Method and apparatus for measuring position and orientation of an object based on a sequence of projected points
First Claim
1. A method for obtaining geometrical information on an object, comprising the steps of:
- a) moving a camera in a predetermined direction with regard to an object subject to measurement;
b) taking a plurality of images of the object by the camera at a plurality of camera positions;
c) extracting a plurality of contour images respectively from the plurality of images taken in step b) by the camera, where each of the plurality of contour images contains at least one image element of the object;
d) projecting at least one image element in each of the plurality of contour images of the object onto a projected point on a predetermined projection surface, for each of the at least one image element, from a predetermined projection center corresponding to a camera center, to obtain, for each of the at least one image element, a plurality of projected points on a predetermined projection surface as a sequence of movement points (xt, t=0, 1, 2, . . .) which line up on a first intersection line at which the predetermined projection surface intersects with a first plane containing the predetermined projection center, where the predetermined projection surface is one of a plane and a surface of the second order;
e) generating as a sequence of reference points (τ
t, t=0, 1, 2, . . .), a plurality of points which line up on a second intersection line of the predetermined projection surface and a second plane containing the projection center, so that the sequence of reference points (τ
t, t=0, 1, 2, . . .) and the sequence of movement points (xt, t=0, 1, 2, . . .) share a point, and the sequence of reference points (τ
t, t=0, 1, 2, . . .) is not identical with the sequence of movement points (xt, t=0, 1, 2, . . .), and has the same cross ratio (inharmonic ratio) as a cross ratio of the sequence of movement points (xt, t=0, 1, 2, . . .);
f) obtaining a first intersection point of a plurality of third intersection lines at which a plurality of third planes respectively intersect the predetermined projection surface, the plurality of third planes each containing the projection center, one movement point in the sequence of movement points (xt, t=0, 1, 2, . . .), and one reference point, corresponding to the movement point, in the sequence of reference points (τ
t, t=0, 1, 2, . . .); and
g) obtaining geometrical information on the object with respect to the camera position, based on the position of the first intersection point to achieve environment recognition.
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Abstract
A method for measuring a position and an orientation of an object. A sequence of movement points which line up on an intersection line of a predetermined projection surface and a plane which contains a predetermined projection center corresponding to a position of a camera, is obtained by obtaining projected points respectively generated for a plurality of positions of the camera, onto a point on the predetermined projection surface where the camera position is deemed as the projection center. Then, a sequence of reference points which line up on an intersection line of a plane containing the center of projection and the predetermined projection surface, shares a point with the sequence of movement points, and has the same cross ratio (inharmonic ratio) as a cross ratio of the sequence of movement points, is generated. An intersection point of intersection lines which are respectively intersection lines of the predetermined projection surface and planes each containing the center of projection and a pair of corresponding points one of which belongs to the sequence of movement points, and the other of which belongs to the sequence of reference points, is obtained. Then, geometrical information on the image element of the object when using the projection center in the three-dimensional space as a reference position is obtained based on the position of the above intersection point.
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Citations
84 Claims
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1. A method for obtaining geometrical information on an object, comprising the steps of:
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a) moving a camera in a predetermined direction with regard to an object subject to measurement; b) taking a plurality of images of the object by the camera at a plurality of camera positions; c) extracting a plurality of contour images respectively from the plurality of images taken in step b) by the camera, where each of the plurality of contour images contains at least one image element of the object; d) projecting at least one image element in each of the plurality of contour images of the object onto a projected point on a predetermined projection surface, for each of the at least one image element, from a predetermined projection center corresponding to a camera center, to obtain, for each of the at least one image element, a plurality of projected points on a predetermined projection surface as a sequence of movement points (xt, t=0, 1, 2, . . .) which line up on a first intersection line at which the predetermined projection surface intersects with a first plane containing the predetermined projection center, where the predetermined projection surface is one of a plane and a surface of the second order; e) generating as a sequence of reference points (τ
t, t=0, 1, 2, . . .), a plurality of points which line up on a second intersection line of the predetermined projection surface and a second plane containing the projection center, so that the sequence of reference points (τ
t, t=0, 1, 2, . . .) and the sequence of movement points (xt, t=0, 1, 2, . . .) share a point, and the sequence of reference points (τ
t, t=0, 1, 2, . . .) is not identical with the sequence of movement points (xt, t=0, 1, 2, . . .), and has the same cross ratio (inharmonic ratio) as a cross ratio of the sequence of movement points (xt, t=0, 1, 2, . . .);f) obtaining a first intersection point of a plurality of third intersection lines at which a plurality of third planes respectively intersect the predetermined projection surface, the plurality of third planes each containing the projection center, one movement point in the sequence of movement points (xt, t=0, 1, 2, . . .), and one reference point, corresponding to the movement point, in the sequence of reference points (τ
