• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.150-151
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• 2005

Integral imaging is one of the three-dimensional(3D) display methods, which is an autostereoscopic method. The integral imaging system can provide volumetric 3D image which has both vertical and horizontal parallaxes. The elemental image which is obtained in the pickup process by lens array has the 3D information of the object and can be used for the depth perception and the 3D correlation. Moreover, the elemental image which represents a cyber-space can be generated by computer process.

• Journal of information and communication convergence engineering
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• v.14 no.1
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• pp.51-56
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• 2016

In this paper, we present a three-dimensional (3-D) automatic target recognition system based on optical integral imaging reconstruction. In integral imaging, elemental images of the reference and target 3-D objects are obtained through a lenslet array or a camera array. Then, reconstructed 3-D images at various reconstruction depths can be optically generated on the output plane by back-projecting these elemental images onto a display panel. 3-D automatic target recognition can be implemented using computational integral imaging reconstruction and digital nonlinear correlation filters. However, these methods require non-trivial computation time for reconstruction and recognition. Instead, we implement 3-D automatic target recognition using optical cross-correlation between the reconstructed 3-D reference and target images at the same reconstruction depth. Our method depends on an all-optical structure to realize a real-time 3-D automatic target recognition system. In addition, we use a nonlinear correlation filter to improve recognition performance. To prove our proposed method, we carry out the optical experiments and report recognition results.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.98-104
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• 2003

Various nondestructive evaluation (NDE) techniques have been studied to locate steel rebars of dowel, and to detect invisible damage such as voids and cracks inside concrete and debonding between rebars and concrete caused by corrosions and earthquakes. In this study, the aurhors developed 3-dimensional (3D) electromagnetic (EM) imaging technology to detect such damage and to identify exact location of steel rebars of dowel. The authors have developed sub-surface two-dimensional (2D) imaging technique using tomographic antenna array in previous works. In this study, extending the earlier analytical and experimental works on 2D image reconstruction, a 3D microwave imaging system using tomographic antenna array was developed, and multi-frequency technique was applied to improve quality of the reconstructed image and to reduce background noises. This paper presents the analytical expressions of numerical focusing procedures for 3D image reconstruction and numerical simulation to study the resolution of the system and the effectiveness of multi-frequency technique. Also, the design of 4?4 antenna array with switching devices is introduced as a preliminary study for the final design of whole array.

• Investigative Magnetic Resonance Imaging
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• v.11 no.2
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• pp.87-94
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• 2007

Purpose: The purpose of this study was to evaluate the usefulness of fast inversion recovery (FIR) and magnetization-prepared three dimensional gradient echo sequence (3D GRE) T1-weighted sequences for neonatal brain imaging compared with spin echo (SE) sequence in a 3T MR unit. Materials and Methods: T1-weighted axial SE, FIR and 3D GRE sequences were evaluated from 3T brain MR imaging in 20 neonates. The signal-to-noise ratio (SNR) of different tissues was measured and contrast-to-noise ratios (CNR) were determined and compared in each of the sequences. Visual analysis was carried out by grading gray-white matter differentiation, myelination, and artifacts. The Wilcoxon signed ranked test was used for evaluation of the statistical significance of CNR differences between the sequences. Results: Among the three sequences, the 3D GRE had the best SNRs. CNRs obtained with FIR and 3D GRE were statistically superior to those obtained with SE; these CNRs were better on the 3D GRE compared to the FIR. Gray to white matter differentiation and myelination were better delineated on the FIR and 3D GRE than the SE. However, motion artifacts were more commonly observed on the 3D GRE and flow-related artifacts of vessels were frequently seen on the FIR. Conclusion: FIR and 3D GRE are valuable alternative T1-weighted sequences to conventional SE imaging of the neonatal brain at 3T providing superior image quality.

