Non-contact sensor, system and method with particular utility for measurement of road profile
First Claim
1. Apparatus for measuring distance to a surface comprising first means for directing a light beam onto a surface to illuminate a portion of the surface;
- optical scanner means comprising means rotatable about an axis and a plurality of reflective facets mounted in a circumferential array about the periphery of said rotatable means, said scanner means being disposed to receive light from said first means reflected by the surface;
first light responsive means mounted in fixed position with respect to said axis to receive optical images of the illuminated portion of the surface successively reflected thereon by said facets in turn for providing a surface image signal in response to incidence thereon of each said optical image;
second means including reference light source means for directing light energy onto each said facet in turn as said scanner means rotates, and reference detection means disposed to receive light energy from said reference light source means reflected in turn by each said facet for providing a reference signal; and
third means responsive to a temporal relationship between said image signal and said reference signal for measuring distance to the surface.
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Accused Products
Abstract
Electro-optical apparatus, system and method for measuring distance to a relatively moving surface, such as distance to a road surface from a vehicle frame of reference passing thereover. The apparatus includes a light transmitter for projecting a rectangular beam vertically downwardly onto the road surface. A rotating scanner includes a circumferential array of facets for sequentially receiving the image diffusely reflected from the road surface and reflecting such image through a rectangular reticle onto a photodetector. Reference beams are sequentially reflected by the road image-reflecting scanner facets onto a reference detector. Distance to the road surface is then determined as a function of the angle of incidence of the road image onto the scanner by comparing the time of incidence of the road image to the times of occurrence of the reference reflections on the reference detector.
28 Citations
18 Claims
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1. Apparatus for measuring distance to a surface comprising first means for directing a light beam onto a surface to illuminate a portion of the surface;
- optical scanner means comprising means rotatable about an axis and a plurality of reflective facets mounted in a circumferential array about the periphery of said rotatable means, said scanner means being disposed to receive light from said first means reflected by the surface;
first light responsive means mounted in fixed position with respect to said axis to receive optical images of the illuminated portion of the surface successively reflected thereon by said facets in turn for providing a surface image signal in response to incidence thereon of each said optical image;
second means including reference light source means for directing light energy onto each said facet in turn as said scanner means rotates, and reference detection means disposed to receive light energy from said reference light source means reflected in turn by each said facet for providing a reference signal; and
third means responsive to a temporal relationship between said image signal and said reference signal for measuring distance to the surface. - View Dependent Claims (2, 3, 4)
- optical scanner means comprising means rotatable about an axis and a plurality of reflective facets mounted in a circumferential array about the periphery of said rotatable means, said scanner means being disposed to receive light from said first means reflected by the surface;
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5. Apparatus for measuring road surface profile as a function of distance between a road surface and a vehicle frame of reference travelling on the road surface comprising first means adapted to be mounted on a veicle for directing a continuous beam of light energy downwardly towardly a road surface;
- second means including light sensitive means adapted to be mounted in fixed position of the vehicle, a plurality of plane reflective means, means mounting said plurality of plane reflective means in a circumferential array wherein each said reflective means is tangetial to an axis which is fixed with respect to said frame of reference, and means for continuously rotating said mounting means and said plurality of reflective means about said axis, said first and second means cooperating to define a frame of reference onthe vehicle; and
third means responsive to angular position of said reflective means for measuring thedistance between the vehicle frame of reference and the road surface, said third means comprising reference means mounted in fixed position with respect to said axis and including reference source means for directing a continuous beam of light energy sequentially onto said plurality of reflective means, and reference light energy responsive means mounted to receive first and second beams of light energy from said reference source means reflected by one of said plurality of reflectvie means at angular orientations of said reflective means respectively corresponding to first and secon angles correlated with first and second distances between said frame of reference and theroad surface. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