t, t=0, 1, 2, . . .); andg) obtaining geometrical information on the object with respect to the camera position, based on the position of the first intersection point to achieve environment recognition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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13. A method according to claim 9, wherein said plurality of positions of the camera line up in the predetermined direction with an equal pitch (Δ
- X), and
wherein said step d) for generating said sequence of reference points (τ
t, t=0, 1, 2, . . .) comprises the substeps of;(i) generating an auxiliary sequence of points (Tt, t=0, 1, 2, . . .) which line up with the same pitch as the equal pitch (Δ
X) on an arbitrary straight line (lT) parallel to another straight line passing through the projection center and the first point at infinity (x∞
) of the sequence of movement points, where the beginning point (T0) is the arbitrary position; andii) projecting each point of the auxiliary sequence of points (Tt, t=0, 1, 2, . . .) onto the predetermined projection surface from the projection center.
- X), and
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14. A method according to claim 1, wherein the predetermined projection surface onto which the at least one image element is projected in the projection step is a plane.
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15. A method according to claim 1, wherein the predetermined projection surface onto which the at least one image is projected in the projection step is a sphere, and the projection center is the center of the sphere.
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16. A method according to claim 1, wherein the predetermined projection surface onto which the at least one image is projected in the projection step is a circular cylinder, and the projection center is a point on an axis of the circular cylinder.
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17. A method for obtaining geometrical information on an object, comprising the steps of:
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a) moving a camera in a predetermined direction with regard to an object subject to measurement; and b) taking a plurality of images of the object by the camera at a plurality of camera positions, respectively, by moving a camera in a predetermined direction; c) extracting a plurality of contour images respectively from the plurality of images taken in said step b) by the camera, where each of the plurality of contour images contains at least one image element of the object; d) projecting the at least one image element in each of the plurality of contour images of the object onto a projected point on a predetermined projection surface, for each of the at least one image element, from a predetermined projection center corresponding to a camera center, to obtain, for each of the at least one image element, a plurality of projected points on a predetermined projection surface as a sequence of movement points (xt, t=0, 1, 2, . . .) which line up on a first intersection line at which the predetermined projection surface intersects with a first plane containing the predetermined projection center, and where the predetermined projection surface is one of a plane and a surface of the second order; e) generating as a first sequence of reference points (τ
t, t=0, 1, 2, . . .), a plurality of points which line up on a second intersection line of the predetermined projection surface and a second plane containing the projection center, so that the first sequence of reference points (τ
t, t=0, 1, 2, . . .) and the sequence of movement points (xt, t=0, 1, 2, . . .) share a point, and the sequence of reference points (τ
t, t=0, 1, 2, . . .) is not identical with the sequence of movement points (xt, t=0, 1, 2, . . .), and has the same cross ratio (inharmonic ratio) as a cross ratio of the sequence of movement points (xt, t=0, 1, 2, . . .);f) generating as a second sequence of reference points (-τ
t, t=0, 1, 2, . . .), a plurality of points which line up on the second intersection line, so that the second sequence of reference points (-τ
t, t=0, 1, 2, . . .) and the first sequence of reference points (τ
t, t=0, 1, 2, . . .) share a beginning point (τ
0), and the second sequence of reference points (-τ
t) has the same cross ratio (inharmonic ratio) as the cross ratio of the first sequence of reference points (τ
t, t=0, 1, 2, . . .);g) obtaining a first intersection point of a plurality of third intersection lines at which a plurality of third planes respectively intersects the predetermined projection surface, the plurality of third planes each containing the projection center, one movement point in the sequence of movement points (xt, t=0, 1, 2, . . .) and one reference point, corresponding to the movement point in the first sequence of reference points (τ
t, t=0, 1, 2, . . .); andh) obtaining a second intersection point of a plurality of fourth intersection lines at which a plurality of fourth planes respectively intersects the predetermined projection surface, the plurality of fourth planes each containing the projection center, one movement point in the sequence of movement points (xt, t=0, 1, 2, . . .) and one reference point, corresponding to the movement point in said second sequence of reference points (-τ
t, t=0, 1, 2, . . .); andi) obtaining geometrical information on the object with respect to the camera position, based on the positions of the first and second intersection points to achieve environment recognition. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. A method for obtaining geometrical information on an object, comprising the steps of:
