A Motion compensated, Image derotated, Holographic Interferometer

Abstract

Over the last few years the scientific community has shown an increasing interest in the application of Holographic Interferometry to the study of the vibrations of rotating objects, Ref. [l–3]. Recently, image derotation techniques have been successfully applied to greatly extend the range of problems that can be studied, Ref. [4]. However, Image Derotated Holographic Interferometry (I.D.H.I.) as it has come to be called, does suffer some limitations, Ref. [5], as rigid body motions of the rotating axis sometime require that special methods be employed to record the holograms and also that real time holography, for all but simple objects and slow speeds, Ref. [6], is very difficult. The present paper describes a motion compensated, image derotated holographic interferometer which compensates for some of the rigid body motions of the component’s axis relative to the derotator’s axis.