Automatic ultrasonic inspection of flaws in a propeller-blade

Ultrasonic technique is very promising for non destructive inspection. In this paper, a method is presented on automatic ultrasonic inspection of defects in a propeller-blade without computer aided design (CAD) models. The 3D surface data are obtained by ultrasonic measurement, and then the inspection path is planned after the CAD model has been reconstructed. A C-scan image is obtained in real-time ultrasonic automatic inspection. Thereafter, defective area and sound area are separated through binarisation of the C-scan image, and an auxiliary table is used to segment defects in order that defects are disconnected to each other. Then, an algorithm based on edge element is proposed, simplifying the process of extracting edge. Finally, application of these procedures for inspecting a propeller-blade is demonstrated.