Moire distance measurements using a grating printed on or attached to a surface
First Claim
1. A method of providing Moire distance measurements comprising the steps of:
- (a) locating, forming, or printing a first grating on a diffusely reflective surface to be measured;
(b) forming an image of the first grating on a second grating with an imaging means for producing a Moire pattern; and
(c) detecting changes in the Moire pattern as the diffusely reflective surface moves normal to a plane thereof for providing information related to the distance of the diffusely reflective surface relative from an initial position.
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Accused Products
Abstract
Method and apparatus are disclosed for providing Moire distance and displacement measurements of a diffusely reflective surface of an object or support. More particularly, a first grating is physically located, formed, or printed on the diffusely reflective surface. An image of the first grating is formed on a second grating by an imaging means for generating a Moire pattern behind the second grating. At an initial position of the diffusely reflective surface relative to the imaging means, the periods of the image of the first grating and the second grating match. Movement of the diffusely reflective surface in a direction normal thereto and away from the initial position produces a spatially varying intensity pattern caused by the Moire between a shifting and changing magnified pattern of the image of the first grating and a pattern of the second grating. The temporal intensity changs in the Moire pattern are detected and are used to produce information related to the instantaneous distance and displacement of the diffusely reflective surface from the initial position.
50 Citations
19 Claims
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1. A method of providing Moire distance measurements comprising the steps of:
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(a) locating, forming, or printing a first grating on a diffusely reflective surface to be measured; (b) forming an image of the first grating on a second grating with an imaging means for producing a Moire pattern; and (c) detecting changes in the Moire pattern as the diffusely reflective surface moves normal to a plane thereof for providing information related to the distance of the diffusely reflective surface relative from an initial position. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Moire distance measurement apparatus comprising:
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a first grating which is located, formed, or printed on a diffusely reflective surface to be measured; a second grating; imaging means for forming an image of the first grating on the second grating to generate a Moire pattern; and means for optically detecting a change in the Moire pattern as the diffusely reflective surface moves in a direction normal thereto, and for providing information related to a distance measurement of the diffusely reflective surface relative from an initial position. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A Moire distance measurement system for measuring the distance or displacement of a diffusely reflective surface of an object or support, the system comprising:
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a first grating physically located, formed, or printed on the diffusely reflective surface comprising opaque and non-opaque parallel lines or areas with a predetermined period therebetween; a light source for illuminating the diffusely reflective surface of the object or support; an imaging means for forming an image of the first grating; a second grating positioned at the image of the first grating comprising opaque and nonopaque parallel lines with a predetermined period that matches the period of the image of the first grating when the imaging means is at an initial distance; and detecting means for viewing resultant Moire patterns produced by the first and second gratings. - View Dependent Claims (16, 17, 18, 19)
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Specification