• 한국광학회지
• /
• 제12권4호
• /
• pp.281-288
• /
• 2001

본 연구에서는 넓은 운용온도에서 열영상 장비의 광학성능을 유지하도록 하기 위한 비열화 분석 및 시험을 수행하였다. 비열화 분석은 광학계 설계를 위한 컴퓨터 프로그램인 Code-V와 SIGMA2100으로 수행하였으며 비열화 시험은 열영상 장비와 콜리메이터를 온도챔버에 함께 넣어 온도에 따른 영상을 녹화하였다. 2차원배열 검출기를 사용한 20:1 줌 열영상 장비를 가지고 비열화 시뮬레이션을 수행하였으며 그 결과를 이용하여 줌궤적을 보상하였다. 비열화 시험을 통하여 온도변화에 따라 줌궤적어 적절히 작동되어 $-32^{\circ}C-+50^{\circ}C$의 온도범위 내에서 만족할 만한 광학성능이 유지되는 것을 확인하였다.

• 정보저장시스템학회논문집
• /
• 제9권1호
• /
• pp.17-21
• /
• 2013

Optical coherence tomography (OCT) allows non-invasive, cross-sectional optical imaging of biological tissue with high spatial resolution and acquisition speed. In principle, it is analogous to ultrasound imaging, but uses near-infrared light instead of ultrasound, measuring the time-delay of back-scattered light from within biological tissue. Compared to ultrasound imaging, it exhibits superior spatial resolution (1~10 um) and high sensitivity. Therefore, OCT has been applied to a wide range of applications such as cellular imaging, ophthalmology and cardiology. Here, we describe a novel application of OCT technology in visualizing microneedles embedded in tissue that is developed to deliver drugs into the dermis without the injection mark in the human skin. Detailed three-dimensional structural images of microneedles and biological tissues were obtained. Examining structural modification of microneedles and tissues during insertion process would enable to evaluate performance of various types of microneedles in situ.

• Current Optics and Photonics
• /
• 제5권6호
• /
• pp.606-616
• /
• 2021

A photonic integrated interferometric imaging system possesses the characteristics of small-scale, low weight, low power consumption, and better image quality. It has potential application for replacing conventional large space telescopes. In this paper, the principle of photonic integrated interferometric imaging is investigated. A novel lenslet array arrangement and lenslet pairing approach are proposed, which are helpful in improving spatial frequency coverage. For the novel lenslet array arrangement, two short interference arms were evenly distributed between two adjacent long interference arms. Each lenslet in the array would be paired twice through the novel lenslet pairing approach. Moreover, the image reconstruction model for optical interferometric imaging based on compressed sensing was established. Image simulation results show that the peak signal to noise ratio (PSNR) of the reconstructed image based on compressive sensing is about 10 dB higher than that of the direct restored image. Meanwhile, the normalized mean square error (NMSE) of the direct restored image is approximately 0.38 higher than that of the reconstructed image. Structural similarity index measure (SSIM) of the reconstructed image based on compressed sensing is about 0.33 higher than that of the direct restored image. The increased spatial frequency coverage and image reconstruction approach jointly contribute to better image quality of the photonic integrated interferometric imaging system.

• BMB Reports
• /
• 제55권6호
• /
• pp.267-274
• /
• 2022

Molecular imaging is used to improve the disease diagnosis, prognosis, monitoring of treatment in living subjects. Numerous molecular targets have been developed for various cellular and molecular processes in genetic, metabolic, proteomic, and cellular biologic level. Molecular imaging modalities such as Optical Imaging, Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), and Computed Tomography (CT) can be used to visualize anatomic, genetic, biochemical, and physiologic changes in vivo. For in vivo cell imaging, certain cells such as cancer cells, immune cells, stem cells could be labeled by direct and indirect labeling methods to monitor cell migration, cell activity, and cell effects in cell-based therapy. In case of cancer, it could be used to investigate biological processes such as cancer metastasis and to analyze the drug treatment process. In addition, transplanted stem cells and immune cells in cell-based therapy could be visualized and tracked to confirm the fate, activity, and function of cells. In conventional molecular imaging, cells can be monitored in vivo in bulk non-invasively with optical imaging, MRI, PET, and SPECT imaging. However, single cell imaging in vivo has been a great challenge due to an extremely high sensitive detection of single cell. Recently, there has been great attention for in vivo single cell imaging due to the development of single cell study. In vivo single imaging could analyze the survival or death, movement direction, and characteristics of a single cell in live subjects. In this article, we reviewed basic principle of in vivo molecular imaging and introduced recent studies for in vivo single cell imaging based on the concept of in vivo molecular imaging.

