METHOD FOR DETERMINING DISTANCES
First Claim
1. A method of determining the distance of a point on a surface from a given point, comprising directing a beam of electromagnetic radiation from said given point along a given axis of emission onto said surface;
- receiving rays reflected from said surface, by means of a television camera having an objective lens having an optical axis which is fixed in relation to said axis of emission, whereby an image of said point on the surface is formed on said photosensitive screen;
electronically scanning said photosensitive screen;
measuring the time taken to scan between a given reference point and said image; and
calculating said distance from said time.
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Accused Products
Abstract
The invention is a method for determining distances and in particular for determining the profile of a surface. A ray of electromagnetic radiation is directed from a given emission point on to the surface whose profile is to be determined. A television camera, whose optical axis is fixed in relation to the axis of emission, is arranged at a reception point which is fixed in relation to the emission point. A ray reflected by the surface is collected by the camera. The position of the axis of emission is measured while the position of the image on the sensitive surface of the camera is recorded by carrying out a single time count. The distance of the surface from the point of emission is computed from this time count.
30 Citations
9 Claims
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1. A method of determining the distance of a point on a surface from a given point, comprising directing a beam of electromagnetic radiation from said given point along a given axis of emission onto said surface;
- receiving rays reflected from said surface, by means of a television camera having an objective lens having an optical axis which is fixed in relation to said axis of emission, whereby an image of said point on the surface is formed on said photosensitive screen;
electronically scanning said photosensitive screen;
measuring the time taken to scan between a given reference point and said image; and
calculating said distance from said time.
- receiving rays reflected from said surface, by means of a television camera having an objective lens having an optical axis which is fixed in relation to said axis of emission, whereby an image of said point on the surface is formed on said photosensitive screen;
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2. A method as claimed in claim 1, wherein said distance is calculated from said time and from the geometry of the system.
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3. A method as claimed in claim 1, further comprising generating an electrical signal representative of said time, and feeding said signal into an analog computer arranged to provide an output signal representing said distance.
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4. A method as claimed in claim 1, wherein said objective lens has a solid angle of observation which presents, in a plane perpendicular to its optical axis, an elongate cross section whose greatest dimension lies in a plane parallel to the plane defined by said axis of emission and the optical center of said objective lens.
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5. A method as claimed in claim 1, wherein the electromagnetic radiation is laser radiation.
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6. A method as claimed in claim 5, wherein the electromagnetic radiation is pulsed laser radiation.
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7. A method as claimed in claim 1, further comprising filtering the radiation received by the camera, by means of a highly selective interference filter, to eliminate radiation originating from the surface itself.
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8. A method as claimed in claim 6, further comprising synchronizing the release of a pulse of radiation with the line synchronizing pulse of the scanning line on which time counting is to be carried out.
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9. A method as claimed in claim 1, wherein said given reference point is the frame synchronization signal.
Specification