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公开(公告)号：US20230095500A1
公开(公告)日：2023-03-30
申请号：US17467664
申请日：2021-09-07
Inventor： Ho Man Cheng , Yao Cheng Liang , Ka Ho Mui
Abstract: Described is a method of calibrating a camera. The method comprises obtaining geographical coordinates of a selected physical point location within an image view of the camera and measuring an angle between an x-axis of a real-world coordinate system passing through said selected point location with respect to true north. The method includes using said obtained geographical coordinates, said measured angle, and projection data derived from characteristics of the camera to derive modified projection data for transforming a two-dimensional pixel coordinate system of the camera image view into a three-dimensional geographical coordinate system for point locations within the image view of the camera.
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公开(公告)号：US12125240B2
公开(公告)日：2024-10-22
申请号：US17467683
申请日：2021-09-07
Inventor： Yao Cheng Liang , Ho Man Cheng , Ka Ho Mui
CPC classification number: G06T7/80 , G06T7/74 , G06T2207/30236
Abstract: Described is a method of calibrating a camera. The method comprises defining an area observed in a field of view (FOV) of the camera as a region of interest (ROI). The method includes selecting a plurality of physical reference points in said ROI and obtaining for each reference point physical position coordinates. The method also includes obtaining from said camera FOV or camera image data pixel locations for each point of reference and pairing each pixel location with the physical position coordinates of its respective reference point. Then, a relationship is derived from the paired pixel locations and physical position coordinates to enable a selected or identified pixel location in the camera FOV or camera image data to be transformed to physical position coordinates for a corresponding physical location in said ROI.
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公开(公告)号：US11625860B1
公开(公告)日：2023-04-11
申请号：US17467664
申请日：2021-09-07
Inventor： Ho Man Cheng , Yao Cheng Liang , Ka Ho Mui
Abstract: Described is a method of calibrating a camera. The method comprises obtaining geographical coordinates of a selected physical point location within an image view of the camera and measuring an angle between an x-axis of a real-world coordinate system passing through said selected point location with respect to true north. The method includes using said obtained geographical coordinates, said measured angle, and projection data derived from characteristics of the camera to derive modified projection data for transforming a two-dimensional pixel coordinate system of the camera image view into a three-dimensional geographical coordinate system for point locations within the image view of the camera.
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公开(公告)号：US20230083307A1
公开(公告)日：2023-03-16
申请号：US17467683
申请日：2021-09-07
Inventor： Yao Cheng Liang , Ho Man Cheng , Ka Ho Mui
Abstract: Described is a method of calibrating a camera. The method comprises defining an area observed in a field of view (FOV) of the camera as a region of interest (ROI). The method includes selecting a plurality of physical reference points in said ROI and obtaining for each reference point physical position coordinates. The method also includes obtaining from said camera FOV or camera image data pixel locations for each point of reference and pairing each pixel location with the physical position coordinates of its respective reference point. Then, a relationship is derived from the paired pixel locations and physical position coordinates to enable a selected or identified pixel location in the camera FOV or camera image data to be transformed to physical position coordinates for a corresponding physical location in said ROI.
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