Method and system for measuring the speed of a vehicle
First Claim
Patent Images
1. A system for measuring the speed of a vehicle having a feature of known size, comprising:
- one or more cameras for capturing images of vehicles on a road;
timing means for timing the capture of the images;
a processor arranged to operate in at least a calibration mode and a monitoring mode,wherein;
(i) in the calibration mode the processor;
identifies in the captured images the feature of a vehicle;
calculates the size in pixels of the feature of the vehicle in two or more of the captured images;
receives as an input the vehicle'"'"'s geodesic distance along the road at the times of capture of the captured images; and
generates a look-up table or function correlating the calculated size of the feature to the vehicle'"'"'s geodesic distance along the road; and
(ii) in the monitoring mode the processor;
identifies in the captured images the feature of the vehicle;
calculates the size in pixels of the feature of the vehicle in two or more of the captured images;
determines the vehicle'"'"'s geodesic distance along the road in each image by using the calculated sizes as an input to the generated look-up table or function; and
determines the speed of the vehicle based on the determination of the vehicle'"'"'s geodesic distance along the road in each image and the times at which each image was captured.
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Abstract
A system for measuring the speed of a vehicle includes: one or more cameras (200) for capturing images of vehicles (100) on a road (50); timing means for timing the capture of the images; a processor arranged to: identify in the captured images a feature (150) of the vehicle; calculate the size in pixels of the feature (150) of the vehicle in two or more of the captured images; and determine the speed of the vehicle (100) based at least in part on the calculated sizes and the times at which each image was captured.
11 Citations
29 Claims
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1. A system for measuring the speed of a vehicle having a feature of known size, comprising:
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one or more cameras for capturing images of vehicles on a road; timing means for timing the capture of the images; a processor arranged to operate in at least a calibration mode and a monitoring mode, wherein; (i) in the calibration mode the processor; identifies in the captured images the feature of a vehicle; calculates the size in pixels of the feature of the vehicle in two or more of the captured images; receives as an input the vehicle'"'"'s geodesic distance along the road at the times of capture of the captured images; and generates a look-up table or function correlating the calculated size of the feature to the vehicle'"'"'s geodesic distance along the road; and (ii) in the monitoring mode the processor; identifies in the captured images the feature of the vehicle; calculates the size in pixels of the feature of the vehicle in two or more of the captured images; determines the vehicle'"'"'s geodesic distance along the road in each image by using the calculated sizes as an input to the generated look-up table or function; and determines the speed of the vehicle based on the determination of the vehicle'"'"'s geodesic distance along the road in each image and the times at which each image was captured. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of measuring the speed of a vehicle having a feature of known size, comprising:
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capturing a plurality of images of the vehicle; timing the capturing of the plurality of images; in a calibration mode; identifying in the captured images the feature of the vehicle; calculating the size in pixels of the feature of the vehicle in two or more of the captured images; and generating a look-up table or function that correlates the calculated size of the feature to the vehicle'"'"'s geodesic distance along the road to determine the vehicle'"'"'s position on the road from each image; and in a monitoring mode; identifying in the captured images the feature of the vehicle; calculating the size in pixels of the feature of the vehicle in two or more of the captured images; using the look-up table or function that correlates the calculated size of the feature to the vehicle'"'"'s geodesic distance along the road to determine the vehicle'"'"'s position on the road from each image; and determining the speed of the vehicle using the determination of the vehicle'"'"'s geodesic distance on the road from each image and the times at which each image was captured. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification