Grouping and establishing correspondence of calibration holes for underwater machine vision

Underwater machine vision should start with careful calibration of the lens distortions. Inhomogeneous lighting and loss of contrast require special solutions. On the Fraunhofer/IOSB experimental platforms a calibration plate with a lattice of holes is used. Detection and grouping of these hole-objects from the images is presented. The discussion extends the investigation from the special application (calibration of distortions for underwater cameras) to more general problems of grouping and automatic gestalt perception.