• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.413-413
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• 2000

In this paper, we propose a series of calibrations f3r the x-ray three dimensional imaging system. In the developed x-ray system, a three dimensional inner and outer shape of an object can be reconstructed out of two dimensional transmitted x-ray image set, which are acquired by projecting x-ray to the object from different views. To achieve this, a reconstruction algorithm which estimates and updates the three dimensional volume from x-ray images is developed. The algorithm is named as uniform and simultaneous algebraic reconstruction technique(USART) which is an iterative method estimating a 3D volume based on its projected images. In this method, it is assumed that the imaging conditions that are the relative positions between the x-ray sources, object and the image planes are blown. Practically it is not easy to know the three dimensional coordinate of the components of the system, since the x-ray is not visible and the image distortions are present due to the optical components in the system. In this paper, methods of correcting image distortions are present firstly. Then the coordinates of the x-ray systems are calibrated from the x-ray images of the grid pattern. Some experimental results on these calibrations are present and discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.50-53
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• 2005

An analysis on the viewing parameters of floating display system based on integral imaging is introduced. A floating display system based on integral imaging is a three-dimensional display system which can display three-dimensional moving pictures with impressive feeling of depth. The analysis given in this paper will optimize the design of the floating display system for the specific application.

• 대한치과교정학회지
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• 제48권5호
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• pp.292-303
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• 2018

Objective: Biplanar imaging systems allow for simultaneous acquisition of lateral and frontal cephalograms. The purpose of this study was to compare measurements recorded on three-dimensional (3D) cephalograms constructed from two-dimensional conventional radiographs and biplanar radiographs generated using a new biplanar imaging system with those recorded on cone-beam computed tomography (CBCT)-generated cephalograms in order to evaluate the accuracy of the 3D cephalograms generated using the biplanar imaging system. Methods: Three sets of lateral and frontal radiographs of 15 human dry skulls with prominent facial asymmetry were obtained using conventional radiography, the biplanar imaging system, and CBCT. To minimize errors in the construction of 3D cephalograms, fiducial markers were attached to anatomical landmarks prior to the acquisition of radiographs. Using the 3D $Ceph^{TM}$ program, 3D cephalograms were constructed from the images obtained using the biplanar imaging system (3D $ceph_{biplanar}$), conventional radiography (3D $ceph_{conv}$), and CBCT (3D $ceph_{cbct}$). A total of 34 measurements were obtained compared among the three image sets using paired t-tests and Bland-Altman plotting. Results: There were no statistically significant differences between the 3D $ceph_{biplanar}$ and 3D $ceph_{cbct}$ measurements. In addition, with the exception of one measurement, there were no significant differences between the 3D $ceph_{cbct}$ and 3D $ceph_{conv}$ measurements. However, the values obtained from 3D $ceph_{conv}$ showed larger deviations than those obtained from 3D $ceph_{biplanar}$. Conclusions: The results of this study suggest that the new biplanar imaging system enables the construction of accurate 3D cephalograms and could be a useful alternative to conventional radiography.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.63.3-63
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• 2001

Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. In this paper, we propose a three dimensional volume reconstruction method, which is an iterative method and as uniform and simulated algebraic reconstruction technique (USART). In this method, two or more x-ray images projected from different views are needed, and also the geometry of the imaging system need to be a priori identified well. That is to say, the relative locations between the x-ray source, imaging plane and the object should be determined exactly by calibration. To achieve this, we propose a series of coordinate calibration methods of the x-ray imaging system using grid pattern images. Some experimental results of these calibrations is presented and discussed in detail ...

