalued multi-user records with marked and classified errors. As a specialist for fully automated inspection systems, VisiConsult has developed a patent for automatic robot positioning: Through the combination of robotics, 3D sensors and image registration a high positioning repeatability can be achieved without additional components. This system will now be combined with the new AI solutions, reducing the ramp-up process from several days to a few hours. Components are then moved in mixed operation on a conveyor belt in the system and are automatically detected by the system. The software would recognize which component is to be inspected and guides the robotics to the exact inspection-position. This would eliminate set-up times completely and increase the throughput massively. As a side effect, the pseudo-rejects are reduced and the detection probability is increased. Both are requirements for an aerospace approval of the system. The family owned company with more than 70 employees from Northern Germany is considered to be the leading supplier of customer-specific X-ray inspection systems and is still looking for project partners for the implementation of pilot projects in fully automatic testing.