Abstract
Shearography is an optical sensing technique that uses a laser to detect flaws. Compared to ultrasound which is currently the most commonly employed technique for non-destructive testing, the superiority of shearography is obvious. Shearography is a full-field and non-contact technique, whereas ultrasound inspection requires a time-consuming process of point-by-point scanning of the part. Moreover, the ultrasonic inspection process requires contact and fluid coupling of transducers. Shearography can reveal the flaws in a fraction of a second, while the scanning process of the ultrasonic technique takes a couple of minutes.

Applications
Prof Hung developed the world's first tire testing machine using shearography. The machine is widely used by the rubber industry for inspecting tire quality. He also developed the world's first non-destructive testing system based on shearography. The system was adopted by NASA for testing space shuttles and by the aircraft industry for inspecting aircraft structures. The technology can also be applied to the non-destructive inspection of tunnels, bridges, dams, MTR, power-plants, pipelines and other structures, and even medical devices and biological organs.

Contact Information
Mr H Y Wong
Director, Technology Transfer Office
City University of Hong Kong
83 Tat Chee Avenue
Kowloon, Hong Kong
Tel : (852) 2788 8428
Fax : (852) 2788 9119
Email : hy.wong@cityu.edu.hk