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# Optical Encoding of 3 Dimensional Objects

IP.com Disclosure Number: IPCOM000080889D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 36K

IBM

Will, PM: AUTHOR

## Abstract

Apparatus is provided for use in determining coordinate points on a 3-dimensional object. In Fig. 1, a light box 10 is provided having three sides 12, 14 and 16. The box has parallel grooves 18 formed in the three sides running in an X direction perpendicular to the Y direction.

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Optical Encoding of 3 Dimensional Objects

Apparatus is provided for use in determining coordinate points on a 3- dimensional object. In Fig. 1, a light box 10 is provided having three sides 12, 14 and 16. The box has parallel grooves 18 formed in the three sides running in an X direction perpendicular to the Y direction.

A light source in each groove 18 provides a plane of light emanating from all three sides and perpendicular to the sides. A camera 20 is fixed at a known X, Y and Z position relative to the coordinate positions of the grooves.

Referring to Fig. 2, a 3-D object 22 in the light box will be illuminated by stripes of light 24. The distortion in each stripe of light, as viewed from the camera point, will be dependent upon the surface topology of the object. It is desired to find the Z measurement of various points along the distorted portion of the stripes, as shown in Fig. 3.

In Fig. 3, triangle 26 illustrates a vertical plane which includes a specific point 28 on the distorted stripe and the camera position. The height Z1, of the camera 20 above the box side 14 is known; the distances Y1 and Y2 of the camera from the groove 18 and the projected point 30, respectively, are known. Thus, the distance Y3 of the point 30 from the groove 18 is known. It is a simple calculation based on similar triangles to determine the height Z2 of the point 28 above the plane of side 14.

By repeated computations, the elevation of every point on the distorted curve may b...