• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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• pp.39-45
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• 1997

Shadow moire topography has been used as a noncontact method for measuring the 3-D shapes of objects. The moire fringes are results from the superposition of a master grating and its shadow projected on the surface of an object. But in case of the classical shadow moire method, in general, the resolution is a few tenths of millimeter. It is difficult to use a phase -shifting method in shadow moire because it is impossible to obtain uniform phase shifts on the whole field. But in this study , We introduce a phase-shifting method to improve the resolution of the classical shadow moire method. This method is based on the fact that if the depth of object is much less than the distance between the observer and the master grating, the phase shifts are almost uniform on the whole field area. Finally, we applied this new phase-shifting method to the measurement of the 3-D shape of a coin.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.96-100
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• 1997

The shadow moire is one of the optical techniques which is able to give contour lines of an object with respect to a master grating plane. The moire patterns are issued from the superposition of a master grating and its shadow projected on the surface of an object. In case of the classical shadow moire method, the sensitivity was a few tenths millimeters. generally, it is difficult to use a phase shift method in shadow moire because it is impossible to obtain uniform phase shifts on the whole field. But in this study we use the fact that if the depth of object is much less than the distance between the observer and the master grating, and the object is displaced perpendicularly to the grating plane, phase shifts are almost uniform. Finally we obtained a better resolution by using a phase shift procedure and applied the phase shifting shadow moire to three dimensional shape measurement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.402-406
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• 1995

The shadow moire is one the optical techniques which able to give contour lines of an object with respect to a master grating plane. The moire patterns are issued from the superposition of a grating and its shadow projected on the surface of an object. But in the conventional shadow moire method the reference grating and deformed grating are mutually dependent, it is impossible to obtain uniform phase shifts on the whole field by moving the reference grating. Here we propose ane trial to apply phase shifting to conventional shadow moire. When, in the conventional arrangement, Phase-shifting that is sctually constant regardless of fringe orders is achieved by moving the grating and the light source. Finally we obtained a better result by using this procedure and applied the phase shifting shadow moire to three dimensional measurement.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.96-102
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• 1998

In this study, the theory and application of phase-shifting shadow moire topography is focused on the non-contact measurement of object surfaces for practical use in the field of production engineering. Shadow moire topography has been studied during last few decades in the area of the optical physics, and now its mathmatical theory has been established. Generally, in case of the classical shadow moire topography, the sensitivity is a few tenths of millimeter in best cases. Here we tried the application of phase-shifting method to the conventional shadow moire topography. But the reference grating and the deformed grating are mutually dependent because it is impossible to obtain uniform phase shifts on the whole Held. Therefore it is difficult to use a phase-shifting method in shadow moire topography. However, it was shown that constant phase-shifting was able to be measured by moving both the grating and light source. Finally we obtained a better result by using this procedure and applied the phase-shifting shadow moire to three dimensional object measurement.

• Korean Journal of Oriental Medicine
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• v.1 no.1
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• pp.273-287
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• 1995

Moire topography, a simple technique for three-dimensional quantitation, was used to provide interference fringe photographs of the human back with sufficient accuracy to be used for detecting patient with asymmetry due to scoliosis, the disease of cervix and lumbar, muscle dysfunction. Contour lines are a suitable and widely accepted method of describing a three-dimensional surface. In the moire technique, contour lines of an object are produced as interference fringes while the object is illuminated by a spotlight through a special grating. The fringe pattern is produced by the interference of the grating and its shadow on the object. A photograph of a moire pattern on the human back will permit an assessment of the overall body shape and the symmetry of the back. This study uses shadow moire topography. Moire topography provides a non-invasive technique for quantifying the shape of the human body. In the use of moire topography for the Oriental Medicine Diagnosis, the strength of moire lies in the ablility to detect change due to deformity of human body.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.175-180
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• 1999

Generally, When we measure of object 3D surfaces with phase shifting shadow moire method, it is use of optical system consist of light source, grating, and ccd camera. At this time, it is important parameter that vertical distance of grating and camera, grating and light source, and horizontal distance of camera and light source. When use camera consist of complex lens vertical distance of grating and camera is unknown parameter. From this cause equivalent wave length of moire fringe is uncertain. In this study, We exactly obtain a vertical distance of grating and camera so improve on measurement accuracy.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.179-180
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• 2007

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.413-418
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• 2001

The moire phenomena, which are induced by mask vibration due to the excitation of speakers, degrades the color purity of CRT. So it is important to eliminate this phenomena to obtain a good CRT design. In this study we analyze the mask vibration by experiment as well as finite element method. To obtain the finite element solutions efficiently, an equivalent model was employed. The experimental and analysis results show reasonable agreements. An enhanced design configuration of mask welding points are suggested through this study.

• Korean Journal of Optics and Photonics
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• v.9 no.1
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• pp.9-14
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• 1998

We present a simple method of determining the absolute order of moire fringes formed by the moire shadow topography with a criss-crossed grating. Two experimental methods in this topography are proposed and demonstrated; one is to change the ratio of x and y pitches in a criss-crossed grating after fixing the position of a light source and a camera, and the other is to change the position of a light source and a camera after fixing the ratio of x and y pitches in a criss-crossed grating.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.63-64
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• 2007