• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.887-894
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• 2009

There is no standard rule for the test of the railway abrasion measurement system composed of the line laser and the camera. This paper is proposed of the method to estimate the performance of the railway abrasion measurement system. The performance estimation is achieved by the quantitative analysis parameters such as MTF, NPS and DQE.

• Journal of Advanced Navigation Technology
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• v.6 no.2
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• pp.97-103
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• 2002

A recent technology trends in synthetic aperture radar(SAR) requires the ultra high resolution performance in detecting and precisely identifying the targets. In this paper, as a technique for enhancing the radar range resolution, the wide band chirp connection algorithm is presented by stitching the several chirp modules with unit bandwidth based on the linear frequency modulated chirp signal waveform. The principles of the digital chirp signal generation and its architecture for implementation is described with the wide band chirp signal generator, modulator, and demodulator. The performance analysis for the presented algorithm is given with the simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.70-78
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• 2019

In this paper, modeling of a high-resolution multi-function radar is proposed to simulate radar performance in a war game simulator, called AddSIM. To incorporate the multi-function radar model into the AddSIM, the modeling must comprise a component-based structure consisting of physics, logics, and information blocks. Therefore, we assign the RF hardware of a RADAR as the physic block, a controller as the logics block, and the RF specifications of the RADAR as the information block. Detailed modeling of the physics and logics blocks are addressed, and data structure is also presented on an engineering level. On a multi-target engaged scenario, the performance of the multi-function radar is numerically analyzed and its validation is examined.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.304-305
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• 2010

지금까지는 영화나 3DTV같은 대형 모니터에 사용하기 위하여 입체영상이 제작되어 왔다, 하지만 최근 3D 디스플레이가 스마트폰이나 태블릿PC와 같이 작은 디스플레이 사이즈와 해상도를 가지는 휴대용 기기들에도 적용되어 다양한 형태로 보급되어 보다 많은 관심을 받고 있다. 하지만 모바일 기기와 같은 경우 영화와 고해상도 영상에서와 같은 3D 입체감을 느끼기 어려운 경우가 종종 발생한다. 본 논문에서는 작은 디스플레이 사이즈와 해상도를 가지는 모바일 기기와 같은 장치에서 3D 효과 향상을 위한 깊이맵 재구성의 방법으로 레이어의 개수를 제안하여 3D 효과를 향상 시키는 방법을 제안한다. 이를 위해 고해상도 영상에서 깊이값에 따른 레이어를 6개에서 2개까지 수를 줄여 깊이맵을 생성하였고 영상의 크기를 줄여 영상의 크기와 깊이 레이어에 따라 달라지는 입체 효과를 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.117-124
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• 2008

The approaches to overcome the limited spatial resolution and the limited dynamic range of image sensors have been studied independently. A high resolution image is reconstructed from multiple low resolution observations and a wide dynamic range image is reconstructed from differently exposed multiple low dynamic range in es based on signal processing approach. In practical situations, it is reasonable to address them in a unified context because the recorded image suffers from limitations of both spatial resolution and dynamic range. In this paper, the image acquisition process including limited spatial resolution and limited dynamic range is modelled. With the image acquisition model, the response function of the imaging system is estimated and the single image of which spatial resolution and dynamic range are simultaneously enhanced is obtained. Experimental results indicate that the proposed algorithm outperforms the conventional approaches that perform the high resolution and wide dynamic range reconstruction sequentially with respect to both objective and subjective criteria.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.9-11
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• 2016

최근 UHDTV(ultra high definition television) 등의 고해상도 디스플레이가 시장에 등장하면서, 기존의 저해상도 FHD(full high definition) 영상을 고해상도 영상으로 변환할 수 있는 초해상화(super-resolution, SR) 기법들이 각광을 받고 있다. 그 중, 선형 매핑(linear mapping)을 사용하여 저해상도 패치(patch)로부터 고해상도 패치를 복원하는 초해상화 기법은 상대적으로 낮은 복잡도로 좋은 품질의 고해상도 영상을 생성한다. 그러나 이러한 기법은 단순한 선형 매핑을 기반으로 하기 때문에 복잡한 비선형적(nonlinear) 저해상도-고해상도 관계를 예측하기 힘든 단점이 있다. 최근 각광받는 딥러닝(deep learning) 기술은 다층(multi-layer) 네트워크를 쌓아 입력과 출력 간의 복잡한 비선형 관계를 훈련시켜 좋은 성능을 보이는데, 이를 바탕으로 본 논문에서는 다중의 레이어로 구성된 다층 선형 매핑(multi-layer linear mappings, MLLM)을 기반으로 하는 초해상화 기법을 새롭게 제안한다. 제안하는 다층 선형 매핑은 기존 선형 매핑보다 비선형적 관계를 더 잘 예측하여 높은 품질의 고해상도 영상을 생성할 수 있게 한다. 제안된 초해상화 기법은 딥러닝 기반 초해상화 기법과 필적하는 품질의 고해상도 영상을 생성하면서도 더 낮은 복잡도를 지니는 것을 확인하였다.