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a) moving a camera in a predetermined direction with regard to an object subject to measurement; and b) taking a plurality of images of the object by the camera at a plurality of camera positions, respectively, by moving a camera in a predetermined direction; c) extracting a plurality of contour images respectively from the plurality of images taken in said step b) by the camera, where each of the plurality of contour images contains at least one image element of the object; d) projecting at least one image element in each of the plurality of contour images of the object onto a projected point on a predetermined projection surface, for each of the at least one image element, from a predetermined projection center corresponding to a camera center, to obtain, for each of the at least one image element, a plurality of projected points on a predetermined projection surface as a sequence of movement points (xt, t=0, 1, 2, . . .) which line up on a first intersection line at which the predetermined projection surface intersects a first plane containing the predetermined projection center, where the predetermined projection surface is one of a plane and a surface of the second order; e) obtaining, as a reference point for plane projection, a first intersection point of the predetermined projection surface and a straight line which passes through the projection center and is perpendicular to an arbitrary projection plane which contains the projection center; f) obtaining a sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .), comprising the substeps of; (i) obtaining a plurality of second planes each containing the projection center, the reference point for plane projection, and one movement point of the sequence of movement points (xt, t=0, 1, 2, . . .); (ii) obtaining a plurality of second intersection lines at which the plurality of second planes respectively intersect the predetermined projection surface; and (iii) obtaining, as the sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .), a plurality of second intersection points at which the plurality of second intersection lines respectively intersect the predetermined projection surface; g) generating, as a sequence of reference points (τ
t, t=0, 1, 2, . . .), a plurality of points which line up on a third intersection line of the predetermined projection surface and a third plane containing the projection center, so that the sequence of reference points (τ
t, t=0, 1, 2, . . .) and the sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .) share a point, and the sequence of reference points (τ
t, t=0, 1, 2, . . .) is not identical with either of the sequence of movement points (xt, t=0, 1, 2, . . .) and the sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .), and has the same cross ratio (inharmonic ratio) as a cross ratio of the sequence of projected movement points (xt, t=0, 1, 2, . . .);h) obtaining a third intersection point of a plurality of third intersection lines at which a plurality of fourth planes respectively intersects the predetermined projection surface, the plurality of fourth planes each containing the projection center, one projected movement point in the sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .) and one reference point corresponding to the projected movement point in the sequence of reference points (τ
t, t=0, 1, 2, . . .); andi) obtaining geometrical information which receives the third intersection point, on the object with respect to the camera position, based on the position of the third intersection point to achieve environment recognition. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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57. A method according to claim 56, further comprising the steps of:
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i) selecting a point of the contour image which is extracted from the image taken in the initial camera position of the plurality of camera positions, and in said projection step c), the selected point of contour is regarded as the image element to be projected onto the predetermined projection surface; and wherein in said geometrical information obtaining step c), a distance to a point on the object corresponding to the point of the contour image selected in the point selecting step is obtained determining a fourth reference point (w) for plane projection, and assuming that a direction of the point at infinity of the sequence of projected movement points is equal to a known direction (v) of the movement of the camera.
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58. A method according to claim 56, further comprising the steps of:
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i) extracting a contour line segment (l) from each of the contour images extracted in said step b); and wherein in said projection step c), a fourth intersection point of the predetermined projection surface and a normal line, passing through the projection center of a sixth plane containing the projection center and the contour line segment (l), is obtained as a projected point (s) of each contour line segment for each of a plurality of images, where the projected points (s) obtained from the plurality of images are regarded as the points of the sequence of movement points; wherein said step h) further comprises the substeps of; (i) determining the fourth reference point (w) for plane projection in a direction perpendicular to a known direction of the movement of the camera regarding the projection center; and (ii) obtaining the point at infinity of the sequence of projected movement points by an exterior product of a first vector directed in the known direction (v) of the camera and a second vector directed to the fourth reference point (w) for plane projection, the first point at infinity (s'"'"'.sup.∞
) of the sequence of projected movement points is regarded to be the same as the second point-at-infinity of the first and second sequence of reference points, and the distance from the initial camera position to a fifth intersection point at which a line segment, corresponding to the contour line segment on the object or a straight line containing the line segment, intersects with the predetermined projection plane in the three-dimensional space, is obtained by the distance r.
