CALIBRATION METHOD FOR VIDEO AND RADIATION IMAGERS
First Claim
1. An apparatus for detecting a radiation source, said apparatus comprising:
- a visible light camera that detects electromagnetic radiation in a visible range;
a high energy radiation imager that detects high energy radiation; and
an image analysis device that is configured to execute a program of machine-executable instructions to calibrate high energy radiation imager pixels of said high energy radiation imager to a real-world coordinate of a moving vehicle, wherein said program includes the steps of;
determining a visible light camera pixel coordinate of a moving vehicle;
determining a real-world coordinate of said moving vehicle based on said visible light camera pixel coordinate;
determining a high energy radiation imager pixel position based on said real-world coordinate of said moving vehicle; and
determining a scale parameter for said high energy radiation imager based on said real-world coordinate, wherein said scale parameter correlates a change in said high energy radiation imager pixel position to a change in an x-coordinate of said real-world coordinate in a real-world coordinate system having an x-axis that is parallel to an image plane of said high energy radiation imager.
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Abstract
The relationship between the high energy radiation imager pixel (HERIP) coordinate and real-world x-coordinate is determined by a least square fit between the HERIP x-coordinate and the measured real-world x-coordinates of calibration markers that emit high energy radiation imager and reflect visible light. Upon calibration, a high energy radiation imager pixel position may be determined based on a real-world coordinate of a moving vehicle. Further, a scale parameter for said high energy radiation imager may be determined based on the real-world coordinate. The scale parameter depends on the y-coordinate of the moving vehicle as provided by a visible light camera. The high energy radiation imager may be employed to detect radiation from moving vehicles in multiple lanes, which correspondingly have different distances to the high energy radiation imager.
31 Citations
41 Claims
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1. An apparatus for detecting a radiation source, said apparatus comprising:
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a visible light camera that detects electromagnetic radiation in a visible range; a high energy radiation imager that detects high energy radiation; and an image analysis device that is configured to execute a program of machine-executable instructions to calibrate high energy radiation imager pixels of said high energy radiation imager to a real-world coordinate of a moving vehicle, wherein said program includes the steps of; determining a visible light camera pixel coordinate of a moving vehicle; determining a real-world coordinate of said moving vehicle based on said visible light camera pixel coordinate; determining a high energy radiation imager pixel position based on said real-world coordinate of said moving vehicle; and determining a scale parameter for said high energy radiation imager based on said real-world coordinate, wherein said scale parameter correlates a change in said high energy radiation imager pixel position to a change in an x-coordinate of said real-world coordinate in a real-world coordinate system having an x-axis that is parallel to an image plane of said high energy radiation imager. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for calibrating high energy radiation imager pixels to a real-world coordinate of a moving vehicle, said method comprising:
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generating a visible light camera image of a moving vehicle; determining a visible light camera pixel coordinate of said moving vehicle in said visible light camera image; determining a real-world coordinate of said moving vehicle based on said visible light camera pixel coordinate; determining a high energy radiation imager pixel position of a high energy radiation imager based on said real-world coordinate of said moving vehicle; and determining a scale parameter for said high energy radiation imager based on said real-world coordinate, wherein said scale parameter correlates a change in said high energy radiation imager pixel position to a change in an x-coordinate of said real-world coordinate in a real-world coordinate system having an x-axis that is parallel to an image plane of said high energy radiation imager. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A method of detecting a radiation source, said method comprising:
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providing a visible light camera that detects electromagnetic radiation in a visible range; providing a high energy radiation imager that detects high energy radiation; calibrating high energy radiation imager pixels to a real-world coordinate of a moving vehicle by generating a visible light camera image of a moving vehicle;
by determining a visible light camera pixel coordinate of said moving vehicle in said visible light camera image;
by determining a real-world coordinate of said moving vehicle based on said visible light camera pixel coordinate;
by determining a high energy radiation imager pixel position of a high energy radiation imager based on said real-world coordinate of said moving vehicle; and
by determining a scale parameter for said high energy radiation imager based on said real-world coordinate, wherein said scale parameter correlates a change in said high energy radiation imager pixel position to a change in an x-coordinate of said real-world coordinate in a real-world coordinate system having an x-axis that is parallel to an image plane of said high energy radiation imager; andintegrating an intensity of detected high energy radiation imager around said high energy radiation imager pixel position over time, wherein said high energy radiation imager pixel position changes at a rate of change that is calculated from said speed and said scale parameter. - View Dependent Claims (32)
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33. A machine-readable data storage device embodying a program of machine-executable instructions to calibrate high energy radiation imager pixels to a real-world coordinate of a moving vehicle, wherein said program includes the steps of:
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determining a visible light camera pixel coordinate of a moving vehicle in a visible light camera image; determining a real-world coordinate of said moving vehicle based on said visible light camera pixel coordinate; determining a high energy radiation imager pixel position of a high energy radiation imager based on said real-world coordinate of said moving vehicle; and determining a scale parameter for said high energy radiation imager based on said real-world coordinate, wherein said scale parameter correlates a change in said high energy radiation imager pixel position to a change in an x-coordinate of said real-world coordinate, wherein an x-axis of said real-world coordinate system is parallel to an image plane of said high energy radiation imager. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41)
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Specification