Image analysis – Applications – 3-d or stereo imaging analysis
Reexamination Certificate
1998-07-23
2002-03-26
Boudreau, Leo (Department: 2621)
Image analysis
Applications
3-d or stereo imaging analysis
Reexamination Certificate
active
06363169
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and method of three-dimensional modeling, and a medium on which a three-dimensional modeling program is recorded. More particularly, the present invention relates to an apparatus and method of three-dimensional modeling for generating a three-dimensional model of an object of interest, and a medium on which a three-dimensional modeling program is recorded.
2. Description of the Background Art
Recently, various three-dimensional scanners that input the shape and texture (color and pattern) of a three-dimensional object of interest are developed for the purpose of obtaining a three-dimensional graphic image.
For example, Japanese Patent Laying-Open No. 5-135155 discloses a three-dimensional modeling apparatus that generates a three-dimensional model of an object of interest by shooting the object of interest mounted on a turntable with a monocular camera to obtain a plurality of silhouette images. According to this apparatus, a plurality of cross sectional shapes of the object of interest in a plurality of horizontal planes (plane perpendicular to the axis of rotation of the turntable) on the basis of the obtained plurality of silhouette images. Then, the points on the contour line of the shape of the object of interest in adjacent horizontal planes are joined together to form a triangular patch, from which a three-dimensional model of the object is produced. In such a three-dimensional modeling apparatus, the camera position can be fixed since the object of interest is rotated on a turntable. It is therefore not necessary to calculate the camera position.
However, such a turntable is extremely costly, which has become the bottleneck in realizing a simple and economic three-dimensional modeling apparatus.
A method of calculating the camera position from an object image obtained by shooting an object of interest using the commonly called factorization method is disclosed by Takeo Kanade, Conrad J. Poelman, and Toshihiko Morita in “A Factorization Method for Shape and Motion Recovery” Transaction of Institute of Electronics, Information and Communication Engineers of Japan, D-II, Vol. J76-D-II, No. 8, pp. 1497-1505, August 1993. However, this method is inadequate to generate a full model of an object of interest since there was a problem that a calculation error is sequentially accumulated.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide a simple and economic apparatus and method of three-dimensional modeling that does not require a turntable, and a medium on which a three-dimensional modeling program is recorded.
According to an aspect of the present invention, a three-dimensional modeling apparatus generates a three-dimensional model of an object of interest, and includes a plurality of reference subjects (objects), an image capture device, a calculation device, and a generator. The plurality of reference subjects are arranged at predetermined positions. The image capture device, a camera for example, picks up the image of the object of interest together with the reference subject to obtain an object image. The calculation device refers to the reference subject in the object image to calculate the shooting position of the image capture device. The generator generates a three-dimensional model according to the object image and the shooting position.
Preferably, the reference subjects are arranged irregularly and asymmetrically. Preferably, the reference subjects are arranged in a scattered manner. More specifically, when the distance from one certain reference subject to another reference subject is l, and the angle between two direction vectors from that certain reference subject to two other reference subjects is &thgr;, it is desired that the arrangement of the reference subjects is determined so that the distribution of the number of reference subjects at distance l and the distribution of the number of reference subjects with angle &thgr; are uniform. Reference subjects arranged regularly can be provided in addition to reference subjects arranged irregularly.
Preferably, the plurality of reference subjects have a plurality of attributes. When the reference subject has an attribute, it is desirable to determine the arrangement of the reference subjects so that the distribution of the number of reference subjects at distance l and the distribution of the number of reference subjects with angle &thgr; are uniform for each attribute.
Preferably, the attribute is a color. When the plurality of reference subjects have a plurality of color attributes and the hue of 360 degrees at a predetermined color space is divided into that plurality of colors, the plurality of colors are preferably selected so that the angle between two adjacent colors in the divided hue is as large as possible.
Preferably, the reference subjects are formed on a 2-D plane e.g. a reference sheet. However, the reference subject can be formed on a plane of a plate thicker than the reference sheet, a platform, or the floor.
The reference subjects are formed at a reference object having a stereoscopic structure. Here, an object having a stereoscopic structure covered with the reference sheet can be used as a reference object.
Preferably, the calculation device calculates the shooting position according to the Hough transform method.
Preferably, the shooting position calculation device includes an extractor, a selector, an allocation device, a candidate calculation device, an evaluation device, and a determination device. The extractor extracts a shot reference subject from the object image. The selector selects a plurality of reference subjects from the extracted reference subject. The allocation device establishes correspondence between each of the selected reference subjects and any one of the arranged plurality of reference subjects (the position data of which are stored to the allocation device) to allocate the position of a corresponding reference subject as the position candidate. The candidate calculation device calculates the shooting position candidate of the capture device according to the position candidate of the reference subject. The evaluation device applies an evaluation value (evaluation based on probability, for example points) to the shooting position candidate. The determination device determines the shooting position candidate having the greatest evaluation value out of the calculated plurality of shooting position candidates as the shooting position for the image capture device.
Preferably, the plurality of reference subjects have a plurality of attributes. The shooting position calculation device includes an extractor, a selector, an allocation device, a candidate calculation device, an evaluation device, and a determination device. The extractor extracts a shot reference subject from the object image. The selector selects a plurality of reference subjects from the extracted reference subject. The allocation device establishes correspondence between each of the selected reference subjects and any one of the arranged plurality of reference subjects (the position data of which are stored to the allocation device) having the same attribute to allocate the position of a corresponding reference subject as the position candidate. The candidate calculation device calculates the shooting position candidate of the image capture device according to the position candidates of the reference subject. The evaluation device applies an evaluation value (evaluation based on probability, for example points) to the shooting position candidate. The determination device determines the shooting position candidate having the greatest evaluation value out of the calculated plurality of shooting position candidates as the shooting position for the image capture device.
Preferably, the reference subject is formed at a reference object having a stereoscopic structure. The shooting position calculation device includes an extractor, a selector, an allocation device, a ca
Arakawa Tsutomu
Matsumoto Yukinori
Ritter Dieter
Sugimoto Kazuhide
Boudreau Leo
Sanyo Electric Co,. Ltd.
Werner Brian P.
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