• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.161.6-161
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• 2001

Confocal scanning microscopy (CSM) has an important role as the three-dimensional profiler. An image distribution can be reconstructed by a correlation analysis of spots with the bandwidth of radio frequency. But it is a serious problem for the high performance to align the optical components. Especially, the parasitic motion of focus on the detector gives rise to the fatal distortion of an image profile named the extinction effect while using acousto-optical(AO) deflector. An image profile can be regenerated in CSM with many advantages of non-contact, high speed and high resolution comparatively. In addition to the axial response of the primary focus, the lateral movement of it gives a necessity of the unitary lens to the scanning system. While using the beam deflector, the pupil of beam may be fixed at the nominal position. Furthermore, the use of a deflector may result in ...

• Journal of the Korean Physical Society
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• v.80
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• pp.117-122
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• 2022

The Belle II detector at the SuperKEKB e⁺e^- collider in Japan is designed for precise measurements of weak interaction parameters and new physics beyond the Standard Model; therefore, it requires very high instantaneous luminosity. To handle such high luminosity, the level-1 trigger system in the Belle II experiment is designed to efficiently trigger events of interest with the highest efficiency. Among many sub-detectors, track reconstruction of charged particles is performed using information collected from the central drift chamber. Therefore, the central drift chamber-based trigger plays a central role in distinguishing specific types of physics based on fast track reconstruction. To improve the longitudinal position resolution of a track vertex and for the fine-tuning of trigger signal timing, the time of the collision, which we call event time, is necessary. We developed an event time finding algorithm using the wire hit time information obtained from the central drift chamber and validated our algorithm through Monte Carlo simulation.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.33-38
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• 2008

Purpose: The Gated cardiac blood pool scan is non-invasive method that a quantitative evaluation of left ventricular function. Also this scan have shown the value of radionuclide ejection fraction measurements during the course of chemotherapy as a predictor of cardiac toxicity. Therefore a reliable method of monitoring its cardiotoxic effects is necessary. the purpose of this study is to minimize the overestimate of left ventricular ejection fraction (LVEF) by modified body position to reduce the influence of scattered rays from surrounding organs of the heart in the background region of interest. Materials and Methods: Gated cardiac blood pool scan using in vivo $^{99m}Tc$-red blood cell (RBC) was carried out in 20 patients (mean $44.8{\pm}8.6$ yr) with chemotherapy for a breast carcinoma. Data acquisition requires about 600 seconds and 24 frames of one heart cycle by the multigated acquisition mode, Synchronization deteriorates toward the end of the cycle and with the distance from the trigger signal (R-wave) by ECG gating. Gated cardiac blood pool scan was studied with conventional method (supine position and the detector head in $30-45^{\circ}$ left anterior oblique position and caudal $10-20^{\circ}$ tilt) and compared with modified method (left lateral flexion position with 360 mL of drinking water). LVEF analysis was performed by using the automatically computer mode. Results: The ROI counts of modified scan method were lower than LV conventional method ($1429{\pm}251$ versus $1853{\pm}243$, <0.01). And LVEF of modified method was also decrease compared with conventional method ($58.3{\pm}5.6%$ versus $65.3{\pm}6.1%$, <0.01). Imaging analysis indicated that stomach was expanded because of water and spleen position was changed to lateral inferior compared with conventional method. Conclusion: This study shows that the modified method in MUGA reduce the influence of scattered rays from surrounding organs. Because after change the body position to left lateral flexion and drinking water, the location of spleen, left lobe of liver and stomach had changed and they could escaped from background ROI. Therefore, modified method could help to minimize the overestimate LVEF (%).

• Korean Journal of Digital Imaging in Medicine
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• v.14 no.2
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• pp.39-46
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• 2012

Purpose : The purpose of this study was to reduce Entrance Surface Dose and maintain image quality by changing Source to Image receptor Distance. And we'd like to compare ESD on this study to DRLs in other contries. Materials and Methods : We used indirect DR system(Definium 8000, General Electric, USA)and phantom(ART-200X, Flukebiomedical, USA),glass dosimeters(GD-352M, Asahi Techno Glass, Japan)for this study. The imagies were obtained throuh 80kVp fixed, and different tube currents using AEC mode in $16{\times}16$(inch) field size and changing Source to Image receptor Distance from 100 cm to 130 cm per 10 cm unit. The phantom with attaching 5 glass dosimeters on abdomonal skin was set at supine and erect position as a anterioposterial projection on detector For measuring Entrance Surface Dose. Image analysis was conducted by histograms of Image J(1.46r) which was given from National Institutes of Health(NIH). Results : Due to inverse square law of distance, the tube currents were increasing 42.6 % in supine position and 32.6 % in erect position according to the change of Source to Image receptor Distance. While Entrance Surface Doses were rapidly decreasing 14.2 % in supine position and 29.4 % in erect position according to the change of Source to Image receptor Distance. As the results of histogram using Image J, pixel mean values from 100 cm to 110 cm, 120 cm and 130 cm were decreasing each 1.4%, 2.5%, 2.7%, 4.5%, 2.2 %, 5.8 % in supine, erect position. While standard deviations from 100 cm to 110 cm, 120 cm and 130 cm were increasing each 1.4 %, 2.5 %, 2.5 %, 4.0 %, 2.0 %, 4.9 % Consequently, there are no significant differences in abdomen images taken. Conclusion: As the results described above, we strongly recommend using long Sourceto Image receptor Distance than 100cm that we have been using. So, we should deliver less Entrance Surface Dose to the patients while maintaining image quality in abdomen radiography.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.4
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• pp.377-385
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• 2015