• Journal of Advanced Navigation Technology
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• v.5 no.2
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• pp.149-157
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• 2001

A high speed data link capability is one of the critical factors in determining the performance of the spaceborne SAR system with high resolution. It is due to the strict requirement for the real-time data transmission from a series of massive raw image data of spaceborne SAR to the ground station in a limited time of mission. In this paper, based on the data link model characterized by the spaceborne small SAR system, the high rate multi-channel data link module is designed including link storage, link processor, transmitter, and wide-angle antenna. The design results are presented with the performance analysis on the data link budget as well as the multi-mode data rate in association with the SAR imaging mode of operation from high resolution to the wide swath.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.11a
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• pp.117-118
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• 2016

최근 UHDTV(ultra high definition television)가 가정에 보급이 많이 되고 있는 추세지만, UHD급 콘텐츠가 매우 부족한 실정이다. 따라서 저해상도 FHD(full high definition) 영상을 고해상도 영상으로 변환시켜 재활용할 수 있는 초해상화(super-resolution, SR) 기술의 필요성이 커졌다. 그 중, 다층의 레이어로 구성된 다층 선형 매핑(multi-layer linear mappings, MLLM)을 기반으로 하는 제안된 초해상화 기법은 상대적으로 낮은 복잡도로 좋은 품질의 고해상도 영상을 복원할 수 있었다. 최근에는 강화 예측법을 추가하여 복원된 고해상도 영상의 품질을 더 향상시키는 기법이 등장하였는데, 이를 바탕으로 본 논문에서는 제안했었던 MLLM 기법을 위한 강화 예측법 기법을 새롭게 제안한다. 제안하는 초해상화 기법은 기존 MLLM 기법과 딥러닝 기반 초해상화 기법보다 높은 품질의 고해상도 영상을 생성하는 것을 확인하였다.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.339-353
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• 2023

As the availability of high-resolution satellite imagery increases, improvement of positioning accuracy of satellite images is required. The importance of orthorectified images is also increasing, which removes relief displacement and establishes true localization of man-made structures. In this paper, we performed automated extraction of building rooftops and total building areas within original satellite images using the existing building height database. We relocated the rooftop sin their true position and generated an orthorectified building layer. The extracted total building areas were used to blank out building areas and generate true orthographic non-building layer. A final orthorectified image was provided by overlapping the building layer and non-building layer.We tested the proposed method with KOMPSAT-3 and KOMPSAT-3A satellite images and verified the results by overlapping with a digital topographical map. Test results showed that orthorectified building layers were generated with a position error of 0.4m.Through the proposed method, the feasibility of automated true orthoimage generation within dense urban areas was confirmed.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.323-330
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• 2018

In this paper, design and fabrication of a MSP(Multiple Scattering Points) discriminator for a simulated target measurement using a HRR(High Range Resolution) RADAR are described. The MSP discriminator is designed to provide a reference signal at the installed point on the simulated target in an outdoor test. The MSP discriminator is designed to have a remote control function that can turn the MSP discriminator on and off when the target moves to a remote location. While the MSP discriminator is off, the MSP discriminator is designed to be small enough not to spoil the target's unique RCS. The MSP discriminator consists of RF components in the Ku-band. In order to prevent spreading of the signal, a cable were added to the MSP discriminator to have an appropriate feedback loop delay considering the resolution of the RADAR. The fabricated MSP discriminator provided a reference scattering point as an RCS of approximately 1 dBsm. As a result, by using the MSP discriminator, the physical scattering points of the target were clearly identified in the measured signals with the RADAR.