Video camera-based visibility measurement system
First Claim
1. A visibility measurement system comprising an image sensing device for sensing at least a first and a second image of an environment, the visibility measurement system comprising a digital conversion system that maps the image of the environment into a two-dimensional data array, and a processor that computes a benchmark visibility index as a summation of measurable visual characteristics that influence visibility under a benchmark environmental condition, computes a second visibility index for a second environmental condition, and computes a relative visibility value as the ratio of the second visibility index to the benchmark visibility index.
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Abstract
A visibility measurement system that computes relative visibility by comparing an images of an environment against a benchmark image. A sensing device receives an image and a digital conversion system maps the image into a two-dimensional data array. A processor converts the digital data to a value that represents visibility by identifying a region in the image that has a uniform distance from the sensing device over time, computing a benchmark visibility index for the region as a summation of measurable visual characteristics that influence visibility in the region under a benchmark environmental condition, computing a second visibility index for a second environmental condition, and computing a relative visibility value as the ration of the second visibility index in relation to the benchmark visibility index.
30 Citations
22 Claims
- 1. A visibility measurement system comprising an image sensing device for sensing at least a first and a second image of an environment, the visibility measurement system comprising a digital conversion system that maps the image of the environment into a two-dimensional data array, and a processor that computes a benchmark visibility index as a summation of measurable visual characteristics that influence visibility under a benchmark environmental condition, computes a second visibility index for a second environmental condition, and computes a relative visibility value as the ratio of the second visibility index to the benchmark visibility index.
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6. A method for computing visibility comprising:
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sensing with a sensing device a benchmark image of an environment under a benchmark condition with a sensing device;
sensing with the sensing device a second image of an environment under a second condition;
computing a benchmark visibility index from the benchmark image as a summation of measurable visual characteristics that influence visibility;
computing a second visibility index from the second image as a summation of measurable visual characteristics that influence visibility;
computing a relative visibility value as the ratio of the second visibility index to the benchmark visibility index. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A relative visibility measurement system comprising:
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means for sensing an image of an environment;
means for identifying a region in the image that has a uniform distance from the sensing device over time;
means for computing a benchmark visibility index for the region as a summation of measurable visual characteristics that influence visibility in the region under a benchmark environmental condition;
means for computing a second visibility index for a second environmental condition;
means for computing the relative visibility in terms of the magnitude of the second visibility index in relation to the benchmark visibility index.
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16. A relative visibility measurement system comprising:
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an image sensing device for sensing an image of an environment;
a code segment for identifying a region in the image that has a uniform distance from the sensing device over time;
a code segment for computing a benchmark visibility index for the region as a summation of measurable visual characteristics that influence visibility in the region under a benchmark environmental condition;
a code segment for computing a second visibility index for a second environmental condition; and
a code segment for computing the relative visibility in terms of the magnitude of the second visibility index in relation to the benchmark visibility index.
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17. A system for measuring relative visibility, comprising:
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a video camera that is positioned to perceive a scene including objects located at various distances from the camera, the video camera providing an output comprising an image of the scene;
a processor that computes relative visibility by approximating the distance from the camera of objects in the image and comparing a region of the image to a corresponding region in a benchmark image to determine relative visibility. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification