• Tunnel and Underground Space
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• v.32 no.2
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• pp.131-143
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• 2022

The lunar exploration autonomous vehicle operates based on the lunar topography information obtained from real-time image characterization. For highly accurate topography characterization, a large number of training images with various background conditions are required. Since the real lunar topography images are difficult to obtain, it should be helpful to be able to generate mimic lunar image data artificially on the basis of the planetary analogs site images and real lunar images available. In this study, we aim to artificially create lunar topography images by using the location information-based style transfer algorithm known as Wavelet Correct Transform (WCT2). We conducted comparative experiments using lunar analog site images and real lunar topography images taken during China's and America's lunar-exploring projects (i.e., Chang'e and Apollo) to assess the efficacy of our suggested approach. The results show that the proposed techniques can create realistic images, which preserve the topography information of the analog site image while still showing the same condition as an image taken on lunar surface. The proposed algorithm also outperforms a conventional algorithm, Deep Photo Style Transfer (DPST) in terms of temporal and visual aspects. For future work, we intend to use the generated styled image data in combination with real image data for training lunar topography objects to be applied for topographic detection and segmentation. It is expected that this approach can significantly improve the performance of detection and segmentation models on real lunar topography images.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.1-11
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• 2015

Purpose : Evaluating absorbed dose related to 2D and 3D imaging confirmation devices Materials and Methods : According to the radiographic projection conditions, absorbed doses are measured that 3 glass dosimeters attached to the centers of 0', 90', 180' and 270' in the head, thorax and abdomen each with Rando phantom are used in field size $26.6{\times}20$, $15{\times}15$. In the same way, absorbed doses are measured for width 16cm and 10cm of CBCT each. OBI(version 1.5) system and calibrated glass dosimeters are used for the measurement. Results : AP projection for 2D imaging check, In $0^{\circ}$ degree absorbed doses measured in the head were $1.44{\pm}0.26mGy$ with the field size $26.6{\times}20$, $1.17{\pm}0.02mGy$ with the field size $15{\times}15$. With the same method, absorbed doses in the thorax were $3.08{\pm}0.86mGy$ to $0.57{\pm}0.02mGy$ by reducing field size. In the abdomen, absorbed dose were reduced $8.19{\pm}0.54mGy$ to $4.19{\pm}0.09mGy$. Finally according to the field size, absorbed doses has decreased by average 5~12%. With Lateral projection, absorbed doses showed average 5~8% decrease. CBCT for 3D imaging check, CBDI in the head were $4.39{\pm}0.11mGy$ to $3.99{\pm}0.13mGy$ by reducing the width 16cm to 10cm. In the same way in thorax the absorbed dose were reduced $34.88{\pm}0.93(10.48{\pm}0.09)mGy$ to $31.01{\pm}0.3(9.30{\pm}0.09)mGy$ and $35.99{\pm}1.86mGy$ to $32.27{\pm}1.35mGy$ in the abdomen. With variation of width 16cm and 10cm, they showed 8~11% decrease. Conclusion : By means of reducing 2D field size, absorbed dose were decreased average 5~12% in 3D width size 8~11%. So that it is necessary for radiation therapists to recognize systematical management for absorbed dose for Imaging confirmation. and also for frequent CBCT, it is considered whether or not prescribed dose for RT refer to imaging dose.

• Journal of Korea Multimedia Society
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• v.12 no.7
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• pp.1006-1015
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• 2009

This paper developed FRESH(Face image REcognition System for intelligent Home), proposed by Hopkins, which was to recognize the face of family members applying for HTM system that integrates a principal movement of human brain's neocortex with computers. For the purpose of confirming a result of the works, we took real photographs of both clear and distorted images, but the result produced higher accuracy about the distorted images providing by a real environment as well as clear images. In addition, the existing studies were focused on the recognition of facial zone that it was difficult to adapt for System for intelligent home. However, this thesis developed a system suitable for intelligent home which corresponds a facial image to his or her name.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.65-65
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• 2003

