System for automated determination of retroreflectivity of road signs and other reflective objects
First Claim
1. A method of automated determination of retroreflectivity values for reflective surfaces comprising:
- strobing a light source to illuminate an area that includes at least one reflective surface without targeting the light source on a particular reflective surface;
collecting a plurality of light intensity measurements with at least one intensity sensor directed to cover a field of view which includes at least a portion of the area illuminated by the light source;
using a computer processing system to;
identify a portion of at least one light intensity measurement associated with one of the at least one reflective surfaces; and
analyze the portion of the at least one light intensity measurement to determine at least one retroreflectivity value for that reflective surface;
creating a characterization profile for the light source, the characterization profile including an array of known luminance values of reflections of the light source; and
utilizing the characterization profile for the light source as part of determining the at least one retroreflectivity value for that reflective surface.
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Accused Products
Abstract
A system for the automated determination of retroreflectivity values for reflective surfaces disposed along a roadway repeatedly illuminates an area along the roadway that includes at least one reflective surface using a strobing light source. Multiple light intensity values are measured over a field of view which includes at least a portion of the area illuminated by the light source. A computer processing system is used to identifying a portion of the light intensity values associated with a reflective surface and analyze the portion of the light intensity values to determine at least one retroreflectivity value for that reflective surface.
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Citations
11 Claims
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1. A method of automated determination of retroreflectivity values for reflective surfaces comprising:
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strobing a light source to illuminate an area that includes at least one reflective surface without targeting the light source on a particular reflective surface; collecting a plurality of light intensity measurements with at least one intensity sensor directed to cover a field of view which includes at least a portion of the area illuminated by the light source; using a computer processing system to; identify a portion of at least one light intensity measurement associated with one of the at least one reflective surfaces; and analyze the portion of the at least one light intensity measurement to determine at least one retroreflectivity value for that reflective surface; creating a characterization profile for the light source, the characterization profile including an array of known luminance values of reflections of the light source; and utilizing the characterization profile for the light source as part of determining the at least one retroreflectivity value for that reflective surface. - View Dependent Claims (2, 3)
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4. A method of automated determination of retroreflectivity values for reflective surfaces comprising:
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strobing a light source to illuminate an area that includes at least one reflective surface withhout targeting the light source on a particular reflective surface; collecting a plurality of light intensity measurements with at least one intensity sensor directed to cover a field of view which includes at least a portion of the area illuminated by the light source; using a computer processing system to; identify a portion of at least one light intensity measurement associated with one of the at least one reflective surfaces; and analyze the portion of the at least one light intensity measurement to determine at least one retroreflectivity value for that reflective surface; creating a characterization profile for the intensity sensor, the characterization profile including an array of intensity values of reflections measured for a known light source; and utilizing the characterization profile for the intensity sensor as part of determining the at least one retroreflectivity value for that reflective surface.
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5. A method of automated determination of retroreflectivity values for reflective surfaces comprising:
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strobing a light source to illuminate an area that includes at least one reflective surface without targeting the light source on a particular reflective surface; collecting a plurality of light intensity measurements with at least one intensity sensor directed to cover a field of view which includes at least a portion of the area illuminated by the light source; using a computer processing system to; identify a portion of at least one light intensity measurement associated with one of the at least one reflective surfaces; and analyze the portion of the at least one light intensity measurement to determine at least one retroreflectivity value for that reflective surface; wherein each light intensity measurement comprises a frame of pixel intensity values and a plurality of reflective surfaces are present in at least one of the light intensity measurements.
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6. A method of automated determination of retroreflectivity values for reflective surfaces comprising:
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strobing a light source to illuminate an area that includes at least one reflective surface without targeting the light source on a particular reflective surface; collecting a plurality of light intensity measurements with at least one intensity sensor directed to cover a field of view which includes at least a portion of the area illuminated by the light source; using a computer processing system to; identify a portion of at least one light intensity measurement associated with one of the at least one reflective surfaces; and analyze the portion of the at least one light intensity measurement to determine at least one retroreflectivity value for that reflective surface; wherein the step of strobing the light source is synchronized to the step of collecting the plurality of light intensity measurements.
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7. A method of automated determination of retroreflectivity values for reflective surfaces comprising:
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creating a characterization profile for a light source, the characterization profile including an array of known luminance values associated with reflections of the light source; creating a characterization profile for an intensity sensor, the characterization profile including an array of intensity values measured for reflections of a known light source; and using the light source to illuminate an area that includes at least one reflective surface; collecting a plurality of light intensity measurements with at least one intensity sensor without targeting a particular reflective surface; collecting a plurality of color images with at least one color camera directed to cover a field of view which includes at least a portion of the area illuminated by the light source; using a computer processing system to determine at least one retroreflectivity value for one of the at least one reflective surfaces that reflective surface, including; identifying a portion of at least one light intensity measurement associated with one of the at least one reflective surfaces; utilizing at least one of the plurality of color images to identify at least one color associated with that reflective surface; utilizing the characterization profile of the light source and the characterization profile for the intensity sensor to determine a luminance value associated with the portion of that light intensity measurement associated with that reflective surface based on the at least one color associated with that reflective surface; and converting the luminance value to a retroreflectivity value. - View Dependent Claims (8)
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9. A system for automated determination of retroreflectivity values for reflective surfaces comprising:
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means for repeatedly illuminating an area that includes at least one reflective surface; means for repeatedly measuring light intensity values over a field of view which includes at least a portion of the area illuminated by the light source; and at least one computer processing system, including; means for identifying a portion of the light intensity values associated with one of the at least one reflective surfaces; means for analyzing the portion of the light intensity values to determine at least one retroreflectivity value for that reflective surface; and wherein the means for analyzing utilizes the color images as part of determining the at least retroreflectivity value for that reflective surface. - View Dependent Claims (10, 11)
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Specification