• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.1
• /
• pp.70-77
• /
• 2014

This paper proposes a novel localization algorithm based on ego-motion which used Lucas-Kanade Optical Flow and warping image obtained through fish-eye lenses mounted on the robots. The omnidirectional image sensor is a desirable sensor for real-time view-based recognition of a robot because the all information around the robot can be obtained simultaneously. The preprocessing (distortion correction, image merge, etc.) of the omnidirectional image which obtained by camera using reflect in mirror or by connection of multiple camera images is essential because it is difficult to obtain information from the original image. The core of the proposed algorithm may be summarized as follows: First, we capture instantaneous $360^{\circ}$ panoramic images around a robot through fish-eye lenses which are mounted in the bottom direction. Second, we extract motion vectors using Lucas-Kanade Optical Flow in preprocessed image. Third, we estimate the robot position and angle using ego-motion method which used direction of vector and vanishing point obtained by RANSAC. We confirmed the reliability of localization algorithm using ego-motion based on fisheye warping image through comparison between results (position and angle) of the experiment obtained using the proposed algorithm and results of the experiment measured from Global Vision Localization System.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.39.4-40
• /
• 2017

According to the Korean government's Long-term Space Development Plan 2040, "Creative space science research" is included in a statement to investigate the origin and evolution of the universe by conducting a series of Korean space telescope missions: launch of space telescopes on a small satellite and an international collaboration explorer by 2020, a mid-size domestic space telescope by 2030, and a large size Korea leading international space telescope by 2040. We studied the feasibility of the future Korean Space Telescope (KST) for a mid-size domestic satellite platform. In order to pursue the uniqueness of the science program, we consider a wide range of observing wavelength (0.2um ~ 2.0um) with a spectral resolution of R~6 in the NUV and optical bands, and R~30 for NIR, utilizing an off-axis TMS(Three Mirror System) optics with a wide field of view ($2{\times}4$ degrees) which is optimized for ultra-low surface brightness sources. The main science goals of the mission include investigations of the galaxy formation, cosmic web, and the cosmic background radiation in the NUV-NIR regions. In this paper, we present the science cases and several technical challenges to be resolved along with the future milestones for the success of the KST mission.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.1
• /
• pp.147-154
• /
• 2009

This paper presents a grating~integrated SPR (Surface Plasmon Resonance) sensor chip for simple and inexpensive biomolecule detection. The grating-integrated SPR sensor chip has two sensing channels having a nano grating for SPR coupling. An external mirror is used for multi channel SPR sensing. The present sensor chip replaces bulky and expensive optical components, such as fiber-optic switches or special shaped prisms, resulting in a simple and inexpensive wavelength modulated multi-channel SPR sensing system. We fabricate a SPR sensor chip integrated with 835 nm-pitch gratings by a micromolding technique to reduce the fabrication cost. In the experimental characterization, the refractive index sensitivity of each sensing channel is measured as $321.8{\pm}8.1nm$/RI and $514.3{\pm}8.lnm$/RI, respectively. 0.5uM of the target biomolecule (streptavidin) was detected by a $1.13{\pm}0.16nm$ shift of the SPR dip in the 10%-biotinylated sample channel, while the SPR dip in the reference channel for environmental perturbation monitoring remained at the same position. From the experimental results, multi-channel biomolecule detection capability of the present grating-integrated SPR sensor chip has been verified. On the basis of the preliminary experiments, we successfully measured the binding reaction rate for the $2\;nM{\sim}200\;nM$ monoclonal-antibiotin, thus verifying biomolecule concentration detectability of the present SPR sensor chip. The binding reaction rates measured from the present SPR sensor chip agredd well with those from a commercialized SPR sensor.

• Applied Microscopy
• /
• v.41 no.4
• /
• pp.223-228
• /
• 2011

White light scanning interferometry has been employed to analyze surface features of diverse specimens. Long established in the field of materials engineering, the technique provides quantitative three-dimensional data as well as qualitative morphological images. It uses white light that is split and reflected from a reference mirror and an object. Merged together, the light generates interference patterns representing topographical contours of the object surface. The amplitude of the z-axis data is differentiated by gray scale. The technique allows the rapid, noncontact, and wide-field measurements for morphometry of biological specimens including chondrocytes, tooth enamel, and plant leaves. Quantification of the dimension of surface structures such as width, length, and elevation angle could be achievable by white light scanning interferometry. The light reflection from plant leaves has been assumed to be sufficient for the technique. Without special specimen preparations like conductive metal coating, the technique can be increasingly used for quantitative three-dimensional surface measurements of biological specimens.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.4
• /
• pp.1072-1086
• /
• 1998

Transform, subband, and wavelet transform decompositions are powerful linear transformation tools in image coding because of their decorrelating effects on image pixels, the concentration of energy in a few coefficients, their multirat/multiresolution framework, and their frequency splitting, which allows for efficient coding matched to the statistics of each frequency band and to the characteristics of the human visulal system. Thus, a growingbody of research has bee performed to extend these tools in various kinds of modified formations. Hence, in this paper, an overall survey to achieve a general view on these transformation tools have been attempted. Starting from basic tools such as orthogonal transforms, lapped transforms, QMF(quadrature mirror filter) subband filter banks, and wavelet transforms, their hierarchical extensions, vector extensions, and linear time-varying extensions are investugated in detail.