목적 : 방사선치료기술이 날로 발전함에 따라 방사선치료계획시스템에 대한 주기적인 정도관리의 필요성은 증대하고 있으나, 국내 실정에 적합한 표준화된 정도관리절차서가 없는 실정이다. 따라서 본 연구에서는 방사선치료계획용 시스템에 대한 정도관리용 고체팬톰을 제작하여 주기적인 정도관리 활용 및 절차서를 제시하고자 한다. 대상 및 방법 : 체윤곽 보정을 위한 삼각기둥 모형 (30cm$\times$30cm$\times$5cm, 30cm$\times$15cm$\times$5$\times$) 및 정형ㆍ부정형, 불균질 측정이 가능한 물등가고체팬톰을 제작하였고, 컴퓨터단층촬영(AcQsim)을 통해 영상을 얻었으며, RTPS(AcQplan)에 입력하여 영상 내 기준점에서의 선량값을 계산하였다. RTPS를 통해 계산된 값의 평가를 위해 동일한 조건하에서 각 기준점에 대한 실제 측정을 이온함을 이용하여 측정하였다. 평가 항목으로는 정방형 조사면, 부정형 조사면, 쐐기 조사면, 불균질 물질 보정, 사방향 조사 등에 대해서 알고리즘별로 수행하였다. 결과 : RTPS를 이용하여 계산된 값과 실제 측정한 값을 비교하여 RTPS의 정확성을 평가한 결과로 합성의 불확도 허용 기준 (3%), 선속 중심축 상에서의 허용 기준 (2%) 등, 선진 각국 및 각 학회에서 권고하고 있는 허용 범위 내에서 잘 일치하였다. 결론 : RTPS는 측정된 심부선량과 선량분포 등 물리적인 인자에 의존하는 제한성이 있고, 실제로 선량계산 알고리즘과 기하학적 변화에 따라 계산값과 측정값 간에 차이가 발생할 수 있었다. 실제 인체의 체윤곽 불균일성과 불균질성을 모사한 팬톰을 제작하여 이용함으로써 다양한 RTPS간의 비교를 통한 치료 선량의 정확성을 평가하고, 방사선 치료의 원활하고 정확한 수행을 위해 실용적이고, 보편적인 치료계획 시스템의 정도관리 방법과 절차서를 수립하는데에 유용할 것으로 사료된다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.37-44
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• 2009

Density is the most important congestion indicator among the three fundamental flow variables, flow, speed and density. Measuring density in the field has two different ways, direct and indirect. Taking photos with wide views is one of direct ways, which is not widely used because of its cost and lacking of proper positions. Another direct density measuring method using two spot detectors has been introduced with the concept of instantaneous density, average density and measurement interval. The relationship between accuracy and measurement interval has been investigated using the simulation data produced by Paramics API function. Finally, density measurement algorithm has been suggested including exponential smoothing for device development.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.2
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• pp.49-56
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• 2008

Image registration is one of the critical techniques of image mosaic which has many applications such as generating panoramas, video monitoring, image rendering and reconstruction, etc. The fundamental tasks of image registration are point features extraction and tracking which take much computation time. KLT(Kanade-Lucas-Tomasi) feature tracker has proposed for extracting and tracking features through image sequences. The aim of this study is to demonstrate the usage of effective and robust KLT feature detector and tracker for an image registration using the sequence image frames captured by UAV video camera. In result, by using iterative implementation of the KLT tracker, the features extracted from the first frame of image sequences could be successfully tracked through all frames. The process of feature tracking in the various frames with rotation, translation and small scaling could be improved by a careful choice of the process condition and KLT pyramid implementation.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.126-133
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• 2004

Photogrammetry, as its name implies, is a 3-dimensional coordinate measuring technique that uses photographs as the fundamental medium for metrology. In the last few years the accuracy of photogrammetry has increased dramatically thanks to the rapid advance of digital camera manufacturing technique. This paper discusses photogrammetric measurement of the interface surface of MSC(Multi-Spectral Camera), which is a main payload of KOMPSAT-2. Total 24 paper targets on the objective surfaces and two scale bars calibrated with high accuracy were used for measurement, and multiple images were taken from 11 different camera angles by using a spacecraft rotation dolly. As a result of analysis, 3D coordinates of each targeted point were obtained and the flatness value based on the selected reference plane was calculated and compared with the pre-determined requirement. The technique acquired by this study is expected to be used for the 3D precise measurement of ultra-light weight and inflatable space structures such as a satellite antenna and a solar array.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.547-557
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• 2014

