Road surface discriminator and apparatus applying same
First Claim
1. A road surface discriminator comprising:
- a first light source for projecting light toward a road surface;
a first spatial filter light-receiving optical system having first spatial filter means and first light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by the first light-receiving means through said first spatial filter means and the first-light receiving means outputs an electric signal representing the reflected light received;
a second light-receiving optical system having second light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by said second light-receiving means and said second-light receiving means outputs an electric signal representing the reflected light received;
a first signal processing circuit for detecting intensity of a center-frequency component, which corresponds to the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said first spatial filter light-receiving optical system;
a second signal processing circuit for detecting intensity of a low-frequency component, which corresponds to a spatial frequency lower than the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said second light-receiving optical system; and
discriminating means for discriminating condition of the road surface based upon the intensity of the center-frequency component detected by said first signal processing circuit and the intensity of the low-frequency component detected by the second signal processing circuit.
1 Assignment
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Accused Products
Abstract
Light is projected upon a road surface (LD) from a light source (11) for illuminating the road surface. Diffuse reflected light from the road surface (LD) is received by light sensors (31A, 31B) through a spatial filter, and the resulting light-reception signals are applied to a differential amplifier circuit (51). A center-frequency component corresponding to the spatial frequency of the spatial filter is extracted by a tracking band-pass filter (52), and the intensity (Da) thereof is detected by an amplitude detector circuit (54). Low-frequency component intensity (Db) corresponding to a spatial frequency lower than the spatial frequency of the spatial filter is detected by a tracking low-pass filter (55) and an amplitude detector circuit (56). The condition of the road surface is judged to be snow, gravel or asphalt in a discriminating circuit (60) based upon the center-frequency component intensity (Da) and the low-frequency component intensity (Db).
35 Citations
44 Claims
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1. A road surface discriminator comprising:
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a first light source for projecting light toward a road surface; a first spatial filter light-receiving optical system having first spatial filter means and first light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by the first light-receiving means through said first spatial filter means and the first-light receiving means outputs an electric signal representing the reflected light received; a second light-receiving optical system having second light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by said second light-receiving means and said second-light receiving means outputs an electric signal representing the reflected light received; a first signal processing circuit for detecting intensity of a center-frequency component, which corresponds to the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said first spatial filter light-receiving optical system; a second signal processing circuit for detecting intensity of a low-frequency component, which corresponds to a spatial frequency lower than the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said second light-receiving optical system; and discriminating means for discriminating condition of the road surface based upon the intensity of the center-frequency component detected by said first signal processing circuit and the intensity of the low-frequency component detected by the second signal processing circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A road surface discriminator comprising:
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a source for projecting light toward a road surface; a spatial filter light-receiving optical system for receiving diffuse reflected light from the road surface, on which light is projected from said light source, through a spatial filter and outputting an electric signal representing the reflected light received; a first signal processing circuit for detecting intensity of a center-frequency component, which corresponds to the spatial frequency of the spatial filter, based upon the electric signal outputted by said spatial filter light-receiving optical system; a second signal processing circuit for detecting intensity of a low-frequency component, which corresponds to a spatial frequency lower than the spatial frequency of said spatial filter means, based upon the electric signal outputted by said spatial filter light-receiving optical system; and discriminating means for discriminating condition of the road surface based upon the intensity of the center-frequency component detected by said first signal processing circuit and the intensity of the low-frequency component detected by the second signal processing circuit. - View Dependent Claims (27, 28, 29)
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30. A road surface discriminator comprising:
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a light source for projecting light toward a road surface; a spatial filter light-receiving optical system for receiving diffuse reflected light from the road surface, on which light is projected from said light source, through a spatial filter and outputting an electric signal representing the reflected light received; a signal processing circuit for detecting a center-frequency component, which corresponds to the spatial frequency of said spatial filter, based upon the electric signal outputted by said spatial filter light-receiving optical system; first counting means for counting zero cross points of the center-frequency component outputted by said signal processing circuit; second counting means for counting zero cross points of the electric signal outputted by said spatial filter light-receiving optical system; and discriminating means for discriminating condition of the road surface based upon a count value in said first counting means and a count value in said second counting means. - View Dependent Claims (31, 32, 33, 34, 35, 36)
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37. An object discriminator comprising:
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a first light source for projecting light toward a surface of the object; a first spatial filter light-receiving optical system having first spatial filter means and first light-receiving means, wherein reflected light from the surface of the object on which light is projected from said first light source is received by the first light-receiving means through said first spatial filter means and the first-light receiving means outputs an electric signal representing the reflected light received; a second light-receiving optical system having second light-receiving means, wherein reflected light from the surface of the object on which light is projected from said first light source is received by said second light-receiving means and said second-light receiving means outputs an electric signal representing the reflected light received; a first signal processing circuit for detecting intensity of a center-frequency component, which corresponds to the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said first spatial filter light-receiving optical system; a second signal processing circuit for detecting intensity of a second frequency component, which corresponds to a spatial frequency lower or higher than the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said second light-receiving optical system; and discriminating means for discriminating condition of the surface of the object based upon the intensity of the center-frequency component detected by said first signal processing circuit and intensity of the second frequency component detected by the second signal processing circuit.