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59. A method according to claim 58, further comprising, in said step h), after executing the operation of obtaining the point at infinity (s.sup.∞
- ) of a sequence of movement points (st, t=0, 1, 2, . . . , t is a frame number), the substep of;
i) rotating the beginning point of the sequence of projected movement points by 90 degrees around the direction of the fourth reference point (w) for plane projection, to obtain a direction from the initial camera position to the fifth intersection point of the line segment and the predetermined projection plane.
- ) of a sequence of movement points (st, t=0, 1, 2, . . . , t is a frame number), the substep of;
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60. A method according to claim 59, further comprising the steps of:
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i) executing the operations of said geometrical information obtaining step h) for a plurality of fourth reference points (w) for plane projection which are perpendicular to the known direction of the movement of the camera, to obtaining the distance r and direction to the line segment or the straight line containing the line segment on the object for each of the plurality of the fourth reference points (w) for plane projection; and j) determining positions and orientations of the line segment on the object in the three-dimensional space based on the distances r and the directions of the intersection points of the line segment and the predetermined projection plane, where the intersection points are obtained in the plural projection plane step for the plurality of fourth reference points (w) for plane projection.
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61. A method according to claim 53, wherein the plurality of positions of the camera line up in the predetermined direction with an equal pitch (Δ
- X), and
wherein said step f) for generating the sequence of reference points (τ
t, t=0, 1, 2, . . .) comprises the substeps of;(i) generating an auxiliary sequence of points (Tt, t=0, 1, 2, . . .) which line up with the same pitch as the equal pitch (Δ
X) on an arbitrary straight line (lT) parallel to another straight line passing through the projection center and the first point at infinity (x'"'"'.sup.∞
) of the sequence of projected movement points, where the beginning point (T0) is the arbitrary position; and(iii) projecting each point of the auxiliary sequence of points (Tt, t=0, 1, 2, . . .) onto the predetermined projection surface from the projection center.
- X), and
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62. A method according to claim 45, wherein the predetermined projection surface is a plane.
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63. A method according to claim 45, wherein the predetermined projection surface is a sphere, and the projection center is the center of the sphere.
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64. A method according to claim 45, wherein the predetermined plane or surface of the second class is a circular cylinder, and the projection center is a point on an axis of the circular cylinder.
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65. An apparatus comprising:
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a camera, for taking a plurality of images of an object which is subject to measurement, at a plurality of camera positions, respectively, by moving said camera in a predetermined direction; and data processing means for processing image data which is taken by said camera, said data processing means comprising; a contour image extracting circuit, operatively connected to said camera, for extracting a plurality of contour images respectively from said plurality of images taken by said camera, where each of said plurality of contour images contains at least one image element of said object; a projection circuit, operatively connected to said contour image extracting circuit, for projecting said at least one image element in each of said plurality of contour images of said object onto a projected point on a predetermined projection surface, for each of said at least one image element, from a predetermined projection center corresponding to a camera center, to obtain, for each of said at least one image element, a plurality of projected points on a predetermined projection surface as a sequence of movement points (xt, t=0, 1, 2, . . .) which line up on a first intersection line at which said predetermined projection surface intersects with a first plane containing said predetermined projection center, said predetermined projection surface is one of a plane and a surface of the second order; a reference-point-sequence generating circuit for generating, as a sequence of reference points (τ
t, t=0, 1, 2, . . .), a plurality of points which line up on a second intersection line of said predetermined projection surface and a second plane containing said projection center, so that said sequence of reference points (τ
t, t=0, 1, 2, . . .) and said sequence of movement points (xt, t=0, 1, 2, . . .) share a point, and said sequence of reference points (τ
t, t=0, 1, 2, . . .) is not identical with said sequence of movement points (xt, t=0, 1, 2, . . .), and has the same cross ratio (inharmonic ratio) as a cross ratio of said sequence of movement points (xt, t=0, 1, 2, . . .);an intersection-point obtaining circuit for obtaining a first intersection point of a plurality of third intersection lines at which a plurality of third planes respectively intersecting the predetermined projection surface, said plurality of third planes each containing said projection center, one movement point in said sequence of movement points (xt, t=0, 1, 2, . . .), and one reference point, corresponding to the movement point, in said sequence of reference points (τ
t, t=0, 1, 2, . . .); anda geometrical information obtaining circuit, operatively connected to said intersection-point-obtaining circuit, for obtaining geometrical information on said object with respect to said camera position, based on the position of said first intersection point.
