PRACTICAL INTERPRETATION OF HOLOGRAPHIC INTERFEROGRAMS.

Usually it is easy to understand holographic interference fringe patterns but there might suddenly appear strange complex patterns caused by e. g. a simple translation or rotation. If one does not understand the basic principles of fringe formation these patterns will most certainly be misinterpreted as caused by a complex deformation of the object. In the opinion of the author equations are not sufficient to solve this problem. Other ways have to be found if mechanical engineers are to accept holographic interferometry as an ordinary practical measuring tool.