• 대한핵의학회지
• /
• 제38권2호
• /
• pp.111-114
• /
• 2004

Molecular imaging provides a visualization of normal as well as abnormal cellular processes at a molecular or genetic level rather than at a anatomical level. Conventional medical imaging methods utilize the imaging signals produced by nonspecific physico-chemical interaction. However, molecular imaging methods utilize the imaging signals derived from specific cellular or molecular events. Because molecular and genetic changes precede anatomical change in the course of disease development, molecular imaging can detect early events in disease progression. in the near future, through molecular imaging we can understand basic mechanisms of disease, and diagnose earlier and, subsequently, treat earlier intractable diseases such as cancer, neuro-degenerative diseases, and immunologic disorders. In beginning period, nuclear medicine started as a molecular imaging, and has had a leading role in the field of molecular imaging. But recently molecular imaging has been rapidly developed. Besides nuclear imaging, molecular imaging methods such as optical imaging, magnetic resonance imaging are emerging. Each imaging modalities have their advantages and weaknesses. The opportunities from molecular imaging look bright. We should try nuclear medicine continues to have a leading role in molecular imaging.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
• /
• pp.290-291
• /
• 2003

Optical Coherence Tomography is a new medical dianostic imaging technology which can perform micron resolution cross-sectional or tomograpic imaging in biological tissue. In this paper, we analyze OCT system. And we have 2-dimensional OCT image implementation using low coherence SLD.

• Journal of Information Display
• /
• 제13권2호
• /
• pp.83-89
• /
• 2012

The crosstalk evaluation of multiview autostereoscopic three-dimensional (3D) displays is discussed, with both the human and technical factors investigated via image quality assessment. In the imaging performance measurements and analysis for a multiview autostereoscopic display prototype equipment, it was inferred that crosstalk would have both a positive and a negative effect on the imaging performance of the equipment. The importance of the attached diaphragm in the crosstalk evaluation was proposed and then experimentally verified, using the developed prototype equipment. The luminance distribution and crosstalk situation were given, with two different diaphragm arrays applied. The analysis results showed that the imaging performance of this 3D display system can be improved with minimum changes to the system structure.

• Journal of the Optical Society of Korea
• /
• 제16권1호
• /
• pp.42-46
• /
• 2012

We have developed a fluorescence optical detection system using a digital micromirror device (DMD) for monitoring 3D cell culture matrices in situ. Full 3D imaging with fast scanning speed was implemented by the combined action of a DMD and a motorized stage. Imaging results with fluorescent microbeads measure the minimum axial resolution of the system as $6.3{\mu}m$, while full 1-mm scanning through 3D alginate-based matrix was demonstrated. For cell imaging, improved images were obtained by removing background fluorescence although the scanning distance was reduced because of low intracellular fluorescence efficiency. The system is expected to be useful to study various dynamics and behaviors of 3-dimensionally cultured cells in microfluidic systems.

• Current Optics and Photonics
• /
• 제7권5호
• /
• pp.537-544
• /
• 2023

Differential phase contrast (DPC) microscopy, a central quantitative phase imaging (QPI) technique in cell biology, facilitates label-free, real-time monitoring of intrinsic optical phase variations in biological samples. The existing DPC imaging theory, while important for QPI, is grounded in paraxial diffraction theory. However, this theory lacks accuracy when applied to high numerical aperture (NA) systems that are vital for high-resolution cellular studies. To tackle this limitation, we have, for the first time, formulated a nonparaxial DPC imaging equation with a transmission cross-coefficient (TCC) for high NA DPC microscopy. Our theoretical framework incorporates the apodization of the high NA objective lens, nonparaxial light propagation, and the angular distribution of source intensity or detector sensitivity. Thus, our TCC model deviates significantly from traditional paraxial TCCs, influenced by both NA and the angular variation of illumination or detection. Our nonparaxial imaging theory could enhance phase retrieval accuracy in QPI based on high NA DPC imaging.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2001년도 하계학술발표회
• /
• pp.164-165
• /
• 2001

No Abstract.See Full-text