• Current Optics and Photonics
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• v.3 no.1
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• pp.16-21
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• 2019

We present a broad-bandwidth comb-spacing-swept source (CSWS) based on a differential polarization delay line (DPDL) for interferometric three-dimensional (3D) imaging. The comb spacing of the CSWS is repeatedly swept by the tunable DPDL in the multiwavelength source to provide depth-scanning optical coherence tomography (OCT). As the polarization differential delay of the DPDL is tuned from 5 to 15 ps, the comb spacing along the wavelength continuously varies from 1.6 to 0.53 nm, respectively. The wavelength range of various semiconductor optical amplifiers and the cavity feedback ratio of the tunable fiber coupler are experimentally selected to obtain optimal conditions for a broader 3-dB bandwidth of the multiwavelength spectrum and thus provide a higher axial resolution of $35{\mu}m$ in interferometric OCT imaging. The proposed CSWS-OCT has a simple imaging interferometer configuration without reference-path scanning and a simple imaging process without the complex Fourier transform. 3D surface images of a via-hole structure on a printed circuit board and the top surface of a coin were acquired.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.283-289
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• 2023

The apnea-hypopnea index is widely regarded as a measure of the severity of obstructive sleep apnea (OSA), a condition characterized by recurrent episodes of apnea or hypopnea during sleep that induce airway collapse. OSA is a catastrophic problem due to the wide range of health issues it can cause, including cardiovascular disease and memory loss. This review was conducted to clarify the roles of various imaging modalities, particularly cone-beam computed tomography (CBCT), in the diagnosis of and preoperative planning for OSA. Unfortunately, 2-dimensional imaging techniques yield insufficient data for a comprehensive diagnosis, given the complex anatomy of the airway. Three-dimensional (3D) imaging is favored as it more accurately represents the patient's airway structure. Although computed tomography and magnetic resonance imaging can depict the actual 3D airway architecture, their use is limited by factors such as high radiation dose and noise associated with the scans. This review indicates that CBCT is a low-radiation imaging technique that can be used to incidentally identify patients with OSA, thereby facilitating early referral and ultimately enhancing the accuracy of surgical outcome predictions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2363-2369
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• 2016

In this paper, we propose three-dimensional (3D) quick-response (QR) code generation technique using passive 3D integral imaging and computational integral imaging reconstruction technique. In our proposed method, we divide 2D QR code into 4 planes with different reconstruction depths and then we generate 3D QR code using synthetic aperture integral imaging and computational reconstruction. In this 3D QR code generation process, we use integral imaging which is one of 3D imaging technologies. Finally, 3D QR code can be scanned by reconstructing and merging 3D QR codes at 4 different planes with computational reconstruction. Therefore, the security level for QR code scanning may be enhanced when QR code is scanned. To show that our proposed method can improve the security level for QR code scanning, in this paper, we carry out the optical experiments and computational reconstruction. In addition, we show that 3D QR code can be scanned when reconstruction depths are known.

• Journal of the Optical Society of Korea
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• v.6 no.4
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• pp.133-142
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• 2002

In this paper, we describe one of the most attractive techniques in autostereoscopic three-dimensional display-integral imaging. We explain the weak points of the integral photography in the early days and the methods to overcome these problems. Finally we describe the technical trends developed recently.

• Journal of Korean Neurosurgical Society
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• v.55 no.6
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• pp.357-361
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• 2014

Computed tomography angiography (CTA) is commonly used in setting of subarachnoid hemorrhage, but imaging features of aneurysm rupturing taking place at the time of scanning has rarely been described. The author reports a case of actively rebleeding aneurysm of the anterior communicating artery with intraventricular extravasation on the hyperacute CTA imaging. The rebleeding route, not into the third ventricle but into the lateral ventricles, can be visualized by real-time three-dimensional CT pictures. The hemorrhage broke the septum pellucidum and the lamina rostralis rather than the lamina terminalis.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1569-1574
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• 2006

We have studied elemental image compatibility between integral imaging(II) and parallax generation(PG) system for three-dimensional display. The elemental images of PG can be obtained by recombination of the elemental images picked up in II system. The theoretical verification and the experimental results show that the elemental images of PG are in correspondence with the elemental images of II system with proper transformation conditions.

• Korean Journal of Bronchoesophagology
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• v.1 no.1
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• pp.82-93
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• 1995

Three-dimensional reconstruction of computed tomographic image(3D CT) is a well-established imaging modality which has been investigated in various clinical settings. It is commonly performed in case of congenital or developmental abnormalities, and traumatic fracture of skull and face that requires reconstruction of osseous structure. However reporting the 3D CT in laryngeal or tracheal stenosis is rare and its results are obscure. The authors performed 3D CT in six cases of tracheal stenosis and found diagnostic value of 3D CT. A Comparision of diagnostic information obtained from plain X-ray, 2D CT and 3D CT has performed in total six cases of tracheal stenosis. Surgical treatment of the tracheal stenosis was following in these cases : tracheal end to end anastomosis In 1 case, laryngotracheal end to end anastomosis in 2 cases. 3D CT information was compared with operative finding. In two of six cases, satisfactory information was not obtained from 3D CT in evaluating an exact stenosis of trachea. Future, it will be helped in evaluating of tracheal stenosis by 3D CT.

• Current Optics and Photonics
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• v.2 no.5
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• pp.460-467
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• 2018

Three-dimensional (3D) refractive-index (RI) imaging and quantitative analyses of angiosperm pollen grains are presented. Using optical diffraction tomography, the 3D RI structures of individual angiosperm pollen grains were measured without using labeling or other preparation techniques. Various physical quantities including volume, surface area, exine volume, and sphericity were determined from the measured RI tomograms of pollen grains. Exine skeletons, the distinct internal structures of angiosperm pollen grains, were identified and systematically analyzed.

• Journal of information and communication convergence engineering
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• v.19 no.2
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• pp.102-107
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• 2021

In this paper, we propose a new three-dimensional (3D) photon-counting integral imaging reconstruction method using a merging reconstruction process and maximum likelihood estimation (MLE). The conventional 3D photon-counting reconstruction method extracts photons from elemental images using a Poisson random process and estimates the scene using statistical methods such as MLE. However, it can reduce the photon levels because of an average overlapping calculation. Thus, it may not visualize 3D objects in severely low light environments. In addition, it may not generate high-quality reconstructed 3D images when the number of elemental images is insufficient. To solve these problems, we propose a new 3D photon-counting merging reconstruction method using MLE. It can visualize 3D objects without photon-level loss through a proposed overlapping calculation during the reconstruction process. We confirmed the image quality of our proposed method by performing optical experiments.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1486-1489
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• 2007

Generally many kind of phase unwrapping method are used to obtain three-dimensional feature in digital holography. Goldstein algorithm is representative method. But Goldstein algorithm has some problems. We developed a modified Goldstein algorithm that could solve the problem of Goldstein algorithm using the boundary information. Obtained three-dimensional information can be applied to 3-D contents of stereoscopic, multi-view, SMV, or holographic display.