• Nuclear Medicine and Molecular Imaging
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• v.42 no.2
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• pp.88-97
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• 2008

In this review paper, basic configurations of gamma detectors in SPECT and PET systems were reviewed together with key performance parameters of the imaging system, such as the detection efficiency, the spatial resolution, the contrast resolution, and the data acquisition time for quick understanding of the system-component relationship and future design of advanced systems. Also key elements of SPECT and PET detectors, such as collimators, gamma detectors were discussed in conjunction with their current and future trend. Especially development trend of new scintillation crystals, innovative silicon-based photo-sensors and futuristic room-temperature semiconductor detectors were reviewed for researchers who are interested in the development of future nuclear medical imaging instruments.

• Journal of Biomedical Engineering Research
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• v.36 no.4
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• pp.123-127
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• 2015

Recently, new gamma camera systems enabling low radiation dose imaging have been developed. We reviewed the recent development of these low dose gamma camera systems including high sensitivity detectors, device structures, noise reduction filters, efficient image reconstruction algorithms, low dose protocols, and so on. It is expected that further technological advances reduce both radiation dose and imaging time in gamma camera imaging especially for radiation-sensitive patients such as pediatric patients.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.6
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• pp.391-402
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• 2015

In this paper, we present implementation of backward movement control of truck-trailer vehicles using a fuzzy mode-based control scheme considering practical constraints and computational overhead. We propose a fuzzy feedback controller where output is predicted with the delay of a unit sampling period. Analysis and design of the proposed controller is very easy, because it is synchronized with sampling time. Stability analysis is also possible when quantization exists in the implementation of fuzzy control architectures, and we show that if the trivial solution of the fuzzy control system without quantization is asymptotically stable, then the solutions of the fuzzy control system with quantization are uniformly ultimately bounded. Experimental results using a toy truck show that the proposed control system outperforms a conventional system.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.63-68
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• 2016

Peptides have been developed for in vivo imaging probes against to the specific biomarker in the biological process of living systems. Peptide based imaging probes have been applied to identify and detect their active sites using imaging modalities, such as PET, SPECT and MRI. Especially, tumor receptor imaging with the peptides has been widely used to specific tumor detection. This review discusses the targeting peptides that have been successfully characterized for tumor diagnosis by receptor imaging.

• Current Optics and Photonics
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• v.3 no.4
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• pp.329-335
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• 2019

Wide FOV imaging systems are important for acquiring rich visual information. A conventional catadioptric imaging system deploys a camera in front of a curved mirror to acquire a wide FOV image. This is a cumbersome setup and causes unnecessary occlusions in the acquired image. In order to reduce both the burden of the camera deployment and the occlusions in the images, this study uses a secondary planar mirror in the catadioptric imaging system. A compact design of the catadioptric imaging system and a condition for the position of the secondary planar mirror to satisfy the central imaging are presented. The image acquisition model of the catadioptric imaging system with a secondary planar mirror is discussed based on the principles of geometric optics in this study. As a backward mapping, the acquired image is restored to a distortion-free image in the experiments.

• International Journal of Control, Automation, and Systems
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• v.6 no.6
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• pp.794-799
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• 2008

This paper presents a user identification method at H.264 streaming using watermarking with fingerprints. The watermark can efficiently reduce the potential danger of forgery or alteration. Especially a biometric watermark has convenient, economical advantages. The fingerprint watermark can also improve reliability of verification using automated fingerprint identification systems. These algorithms, however, are not robust against common video compression. To overcome this problem, we analyze H.264 compression pattern and extract watermark after restoring damaged watermark using various filters. The proposed algorithm consists of enhancement of a fingerprint image, watermark insertion using discrete wavelet transform and extraction after restoring. The proposed algorithm can achieve robust watermark extraction against H.264 compressed videos.

• Journal of IKEEE
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• v.15 no.1
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• pp.10-14
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• 2011

In this paper, we present an efficient hardware architecture of unrolling image mapper of catadioptric omnidirectional imaging systems. The catadioptric omnidirectional imaging systems generate images of 360 degrees of view and need to be transformed into panorama images in rectangular coordinate. In most application, it has to perform the panorama unrolling in real-time and at low-cost, especially for high-resolution images. The proposed hardware architecture adopts a software/hardware cooperative structure and employs several optimization schemes using look-up-table(LUT) of coordinate conversion. To avoid the on-line division operation caused by the coordinate transformation algorithm, the proposed architecture has the LUT which has pre-computed division factors. And then, the amount of memory used by the LUT is reduced to 1/4 by using symmetrical characteristic compared with the conventional architecture. Experimental results show that the proposed hardware architecture achieves an effective real-time performance and lower implementation cost, and it can be applied to other kinds of catadioptric omnidirectional imaging systems.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.179-181
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• 2022

동적 비전 센서(Dynamic Vision Sensor)라고도 알려진 이벤트 카메라는 생체에서 영감을 받은 새로운 시각 센서이다. 고정된 속도로 이미지를 생성하는 기존 카메라와 달리 이벤트 기반 카메라의 픽셀은 독립적이고 비동기적으로 작동한다. 기존 프레임 기반 카메라보다 이벤트 기반 카메라가 움직임을 포착하는데 더 적합하며 모션 블러(Motion Blur)가 없고 시간 해상도가 높다는 이점을 통해 고속카메라로 활용할 수 있다. 본 논문은 이벤트 카메라의 높은 시간 해상도와 동적 범위, 낮은 지연시간, 전력 소비량의 이점을 활용하여 움직이는 물체를 모션 블러 없이 포착하는 이벤트 기반 물체 추적 시스템을 제안한다. 실험을 통해 전체 영상을 포착하는 기존 프레임 기반 카메라에 비해 밝기 변화에 따른 동적 변화만을 추적하는 이벤트 기반 카메라는 모션 블러가 없다는 점을 검증하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.6
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• pp.703-713
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• 2024

Video bit-rate control techniques are essential for efficiently transmitting videos over communication networks. These techniques have been pivotal in broadcasting and internet streaming services, and they could significantly enhance defense capabilities if applied to defense and aerospace imaging systems. Therefore, this paper first reviews the history and standard technologies of video coding, then describes the standard trends of the latest video coding technologies. Finally, it outlines the features of the latest video bit-rate control techniques and discusses their applicability in the defense and aerospace fields.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.821-824
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• 1993

In hazardous conditions, where entry of human operators is restricted, such as high radiation regions in nuclear facilities, a lot of remote inspections and remote handling tasks must be performed. In this study, the stereo imaging system has been developed and the remote handling technique, has been studied to enhance the efficiency of tele-operation. The nozzle dam handling robot is one of the most important robots applied to nuclear facility. The robot will be equipped with the developed stereo imaging system. The stereo imaging system will outstandingly improve the tele installing/removal tasks for nozzle dam.