METHOD AND DEVICE FOR EXAMINING AN OBJECT IN A CONTACTLESS MANNER, ESPECIALLY FOR EXAMINING THE SURFACE FORM OF THE SAME

摘要

According to the invention, in order to optically examine an object in a contactless manner, the light which successively impinges on the surface (21) of said object at different angles of incidence and reflects off said surface is measured by an image sensor (40), producing a plurality of image data sets having different contents. In this way, a first image data set is produced with the incident light (43 a, b), from which form-independent or non-topographical characteristics, such as colour errors, can be derived. Form-dependent or topographical characteristics, such as scratches, are derived from a second image data set formed with glancing light or oblique light (42 a). Before the form characteristics are derived from the first image data set, it is essential that the distorting influences of form-independent characteristics are eliminated from the first image data set by means of the second image data set. Furthermore, the device is embodied as a portable manual appliance which is placed by hand, in an approximately light-permeable manner, on the surface of the fixed object, or is displaced in contact with the surface. In one form of embodiment, the incident light is replaced or complemented by transmitted light, so that translucent objects, e.g. paper, can also be examined.