This paper proposes a novel forward vehicle tracking algorithm based on the WMIL(Weighted Multiple Instance Learning) equipped with a particle filter. In the proposed algorithm Haar-like features are used to train a vehicle object detector to be tracked and the location of the object are obtained from the recognition result. In order to combine both the WMIL to construct the vehicle detector and the particle filter, the proposed algorithm updates the object location by executing the propagation, observation, estimation, and selection processes involved in particle filter instead of finding the credence map in the search area for every frame. The proposed algorithm inevitably increases the computation time because of the particle filter, but the tracking accuracy was highly improved compared to Ababoost, MIL(Multiple Instance Learning) and MIL-based ones so that the position error was 4.5 pixels in average for the videos of national high-way, express high-way, tunnel and urban paved road scene.

• Journal of Sensor Science and Technology
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• v.4 no.4
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• pp.62-69
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• 1995

We have developed the digital radiography system applied by the one dimensional multiwire proportional chamber. X-ray position signals were obtained from anode wires which were connected to counters through amplifiers and discriminators. The chamber was made of gas flow type and detector gas was P10. The threshold voltage which gives to the discriminator is independent on the neighboring channels. This improved the uniformity of the detector. Then the differential nonlineality is ${\pm}4%$. Increasing the gas pressure, the spatial resolution is about 1.4-mm at which the pitch of the anode wire is 2-mm. The object is scanned in vertical direction to take an image. The number of pixels in the image is $32{\times}32$.

• Journal of Astronomy and Space Sciences
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• v.24 no.2
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• pp.155-166
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• 2007

We have designed a high resolution proton and electron telescope for the detection of high energy particles, which constitute a major part of the space environment. The flux of the particles, in the satellite orbits, can vary abruptly according to the position and solar activities. In this study, a conceptual design of the detector, for adapting these variations with a high energy resolution, was made and the performance was estimated. In addition, a parallel processing algorithm was devised and embodied using FPGA for the high speed data processing, capable of detecting high flux without losing energy resolution, on board a satellite.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.165-170
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• 2003

This paper presents an integrated approach to unconstrained face recognition in arbitrary scenes. The front end of the system comprises of a scale and pose tolerant face detector. Scale normalization is achieved through novel combination of a skin color segmentation and log-polar mapping procedure. Principal component analysis is used with the multi-view approach proposed in[10] to handle the pose variations. For a given color input image, the detector encloses a face in a complex scene within a circular boundary and indicates the position of the nose. Next, for recognition, a radial grid mapping centered on the nose yields a feature vector within the circular boundary. As the width of the color segmented region provides an estimated size for the face, the extracted feature vector is scale normalized by the estimated size. The feature vector is input to a trained neural network classifier for face identification. The system was evaluated using a database of 20 person's faces with varying scale and pose obtained on different complex backgrounds. The performance of the face recognizer was also quite good except for sensitivity to small scale face images. The integrated system achieved average recognition rates of 87% to 92%.

• Journal of Biomedical Engineering Research
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• v.41 no.4
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• pp.165-171
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• 2020

In this study, it focuses on the development of radiographic devices for patellar imaging. On the previous X-ray examination of patella and patellofemoral joint, it analyzed the problems which could affect the results: unstable patients' pose, radiation exposure, and deterioration of image quality. The purpose of the research is to propose a future use of a developed device with an explanation of the process, function, and advantage of the device including the methods. The device is developed to focus on the diagnosis of the longitudinal and longitudinal fractures of the patella and patella/femoral joint, displacement such as dislocation, bone formation, stenosis of the patella/femorla joint, and cartilage wear. Due to the patient's anxious posture, it caused a shaking image, overlapping structures, and etcs, these factors challenge to diagnose accurately. In addition, the existing Settegast method and Hughston method, which are most frequently performed in the hospital field, are not suitable for the presence or absence of features or dislocation due to the heavy load on the patella of the patient. The developed device requires patients in a lying position and placing only their leg on the device, it increases the conveniences of the examination and decreases unnecessary radiation exposure of the patient except the patellar examination area. Moreover, one of the systems in the device fixes the detector, where the patients no longer need to hold the detector nor be in unstable posture, but describes the structure of the patella/femoral joint more clearly. Hoping the device will apply to more patients.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1312-1317
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• 2003

This paper presents an integrated approach to unconstrained face recognition in arbitrary scenes. The front end of the system comprises of a scale and pose tolerant face detector. Scale normalization is achieved through novel combination of a skin color segmentation and log-polar mapping procedure. Principal component analysis is used with the multi-view approach proposed in[10] to handle the pose variations. For a given color input image, the detector encloses a face in a complex scene within a circular boundary and indicates the position of the nose. Next, for recognition, a radial grid mapping centered on the nose yields a feature vector within the circular boundary. As the width of the color segmented region provides an estimated size for the face, the extracted feature vector is scale normalized by the estimated size. The feature vector is input to a trained neural network classifier for face identification. The system was evaluated using a database of 20 person's faces with varying scale and pose obtained on different complex backgrounds. The performance of the face recognizer was also quite good except for sensitivity to small scale face images. The integrated system achieved average recognition rates of 87% to 92%.