• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.422-430
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• 1996

The automated scanning laser Doppler vibrometer (LDV) has been designed, and built to measure in-plane displacements associated with waves propagating on vibrating structures. Use of optical fibers allows the compact design of a laser probe head which can be scanned over the vibrating structures. An algorithm for automated self-alignment of the laser probe is developed. The system is completely automated for scanning over the structures, focusing two laser beams at each data point until the detected vibration signal is stable, and for recording and transferring the data to a system computer. The automated system allows one to get extensive data of the vibration field over the structures. The system is tested by scanning a piezoelectric cylindrical shell and a plate excited by a continuous signal and by a pulse signal, respectively. Results show that the automated scanning LDV system can be a useful tool to measure the in-plane vibration field and to detect the elastic waves propagating on the vibrating structures.

• Explosives and Blasting
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• v.37 no.3
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• pp.34-42
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• 2019

An electronic initiation system that can support various types of field blasting works has been developed and put into practice. The newly developed equipment called Hanwha Electronic Blasting System (HEBS) II has three basic operation modes of scanning, logging, and tagging, among which the blaster can choose the most suitable one for the specific site conditions. In the present study, the work efficiency of the system in the scanning, logging and tagging modes was compared with that of the previous non-electric detonator. The results were estimated based on the aspects of the ground vibration, fragmentation, and digging time. It was found that the ground vibration, fragmentation, and digging time of the new system were decreased by about 45%, 31%, and 13%, respectively, with respect to the previous system. This result confirms that the new system is very efficient in the scanning, logging and tagging modes under the field conditions.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.768-772
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• 2008

Various scanning systems have been studied in many industrial areas to acquire a range data or to reconstruct an explicit 3D model. Currently optical technology has been used widely by virtue of noncontactness and high-accuracy. In this paper, we describe a 3D laser scanning system developped to reconstruct the 3D surface of a large-scale object such as a curved-plate of ship-hull. Our scanning system comprises of 4ch-parallel laser vision modules using a triangulation technique. For multi laser vision, calibration method based on least square technique is applied. In global scanning, an effective method without solving difficulty of matching problem among the scanning results of each camera is presented. Also minimal image processing algorithm and robot-based calibration technique are applied. A prototype had been implemented for testing.

• Korean Journal of Optics and Photonics
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• v.27 no.1
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• pp.32-40
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• 2016

The characteristics of an optical system vary depending on wavelength and ambient temperature. Based on the thin-lens approximation, we investigate the conditions for stabilizing an optical system against wavelength and temperature variations at the same time. The conditions are applied to designing a laser scanning system consisting of two lenses. The change in the effective focal length of the scanning system against wavelength and temperature variations is very small, as expected.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.699-702
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• 2004

Next generation lithography technologies, such as EBL(Electron Beam Lithography), X-ray lithography, SPL(Scanning Probe Lithography), have been studied widely for getting over line width limitation of photolithography. Among the next generation lithography technologies, SPL has been highlighted because of its high resolution advantage. But is also has problem which are slow processing time and sample size limitation. The purpose of this study is complement of present SPL system. Brand new SPL system was made. SPL test was performed with the system in ultra thin PMMA(polymethlymethacrylate) film.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1016-1023
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• 2022

In proton therapy, a highly conformal proton dose can be delivered to the tumor by means of the steep distal dose penumbra at the end of the beam range. The proton beam range, however, is highly sensitive to range uncertainty, which makes accurately locating the proton range in the patient difficult. In-vivo range verification is a method to manage range uncertainty, one of the promising techniques being prompt gamma imaging (PGI). In earlier studies, we proposed gamma electron vertex imaging (GEVI), and constructed a proof-of-principle system. The system successfully demonstrated the GEVI imaging principle for therapeutic proton pencil beams without scanning, but showed some limitations under clinical conditions, particularly for pencil beam scanning proton therapy. In the present study, we upgraded the GEVI system in several aspects and tested the performance improvements such as for range-shift verification in the context of line scanning proton treatment. Specifically, the system showed better performance in obtaining accurate prompt gamma (PG) distributions in the clinical environment. Furthermore, high shift-detection sensitivity and accuracy were shown under various range-shift conditions using line scanning proton beams.

• Current Optics and Photonics
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• v.7 no.2
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• pp.176-182
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• 2023

Optical coherence tomography (OCT) is being developed to guide various ophthalmic surgical procedures. However, the high cost of the intraoperative OCT system limits its availability mostly to the largest hospitals and healthcare systems. In this paper, we present a design and evaluation of a low-cost intraoperative common-path free-hand scanning OCT system. The lensed fiber imaging probe is designed and fabricated for intraocular use and the free-hand scanning algorithm that could operate at a low scanning speed was developed. Since the system operates at low frequencies, the cost of the overall system is significantly lower than other commercial intraoperative OCT systems. The assembled system is characterized and shows that it meets the design specifications. The handheld OCT imaging probe is tested on multilayer tape phantom and ex-vivo porcine eyes. The results show that the system could be used as an intraoperative intraocular OCT imaging device.

• The Korean Journal of Nuclear Medicine
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• v.8 no.1_2
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• pp.39-47
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• 1974

The purpose of this study is to evalute the diagnostic value of the brain scanning and compare the diagnostic accuracy between the scan and carotid angiography. 109 cases which are proved by specific method to each disease, are analized to evalute the diagnostic value of the brain scanning. The 70 cases among the proven 109 case are performed both the scanning and the arteriography and analized to compare the accuracy between the scanning and the arteriography. The results are as follows; 1. The diagnostic accuracy of the brain scanning in the diseases of the central nervous system is 64.2%. 2. The diagnostic accuracy of the brain scanning in the brain tumor is 88%, especially brain abscess. glioma, glioblastoma multiforme, menirgioma and metastic tumor show high positive rate. 3. The diagnostic accuracy in the disease of the brain vessels is 54 %. 4. The comparison of the diagnostic value between the scanning and the arteriography is as follows; 1) The diagnostic value in all diseases of the central nervous system is nearly equal. 2) The diagnostic accuracy in the intracranial tumor is slightly higher in the brain scanning (90.9%) than in the arteriography (81.8%). 3) The diagnostic accuracy in the disease of the brain vessel is higher in the arteriography (77.3%) than in the scanning (54.5%). 5) The diagnostic value when combining the scanning and the arteriography, is 83% in the all central nervous system-lesions, 97% in the cranial tumor and 81.8% in the disease of the central nervous system-vessel. The brain scanning is simple and safe procedure, and moreover has excellent diagnostic value in the diagnosis of the central nervous system lesion.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.841-844
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• 2003

In the semiconductor and the optical industry a new transport system which can replace the conventional sliding system is required. These systems are driven by magnetic field and conveyer belt. The magnetic field damages semiconductor and contact force scratches the optical lens. The ultrasonic wave driven system can solve these problem. In this paper, the vibration behavior of flexural beam in the ultrasonic transport system is verified using Laser Scanning Vibrometer. The experiments for verifying vibration are performed in three conditions such as in the maximum transport speed, in the zero speed, and in the change of transport direction.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.254-257
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• 2011

This study was performed to development a dental three-dimensional laser scanning system and measure the accuracy of new adjustable lower dental impression trays. Multiple impressions of a resin master model were made with custom, stock and new adjustable trays and vinyl polysiloxane impression material. The lower master model and resulting cast were compared using an dental scanning system. Each 3D image was superimposed onto the lower master model image and analyzed with custom software. Multiple measurements of the lower master model and casts were analyzed to determine the accuracy of tray types.