Method and device for determining fractures on the surface of workpieces

摘要

The invention relates to a method and a device for determining fractures on the surface of workpieces, in which, or with which, an image of the surface of the workpiece which has preferably been pretreated by means of the magnetic powder process or the dye penetration process is taken by means of an image producing camera and the resulting image information is sensed and is evaluated. In order to provide a means, which is practicable in the industrial sphere, for automating the work process here for detecting fractures and evaluating them whilst at the same time discriminating both planar and linear apparent displays, according to the invention the image information of the camera image is digitised with respect to the grey values and the digital values obtained in this way are stored in a semi-conductor memory as a matrix of pixels which are processed by means of a computer in such a way that, in a first processing step, a binary image is produced in accordance with a predeterminable computing operation, from which image all the displays of planar and dot-shaped structures whose extent does not exceed a predeterminable number of pixels are eliminated in a second processing step, after which, in a third processing step, the remaining displays of planar structures in each imaging direction are extended in extent by at least one pixel further than their original extent and in a fourth ... Original abstract incomplete.