Holographic And Speckle Interferometry In The UK A Review Of Recent Developments

Abstract

From its inception, the technique of holographic interferometry has been continuously developed within the UK. Non-destructive testing (NDT) and metrological applications of holography have grown over the last 20 years, with major contributions coming from NPL, Loughborough University, Rolls Royce Advanced Research Laboratory and many others. More recently the technique of Electronic Speckle Pattern Interferometry (Electro-Optic Holography) has added to the list of available methods and given a spur to holographic metrology in industry. This paper will review recent developments within the UK, in optical systems and data analysis techniques (for both holographic and speckle interferometry). These are promising to provide the mechanical engineer with commercial products based on automated non-contacting optical measurement systems, for applications in industrial design and testing. Important developments include the use of fibre optics, CCD cameras, speckle averaging, heterodyning, 3-D deformation and strain measurement, together with a range of fringe analysis techniques. These will be discussed within the context of typical applications of holographic interferometry in the UK. Finally a view to the future will be given.