환경 왜란 조건에 강한 진동자 위상이동 디지털 홀로그래피에 관한 연구

Abstract

Holography began in 1948 as a wave reconstruction method of D.Gabor's two-stage lensless image, and D.Garbor’s found that the waves that cause interference can obtain the amplitude and phase information of light due to diffracted or scattered light by the object. Thus, the use of interference pattern of recorded waves was proved to the acquisition of the original image of the object. Although the holographic technology research has been reduced due to the limitations of image quality, new research has been relaunched due to the discovery of coherence lasers. The existing holography recorded light using a special film using a chemical method and obtained images through a reconstructing process. However, in the process of acquiring the images, in the case of D.Gabor's in-line method, there was a problem in which the real image, the virtual image and the zero diffraction light were not separated in space. To solve this, E.N.Leith and Y.Upatnis proposed an off-axis method, and developed it to present a three-dimensional hologram technology of the object. In addition, due to development of imaging devices and computers, the process of using chemical films for recording and reproducing can now be processed by computers, and this is called digital holography. In addition, the I.Yamaguchi's developed a phase-shift method for removing a DC term and a Twin image from a digital holographic imaging. This resulted in clearer picture quality. However, digital holography for measuring the existing was used as the piezoelectric transducer for the phase shift. This is very precise in the place where sufficient external environments (no noise, no vibration, etc.) are provided for optical experiments. However, when affected by the external environment, the piezoelectric transducer has the disadvantage of not performing its role. In general, after forming an interference pattern (a physical phenomenon in which two waves of the same wavelength and amplitude meet and form a dark and white band), the interference pattern does not move without the effect of the external environment. Therefore, phase shift are usually performed by precisely moving the piezoelectric tanducer applied to the reference wave mirror. However, it can not perform accurate phase shift, because the interference pattern to move if there is external environmental effects. Therefore it is a problem that affects the measurement results. In this paper, we use a vibrator instead of piezoelectric transducer that is used for phase shift to solve the problems with the external environment effect(movements of the interference fringes due to the most of the vibration). The object was measured by applying a stronger vibration than the external environment (which does not affect the object and moves only the interference pattern). As a result, without the use of a piezoelectric transducer, it could perform a robust digital holography measurements to environmental effects.| Holography began in 1948 as a wave reconstruction method of D.Gabor's two-stage lensless image, and D.Garbor’s found that the waves that cause interference can obtain the amplitude and phase information of light due to diffracted or scattered light by the object. Thus, the use of interference pattern of recorded waves was proved to the acquisition of the original image of the object. Although the holographic technology research has been reduced due to the limitations of image quality, new research has been relaunched due to the discovery of coherence lasers. The existing holography recorded light using a special film using a chemical method and obtained images through a reconstructing process. However, in the process of acquiring the images, in the case of D.Gabor's in-line method, there was a problem in which the real image, the virtual image and the zero diffraction light were not separated in space. To solve this, E.N.Leith and Y.Upatnis proposed an off-axis method, and developed it to present a three-dimensional hologram technology of the object. In addition, due to development of imaging devices and computers, the process of using chemical films for recording and reproducing can now be processed by computers, and this is called digital holography. In addition, the I.Yamaguchi's developed a phase-shift method for removing a DC term and a Twin image from a digital holographic imaging. This resulted in clearer picture quality. However, digital holography for measuring the existing was used as the piezoelectric transducer for the phase shift. This is very precise in the place where sufficient external environments (no noise, no vibration, etc.) are provided for optical experiments. However, when affected by the external environment, the piezoelectric transducer has the disadvantage of not performing its role. In general, after forming an interference pattern (a physical phenomenon in which two waves of the same wavelength and amplitude meet and form a dark and white band), the interference pattern does not move without the effect of the external environment. Therefore, phase shift are usually performed by precisely moving the piezoelectric tanducer applied to the reference wave mirror. However, it can not perform accurate phase shift, because the interference pattern to move if there is external environmental effects. Therefore it is a problem that affects the measurement results. In this paper, we use a vibrator instead of piezoelectric transducer that is used for phase shift to solve the problems with the external environment effect(movements of the interference fringes due to the most of the vibration). The object was measured by applying a stronger vibration than the external environment (which does not affect the object and moves only the interference pattern). As a result, without the use of a piezoelectric transducer, it could perform a robust digital holography measurements to environmental effects.