EP0631250A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for reconstructing three-dimensional objects
Assignee: NTT Inc
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Filing: 1994-06-20
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Granted: —
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Expires: 2014-06-20
Abstract
Abstract One of images of an object (19) captured by at least three cameras (111-11n) is defined as a basic image, and a basic backprojection line is defined which passes through a feature point in the basic image corresponding to a noted three-dimensional feature point on the object and the optical center of the camera having captured the basic image. Reference backprojection lines are calculated respective feature points on an epipolar line, obtained by projecting the basic backprojection line onto the image by each of the other cameras, and the optical center of said each camera. The coordinates of intersection points of the basic backprojection line and the reference backprojection lines are calculated and the number of the reference backprojection lines intersecting at each intersection point on the basic backprojection line is counted. The point having the maximum number of intersections is determined to be the position of the noted three-dimensional feature point. Similar processing is performed for all of the feature points in the basic image, by which the positions of corresponding three-dimensional feature points of the object are determined.
Inventors
- 👤 Takeaki Mori
- 👤 Satoshi Suzuki
- 👤 Takayuki Yasuno
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:23
CPC Classifications
G; G06; G06T; G06T12/00; G06T12/20; G06T7/00; G06T7/50; G06T7/55; G06V; G06V10/00; G06V10/10; G06V10/12; G06V10/14; G06V10/147; H; H04; H04N; H04N13/00; H04N13/20; H04N13/204; H04N13/243; H04N13/296; G06T2207/00; G06T2207/10; G06T2207/10004; G06T2207/10012; H04N13/10; H04N13/189; H04N13/207; H04N13/221; H04N2013/0074; H04N2013/0081
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
326 words
A method of obtaining three-dimensional information of an object by capturing images of said object by a plurality of cameras and making three-dimensional feature points on said object to correspond to feature points in said images, said method comprising the steps: (a) wherein said object is imaged by n cameras to obtain n frames of images and said images are output as image data, said n being an integer equal to or greater than 3; (b) wherein said image data is received and feature points of said object on said n frames of images are respectively extracted; (c) wherein one of said n cameras is defined as a basic camera, the image picked up by said basic camera as a basic image the other remaining cameras as reference cameras, the images captured by said reference cameras as reference images, and a backprojection line, which passes through the optical center of said basic camera and a feature point in said basic image chosen in correspondence to a noted three-dimensional feature point on said object, is defined as a basic backprojection line; (d) wherein said basic backprojection line is projected onto said reference images to define thereon epipolar lines, respectively; (e) wherein backprojection lines, which pass through said feature points on said epipolar lines on said reference images and optical centers of said reference cameras, are defined as reference backprojection lines; (f) wherein the coordinates of intersection points of said basic backprojection line and said reference backprojection lines are calculated, the numbers of intersections of said basic backprojection line and said reference backprojection lines at their respective intersection points are counted, and the intersection point of the maximum count value is determined to be the position of said noted three-dimensional feature point; and (g) wherein said steps (c) through (f) are repeated for each of said feature points on said basic image to obtain the position of said three-dimensional feature points on said object as its three-dimensional information.
Claim 2
Independent Claim
334 words
A method of obtaining three-dimensional information of an object by capturing images of said object by a plurality of cameras and making three-dimensional feature points on said object to correspond to feature point in said images, said method comprising the step: (a) wherein said object is imaged by n cameras to obtain n frames of images and said images are output as image data, said n being an integer equal to or greater than 3; (b) wherein said image data is received and feature points of said object on said n frame of images are respectively extracted; (c) wherein one of said n cameras is defined as a basic camera, the image taken by said basic camera as a basic image, the other remaining cameras as reference cameras, the images captured by said reference cameras as reference images, and a backprojection line, which passes through the optical center of said basic camera and a feature point in said basic image chosen in correspondence to a noted three-dimensional feature point on said object, is defined as a basic backprojection line; (d) wherein said basic backprojection line is projected onto said reference images to define thereon epipolar lines, respectively; (e) wherein backprojection lines, which pass through said feature points on said epipolar lines on said reference images and optical centers of said reference cameras, are defined as reference backprojection lines; (f) wherein the coordinates of intersection points of said basic backprojection line and said reference backprojection lines are calculated, the distribution of said intersection points along said basic backprojection line is filtered by convolution to emphasize the concentration of said distribution of said intersection points, and the position where said filtered distribution of the intersection points is maximum is determined to be the position of said noted three-dimensional feature point; and (g) wherein said steps (c) through (f) are repeated for each of said feature points on said basic image to obtain the position of said three-dimensional feature points on said object as its three-dimensional information.
Claim 3
Dependent Claim
62 words
The method of claim 1 or 2, wherein a position said basic backprojection line is defined every predetermined unit length of said basic backprojection line lengthwise thereof and the number of intersections at each of said intersection point is the number of intersections in said unit length at the position on said basic backprojection line through which said reference backprojection lines pass.
Claim 4
Dependent Claim
32 words
The method of claim 3, wherein said reference backprojection lines intersecting with said basic backprojection line are reference backprojection lines lying within a predetermined range of distance from said basic backprojection line.
Claim 5
Dependent Claim
66 words
The method of claim 1, wherein said step of counting said number of intersections is a step wherein the distribution of said intersections along said basic backprojection line is filtered by convolution to emphasize the concentration of said distribution of said intersections and the position where said filtered distribution of said intersections is maximum is determined to be the position of said noted three-dimensional feature point.
Claim 6
Dependent Claim
16 words
The method of claim 2 or 5, wherein said filtering is performed by a Laplacian-Gaussian filter.