- second means including light sensitive means adapted to be mounted in fixed position of the vehicle, a plurality of plane reflective means, means mounting said plurality of plane reflective means in a circumferential array wherein each said reflective means is tangetial to an axis which is fixed with respect to said frame of reference, and means for continuously rotating said mounting means and said plurality of reflective means about said axis, said first and second means cooperating to define a frame of reference onthe vehicle; and
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14. Apparatus for measuring distance to a surface comprising a first light source, a rectangular slit mounted in fixed position relative to said light source and means for focusing light energy from said source through said slit onto said surface to illuminate a portion of said surface, said focusing means having a focal distance from said source;
- reflective means mounted to oscillate about an axis, a photodetector, a rectangular reticle and means for focusing light energy from said source reflected by said portion of said surface and by said reflective means through said reticle onto said photodetector, said reticle being dimensioned to be congruent with the focused and reflected image of said portion of said surface when said surface is at said focal distance from said first source; and
first means responsive to said photodetector and to said reflective means to measure distance to said surface. - View Dependent Claims (15, 16)
- reflective means mounted to oscillate about an axis, a photodetector, a rectangular reticle and means for focusing light energy from said source reflected by said portion of said surface and by said reflective means through said reticle onto said photodetector, said reticle being dimensioned to be congruent with the focused and reflected image of said portion of said surface when said surface is at said focal distance from said first source; and
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17. A system for measuring and recording road surface profile as a function of distance between successive increments of the road surface and a vehicular inertial frame of reference travelling over said road surface comprising first means adapted to be mounted in fixed position with respect to a vehicle frame for directing a measurement light beam onto the road surface beneath the frame, second means adapted to be mounted in fixed position with respect to said frame spaced from said first means in a direction parallel to the direction of travel of the vehicle over the surface and responsive to light energy from said first means reflected by the road surface, third means responsive to the angle of incidence of said reflected light energy for measuring distance from the vehicle frame and the road surface, and means adapted to be responsive to incremental displacement of the vehicle over the road surface for sampling and storing successive measurements of said distance.
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18. Apparatus for measuring road surface profile as a function of distance between a road surface and a vehicle frame of reference travelling on the road surface comprising first means adapted to be mounted on a vehicle and including a light source, a first rectangular reticle and means for focusing a light beam passing from said light source through said reticle onto a road surface as a rectangular image having one rectangular dimension parallel to said axis;
- second means including light sensitive means adapted to be mounted in fixed position on the vehicle, reflective means spaced from said first means and adapted to oscillate about an axis which is fixed with respect to said frame of reference between at least first and second angles with respect to said frame of reference correlated with first and second distances between said frame of reference and the road surface, a second rectangular reticle and means for focusing a light beam reflected by the road surface and said reflective means through said second rectangular reticle onto said light sensitive means, said first and second means cooperating to define a frame of reference on the vehicle; and
third means responsive to angular position of said reflective means and including reference source means for directing light energy onto said reflective means and reference energy responsive means mounted to receive light energy from said reference source means reflected by said reflective means at positions of said reflective means corresponding to said first and second angles for measuring the distance between the vehicle frame of reference and the road surface, said reference source means comprising a reference source of light energy, first rectangular reference reticle means and means for focusing a pair of beams of light energy from said reference source through said first reference reticle means onto said reflective means, said reference energy responsive means comprising a photodetector, second reference reticle means and means for focusing said pair of light beams from said reference source and said first reference reticle means onto said photodetector in turn as a function of rotation of said reflective means.
- second means including light sensitive means adapted to be mounted in fixed position on the vehicle, reflective means spaced from said first means and adapted to oscillate about an axis which is fixed with respect to said frame of reference between at least first and second angles with respect to said frame of reference correlated with first and second distances between said frame of reference and the road surface, a second rectangular reticle and means for focusing a light beam reflected by the road surface and said reflective means through said second rectangular reticle onto said light sensitive means, said first and second means cooperating to define a frame of reference on the vehicle; and
Specification