• Journal of Multimedia Information System
• /
• 제3권3호
• /
• pp.47-52
• /
• 2016

This research paper examines the usage of graphic imaging in Holographic Projections to further advance the medical field. It highlights the importance and necessity of this technology as well as avant-garde techniques applied in the process of displaying images in digital holography. This paper also discusses the different types of applications for holograms in society today. Different tools were utilized to transfer a set of a cancer patient's brain tumor data into data used to produce a 3D holographic image. This image was produced through the transfer of data from one program to another. Through the use of semi-automatic segmentation through the seed region method, we were able to create a 3D visualization from Computed Tomography (CT) data.

• Journal of the Optical Society of Korea
• /
• 제15권3호
• /
• pp.244-251
• /
• 2011

We propose a new 2-step phase-shifting digital holographic optical encryption technique and analyze tolerance error for this cipher system. 2-step phase-shifting digital holograms are acquired by moving the PZT mirror with phase step of 0 or ${\pi}$/2 in the reference beam path of the Mach-Zehnder type interferometer. Digital hologram with the encrypted information is Fourier transform hologram and is recorded on CCD camera with 256 gray-level quantized intensities. The decryption performance of binary bit data and image data is analyzed by considering error factors. One of the most important errors is quantization error in detecting the digital hologram intensity on CCD. The more the number of quantization error pixels and the variation of gray-level increase, the more the number of error bits increases for decryption. Computer experiments show the results to be carried out encryption and decryption with the proposed method and the graph to analyze the tolerance of the quantization error in the system.

• Journal of information and communication convergence engineering
• /
• 제10권2호
• /
• pp.205-209
• /
• 2012

To manufacture a real time digital holographic display system capable of being applied to next-generation television, it is important to rapidly generate a digital hologram. In this paper, we analyze digital hologram rendering based on a computer computation scheme. We analyze previous recursive methods to identify regularity between the depth-map image and the digital hologram.

• 한국광학회지
• /
• 제5권3호
• /
• pp.372-378
• /
• 1994

홀로그램 결상의 비점수차 특성을 이용하여 최적 관찰 위치를 홀로그램으로부터 충분히 멀리 하고, 관찰되는 물체상을 홀로그램면 앞에 튀어나오도록 할 수 있는 2-step 무지개 홀로그램의 제작 구성을 제안하였다. 제안된 구성은 기준빔과 재생빔의 파면차에 의한 비점수차로 생기는 상 분리 특성과 원주형렌즈에 의한 비점수차의 증감 특성을 조합하여 상 분리의 조절이 가능하다는 점을 이용하고 있다. 제안된 방법으로 제작된 비점수차 무지개 홀로그램은 백색광 재생시, 홀로그램으로부터 관찰자를 향해 앞으로 튀어 나온 물체의 상에 대해서도 좋은 선명도를 유지할 수 있음을 보여주었다.

• Journal of the Optical Society of Korea
• /
• 제13권2호
• /
• pp.173-177
• /
• 2009

Digital holographic microscopy allows optical path difference measurement. Optical path difference depends on the both refractive index and morphology of sample. We developed a dual-wavelength in-line digital holographic microscope that can measure simultaneously the refractive index and morphology of a sample, providing highly precise three-dimensional information. Here we propose theoretical and experimental methods for dual-wavelength in-line digital holographic microscopy. The measured data were reasonable, although there was data error. By improving the experimental method, we could measure the refractive index more precisely and obtain more accurate three-dimensional information on samples.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2000년도 춘계학술대회논문집
• /
• pp.1479-1486
• /
• 2000

This paper introduces the improved moving frame acoustic holography (MFAH) method and its application. MFAH allows us to visualize the noise generated by moving noise sources by employing a vertical line array of microphones affixed to the ground. The sound field generated by moving sources is different from that of stationary ones due to the movement of the sources. Therefore the measured sound pressure by the microphone on the ground has to be processed so that it cooperates the effect of the movement. This paper discusses the effect of moving noise sources on the obtained hologram by MFAH. This assures the applicability of MFAH to the visualization of moving sources. This paper also reviews the improved MFAH that can visualize a coherent narrow band noise and a pass-by noise. The practical applicability of the improved MFAH was demonstrated by visualizing tire noise during a pass-by test.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2010년도 춘계학술대회 논문집
• /
• pp.197-200
• /
• 2010

In some cases it is important to be able to measure not only the total sound intensity on a panel surface in a vehicle cabin, but also the components of that intensity due to sound radiation and due to absorption from the incident field. For example, these intensity components may be needed for calibration of energy flow models of the cabin noise. A robust method based on surface absorption coefficient measurement is presented in his paper.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 추계학술대회 논문집
• /
• pp.377-383
• /
• 1996

Recently, a new technique called Electronic Speckle Pattern Inteferometry(ESPI) has been developed to overcome the drawbacks of existing holography. This technique enable real-time interference fringes to be displayed directly on TV monitor without recourse to any form of photographic processing. This research was carried out for the purpose of applying the vibration analysis method employing Electronic Speckle Pattern Interference technique to the vibration analysis of uniform rectangular cantilever plate, The natural vibration frequencies found by ESPI were in fair agreement with theoretical eigen frequencies acquired using theoretical formula G. B. Warburton proposed.

• 대한기계학회논문집B
• /
• 제33권1호
• /
• pp.1-8
• /
• 2009

Recently microscale biofluid flows have been receiving large attention in various research areas. However, most conventional imaging techniques are unsatisfactory due to difficulties encountered in the visualization of microscale biological flows. Recent advances in optics and digital image processing techniques have made it possible to develop several advanced micro-PIV/PTV techniques. They can be used to get quantitative velocity field information of various biofluid flows from visualized images of tracer particles. In this paper, as new advanced micro-PIV techniques suitable for biofluid flow analysis, the basic principle and typical applications of the time-resolved micro-PIV and X-ray micro-PIV methods are explained. As a 3D velocity field measurement technique for measuring microscale flows, holographic micro-PTV method is introduced. These advanced PIV/PTV techniques can be used to reveal the basic physics of various microscale biological flows and will play an important role in visualizing veiled biofluid flow phenomena, for which conventional methods have many difficulties to analyze.

• Journal of the Optical Society of Korea
• /
• 제13권1호
• /
• pp.123-130
• /
• 2009

In this paper, we designed and fabricated an input-output coupler system using two or three volume gratings at 632.8nm wavelength. The additional third grating is added at the output coupler to enhance the overall efficiency. The experimental results show that the total system throughput reaches 63% with two-grating and 75% with three-grating input-output coupler. We also present a design method to obtain the desired output power ratio between the gratings.