• Journal of electromagnetic engineering and science
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• 제12권1호
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• pp.70-76
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• 2012

We compare the detection probabilities of the time-reversal(TR) detection system and the conventional radar system. The target is assumed to be hidden inside a random medium such as a forest. We propose a TR detection system based on the SAR(Synthetic Aperture Radar) algorithm. Unlike the conventional SAR images, the proposed TR-SAR system has an interesting property. Specifically, the target-related signal components due to the time-reversal refocusing characteristics, as well as some of clutter-related signal components are concentrated at the time-reversal reference point. The remaining clutter-related signal components are scattered around that reference point. In this paper, we model the random media as a collection of point scatterers to avoid unnecessary complexities. We calculate the detection probability of the TR radar system based on the proposed simple random media model.

• 한국해양공학회지
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• 제24권2호
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• pp.53-56
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• 2010

Oil spills and red tide can be very damaging to the environment and fishery farming. These catastrophic accidents must be detected as quickly as possible. In this paper, we report the results of applying the wavelet transform to SAR or marine radar images for the detection of the boundaries of an oil spill or red tide. The application of the wavelet transform to these phenomena looks quite promising in detecting the boundaries of oil spills and red tide areas.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1297-1309
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• 2016

In this paper, an efficient connected component labeling (CCL) method was proposed. The proposed method is based on GPU parallelism. The CCL is very important in various applications where images are analysed. However, the label of each pixel is dependent on the connectivity of adjacent pixels so that it is not very easy to be parallelized. In this paper, a GPU-based parallel CCL techniques were proposed and applied to the analysis of radar signal. Since the radar signals contains complex and large data, the efficiency of the algorithm is crucial when realtime analysis is required. The experimental results show the proposed method is efficient enough to be successfully applied to this application.

• 시스템엔지니어링학술지
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• 제16권1호
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• pp.51-57
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• 2020

The fighter pilot uses radar mounted on the fighter to obtain high-resolution SAR (Synthetic Aperture Radar) images for a specific area of distance, and then the pilot visually classifies targets within the image. However, the target configuration captured in the SAR image is relatively small in size, and distortion of that type occurs depending on the depression angle, making it difficult for pilot to classify the type of target. Also, being present with various types of clutters, there should be errors in target classification and pilots should be even worse if tasks such as navigation and situational awareness are carried out simultaneously. In this paper, the concept of operation and functional structure of radar system for fighter jets were presented to transfer the SAR image target classification task of fighter pilots to radar system, and the method of target classification with high accuracy was studied using the CNN ensemble model to archive higher classification accuracy than single CNN model.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2023년도 춘계학술대회
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• pp.40-41
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• 2023

본 논문에서는 VTS 레이더 이미지 기반 객체의 탐지, 인식, 추적 알고리즘의 설계에 대해 소개한다. 레이더 이미지 기반 객체 탐지는 인공지능 기술을 이용하여 객체 유무 여부를 확인하고, 탐지의 경우 인공지능 기술을 이용하여 선종을 구분하게 된다. 추적은 탐지된 객체에 대해 시간에 따른 연속적 추적을 실시하며 이동경로의 혼선을 방지하는 기술이 포함되어 있다. 특히 육상레이더의 경우 지형지물에 따라 탐지가 불필요한 영역이 있어, 레이더 이미지에서 관심영역(ROI)을 설정하여 영역 내 선박을 탐지하고 인식하는 기능이 포함되어 있다. 또한, 추출한 좌표정보를 통해 속도와 방향 등을 계산하여 다양한 응용 해석이 가능하도록 설계하였다.