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66. An apparatus comprising:
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a camera, for taking a plurality of images of an object which is subject to the measurement, at a plurality of camera positions, respectively, by moving said camera in a predetermined direction; and data processing means for processing image data which is taken by said camera, said data processing means comprising; a contour image extracting circuit, operatively connected to said camera, for extracting a plurality of contour images respectively from said plurality of images taken by said camera, where each of said plurality of contour images contains at least one image element of said object; projection means for projecting said at least one image element in each of said plurality of contour images of said object onto a projected point on a predetermined projection surface, for each of said at least one image element, from a predetermined projection center corresponding to a camera center, to obtain, for each of said at least one image element, a plurality of projected points on a predetermined projection surface as a sequence of movement points (xt, t=0, 1, 2, . . .) which line up on a first intersection line at which said predetermined projection surface intersects with a first plane containing said predetermined projection center, where said predetermined projection surface is one of a plane and a surface of the second order; a first reference-point-sequence generating circuit for generating, as a first sequence of reference points (τ
t, t=0, 1, 2, . . .), a plurality of points which line up on a second intersection line of said predetermined projection surface and a second plane containing said projection center, so that said first sequence of reference points (τ
t, t=0, 1, 2, . . .) and said sequence of movement points (xt, t=0, 1, 2, . . .) share a point, and said sequence of reference points (τ
t, t=0, 1, 2, . . .) is not identical to the sequence of movement points (xt, t=0, 1, 2, . . .), and has the same cross ratio (inharmonic ratio) as a cross ratio of said sequence of movement points (xt, t=0, 1, 2, . . .);a second reference-point-sequence generating circuit for generating, as a second sequence of reference points (-τ
t, t=0, 1, 2, . . .), a plurality of points which line up on said second intersection line, so that said second sequence of reference points (-τ
t, t=0, 1, 2, . . .) and said first sequence of reference points (τ
t, t=0, 1, 2, . . .) share a beginning point (τ
0), and said second sequence of reference points (-τ
t, t=0, 1, 2, . . .) has the same cross ratio (inharmonic ratio) as the cross ratio of said first sequence of reference points (τ
t, t=0, 1, 2, . . .);a first intersection-point obtaining circuit for obtaining a first intersection point of a plurality of third intersection lines at which a plurality of third planes respectively intersecting said predetermined projection surface, said plurality of third planes each containing said projection center, one movement point in said sequence of movement points (xt, t=0, 1, 2, . . .), and one reference point, corresponding to the movement point, in said first sequence of reference points (τ
t, t=0, 1, 2, . . .);a second intersection-point obtaining circuit for obtaining a second intersection point of a plurality of fourth intersection lines at which a plurality of fourth planes respectively intersecting the predetermined projection surface, said plurality of fourth planes each containing said projection center, one movement point in said sequence of movement points (xt, t=0, 1, 2, . . .), and one reference point, corresponding to the movement point, in said second sequence of reference points (-τ
t, t=0, 1, 2, . . .); anda geometrical information obtaining circuit, operatively connected to said first and second intersection-point obtaining circuits, for obtaining geometrical information on the object with respect to said camera position, based on the positions of said first and second intersection points. - View Dependent Claims (67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77)
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78. An apparatus comprising:
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a camera, for taking a plurality of images of an object which is subject to the measurement, at a plurality of camera positions, respectively, by moving said camera in a predetermined direction; and a data processor, operatively connected to said camera, for processing image data which is taken by said camera, said data processor comprising; a contour image extracting circuit, operatively connected to said camera, for extracting a plurality of contour images respectively from said plurality of images taken by said camera, where each of said plurality of contour images contains at least one image element of said object; a projector for projecting said at least one image element in each of said plurality of contour images of said object onto a projected point on a predetermined projection surface, for each of said at least one image element, from a predetermined projection center corresponding to a camera center, to obtain, for each of said at least one image element, a plurality of projected points on a predetermined projection surface as a sequence of movement points (xt, t=0, 1, 2, . . .) which line up on a first intersection line at which said predetermined projection surface intersects with a first plane containing said predetermined projection center, where said predetermined projection surface is one of a plane and a surface of the second order; a plane-projection-reference-point obtaining circuit for obtaining, as a