• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.111-115
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• 1998

A phase-shifting projection moire method particularly intended for high-speed three-dimensional shape reconstruction of diffuse objects is presented. Emphasis is on realization of phase-shifting fringe analysis in projection moire topography using a set of line grating pairs designed to provide different phase shifts in sequence. Further a time-integral fringe capturing scheme is devised to remove undesirable high frequency original grating patterns in real-time without time-consuming software image processing. Finally the performances of the proposed method are discussed with measurement results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.04a
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• pp.195-201
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• 1991

This paper presents appliation of optical moire topography to mesuring force profiles of dies and clay models for practical use in the field of production engineering. Moire topography has been studied intensively during last few decades in the area of optical physics and its mathmatical theory has now been established. In this study, two optical configurations are suggested in which resultant moire fringes can be readily analyzed, so that 3D proviles of the models are constructed through a series of image processing by suing ma chine vision techniques. Experimental results demonstreated by using a micro- computer and CCD camera show 0.05mm measuring spatial resulution, so that the optical method can effectively adopted in order to overcome many difficulties arising when using the existing contact-type digitizing methods.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.29-38
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• 1999

In this paper the forming simulation of circular bulge by using PAM-STAMP has been performed to estimate the sheet metal forning and the plastic deformation characteristic of circular bulge. The uniaxial tension tests adn bulge tests are carried out for studying the forming characteristics of materials, and also Moire experiment are carried out for measuring the radius of curvature of the bulge and the polar compressive thickness strain. In order to compare the simulation results with the experiment and Hills theory, the relationships between redius of curvature adn polar height of the bulge, between hydraulic pressure and polar height, and between polar compressive thickness strain and polar height, are used. According to this study, the results of simulation and Hills theory are good agreement to the experiment. So, the results of simulation by using PAM-STAMP and Hills theory will give engineers good information to assess the formagbility and plastic deformation characteristic of hydraulic circular bulge test.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.5
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• pp.703-714
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• 2002

This paper proposed the basic consideration for the reliable 3-D measurement and analysis of middle-aged women's breast using 3-D phase-shifting moire topography. The surface borderline of the breast based on the anatomical structure on the skin was suggested. Various breast dimensions that can be measured using 3-D measurement system and their measuring methods were discussed. Tips for the measurement of sagged breast were also proposed. It is expected that these basic considerations contribute to draw attention to the reliable measurement of women's breast and provide a kind of tools for the standardization of 3-D shape measurement of breast.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3739-3751
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• 2000

The remarkable progress of computer graphic and virtual reality fields has increased the need of 3D graphic data for implementing more realistic environments. However, despite this trend, lots of time and labor required to process 3D graphic information extracted still limits its application only to the specific areas. As one proper solution to this problem, 3D scanner acquiring graphic data in short time and new algorithm for a data processinig are often mentioned. In this paper, A method generatinig a virtual object quickly by not zippering range data obtained from 3D moire-scanner is introduced and its effectiveness is examined.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.419-422
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• 2005

This study is an inspection of press forming product and mould using reverse engineering system. The inspection process on production field involves a lot of errors because of the hand-work so we focussed on improving the measured precision through performing the effective inspection using 3D non-contact scanner. By so doing that, we improved the precision of press forming product by analyzing the cause fellowing the inspection result. Through the inspection, we applied it to the reverse engineering and we could improve the inspection process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.962-965
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• 2005

This study is an inspection of press forming product and mould using reverse engineering system. The inspection process on production field involves a lot of errors because of the hand-work so we focussed on improving the measured precision through performing the effective inspection using 3D non-contact scanner. By so doing that, we improved the precision of press forming product by analyzing the cause following the inspection result. Through the inspection, we applied it to the reverse engineering and we could improve the inspection process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.909-916
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• 2009

This paper presents the automatic vision algorithm to generate and calibrate reference phase plane to improve the accuracy of 3D measuring machine of using phase shifting projection moire method, which is not traditional N-bucket method, but is based on direct image processing method to the pattern projection image. Generally, to acquire accurate reference phase plane, the calibration specimen with well treated surface is needed, and detailed calibration method should be performed. For the cost reduction of specimen manufacturing and the calibration time reduction, on the specimen, not specially designed, with general accuracy level, an efficient calibration procedure for the reference phase generation is proposed. The proposed vision algorithm is developed to extract the line center points of the projected line pattern from acquired images, derive the line feature information consisting of its slope and intercept by using sampled feature points, and finally generate the related reference phase between line pairs. Experimental results show that the proposed method make reference phase plane with a good accuracy under noisy environment and the proposed algorithm can reduce the total cost to make high accurate calibration specimen, also increase the accuracy of reference phase plane, and reduce the complex calibration procedure to move grid via N-bucket algorithm precisely.

• Korean Journal of Optics and Photonics
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• v.19 no.5
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• pp.376-380
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• 2008

This paper presents the Projection Moire method using a line scan camera. The high resolution feature of a line scan camera makes it possible to scan an image quickly, thus enabling a much quicker 3D profile. This method uses a high resolution line scan camera making it possible to scan an image at high speed simultaneously measuring the 3D profile of a large FOV. When using a high resolution scan camera, a full FOV is scanned, thus requiring just one movement of a projection grating. As a result, the number of grating movements is reduced drastically. The end result is a faster and more accurate 3D measurement. Moving the grating too quickly causes vibration in the imaging system, which will normally be required to apply a stitching technique when using an area scan camera. However the technique is not required when using a line scan camera. Compared with the previous techniques, it has the advantages of simple hardware without moving mechanical parts - single exposure for obtaining three-dimensional information. A method using a high resolution line scan camera can be used in mass production to measure the bump height of wafers or the bump height of package substrates.

• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.327-333
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• 2008

In general, a lens with large NA makes image quality better. There are many kinds of cheap concave mirrors with large aperture and NA. This paper presents a method that uses a large aperture projection imaging system to enhance the image used for 3D shape measurement. This method makes it possible to enhance reflection uniformity on the object surface and increases SNR (Signal to Noise Ratio). Using a large aperture lens, it is possible to obtain a brighter image, reducing the shading nature in the image boundary, and enhancing the reflection uniformity even on woven surfaces. Because of the exorbitant cost of a large aperture projection lens larger than 150 mm in diameter, a refractive lens was exchanged with a concave mirror resulting in the same optical effect. In experiment, changing NA $0.15{\sim}0.8$, image contrast was enhanced from 46 to 1.33. Incidentally, the effect of the concave mirror was tested successfully through the experiment.