• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.3C
• /
• pp.255-261
• /
• 2008

Conventional look-up table(LT) has gained a lot of speed increase in generation of digital holograms for 3D objects, but it has required an enormous memory size of the LT. In this paper, a novel approach to dramatically reduce the size of the conventional LT, still keeping its advantage of fast computational speed is proposed, which is called here a N-LT(novel look-up table) method. In the proposed method, only the fringe patterns of the center points on each image plane are pre-calculated, called elemental fringe patterns and stored in the look-up table. Then, the fringe patterns for other object points on each image plane can be obtained by simply shifting this pre-calculated elemental fringe pattern according to the displaced values from the center to those points and adding them together. Some experimental results revealed that the computational speed and the required memory size of the proposed approach are found to be 48.7 times faster than that of the ray-tracing method and 217 times smaller than that of the conventional LT method, respectively.

• Korean Journal of Optics and Photonics
• /
• v.18 no.2
• /
• pp.122-129
• /
• 2007

Generally, many kinds of phase unwrapping algorithm are used to obtain three-dimensional features in digital holography. The Goldstein algorithm is ra epresentative method. which requires small memory capacity and short execution time fer an unwrapping process. However, the Goldstein algorithm has some problems when the dipole residue is located at the boundary. When the opposite residues are located at the boundary and the distance between the opposite residues is longer than the boundary, an incorrect branch cut occurs and results in incorrect calculation. We have modified the Goldstein algorithm to solve the incorrect calculation problem using boundary information. We found that the modified Goldstein algorithm could resolve the Goldstein algorithm's problem.

• Journal of the Optical Society of Korea
• /
• v.19 no.4
• /
• pp.382-389
• /
• 2015

Motility contrast imaging is a coherence-domain imaging technique that uses cellular motility as a fully endogenous imaging contrast agent. Motility is measured inside tissue using a digital holographic coherence gate that extracts dynamic speckle from fixed depths. The dynamic speckle arises from the normal organelle motion inside cells, and from the movement of the cellular membranes driven by the cytoskeleton. It measures cellular activity and the effects of temperature and osmolarity. Motion is sensitive to cytoskeletal drugs, such as the antimitotic drugs used for cancer chemotherapy, and the effects of drug combinations also can be monitored. Motility contrast imaging is a potential tissue-based assay platform for highthroughput screening of pharmaceuticals.

• Journal of KSNVE
• /
• v.9 no.4
• /
• pp.687-692
• /
• 1999

Digital holographic reconstruction method [W. A. Veronesi, et al, 1989, JASA, Vol. 85, pp. 588∼598] reconstructs a whole sound field by using measured sound pressure. This paper reports numerical errors of the method that occur at specific frequencies. The errors occur due to the truncation errors included in the calculation of transfer matrixes. The frequencies of the errors depend on the size of boundary element surfaces. Moreover, a modified calculation technique is proposed in the paper. The technique prevents the truncation errors by employing an indirect calculation procedure.

• Electronics and Telecommunications Trends
• /
• v.35 no.5
• /
• pp.123-133
• /
• 2020

With the development of artificial intelligence (AI) and 5G technology, an ecosystem of digital content is gradually becoming intelligent, immersive, and convergent. However, there is not enough ultra-realistic content for the ecosystem. For ultra-realistic content services, creative content technologies using AI are being developed. This paper introduces the trends in and prospects of creative content technologies such as 3D content creation, digital holography, image-based motion recognition, content analysis/understanding/searching, sport AI, and content distribution.

• Journal of the Optical Society of Korea
• /
• v.18 no.5
• /
• pp.495-499
• /
• 2014

In this paper, a method is proposed for simultaneously measuring the front and back surface profiles of transparent micro-optical components. The proposed method combines a dual-wavelength digital holographic microscope with liquids to record holograms at different wavelengths, and then numerically reconstructs the three-dimensional phase information to image the front and back sides of the sample. A theoretical model is proposed to determine the surface information, and imaging of an achromatic lens is demonstrated experimentally. Unlike conventional interferometry, our proposed method supports nondestructive measurement and direct observation of both front and back profiles of micro-optical elements.

• Current Optics and Photonics
• /
• v.6 no.1
• /
• pp.51-59
• /
• 2022

Holographic display technology is one of the promising 3D display technologies. However, the large amount of computation time required to generate computer-generated holograms (CGH) is a major obstacle to the commercialization of digital hologram. In various systems such as multi-depth head-up-displays with hologram contents, it is important to transmit hologram data in real time. In this paper, we propose a rapid CGH computation method by applying an arraying of a down-scaled hologram with the multiplication of a shifted concave lens function array. Compared to conventional angular spectrum method (ASM) calculation, we achieved about 39 times faster calculation speed for 3840 × 2160 pixel CGH calculation. Through the numerical investigation and experiments, we verified the degradation of reconstructed hologram image quality made by the proposed method is not so much compared to conventional ASM.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.11
• /
• pp.2473-2478
• /
• 2009

The latest, Digital art is attempt new field's Art, that is utilize variously digital media image, sound, simulation, 3D holography. A large number of Digital Art is contact with the audience in pavilion(limit place and limit period). However, It will be possible, Digital Art can use place digital form media even there are indoor, outdoor, anywhere. Prior to study, I was to analyze the feature of Digital Art in order to using Digital Art, Interactivity make communication between humans and the art as well as cause audience participation, and take a role of bridge between human and space. A study was base on the relationship between human and space, space and Digital Art, Digital Art and human taken the focus interaction between human and space, and Interactivity of Digital Art. This paper analyze reciprocal action for utilize Digital Art in indoor space design, and this paper study expression about indoor design base of interactive.

• Journal of the Institute of Convergence Signal Processing
• /
• v.12 no.3
• /
• pp.181-187
• /
• 2011

In this thesis, digital in-line holographic microscopy has been implemented with enhanced phase shifting technique. It was demonstrated that the zero-order diffraction noise and the twin image can be eliminated by phase-shifting interferometry very effectively. Also the experimental and numerical reconstruction has been incorporated into one set-up operating in real time. Experimental results and the analysis of the phase map indicate that the proposed system can be very useful for the measurement of microscopic objects and 3-D microscopy.

• 한국가시화정보학회:학술대회논문집
• /
• 2007.11a
• /
• pp.116-118
• /
• 2007

Three-dimensional (3D) velocity field information of a laminar flow in a curved micro tube of circular cross-section has been measured using a digital micro holographic particle tracking velocimetry (HPTV). The temporal evolution of instantaneous velocity field of a water flow in a curved micro tube of $100\;{\mu}\;m$ and $300\;{\mu}\;m$ in inner diameter was obtained. The 3D mean velocity field distribution was obtained quantitatively by statistical-averaging of instantaneous velocity fields. At low Dean number (De), a secondary flow was not generated in the curved tube. With increasing Dean number, the secondary flow constituted of two large-scale counter-rotating vortices was formed due to enhanced centrifugal force. To reveal the flow characteristics of high Dean numbers, trajectories of fluid particles were evaluated experimentally from the 3D velocity fields data measured by the HPTV technique. The present experimental results, especially the 3D particle trajectories, would be helpful to design and to understand the mixing phenomena in 3D curved passages of various curved micro-tubes or micro-channels.