METHOD AND APPARATUS FOR DETECTING BOUNDED REGIONS OF IMAGES, AND METHOD AND APPARATUS FOR SORTING ARTICLES AND DETECTING FLAWS

摘要

Image processing apparatus for detecting a bounded region of an image includes a scanning device such as a T.V. camera, to scan the image via a raster scan to produce a signal indicative of image intensity at a plurality of picture points and comparators to compare the image intensity at each of the picture points with that of a neighboring point in each of at least two directions to derive therefrom a difference value and thereby detect a positive-going or negative-going boundary. Picture points are labelled as corresponding to region boundaries whenever the difference values exceed a predetermined threshold value. The region boundaries are then expanded by labelling further picture points as region boundaries. All boundaries in a particular direction are expanded in the same direction irrespective of whether they are negative-going or positive-going. Thus, boundaries between neighboring picture elements along the scan line are expanded to successive neighboring picture elements along the scan line and boundaries between neighboring picture elements on neighboring scan lines are expanded to neighboring successive scan lines. The expanded boundaries are then subjected to a time-shift to superimpose the expanded boundaries for a region lying wholly within a bounded region of the image.