OPTO-ELECTRONIC METHOD AND DEVICE FOR INSPECTING A SURFACE PATTERN OF AN ARTICLE

In a method of opto-electronic inspection of a two-dimensional pattern on an object, especially a printed board, a micro-inspection is carried out by subjecting line-by-line scanned picture elements in pixel-by-pixel fashion to a sequence of picture operations for inspection of dimensions and spacings, and the respective result is compared with the corresponding scanned pixel. At the same time a macro-inspection is carried out by combining the scanned pixels to frames and by respective reduction thereof to a single characteristic picture information, whereupon a comparison is again performed, but this time with the corresponding picture information of a reference picture. In this way it is possible to perform a quick and fully automatic real-time inspection of two-dimensional patterns, for instance printed boards, both for minute and hardly visible defects and for macro-defects.