• Journal of information and communication convergence engineering
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• 제15권3호
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• pp.175-181
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• 2017

This paper describes the upgrade of an existing wave information retrieval algorithm by employing noise reduction in the pixel domain. Several algorithms for collecting wave information parameters from X-band radar image sequences including the wind field and current velocity have been developed over the past three decades. Using these algorithms, a band-pass filter (BPF) is applied to remove the non-wave contribution from the image spectra after the sea surface current velocity has been computed. However, such BPF designs have been both complex and insufficient in removing undesired components in X-band radar images. For this study, to improve the performance of wave information retrieval, an efficient noise reduction algorithm is incorporated into a regular wave information retrieval process. That is, the proposed algorithm was designed for operation in a more proper manner by effectively removing the undesired components in the pixel domain. Experiment results demonstrate that the proposed algorithm produces very close estimates to the buoy data records under undesirable noise conditions.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1343-1345
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• 2003

An internal wave observation experiment by SAR in South China Sea is described. Two scenes of Radarsat ScanSAR images were acquired. Internal solitary waves are found in all the two images. It is concluded that these internal waves are generated in Bashi channel. Relationship between internal wave generation and tide is studied based on analyzing of tidal data of Legaspi in Philippine. Using ocean environmental data of this sea area internal waves’ amplitude and wave speed are detected by SAR images.

• 수산해양기술연구
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• 제44권3호
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• pp.229-238
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• 2008

This paper describes on the consolidation of AIS and ARPA radar positions by comparing the AIS and ARPA radar information for the tracked ship targets using a PC-based ECDIS in Busan harbor, Korea. The information of AIS and ARPA radar target was acquired independently, and the tracking parameters such as ship's position, COG, SOG, gyro heading, rate of turn, CPA, TCPA, ship s name and MMSI etc. were displayed automatically on the chart of a PC-based ECDIS with radar overlay and ARPA tracking. The ARPA tracking information obtained from the observed radar images of the target ship was compared with the AIS information received from the same vessel to investigate the difference in the position and movement behavior between AIS and ARPA tracked target ships. For the ARPA radar and AIS targets to be consolidated, the differences in range, speed, course, bearing and distance between their targets were estimated to obtain a clear standards for the consolidation of ARPA radar and AIS targets. The average differences between their ranges, their speeds and their courses were 2.06% of the average range, -0.11 knots with the averaged SOG of 11.62 knots, and $0.02^{\circ}$ with the averaged COG of $37.2^{\circ}$, respectively. The average differences between their bearings and between their positions were $-1.29^{\circ}$ and 68.8m, respectively. From these results, we concluded that if the ROT, COG, SOG, and HDG informations are correct, the AIS system can be improved the prediction of a target ship's path and the OOW(Officer of Watch) s ability to anticipate a traffic situation more accurately.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.208-216
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• 2004

Since 2000, the authors have been developing remote radar network system to observe the vessel traffic in Tokyo Bay. In December 2002, the first operational remote radar station was set at the National Defense Academy in Yokosuka, and vessel traffic observation was started. However, it was impossible to perform accurate observation in the northern part of Tokyo Bay by this Yokosuka radar station only. In September 2003, the second remote radar station and AIS receiving station were installed at Higashi Ogishima in Kawasaki. This second radar enabled us to carry out accurate observation in that area. Both radars can be remotely controlled from the monitoring station in Tokyo University of Marine Science and Technology. On September 30 and October 1,2003, the vessel traffic observation was carried out using both radars. Combining radar images observed by both radars, the ships' tracks were taken and the dangerous ships were extracted by using SJ value and Bumper Model. The time changes of dangerous ship density in some areas in Tokyo Bay and utilization ratio of the traffic routes were also investigated. In addition, analyzing the AIS date received at Kawasaki station, the positions and speed vectors of the ships equipped with AIS were shown.

• 대한원격탐사학회지
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• 제21권1호
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• pp.59-72
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• 2005

Interferometric synthetic aperture radar (InSAR) is a remote sensing technique capable of measuring ground surface deformation with sub-centimeter precision and spatial resolution in tens-of­meters over a large region. This paper describes basics of InSAR and highlights our studies of Alaskan volcanoes with InSAR images acquired from European ERS-l and ERS-2, Canadian Radarsat-l, and Japanese JERS-l satellites.