Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Patent
1993-01-15
1995-04-11
Sikes, William L.
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
356376, 351221, A61B 310
Patent
active
054063426
ABSTRACT:
A system for determining the topography of a curved surface, comprising a device for projecting patterns of lines on the surface to be examined, which device includes two projectors disposed at an angle relative to each other, each provided with a raster of parallel straight lines, which are positioned at right angles to the plane through the projection axes and a rectangular diaphragm, of which the long sides are parallel to the lines of the raster, and a detection device for registering the image formed on the surface. The system is implemented such that an additive moire pattern is produced and that a pilot monitor in conjunction with an electronic filter is provided for real-time visualizing this moire pattern. The detection device is implemented for registering the image without moire interference, suitable for discrete Fourier analysis. The registration of the formed height line map for proper focussing or for obtaining an end product is electronically filtered, with the object of being able to see highly contrasting moire height contours in real time on a monitor. The light source for both projectors is a slit shaped continuous light source combined with a slit shaped flashlamp, which-- by means of synchronization at the end of the first raster period and the beginning of the second raster period respectively--illuminate a complete TV raster in only a few ms, and in which the half rasters can complement each other afterwards through explicit digital analysis.
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patent: 5135308 (1992-08-01), Kuchel
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Frobin et al, "Rasterstereography: A Photogrammetric Method for Meassurement of Body Surfaces", Journal of Biological Photography, vol. 51, No. 1 Jan. 1983.
Nouvelle Revue b'optique, vol. 6, No. 2, pp. 67-86, Oct. 1975 for Characterization and Control of Threedimensional Objects Using Fringe Projection.
Spie, Ecoosa for "Real-Time Contouring of Toothimprints", vol. 492, pp. 500-506, by Jongsma et al.
Applied Optics, vol. 18, No. 21, Nov. 1, 1979, for Corneal Topography Using MoireContour Fringes, by Tetsuo Kawara.
Euclid Medical Instruments
Mai Huy
Sikes William L.
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