METHOD FOR LOCATING POINTS ON A THREE-DIMENSIONAL SURFACE USING LIGHT INTENSITY VARIATIONS

A method for locating points on a surface, in which the surface is irradiated selectively with an irradiating volume which has a varying intensity that defines a first pattern. After irradiating the surface with the first pattern, the surface is irradiated similarly with volume(s) having varying intensity(ies) defining a second (or more) pattern(s). Both (or all) of these patterns are applied to a point to be located on the surface. The radiation impinging on the surface is recorded by a camera which forms images of these patterns. The images are scanned to find the intensities of the point in the two (or more) patterns. The location of the point on the surface is dependent on a predetermined ratio or difference of the intensities of the point in the two (or more) patterns. The patterns may be linear, sinusoidal, smooth, non-smooth and/or two dimensional functions ultimately producing a single valued ratio or difference result.