• Korean Journal of Optics and Photonics
• /
• v.10 no.2
• /
• pp.152-156
• /
• 1999

We have developed the pulse-width variable Quenched Dye Laser (QDL). QDL consisted of the dye cell of 5 mm length containing a $2.5{\times}10^{-3}$[mol/l] solution of Rhodamine 6G and the cylindrical lens focal length of 150 mm and quenching mirror. QDL system was pumped by s XeCl excimer laser with 150 mJ pulse energy in a 20 ns pulse at 1 Hz repetition rate. Pulse-width of QDL was measured by a noncollinear intensity autocorrelator. The focused thckness was measured by changing the position of the focusing cylindrical lens. Pulse-width of QDL as a function of the focused thickness (273.0${\mu}{\textrm}{m}$~845.0${\mu}{\textrm}{m}$) varied continuously from 86 ps to 201 ps.

• Current Optics and Photonics
• /
• v.1 no.2
• /
• pp.132-137
• /
• 2017

To investigate the usefulness of optical coherence tomography (OCT) for imaging lymphedema, we directly compared it to other histological methods in a mouse model of lymphedema. We performed detailed imaging of the lymphedema lesion on a mouse tail. We imaged the mouse tail in vivo with OCT and created histopathological samples. We constructed a spectrometer-based OCT system using a fiber-optic Michelson interferometer. The light was directed to 50:50 couplers that split the light into reference and sample arms. Backscattered light from a reference mirror and the sample produced an interference fringe. An OCT image of the lymphedema model revealed an inflammatory reaction of the skin that was accompanied by edema, leading to an increase in the light attenuation in the dermal and subcutaneous layers. Similar to OCT image findings, histological biopsy showed an inflammatory response that involved edema, increased neutrophils in epidermis and subdermis, and lymphatic microvascular dilatation. Furthermore, the lymphedema model showed an increase in thickness of the dermis in both diagnostic studies. In the mouse tail model of lymphedema, OCT imaging showed very similar results to other histological examinations. OCT provides a quick and useful diagnostic imaging technique for lymphedema and is a valuable addition or complement to other noninvasive imaging tools.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.6
• /
• pp.609-614
• /
• 2014

Cerebellar ataxia is a steadily progressive neurodegenerative disease associated with loss of motor control, leaving patients unable to walk, talk, or perform activities of daily living. Direct motor instruction in cerebella ataxia patients has limited effectiveness, presumably because an inappropriate closed-loop cerebellar response to the inevitable observed error confounds motor learning mechanisms. Recent studies have validated the age-old technique of employing motor imagery training (mental rehearsal of a movement) to boost motor performance in athletes, much as a champion downhill skier visualizes the course prior to embarking on a run. Could the use of EEG based BCI provide advanced biofeedback to improve motor imagery and provide a "backdoor" to improving motor performance in ataxia patients? In order to determine the feasibility of using EEG-based BCI control in this population, we compare the ability to modulate mu-band power (8-12 Hz) by performing a cued motor imagery task in an ataxia patient and healthy control.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.30 no.3
• /
• pp.46-56
• /
• 2002

This landscape design proposal was presented to a design competition for the Culture.Welfare.Administration Complex of Yongin-City which was held by Yongin-City in December, 2001. The site is located at 68-19 Yukbuck-dong, Yongin-City, Kyunggi-do and has an area of 236,449$m^2$. The judging criteria for landscape design set by the Yongin-City could be articulated as follows: an environment friendly design respecting the surrounding environment, a locale as a community center of Yongin-City, a resting place for the welfare of employees and visitors, and finally a place with diverse landscape elements reflecting the individual identity of each facility. This proposal chose the main design concept of this project as‘Nature meets City'. A grove of pine trees fragments the multi building complex, so that‘nature'was brought into the‘city'. A double ground system was introduced to respect the existing topography and to enhance the efficency of the land. This design proposal consists of four segments. Each segment has its own design theme. Outdoor space of this multi-purpose complex was designed with themes of nature, culture, welfare and administration. Space composition with grid and natural looking curvilinear lines was a design motive for this complex. The nature oriented planting design was introduced to respect the existing groves of Mt. Suksung. Specific species were chosen to follow its own spatial character in each space. An environmental sculpture called‘Dream Soaring'was placed in the middle of‘Citizen Plaza'. Its light and feather-looking shape symbolizes the vision of Youngin-City. At night people can watch the diverse color changes on its mirror-like surface.

• Korean Journal of Optics and Photonics
• /
• v.31 no.2
• /
• pp.81-87
• /
• 2020

This study examines the design technology of searchlight optics featuring narrow beam angles and high luminous intensities. Halogen and xenon lamps, which are conventional searchlight sources, are vulnerable to vibration and shock, and are large and heavy, making them difficult to transport. In addition, the parabolic mirror located at the rear of the searchlight has the disadvantages of poor performance and low light efficiency, due to the assembly error produced during manufacturing. To solve this problem, a 1-kW halogen lamp is replaced by a 150-W high-power COB LED, and a high-efficiency TIR lens is designed to meet the target performance. Afterward, the TIR lens array is proposed to solve the surface error generated during optical injection. After a prototype is manufactured based on the designed optical system, the optical performance is confirmed to be excellent, by comparing it to that of a commercial halogen-lamp searchlight.