Real-time surface defect detection and traceable measurement of defect volume in 3D

In recent years, there has been an increased emphasis for quality control in the manufacturing sector. Many manufacturing processes have become fully automated resulting in high production volumes. However, this is not necessarily the case for inspection of aerospace surface defects. Volume measurement of defects is one of the key elements in quality assurance in order to determine the pass or failure of certain manufactured parts within this industrial sector. Existing human visual analysis of surface defects is qualitative and subject to varying interpretation. Noncontact 3D measurement should provide a robust and systematic quantitative approach for surface defect analysis. Instrument native software processing of 3D data is often subject to issues of repeatability and may be non-traceable in nature, leading to significant uncertainty about data quantisation and representation. This is compounded by a lack of traceable surface defect standards and softgauges with which to test the instruments and software respectively. This research is concerned with the development of novel traceable sub-millimetric surface defects produced using a Rockwell hardness test instrument on flat, single curvature (SC), and double curvature (DC) metal plates, and the development of a novel robust, repeatable, mathematical solution for automatic defect detection and characterization. This is then extended to a surface defect on an aerofoil that is measured in real-time and characterized using the novel algorithm. The results show that the new surface defect detection and quantification is more robust, efficient, and repeatable than existing solutions.