Digitalisierung einer Oberfläche eines unregelmässig geformten Körpers, zum Beispiel einer Schuhsohle

摘要

For digitising a last or other irregularly shaped article, an optical system is used comprising a laser device (14) fixed on a machine base (10) and directing a light beam at a last supported for rotation about an axis, perpendicular to which the light beam is directed. Two cameras (16) are also fixed to the base, one at each side of the laser device, and each comprising an array of cells for detecting the point of incidence of the light beam on the last surface. As the last is rotated, the point of incidence will vary in relation to a datum, e.g. the axis of rotation, and the point of maximum intensity of illumination on the array of cells will vary across the array accordingly. By a correlating technique, the distance of the point of incidence from the datum can be determined according to the point of maximum intensity on the array. Thus, for digitising the last, it is necessary merely to rotate it and also move it in a direction along its length for a large number of point positions to be detected, these being then stored as digitised coordinate axis values (R-theta-Z). Because the last is an irregularly shaped object, in certain circumstances it is necessary to provide more digitised point positions than in other areas. Such area requiring greater definition are boundary points of the last bottom, regions of high curvature and also "long arc" regions (i.e. regions where, because of the angle of the light beam to the last surface, the distance between consecutive points of incidence is large). These are all catered for either by flagging for a subsequent in-fill operation or by back- stepping over reduced angles of rotation of the last.