Optics: measuring and testing – Range or remote distance finding – With photodetection
Reexamination Certificate
2002-09-20
2003-05-06
Buczinski, Stephen C. (Department: 3662)
Optics: measuring and testing
Range or remote distance finding
With photodetection
C348S135000, C348S141000, C356S141100, C356S625000, C382S286000, C702S159000, C702S172000
Reexamination Certificate
active
06559931
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a three-dimensional (3-D) coordinate measuring method and a 3-D coordinate measuring apparatus for measuring 3-D coordinates of large structures, such as ships, bridges, civil works, buildings, and components therefor. In addition, the present invention relates to a building method employing the aforementioned 3-D coordinate measuring method and apparatus.
2. Description of Related Arts
Generally, a two-dimensional (2-D) measuring apparatus using, for example, a transit, a measuring tape, and a plumb bob, is employed to measure large structures such as ships, bridges, civil works, and buildings. In recent years, however, such measurement is carried out using a trigonometrical survey developed in the field of measurement. Also used for the measurement is a 3-D measuring apparatus that includes a measuring apparatus with an electrooptical distance-measuring device according to distance-measuring and angle-measuring schemes.
For example, a brand “MONMOS” is commercially marketed by Sokkia Co., Ltd. This brand is a 3-D coordinate measuring system in which an arbitrary point of a measurement target object (or, a measurement target substance) can be measured with a single measuring apparatus. In this system, arbitrary two points are preliminarily measured, and a 3-D coordinate system is set according to the measurement result. Thereafter, reflecting targets (including target points) provided at the individual measuring points are sighted to synchronously measure the three elements, i.e., the horizontal angle, the vertical angle, and the distance. Then, the system performs a coordinate system transformation including analysis and calculations, and obtains a 3-D coordinate according to the transformation. The system is capable of achieving a high-precision measurement with an error of ±1 mm or less per distance of 100 m. The target point is provided on a reflection plane, and is used as a measurement point in the 3-D coordinate measurement. A reflecting target has a specific thickness. As such, predetermined calculations need to be performed according to measurement values and the size and shape of the reflecting target to obtain accurate 3-D coordinates of the target object.
However, conventional measuring systems including the “MONMOS” require use of the human eye to perform, for example, telescope focusing operation and alignment operation between the center (target point) of a reflecting target and cross lines of the telescope in sighting operation. As such, time-consuming complex operations need to be performed, and human errors of a measuring person tend to be included in measurement results. That is, required human operations causes deterioration in, for example, the efficiency and the precision of the measurement. The aforementioned sighting operation refers to the operation of aligning an optical axis of a distance-measuring device to a measurement point projected in a viewfield of, for example, a telescope or magnifying display means for a captured image.
To overcome the above-described problems, there are commercially marketed measurement systems including functions of automating human-eye dependent sighting operation. For example, a brand “TCA1100” series is marketed by Leica Geosystems Corp., and a brand “CYBER MONMOS” is marketed by Sokkia Co., Ltd. Either of the systems includes image capturing means, such as a CCD camera, provided concentric with the optical axis of an electrooptical distance-measuring device. The system is so designed as to detect a central position of a reflecting target from an image captured by the image capturing means. Then, the system performs calculations and thereby obtains the amount of deviation between a central position of the image capturing means and the central position of the reflecting target. When the system finds the positions misaligned, it controls a motor to drive an angle measuring device by an amount corresponding to the amount of the deviation, and aligns the positions with each other. The system of the aforementioned type executes automatic sighting (automatic microscopic sighting) within a relatively narrow viewfield of the image capturing means. In this view, the system can be included in a type that has a microscopic automatic sighting means.
In addition, in the aforementioned system, conditions for the positions of reflecting targets and the measurement sequence thereof are initialized. Thereafter, reflecting targets captured by the image capturing means are extracted by an image processor. Subsequently, the horizontal angle and the vertical angle of the image capturing means are adjusted using a servomotor to align the center of each of the reflecting targets with the optical axis of the image capturing means. In this manner, the measurement is implemented. In this case, the reflecting targets need to be included into the viewfield of the image capturing means. As such, difficulties arise in that the plurality of measurement points (target points) in a wide range are automatically sighted. As such, with this system, when a coordinate of the position of a reflecting target is memorized, an operator needs to directly input the coordinate of the position of the reflecting target from a measurement apparatus according to design data. In contrast, when a coordinate of the position of a reflecting target is not yet memorized, the operator needs to direct the image capturing means manually or by using a controller toward the reflecting target to carry out teaching for the system.
Other methods of performing automatic measurement are proposed under, for example, Japanese Unexamined Patent Application Publications No. 8-136218 and No. 9-14921. In the proposed methods, an analysis-dedicated computer is used to transform the position of a reflecting target into a coordinate from a measuring apparatus. Thereby, the sight direction is determined, and automatic measurement is performed.
However, the methods of the above-described type have problems described below.
When a 3-D coordinate of reflecting targets is not yet memorized, teaching needs to be carried out in the way that a CCD camera is directed to individual measuring points, and the operation of including the individual measuring points into a monitor screen is iterated. Thus, since complex human operations are involved, advantages in automation cannot be expected.
Even when 3-D coordinates of reflecting targets are already memorized to the system, although an analysis-dedicated computer is used to transform the coordinate system, time-consuming human operations are required. That is, the method still requires the operation of aligning a design coordinate system and a measurement coordinate system to be performed in the initialization in the way of measuring at least two points of a reflecting target used for reference.
Moreover, although there are cases in which the method is used to position component members in assembly work, the method requires a relatively long time for measurement. In most cases of assembly work, component members are located in positions deviating from the viewfield of the image capturing means. As such, even when the position of a reflecting target is calculated from design values, since the reflecting target is not found in the viewfield, and a reflecting target needs to be searched from the outside of the viewfield. Consequently, it takes a relatively long time for measurement.
Since the performance of the conventional 3-D coordinate measuring method is as described above, it is difficult to directly use the method in assembly work, for example, shipbuilding assembly work.
Recently, most of shipbuilding methods employ a block-based fabrication method. As shown in
FIG. 17
, in a shipbuilding method, first, processes such as cutting and hot bending are performed for steel plates (material-processing step). Then, processed steel plates are welded and assembled, and intermediate-and-small blocks are thereby fabricated (a step of the above processing will be r
Ito Hisashi
Kawamura Tsutomu
Kawasaki Noboru
Uesugi Mitsuaki
Yanagita Hirohiko
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