Video camera-based visibility measurement system
First Claim
Patent Images
1. A system for measuring atmospheric visibility, comprising:
- a video detector that is aligned to detect an image having contrasting portions, the video detector configured to generate a signal indicative of contrast levels of said contrasting portions of the image; and
a processor that generates a representative contrast number from said contrast levels, and that generates a nonlinear curve based on said representative contrast numbers and a distance value for each contrasting portion, and that generates a visibility number based on the intersection of the nonlinear curve with a lower threshold.
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Abstract
A video camera based atmospheric visibility measurement system that is capable of providing automated measurements of atmospheric visibility during both the day and night. For daylight measurements, the system views an image that has contrasting portions. A representative contrast signal is generated for contrasting portions of the images. The representative contrast number is used to generate an exponential curve of contrast levels versus distance. Atmospheric visibility is determined by detecting where the exponential curve reaches a threshold of visibility.
15 Citations
12 Claims
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1. A system for measuring atmospheric visibility, comprising:
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a video detector that is aligned to detect an image having contrasting portions, the video detector configured to generate a signal indicative of contrast levels of said contrasting portions of the image; and
a processor that generates a representative contrast number from said contrast levels, and that generates a nonlinear curve based on said representative contrast numbers and a distance value for each contrasting portion, and that generates a visibility number based on the intersection of the nonlinear curve with a lower threshold. - View Dependent Claims (2, 3, 4, 5)
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6. A system for measuring atmospheric visibility comprising:
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an image detector disposed at said predetermined location that is aligned to view a plurality of objects and that generates an image signal that is indicative of contrast levels of said objects; and
a processor that generates a visibility range measurement by determining a distance at which said contrast levels can just be distinguished based on the slope of an exponential curve that is representative of contrast levels for each of said objects versus said distance of said objects from said detector. - View Dependent Claims (7, 8, 9, 10)
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11. A method of measuring atmospheric visibility in a region measured from a predetermined location comprising the steps of:
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generating image signals of a plurality of objects, said objects disposed in said region at distances from said predetermined location and defining contrasting portions of the image, said image signal having intensity levels that are indicative of said contrasting portions;
generating contrast signals from said intensity levels of said image signals that are representative of contrast levels that are detected for said plurality of objects;
generating an average high contrast signal that as representative of an average of a predetermined percentage of highest contrast levels of said contrast signal for said plurality of objects;
processing the average high contrast signal to generate an atmospheric visibility measurement. - View Dependent Claims (12)
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Specification