Claim 7
Dependent Claim
16 words
The method of claim 2 or 5, wherein said filtering is performed by a square filter.
Claim 8
Dependent Claim
16 words
The method of claim 2 or 5, wherein said filtering is performed by a triangular filter.
Claim 9
Dependent Claim
16 words
The method of claim 2 or 5, wherein said filtering is performed by a Gaussian filter.
Claim 10
Dependent Claim
55 words
The method of claim 1 or 2, wherein said step (g) includes a step wherein each time said feature point corresponding to said noted three-dimensional feature point is identified by performing said series of steps (c) through (f), said identified feature point is removed from candidates for processing in the subsequent repetition of said steps.
Claim 11
Dependent Claim
23 words
The method of claim 1 or 2, wherein the number n of said cameras is in the range of from 5 to 8.
Claim 12
Dependent Claim
51 words
The method of claim 1 or 2, further comprising a step wherein upon each completion of said step (g), said step (g) is newly repeated for every one of said cameras, using one of said reference cameras as a new basic camera and said basic camera as a new reference camera.
Claim 13
Dependent Claim
43 words
The method of claim 1 or 2, further comprising a step wherein upon each repetition of simultaneous capturing of images of said object by said n cameras at a fixed period, three-dimensional information of said object is obtained following said series of steps.
Claim 14
Dependent Claim
326 words
A three-dimensional information reconstructing apparatus comprising: n camera means disposed at different positions, for capturing images of an object and for outputting said images as image data, said n being an integer equal to or greater than 3; and image information processing means supplied with said image data from said n camera means, for acquiring three-dimensional information of said object from feature points in said images; said image information processing means comprising: feature extracting means for extracting said feature points in said images; basic backprojection line generating means wherein one of said n camera means is defined as a basic camera, the image captured by said basic camera means as a basic image, the other remaining camera means as reference camera means, the images captured by said reference camera means as reference images, and whereby a backprojection line, which passes through the optical center of said basic camera means and a feature point in said basic image chosen in correspondence to a noted three-dimensional feature point on said object, is obtained as a basic backprojection line; epipolar line generating means for projecting said basic backprojection line onto said reference images to obtain epipolar lines; reference backprojection line generating means for obtaining, as reference backprojection lines, backprojection lines which pass through feature points on said epipolar lines on said reference images and the optical centers of said reference camera means; and three-dimensional feature extracting means for calculating the coordinates of intersection points of said basic backprojection line and said reference backprojection lines, for counting the number of intersections of said basic backprojection line and said reference backprojection lines at each of said intersection points and for determining that one of said intersection points which has the maximum count value is the position of said noted three-dimensional feature point; whereby the positions of respective three-dimensional feature points on said object, corresponding to respective feature points on said basic image, are obtained as said three-dimensional information of said object.
Claim 15
Dependent Claim
332 words
A three-dimensional information reconstructing apparatus comprising: n camera means disposed at difference positions, for capturing images of an object and for outputting said images as image data, said n being an integer equal to or greater than 3; and image information processing means supplied with said image data from said n camera means, for acquiring three-dimensional information of said object from feature points in said images; said image information processing means comprising: feature extracting means for extracting feature points in said images; basic backprojection line generating means wherein one of said n camera means is defined as a basic camera means, the image captured by said basic camera means as a basic image, the other remaining camera means as reference cameras, the images captured by said reference camera means as reference imaged, and whereby a backprojection line, which passes through the optical center of said basic camera means and a feature point in said basic image chosen in correspondence to a noted three-dimensional feature point on said object, is obtained as a basic backprojection line; epipolar line generating means for projecting said basic backprojection line onto said reference images to obtain epipolar lines; reference backprojection line generating means for obtaining, as reference backprojection lines, backprojection lines which pass through feature points on said epipolar lines on said reference images and the optical centers of said reference camera means; filtering means which calculates the coordinates of intersection points of said basic backprojection line and said reference backprojection lines, respectively, and filters the distribution of said intersection points along said basic backprojection line by convolution to emphasize the concentration of said distribution of said intersection points; and three-dimensional feature extracting means whereby the position where said filtered distribution of said intersection points is maximum is determined to the position of said noted three-dimensional feature point; whereby the positions of respective three-dimensional feature points on said object, corresponding to respective feature points on said basic image, are obtained as said three-dimensional information of said object.
Claim 16
Dependent Claim
52 words
The apparatus of claim 14, wherein said feature extracting means includes filter means for emphasizing the concentration of said distribution of intersections by convolution along said basic backprojection line and the position where said filtered distribution of intersections is maximum is determined to be the position of said noted three-dimensional feature point.
Claim 17
Dependent Claim
15 words
The method of claim 15 or 16, wherein said filter means is a Laplacian-Gaussian filter.
Claim 18
Dependent Claim
14 words
The apparatus of claim 15 or 16, wherein said filter means is square filter.
Claim 19
Dependent Claim
15 words
The apparatus of claim 15 or 16, wherein said filter means is a triangular filter.
Claim 20
Dependent Claim
15 words
The apparatus of claim 15 or 16, wherein said filter means is a Gaussian filter.
Claim 21
Dependent Claim
23 words
The method of claim 14 or 15, wherein said number n of cameras means is in the range of from 5 to 8.
Claim 22
Dependent Claim
48 words
The apparatus of claim 14 or 15, further comprising camera control means for repeating simultaneous image capturing of said object by said n camera means at a fixed period and for supplying said image data to said image information processing means upon each generation of said image data.
References Cited (Backward Citations)
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