reference point for plane projection, a first intersection point of said predetermined projection surface and a straight line which passes through said projection center and is perpendicular to an arbitrary projection plane which contains said projection center; a plane projection circuit for obtaining a sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .), by obtaining a plurality of second planes each containing said projection center, said reference point for plane projection, and one movement point of the sequence of movement points (xt, t=0, 1, 2, . . .), by obtaining a plurality of second intersection lines at which said plurality of second planes respectively intersect with said predetermined projection surface, and by obtaining, as said sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .), a plurality of second intersection points at which said plurality of second intersection lines respectively intersect with said predetermined projection surface; a reference-point-sequence generating circuit for generating, as a sequence of reference points (τ
t, t=0, 1, 2, . . .), a plurality of points which line up on a third intersection line of said predetermined projection surface and a third plane containing said projection center, so that said sequence of reference points (τ
t, t=0, 1, 2, . . .) and said sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .) share a point, and said sequence of reference points (τ
t, t=0, 1, 2, . . .) is not identical with either of said sequence of movement points (xt, t=0, 1, 2, . . .) and said sequence of projected movement points (x'"'"'t, t=0, 1, 2, . . .), and has the same cross ratio (inharmonic ratio) as a cross ratio of said sequence of projected movement points (xt, t=0, 1, 2, . . .);an intersection-point obtaining circuit for obtaining a third intersection point of a plurality of third intersection lines at which a plurality of fourth planes respectively intersecting the predetermined projection surface, said plurality of fourth planes each containing said projection center, one projected movement point in said sequence of projected movement points (x'"'"'t t, t=0, 1, 2, . . .), and one reference point, corresponding to the projected movement point, in said sequence of reference points (τ
t, t=0, 1, 2, . . .); anda geometrical information obtaining circuit, operatively connected to said intersection-point obtaining circuit, for obtaining geometrical information on said object with respect to said camera position, based on the position of said third intersection point.
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79. A method of measuring a position and orientation of an object, comprising the steps of:
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(a) moving a camera in a predetermined direction with regard to an object subject to measurement; (b) projecting movement points from the image of the object based on positions of the camera onto a plane or second order surface at an intersection with a plane formed by the positions of the camera and a center of projection; (c) generating reference points, each corresponding to one of said movement points, on the plane or second order surface at an intersection with a plane containing the center of projection, said reference points sharing a point with said movement points and having a same cross harmonic ratio as said movement pints; (d) obtaining an intersection point of lines on the plane or second order surface that connect corresponding pairs of said movement points and said reference pints; and (e) obtaining the position and orientation of the object based on the positions of the camera, the center of projection and said intersection point to achieve environment recognition. - View Dependent Claims (80, 81, 82, 83)
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84. A method of measuring a position and orientation of an object, comprising the steps of:
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(a) moving a camera to various positions with regard to an object subject to measurement; (b) projecting movement points from an image of an object based on the positions of a camera onto a plane or second order surface of an intersection with a plane formed by the positions of the camera and a center of projection; (c) generating a first sequence of reference points, each corresponding to one of said movement points, on the plane or second order surface at an intersection with a plane containing the center of projection, said reference points sharing a point with said movement points and having a same cross harmonic ratio as said movement points; (d) generating a second sequence of reference points, each corresponding to one of said movement points, on the plane or second order surface at an intersection with a plane containing the center of projection, said reference points sharing a point with said movement points and having a same cross harmonic ratio as said movement points, said sequence of reference points lining up in the opposite direction to said first sequence of reference points; (e) obtaining a first intersection point of lines on the plane or second order surface that connect corresponding pairs of said movement points and said first sequence of reference points; (f) obtaining a second intersection point of lines on the plane or second order surface that connect corresponding pairs of said movement points and said second sequence of reference points; and (g) obtaining the position and orientation of the object based on the positions of the camera, the center of projection and said first and second intersection points to achieve environment recognition.
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Specification