• International Journal of Contents
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• v.5 no.4
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• pp.30-34
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• 2009

Many studies have been done on the integral imaging pickup whose objective is to get efficiently elemental images from a lens array with respect to three-dimensional (3D) objects. In the integral imaging pickup process, it is necessary to render an elemental image from each elemental lens in a lens array for 3D objects, and then to combine them into one total image. The multiple viewpoint rendering (MVR) is one of various methods for integral imaging pickup. This method, however, has the computing and rendering time problem for obtaining element images from a lot of elemental lens. In order to solve the problems, in this paper, we propose a parallel MVR (PMVR) method to generate elemental images in a parallel through distribution of elemental lenses into multiple threads simultaneously. As a result, the computation time of integral imaging using PMVR is reduced significantly rather than a sequential approach and then we showed that the PMVR is very useful.

• 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 Electrical Engineering and Technology
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• v.11 no.5
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• pp.1486-1491
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• 2016

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.133-134
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• 2009

We have presented our approach to build a 3D display system based on digital holography. For wide viewing angle, we have presented several techniques such as measurement, time-sharing display, and coherent amplification. These techniques can advance the wavefront 3D display system to next stage.

• Journal of Digital Contents Society
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• v.16 no.1
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• pp.127-135
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• 2015

The development of stereoscopic display hardwares and 3D authoring softwares expands its application areas from particular virtual simulation applications to general movies, games, advertising applications. However, the binocular-based 3D stereoscopic images cause fatigue to viewers. Recent performed many research results about the binocular stereoscopy's depth perception and viewers' fatigue are derived from experimental users studies. In some results, watching and making guidelines for 3D stereoscopic imaging contents are introduced. The 3D stereoscopic-related contents have the contradictory aspects, which are audiences' pursuit of a tolerable minimum fatigue and producer's its of excessive depth changes for providing viewers' immersion. This paper provides user experiments and analysis data in aspects of 3D depth changes. For use of producers, a safety zone and translational velocity of 3D depth changes are introduced. Also, on the viewer side, we present the depth change adaptation time by using an EEG device.

• Journal of the Korean Society of Visualization
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• v.12 no.3
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• pp.9-14
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• 2014

Two-photon microscopy (TPM) has been used in plant research as a high-resolution high-depth 3D imaging modality. However, TPM is known to induce photo-damage to the plant in case of long time exposure, and optimal excitation wavelength for plant imaging has not been investigated. Longer excitation wavelength may be appropriate for in vivo two-photon imaging of Arabidopsis thaliana leaves, and effects of longer excitation wavelength were investigated in terms of imaging depth, emission spectrum. Changes of emission spectrum as a function of exposure time at longer excitation wavelength were measured for in vivo longitudinal imaging. Imaging depth was not changed much probably because photon scattering at the cell wall was a limiting factor. Chloroplast emission spectrum showed its intensity peak shift by 20 nm with transition of excitation wavelength from 849 nm or below to 850 nm or higher. Emission spectrum showed different change patterns with excitation wavelengths in longitudinal imaging. Longer excitation wavelengths appeared to interact with chloroplasts differently in comparison with 780 nm excitation wavelength, and may be good for in vivo imaging.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.71-78
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• 2018

In this study, human mimic phantoms outputted by three-dimensional (3D) printing technology are reported. Polylactic acid and a personal 3D printer - fused deposition modeling (FDM) - are used as the main material and the printing device. The output of human mimic phantoms performed in the following order: modeling, slicing and G-code conversion, output variable setting, 3D output, and post-processing. The students' learning satisfaction (anatomical awareness, study interest) was measured on 5-point Likert scale. After that, Twenty of those phantoms were outputted. The total output took 11,691 minutes (194 hours 85 minutes) and the average output took 584.55 minutes (9 hours 7 minutes). The filament used for the experiment was 2,390.2 g, and the average use of the filament was 119.51 g. The learning satisfaction of anatomical awareness was 4.6 points on the average and the interest of the class was on average 4.5 points. It is expecting that 3D printing technology can enhance the learning effect of imaging anatomy education.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.557-561
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• 2009

This paper presents a prototype of high resolution 3D display with a new principle. We have proposed a new 3D display which has the features of both Integral Imaging (II) and volumetric display. The proposed display consists of two lens arrays and a thin volumetric display. When the viewer watches a thin volumetric display through two lens array, he can perceive a thick 3D image. In other words the two lens arrays can play a role of a convex lens which has a large diameter as a amplification of a depth. The advantage of the proposed display is that it has higher resolution than II and it is smaller than volumetric display with a large convex lens. In this paper, we show a detail of a prototype 3D display. We took various errors into consideration when we simulated 3D display and we found suitable lenses parameter from the simulation result. Then we confirm that the prototype will be able to reconstruct 3D images.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2571-2578
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• 2014

In this paper, we propose a computational generation method of elemental images for time-multiplexed 3D integral imaging display based lens division. In the proposed method, we analyze the image formation between 3D object and elemental images based on ray optics. Based on the analyzed formation, we generate the elemental image set for time-multiplexed display. Positions of an object point picked up in proposed method is shifted for half size of lens divided from those in conventional method when generating elemental images. To show the usefulness of the proposed method, we carry out the preliminary experiments and present the results.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.24-30
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• 2007

We have studied depth conversion of a reconstructed image by means of recombination of the elemental images in the integral imaging system for 3D display. With the recombination, depth conversion to the pseudoscopic, the orthoscopic, the real or the virtual as well as to arbitrary depth without any distortion is possible under proper conditions. The conditions on the recombinations for the depth conversion are theoretically derived. The reconstructed images using the converted elemental images are presented.