Holographic interferometry is applied sucessfully in vibration analysis. As the resulting characteristic fringe pattern, the interferograms, are so complicated and can only be evaluated by an expert eye, there is a clear desire for automated evaluation and a lucidly arranged exposition. Therefore, the problem in image processing in interferometry lies in automatically recognizing and evaluating lines, as well as in differentiating the lines from object contours, shadows, etc. This kind of image processing then also makes it possible to evaluate other, non-holographic line systems. The application is not only limited to the automatic evaluation of holographic interferograms, but also in the optical measuring of the form any kind of objects using contour lines projected onto them, in the evaluation of speckle and photoelasticitic diagrams and Moire diagrams.