This paper presents a method for designing circular template used in similarity measurement for image registration. Circular template has translation and rotation invariant property, which results in correct matching of control points for image registration under the condition of translation and rotation between reference and sensed images. Circular template consisting of the pixels located on the multiple circumferences of the circles whose radii vary from zero to a certain distance, is converted to two-dimensional Discrete Polar Coordinate Matrix (DPCM), whose elements are the pixels of the circular template. For sensed image, the same type of circular template and DPCM are created by rotating the circular template repeatedly by a certain degree in the range between 0 and 360 degrees and then similarity is calculated using mutual information of the two DPCMs. The best match is determined when the mutual information for each rotation angle at each pixel in search area is maximum. The proposed algorithm was tested using KOMPSAT-2 images acquired at two different times and the results indicate high accurate matching performance under image rotation.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.260-260
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• 2022

최근 홍수기 유량측정방법은 기존 봉부자를 이용한 접촉식 측정방법에서 영상촬영, 레이더 등 첨단기술을 이용한 비접촉식 표면유속 측정방법으로 변화하고 있다. 비접촉식 측정방법은 각 기술마다 표면유속 측정방법의 차이가 있으나 평균유속환산계수를 적용하여 평균유속을 산정하는 공통적인 과정을 수행한다. 평균유속환산계수는 하천의 각 횡측선 수심-유속분포를 일반적인 분포로 가정하고 표면유속에 0.85를 곱하여 평균유속을 산정한다(Rantz, 1982). 그러나 하천의 측정위치 및 흐름특성에 따라 유속분포가 변화하기 때문에 국내외 많은 연구에서 환산계수의 범위를 0.72에서 1.72까지 제시한 바 있다. 따라서 환산계수 0.85의 일률적인 적용은 실제 유량과 측정 유량의 차이가 발생할 수 있어 측정조건의 적절한 환산계수 산정이 필요하다. 본 연구에서는 20년, 21년 금강의 지류인 봉황천에 위치한 금산군(황풍교) 관측소에서 전자파표면유속계를 이용해 측정한 표면유속과 ADCP를 이용하여 동시 측정한 평균유속의 비교를 통해 환산계수를 산정하였다. 또한 금강 본류의 금산군(제원대교) 관측소에서 저중수위에서 ADCP를 이용하여 측정한 평균유속 분포와 고수위에서 전자파표면유속계로 측정한 표면유속과의 경향성 검토를 통해 평균유속환산계수를 산정하였다. 본 연구에서는 지점의 평균유속환산계수를 단일 값으로 산정하였지만, 추후 하천 흐름특성의 변화를 고려한 평균유속환산계수 산정 기법 개발을 통해 보다 정확한 홍수량을 산정할 수 있을 것으로 판단된다.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.1-8
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• 2017

Currently gas safety management in the industrial field has been done by LDAR as contact method or methane leak detector as non-contact method. But LDAR method requires a lot of man-power and methane leak detector have the limitation of methane only. Therefore the Research on the OGI(optical gas image) has big attention by industry. This research was undertaken to see the effect of background temperature difference of gas cloud on the clarity of OGI. The background temperature control panel was constructed to cool down the background temperature. OGI was taken at the various methane gas ejection rate and the designed temperature difference. The experimental results showed that the OGI(when the temperature difference is $-6^{\circ}C$) is more clear thane the OGI(when the temperature difference is zero). To quantify the clarity difference, MATLAB's RGB analysis method was employed. The RGB value of the OGI at ${\Delta}T-6^{\circ}C$ was 20% lower than the OGI at ${\Delta}T0^{\circ}C$. The clarity difference by T difference can be explained by the total radiation law. When the background temperature of the gas is lower than the air temperature, the radiation energy coming into the OGI lens is increasing. As the energy is increasing, the OGI image becomes clear.