Navigation by a video-camera sensed ground array
First Claim
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1. A method of navigation by a video-camera sensed array comprising:
- sensing beacons of an array with a video camera, wherein the array is located externally to the camera, and the beacons are situated so as to represent corners of a parallelogram;
detecting locations of images of the beacons on an image plane of the camera;
translating the locations of the images into pixel addresses;
processing the pixel addresses in a manner so as to determine a position and an attitude of the camera relative to the beacons of the array, wherein said processing comprises;
defining the images on the image plane of the camera with vectors;
connecting first and second images with a first line;
connecting third and fourth images with a second line;
extending the first and second lines until they meet at a first point;
connecting second and third images with a third line;
connecting first and fourth images with a fourth line;
extending the first and second lines until they meet at a second point;
connecting the first and second points with a line which is an image of a horizon;
connecting the first point and a center point of a focal lens of the camera with a fifth line;
connecting the second point and the center point of the focal lens of the camera with a sixth line;
defining a first plane with the fifth and sixth lines, said plane being parallel with a second plane containing the beacons and defining orientation of the second plane;
determining distance between the first and second planes;
determining orientation of the second plane; and
determining location and orientation of the camera relative to the beacons;
displaying the position and the attitude of the camera relative to the beacons;
storing the position and attitude; and
comparing the position and attitude with formerly stored positions and attitudes.
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Abstract
Navigation by interpretation of images of parallelogram corner points of a ground beacon array. A video camera senses images of the beacon array and a computer interprets the images to provide attitude and location of the platform, on which the camera is mounted, relative to the array.
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Citations
15 Claims
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1. A method of navigation by a video-camera sensed array comprising:
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sensing beacons of an array with a video camera, wherein the array is located externally to the camera, and the beacons are situated so as to represent corners of a parallelogram; detecting locations of images of the beacons on an image plane of the camera; translating the locations of the images into pixel addresses; processing the pixel addresses in a manner so as to determine a position and an attitude of the camera relative to the beacons of the array, wherein said processing comprises; defining the images on the image plane of the camera with vectors; connecting first and second images with a first line; connecting third and fourth images with a second line; extending the first and second lines until they meet at a first point; connecting second and third images with a third line; connecting first and fourth images with a fourth line; extending the first and second lines until they meet at a second point; connecting the first and second points with a line which is an image of a horizon; connecting the first point and a center point of a focal lens of the camera with a fifth line; connecting the second point and the center point of the focal lens of the camera with a sixth line; defining a first plane with the fifth and sixth lines, said plane being parallel with a second plane containing the beacons and defining orientation of the second plane;
determining distance between the first and second planes;
determining orientation of the second plane; and
determining location and orientation of the camera relative to the beacons;displaying the position and the attitude of the camera relative to the beacons; storing the position and attitude; and comparing the position and attitude with formerly stored positions and attitudes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A navigation device comprising:
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sensing means for detecting objects of a ground array, wherein the ground array is a parallelogram in a first plane, having a first, second, third and fourth objects at the first, second, third and fourth corners, respectively, of the parallelogram, and said sensing means comprises;
a focal lens;
an image plane situated at a focal point of said lens; and
addressing means, connected to said image plane for addressing image plane pixel outputs;preprocessing means, connected to said sensing means, for preprocessing data from said sensing means; computing means, connected to said preprocessing means, for processing preprocessed data from said preprocessing means into navigational information, including position and attitude of said sensing means relative to the ground array which lies in an earth-fixed frame of reference, wherein said computing means determines; first, second, third and fourth object vectors that define the first, second, third and fourth objects, respectively; first, second, third and fourth image points on said image plane, corresponding to the first, second, third and fourth objects, respectively; first, second, third and fourth image vectors that define image points on said image plane corresponding to the first, second, third and fourth objects; a coordinate frame having an origin and a reference relative to said sensing means such that the first, second, third and fourth image vectors are positive scalar multiples of the first, second, third and fourth object vectors, respectively; a fifth image point by an intersection of a first line through the first and second image points and of a second line through the third and fourth image points; a sixth image point by an intersection of a third line through the second and third object image points and of a fourth line through the first and fourth image points; a horizon image by a fifth line through the fifth and sixth image points; a second plane by a sixth line from the fifth image point through the origin of the coordinate frame and by a seventh line from the sixth image point through the origin of the coordinate frame, wherein the second plane defines an orientation of the first plane containing the ground array; distance as a range vector between the origin of the coordinate frame and a point in the first plane by exploiting that the first, second, third and fourth objects are at some same perpendicular distance from the origin of the coordinate frame, and that the distances between the objects of the array are known; and an orientation matrix of the first plane that yields location and orientation of said sensing means relative to the first plane. - View Dependent Claims (11, 12, 13)
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14. Method of navigation by a video-camera sensed array comprising:
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sensing, with an image plane in a camera, first, second, third and fourth object image points of first, second, third and fourth objects, respectively, in an array located externally to the camera, wherein the first, second, third and fourth objects are located at first, second, third and fourth corners, respectively, of a parallelogram; determining first, second, third and fourth image vectors that define the first, second, third and fourth object image points, respectively, according to location on the image plane; processing information of the first, second, third and fourth image vectors to determine position and attitude of the camera relative to the first, second, third and fourth objects in the array; determining first, second, third and fourth object vectors that define the first, second third and fourth objects; determining a coordinate frame having reference to the camera in conventional orientation and having an origin at a center of the camera'"'"'s focal lens and such that the first, second, third and fourth image vectors are positive scalar multiples of the first, second, third and fourth object vectors, respectively; determining a fifth image point by an intersection of a first line through the first and second object image points and of a second line through the third and fourth object image points; determining a sixth image point by an intersection of a third line through the second and third object image points and of fourth line through the first and fourth object image points; determining a horizon image by a fifth line through the fifth and sixth image points; determining, parallel to a second plane containing the parallelogram, a first plane, by a sixth line from the fifth image point through the origin of the coordinate frame reference and by a seventh line from the sixth image point through the origin of the coordinate frame of reference, wherein said determining the first plane defines the orientation of the second plane containing the parallelogram; determining distance as a range vector between the origin of the coordinate frame of reference and a point in the second plane by exploiting that the first, second, third and fourth objects are at some same perpendicular distance from the origin of the coordinate frame, that the first, second, third and fourth image vectors are positive scalar multiples of the first, second, third and fourth objects, respectively, and that the magnitudes between the corners of the parallelogram are known; and determining an orientation matrix of the second plane which yields locations and orientation of the camera relative to the second plane. - View Dependent Claims (15)
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Specification