• 한국통신학회논문지
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• 제34권11B호
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• pp.1311-1319
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• 2009

집적 영상 현미경에서 획득한 요소 영상을 이용하여 집적 영상 디스플레이에서 재생하였다. 일반화된 서로 다른 두 렌즈 어레이를 이용하는 집적 영상의 획득과 재생의 관계를 이용하여 집적 영상 현미경 및 디스플레이 시스템에 적용하였다. 집적 영상 현미경에서 획득한 요소 영상을 재생하기 위해서 스케일링이 적용된 요소 영상이 필요하다. 집적 영상을 재생할 때 요소 영상의 정보 손실을 최소화하는 스케일링 계수와 요소 영상의 왜곡을 최소화하는 스케일링 계수를 선택해야 한다. 본 연구에서는 $125{\mu}m$ 피치 사이즈의 마이크로 렌즈 어레이를 가지는 집적 영상 현미경으로 시료를 촬영하고 1mm 피치 사이즈의 렌즈 어레이를 가지는 집적 영상 디스플레이로 촬영된 시료를 3차원 영상으로 재생하는 실험을 수행하였다. 이 때, 요소 영상의 스케일링 계수는 집적 영상 현미경에서 획득한 요소 영상의 정보 손실을 최소화 하는 값으로 설정하였다.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.938-940
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• 2014

This paper discusses a coherence-gated three-dimensional imaging system based on photorefractive holography, which was applied to imaging through turbid media with a view to developing biomedical instrumentation. A rapid response photorefractive device doped with 2,4,7-trinitro-9-fluorenylidene malononitrile was used to generate the hologram grating. The estimated depth resolution was $20{\mu}m$, which corresponds to the coherence length of the light source. In this coherence imaging system, tomographic imaging of a 3-dimensional object composed of a $50{\mu}m$ thick cylindrical layer was achieved. The proposed coherence imaging system using an organic photorefractive material can be used as an optical tomography system for biological applications.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
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• pp.6-7
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• 2009

We proposed the two-dimensional (2D) / three-dimensional (3D) convertible modified integral imaging system using functional polarizing film named $imazer^{TM}$, which transfer or scatter the incident light ray according to the polarizing direction of ray. When the incident light rays transfer to $imazer^{TM}$, the rays generate 3D image through the process of the modified integral imaging system. However, the scattered light rays generate 2D image through the simple backlight scheme when the incident rays are scattered by the film. The proposed method can be implemented the partial 3D display system without any mechanical movements. In this paper, we propose and verify our system using some basic experiments and its results.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.714-717
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• 2008

In this paper, we propose a three-dimensional (3D) integral imaging system using an elastic lens array instead of conventional rigid lens array. The lens array is made of polydimethylsiloxane (PDMS) that is optically transparent and flexible material. We can stretch the PDMS lens array to be expanded into a certain extent, and control the lens pitch of the system easily. That flexible design enables a fine 3D integral imaging display.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.388-394
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• 2010

In this paper the object recognition performance of a photon counting integral imaging system is quantitatively compared with that of a conventional gray scale imaging system. For 3D imaging of objects with a small number of photons, the elemental image set of a 3D scene is obtained using the integral imaging set up. We assume that the elemental image detection follows a Poisson distribution. Computational geometrical ray back propagation algorithm and parametric maximum likelihood estimator are applied to the photon counting elemental image set in order to reconstruct the original 3D scene. To evaluate the photon counting object recognition performance, the normalized correlation peaks between the reconstructed 3D scenes are calculated for the varied and fixed total number of photons in the reconstructed sectional image changing the total number of image channels in the integral imaging system. It is quantitatively illustrated that the recognition performance of the photon counting integral imaging system can be similar to that of a conventional gray scale imaging system as the number of image viewing channels in the photon counting integral imaging (PCII) system is increased up to the threshold point. Also, we present experiments to find the threshold point on the total number of image channels in the PCII system which can guarantee a comparable recognition performance with a gray scale imaging system. To the best of our knowledge, this is the first report on comparisons of object recognition performance with 3D photon counting & gray scale images.

• Journal of Information Display
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• 제3권1호
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• pp.22-26
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• 2002

Three-dimensional dynamic display system based on computer-generated integral imaging is discussed and its feasibility is verified via some basic experiments. Integrated images observed from different viewing points are seen to have full parallax and the animated 3D image was implemented successfully. Moreover, using large size Fresnel lens array was found to helps widen viewing angle and to make the system more practical.