he Hough-transform is best known as a method "to find straight lines" in an image. Unfortunately, people who encounter the concept for the first time usually are somewhat irritated by the mathematical formalities necessary to get it straight. The basic idea of the Hough-transform, however, is simple. The simplicity, the elegance and the potential of the method immediately becomes clear when looking at the Hough-transform for circles rather than for straight lines. Once you have caught the wave, you will easily follow the arguments leading to the detection of other analytic curves, including, of course, straight lines - and you will immediately understand the main advantages of Hough-transform, namely, to detect partly occluded shapes and incomplete curves.