Coherent Photography (Holography) as an Aid to Engineering Design

The paper presents information on the technique of holography applied in a routine engineering application. The extension of photography made possibile by the use of coherent laser light, which enables the recording of far more surface information than was hitherto possible has brought new uses of the photographic process in quantitative measurement and metrology. To realize the full value of the new technique a simple arrangement of equipment is required which can be called upon for routine application. A rig is described which has been tailor-made for vibration testing and inspection of aero engine components. A particular feature is that the rig can be used outside the specialized laboratory