Process and apparatus for determining the condition of a road surface
First Claim
1. A process for determining a condition of a road surface, comprising:
- beaming light onto the road surface, said light including a first light fraction having a first wavelength range which is not significantly absorbed by water/ice, and a second light fraction having a second wavelength range which is significantly absorbed by water/ice, said first light fraction including first light components with differing wavelengths;
detecting backscattered light from the road surface;
analyzing the backscattered light from the road surface to obtain a spectral intensity distribution curve;
determining an approximation reference curve for spectral intensity distribution of the backscattered light when the road is dry using spectral data of the detected backscattered light;
calculating a difference between spectral data of light backscattered from the second light fraction and corresponding data of the approximation reference curve for at least one wavelength of the second wavelength range, to obtain a difference curve; and
determining the condition of the road surface based on the calculated difference curve;
whereinthe second light fraction contains a plurality of different wavelengths; and
the difference between the spectral data of the second backscattered-light fraction and the corresponding approximation reference curve data is determined as a difference curve between a measured spectral curve of the backscattered light and the approximation reference curve in the second wavelength range.
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Accused Products
Abstract
In a process for determining the condition of a road surface, light is beamed onto the road surface and backscattered light is detected and spectrally analyzed. The light beam contains two light fractions, one having wavelength range which is not significantly absorbed by water/ice and another having a wavelength range which is significantly absorbed by these materials. The first light fraction contains light of several different wavelengths and the spectral analysis includes the determination of an approximation reference curve for the spectral plots of the backscattered light when the road is dry. This is accomplished by using the spectral data of the backscattered light fraction in the wavelength range without significant absorption, and the determination of the difference between the spectral data of the backscattered-light fraction in the other wavelength range and the corresponding data of the approximation reference curve for at least one wavelength. A typical use, for example, is for continuous qualitative and quantitative determination of the condition of the road surface on which a road vehicle is driving.
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Citations
20 Claims
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1. A process for determining a condition of a road surface, comprising:
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beaming light onto the road surface, said light including a first light fraction having a first wavelength range which is not significantly absorbed by water/ice, and a second light fraction having a second wavelength range which is significantly absorbed by water/ice, said first light fraction including first light components with differing wavelengths; detecting backscattered light from the road surface; analyzing the backscattered light from the road surface to obtain a spectral intensity distribution curve; determining an approximation reference curve for spectral intensity distribution of the backscattered light when the road is dry using spectral data of the detected backscattered light; calculating a difference between spectral data of light backscattered from the second light fraction and corresponding data of the approximation reference curve for at least one wavelength of the second wavelength range, to obtain a difference curve; and determining the condition of the road surface based on the calculated difference curve;
whereinthe second light fraction contains a plurality of different wavelengths; and the difference between the spectral data of the second backscattered-light fraction and the corresponding approximation reference curve data is determined as a difference curve between a measured spectral curve of the backscattered light and the approximation reference curve in the second wavelength range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for determining a condition of a road surface;
- comprising;
a receiver; a dispersive element located in the receiver and disposed in a path of backscattered light for spectrally dividing the backscattered light; a detector for receiving spectrally divided backscattered light and outputting signals indicative thereof; and an analysis unit coupled to the detector for receiving the signals indicative of the spectrally divided backscattered light; wherein said analysis unit analyzes the backscattered light from the road surface to obtain a spectral intensity distribution curve; determines an approximation reference curve for spectral intensity distribution of the backscattered light when the road is dry using spectral data of the detected backscattered light; calculates a difference between spectral data of light backscattered from the second light fraction and corresponding data of the approximation reference curve for at least one wavelength of the second wavelength range, to obtain a difference curve; and determines the condition of the road surface based on the calculated difference curve; wherein the second light fraction contains a plurality of different wavelengths; and wherein the difference between the spectral data of the second backscattered-light fraction and the corresponding approximation reference curve data is determined as a difference curve between a measured spectral curve of the backscattered light and the approximation reference curve in the second wavelength range. - View Dependent Claims (18, 19, 20)
- comprising;
Specification