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38. An object discriminator comprising:
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a first light source for projecting light toward a surface of the object; a spatial filter light-receiving optical system for receiving diffuse reflected light from the surface of the object, on which light is projected from said light source, through a spatial filter and outputting an electric signal representing the reflected light received; a first signal processing circuit for detecting intensity of a center-frequency component, which corresponds to the spatial frequency of the spatial filter, based upon the electric signal outputted by said spatial filter light-receiving optical system; a second signal processing circuit for detecting intensity of a second frequency component, which corresponds to a spatial frequency lower or higher than the spatial frequency of said spatial filter, based upon the electric signal outputted by said spatial filter light-receiving optical system; and discriminating means for discriminating condition of the surface of the object based upon the intensity of the center-frequency component detected by said first signal processing circuit and intensity of the second frequency component detected by the second signal processing circuit.
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39. An object discriminator comprising:
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a light source for projecting light toward a surface of the object; a spatial filter light-receiving optical system for receiving diffuse reflected light from the surface of the object, on which light is projected from said light source, through a spatial filter and outputting an electric signal representing the reflected light received; a signal processing circuit for detecting a center-frequency component, which corresponds to the spatial frequency of said spatial filter, based upon the electric signal outputted by said spatial filter light-receiving optical system; first counting means for counting zero cross points of the center-frequency component outputted by said signal processing circuit; second counting means for counting zero cross points of the electric signal outputted by said spatial filter light-receiving optical system; and discriminating means for discriminating condition of the surface of the object based upon a count value in said first counting means and a count value in said second counting means.
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40. A mobile body having a road surface discriminator, the road surface discriminator comprising:
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a first light source for projecting light toward a road surface; a first spatial filter light-receiving optical system having first spatial filter means and first light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by the first light-receiving means through said first spatial filter means and the first-light receiving means outputs an electric signal representing the reflected light received; a second light-receiving optical system having second light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by said second light-receiving means and said second-light receiving means outputs an electric signal representing the reflected light received; a first signal processing circuit for detecting intensity of a center-frequency component, which corresponds to the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said first spatial filter light-receiving optical system; a second signal processing circuit for detecting intensity of a low-frequency component, which corresponds to a spatial frequency lower than the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said second light-receiving optical system; and discriminating means for discriminating condition of the road surface based upon the intensity of the center-frequency component detected by said first signal processing circuit and the intensity of the low-frequency component detected by the second signal processing circuit.
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41. A vehicle having a road surface discriminator, the road surface discriminator comprising:
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a first light source for projecting light toward a road surface; a first spatial filter light-receiving optical system having first spatial filter means and first light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by the first light-receiving means through said first spatial filter means and the first-light receiving means outputs an electric signal representing the reflected light received; a second light-receiving optical system having second light-receiving means, wherein reflected light from the road surface on which light is projected from said first light source is received by said second light-receiving means and said second-light receiving means outputs an electric signal representing the reflected light received; a first signal processing circuit for detecting intensity of a center-frequency component, which corresponds to the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said first spatial filter light-receiving optical system; a second signal processing circuit for detecting intensity of a low-frequency component, which corresponds to a spatial frequency lower than the spatial frequency of said first spatial filter means, based upon the electric signal outputted by said second light-receiving optical system; and discriminating means for discriminating condition of the road surface based upon the intensity of the center-frequency component detected by said first signal processing circuit and the intensity of the low-frequency component detected by the second signal processing circuit. - View Dependent Claims (42, 43, 44)
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Specification