Optics: measuring and testing – Shape or surface configuration – Triangulation
Reexamination Certificate
2002-04-24
2004-09-28
Pham, Hoa Q. (Department: 2877)
Optics: measuring and testing
Shape or surface configuration
Triangulation
C356S623000, C356S243400
Reexamination Certificate
active
06798527
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a three-dimensional shape-measuring system which measures a three-dimensional shape of a measuring subject.
2. Description of the Background Art
Conventionally, a three-dimensional shape-measuring system which measures a three-dimensional shape of a measuring subject by a light section method utilizing laser light has been known. In the conventional three-dimensional shape measuring system, laser slit light having a slit shape is directed to a measuring subject from a light-projecting unit, and the laser slit light is allowed to scan in a direction orthogonal to a slit direction, that is, a direction in which light components are distributed in a cross-section of a luminous flux of the laser slit light, so that reflected light from the measuring subject is detected. Then, based upon the reflected light components, a three-dimensional shape of the measuring subject on the plane facing the light-projecting unit.
However, the problem with the conventional three-dimensional shape-measuring system is that, in the case when a measuring subject has a complicated surface shape such as grooves, projected light from the light-projecting unit is not directed thereto appropriately, causing shadows on the corresponding portions and failing to carry out an appropriate shape-measuring process.
In order to solve this problem, for example, the groove portion may be shifted to a position in front of the light-projecting unit so as to project the laser slit light onto the groove portion properly; however, in order to shift the measuring subject, a shifting mechanism for accurately shifting the measuring subject needs to be installed in a separated manner. Moreover, it is difficult to shift the measuring subject accurately.
SUMMARY OF THE INVENTION
The present invention relates to a three-dimensional shape-measuring system.
According to one aspect of the present invention, a three-dimensional shape-measuring system, which measures a three-dimensional shape of a measuring subject by using a light section method, is provided with the followings: a first light projector which directs first laser light to the measuring subject so that the first laser light is allowed to scan the surface of the measuring subject in a first direction; a second light projector which directs second laser light to the measuring subject so that the second laser light is allowed to scan the surface of the measuring subject in a second direction different from the first direction; a light receiver which receives first reflected light derived from the first laser light reflected from the measuring subject and second reflected light derived from the second laser light reflected from the measuring subject; and a calculator which calculates a three-dimensional shape of the measuring subject based upon data obtained from the light receiver.
In accordance with the three-dimensional measuring system of this aspect, the first light projector directs first laser light to the measuring subject so that the directed first laser light is allowed to scan the surface of the measuring subject in a first direction, and the second light projector directs second laser light to the measuring subject so that the directed second laser light is allowed to scan the surface of the measuring subject in a second direction different from the first direction; therefore, since the scanning direction of the first laser light and the scanning direction of the second laser light are different from each other, it becomes possible to reduce shadowed portions appearing on the measuring subject, and consequently to accurately measure a three-dimensional shape of the measuring subject.
Moreover, according to another aspect of the present invention, a three-dimensional shape-measuring system, which measures a three-dimensional shape of a measuring subject by using a light section method, is provided with the followings: a first light projector which directs first laser light to the measuring subject so as to allow the first laser light to scan the surface of the measuring subject; a second light projector which directs second laser light to the measuring subject so as to allow the second laser light to scan the surface of the measuring subject; a light receiver which receives first reflected light derived from the first laser light reflected from the measuring subject and second reflected light derived from the second laser light reflected from the measuring subject; and a calculator which calculates a three-dimensional shape of the measuring subject based upon data obtained from the light receiver.
In accordance with the three-dimensional shape-measuring system, since the direction of the first base length connecting the first light projector and the light receiver and the direction of the second base length connecting the second light projector and the light receiver are set in non-parallel with each other, it becomes possible to reduce shadowed portions appearing on the measuring subject, and consequently to accurately measure a three-dimensional shape of the measuring subject.
According to still another aspect of the present invention, a three-dimensional shape-measuring system, which directs laser light to a measuring subject placed in a measuring space from a plurality of directions by using a light projector so that a light receiver detects reflected light derived from the laser light from the light projector reflected by the measuring subject to generate a three-dimensional shape data of the measuring subject, is provided with the followings: a controller which, prior to measurements on the measuring subject, controls the light projector and light receiver so as to measure a calibration-use subject placed in the measuring space from the plurality of directions; a data processor which finds a conversion parameter used for converting measured data related to the calibration-use subject, obtained respectively in the plurality of directions, to three-dimensional shape data in a world coordinate system; and a memory storing the conversion parameter.
In accordance with the three-dimensional shape-measuring system of this aspect, prior to measurements on the measuring subject, a calibration-use subject placed in the measuring space is measured from the plurality of directions, and a conversion parameter, which is used for converting measured data related to the calibration-use subject, obtained respectively in the plurality of directions, to three-dimensional shape data in a world coordinate system, is obtained. Then, upon measuring the measuring subject, the measured data related to the calibration-use subject, obtained respectively in the plurality of directions, is data-converted by using the conversion parameter that has been preliminarily found, to generate three-dimensional shape data; therefore, it is possible to shorten the time from measurements on the measuring subject until three-dimensional shape data is found, and consequently to carry out the measuring operation efficiently.
Here, the present invention is also directed to a three-dimensional shape-measuring method which directs laser light to a measuring subject placed in a measuring space from a plurality of directions by using a light projector so that a light receiver detects reflected light derived from the laser light from the light projector reflected by the measuring subject to generate a three-dimensional shape data of the measuring subject.
According to the other aspect of the present invention, a three-dimensional shape-measuring method is provided with the following steps: a step of placing a calibration-use subject in the measuring space prior to measurements on the measuring subject; a step of measuring the calibration-use subject in the plurality of directions; a step of finding a conversion parameter used for converting measured data related to the calibration-use subject, obtained respectively in the plurality of directions, to three-dimensional shape data in a world coordinate system; storing th
Abe Yoshihisa
Ariizumi Masahiro
Fukumoto Tadashi
Matsunaga Norio
Osaki Shigeru
McDermott Will & Emery LLP
Minolta Co. , Ltd.
Pham Hoa Q.
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