An automatic three-dimensional whole circumference shapes measurement system using an optical patterns projection
technique has been developed. The system is composed of an optical spatial modulator from which grating patterns are
projected on the surface of the object set on a turntable stage, a CCD camera controlled by a robot arm, and a computer.
The patterns on the surface of the object are taken into the computer by the CCD camera, and the three-dimensional
coordinates of the patterns on the surface of the object are calculated according to a principle of a trigonometry
measurement. The patterns faced to the CCD camera are taken into the computer by the CCD camera, four photographs
at each turntable angle of 0, 90, 180, and 270 degrees are processed and the image processing data are composed as
whole circumference shapes. This improved system using mechanical and optical method and data analysis has the
following advantages. (1) It is possible to capture the surface topography without any contact. (2) The time required for
the measurements is shorter than the light-section method. (3) The optical spatial modulator using a liquid crystal
projector enables to control the striped patterns accurately by the computer. (4) It is possible to measure precisely and to
expand the measurement area using a zoom camera. (5) The improved system has whole circumference shapes
measurement area as well as high resolution.
An automatic measurement system of three-dimensional shapes by a projection method with striped patterns from an optical spatial modulator has been developed. Patterns on the surface of the object were taken into a computer by a CCD camera, and the 3D cocordinate of the surface of the object was calculated according to a principle of a trigonometry measurement. This system has the following advantages. (1) It is possible to capture the surface topography without any contact. (2) The time required for the measurements is shorter than the light-section method. (3) The optical spatial modulator using a liquid crystal projector is possible to control the striped patterns accurately by the computer. (4) It is possible to measure precisely and to expand the measurement area using a zoom camera. In this study, we developed the method with using zooming of a CCD camera image. By using zooming of a CCD camera image, the measurement accuracy improved and the measurement range was expandable.
We have continued research on the three-dimensional shape measurement system, using spatial projections. This method is non-contact, non-invasive, and completes measurement in a short time. However, light diffusion influence on the measurable accuracy. In addition, if marking on the surface of target object, it will become difficult to perform exact measurement. And the sampling density is not fully high. We proposed methods using differentiation and light variation patterns to enhance accuracy of measurement, to eliminate the influence of marking on the surface of target object, and to increase the sampling density. Since our methods involve computational manipulation of the data obtained by the original system, it requires no additional equipment. It is a very practical and effective method.
We have continued research on our 3D shape measurement system, using spatial projections of light variation patterns. This method is non-contact, non-invasive, and completes measurement in a short time. However, light diffusion influence on the measurable accuracy. We proposed a method using differentiation to enhance accuracy of measurement, and were successful in achieving this goal. Moreover, the measurable area was expanded. Since our method involves computational manipulation of the data obtained by the original system, it requires no additional equipment. It is a very practical and effective method.
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