• Journal of information and communication convergence engineering
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• v.13 no.2
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• pp.132-138
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• 2015

Enlarging the horizontal viewing angle is an important feature of integral imaging monitors. Thus far, the horizontal viewing angle has been enlarged in different ways, such as by changing the size of the elemental images or by tilting the lens array in the capture and reconstruction stages. However, these methods are limited by the microlenses used in the capture stage and by the fact that the images obtained cannot be easily projected into different displays. In this study, we upgrade our previously reported method, called SPOC 2.0. In particular, our new approach, which can be called SPOC 2.1, enlarges the viewing angle by increasing the density of the elemental images in the horizontal direction and by an appropriate application of our transformation and reshape algorithm. To illustrate our approach, we have calculated some high-viewing angle elemental images and displayed them on an integral imaging monitor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.155-157
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• 2012

In this paper, we propose a nonlinear 3D image correlator using computational reconstruction of 3D images based on integral imaging. In the proposed method, the elemental images for reference 3D object and target 3D object are recorded through the lens array. The recorded elemental images are reconstructed as reference plane image and target plane images using the computational integral imaging reconstruction algorithm and the nonolinear correlation between them is performed for object recognition. To show the usefulness of the proposed method, the preliminary experiments are carried out and the experimental results are presented compared with the conventional results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.3055-3062
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• 2014

3D integral imaging technique with an active mask is capable of displaying real 3D images with high resolution in space. In this paper, we present a novel 3D/2D convertible integral imaging display system using an active mask. For the proposed method, the principles of 3D, 2D, and 3D/2D composed operations are explained according to the displayed images through two LCD panels. In 3D mode, the elemental images and the mask images are displayed in two display panels. On the other hand, the light source image and 2D image are displayed in 2D mode. In addition, 3D/2D mode is obtained using the spatial separation for 3D and 2D modes. To show the feasibility of the proposed method, we carry out the preliminary experiments and present the optical results.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.506-508
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• 2002

As an advancement of medical imaging modalities and analyzing software with multi-function, active researches to acquire high contrast and high resolution image being done. In recently, development of medical imaging modalities like as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) is aiming to display anatomical structure more accuracy and faster. Thus, one of the important areas in CT today is the use of CT scanner for the quantitative evaluation of 3-D reconstruction images from 2-D tomographic images. In CT system, the effective slice thickness and the quality of 3-D reconstructed image will be influenced by imaging acquisition parameters (e.g. pitch and scan mode). In diagnosis and surgical planning, the accurate distance measurements of 3-D anatomical structures play an important role and the accuracy of distance measurements will depend on the acquisition parameters such as slice thickness, pitch, and scan mode. The skull phantom was scanned with SDCT for various acquisition parameters and acquisition slice thicknesses were 3 and 5 mm, and reconstruction intervals were 1, 2, and 3 mm to each pitch. 3-D visualizations and distance measurements were performed with PC based 3-D rendering and analyzing software. Results showed that the image quality and the measurement accuracy of 3-D SDCT images are independent to the reconstruction intervals and pitches.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.257-261
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• 1995

Confocal laser scanning microscopy (CLSM)는 기존의 coherent or incoherent microscopic imaging 보다 횡축 방향 (lateral direction)으로 고해상도를 가지며, 층과 층 사이를 구분하는 광축 방향 (axial direction)의 optical sectioning에 의해 샘플의 3D 구조를 고해상도로 영상화함으로써 3D 구조 및 생체 기능 분석을 가능하게 해 준다. 본 논문에서는 CLSM에 의한 3D 영상화 원리와 촛점면 부근에서 얻어지는 광세기 분포, 얻어진 2D slice 영상의 시각화 및 응용에 대해 논의된다.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1314-1317
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• 2006

The problem of the conflict between eye convergence and accommodation can be induced at Stereoscopic or multi-view 3D display system using binocular disparity. A multi-focus 3D display system was developed, which can solve the problem. LEDs are used instead of galvano scanner and laser to avoid mechanical moving part at the 3D display system.