• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권4호
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• pp.246-253
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• 2016

Infrared (IR) imaging has been researched for various applications such as surveillance. IR radiation has the capability to detect thermal characteristics of objects under low-light conditions. However, automatic segmentation for finding the object of interest would be challenging since the IR detector often provides the low spatial and contrast resolution image without color and texture information. Another hindrance is that the image can be degraded by noise and clutters. This paper proposes multi-level segmentation for extracting regions of interest (ROIs) and objects of interest (OOIs) in the IR scene. Each level of the multi-level segmentation is composed of a k-means clustering algorithm, an expectation-maximization (EM) algorithm, and a decision process. The k-means clustering initializes the parameters of the Gaussian mixture model (GMM), and the EM algorithm estimates those parameters iteratively. During the multi-level segmentation, the area extracted at one level becomes the input to the next level segmentation. Thus, the segmentation is consecutively performed narrowing the area to be processed. The foreground objects are individually extracted from the final ROI windows. In the experiments, the effectiveness of the proposed method is demonstrated using several IR images, in which human subjects are captured at a long distance. The average probability of error is shown to be lower than that obtained from other conventional methods such as Gonzalez, Otsu, k-means, and EM methods.

• 도시과학
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• 제8권1호
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• pp.7-14
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• 2019

Recently, interest in solar energy, which is the center of new government energy policy, is increasing. However, the focus is on mass production of solar power plants, and policies and related technologies for maintenance and management of existing installed PV modules are insufficient. In this study, we use UAV (Unmanned Aerial Vehicle) to acquire RGB and infrared images, apply it to the structure-from-motion (SfM) based image analysis tool, model the three- And the position of the hot spot was monitored and coordinates were detected. As a result, it is possible to provide basic spatial information for maintenance of solar module by monitoring and position detection of hot-spot suspected solar cells by superimposing infrared image and RGB image based on unmanned aerial vehicle.

• 한국농림기상학회지
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• 제13권2호
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• pp.79-86
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• 2011

산간계곡에는 특히 야간에 찬 공기가 흘러 고이는 일이 흔한데, 이런 곳의 식생은 생장과 발육이 그렇지 않은 주변지역에 비해 달라질 수 있어 관심의 대상이 다. 이 연구는 작은 규모의 집수역에서 적외선 영상을 이용하여 냉기호와 온난대의 형상을 가시화 할 수 있는지 알기 위해 수행하였다. 경남 하동군 악양면 형제봉(해발 1,117m)에 적외선 영상 복사계를 설치하여 관측여건이 양호했던 2011년 5월 17일 새벽부터 일출시까지 악양계곡의 열영상을 $640{\times}480$ 해상도로 획득하였다. 열영상 분석결과 계곡의 바닥에 나타난 낮은 온도 분포에 의해 찬공기의 배수를 인지할 수 있었고, 계곡 양쪽 사면에서 바닥보다 $5^{\circ}C$ 높은 온난대의 실체를 확인할 수 있었다. 적외선 영상을 이용하면 기존 고해상도 디지털 기온분포도 '전자기후도'의 신뢰성 검증이 한층 수월해져서 전자기후도 실용성 확보에 도움이 될 것이다.

• 터널과지하공간
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• 제25권2호
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• pp.144-154
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• 2015

암석시료에 응력이 가해질 경우 역학적 에너지가 대상 물체에 누적되고, 대상 암석에 한계응력 이상이 가해질 경우 시료의 파괴가 발생한다. 이 때 시료 내부에 저장되어 있던 역학적 에너지는 물리적 변형뿐만 아니라 빛, 열, 소리 등 다양한 형태의 에너지로 발산된다. 본 연구에서는 $-10^{\circ}C$ 저온 환경에서 섬록암, 현무암, 응회암을 대상으로 일축압축강도 시험과 점하중강도 시험을 수행하고, 이때 발생하는 온도 변화를 열적외선카메라를 이용해 측정하고 정량적으로 분석하였다. 파괴 직전 파괴면에 응력이 집중되어 온도가 상승하였고, 파괴 순간 축적된 에너지가 열에너지의 형태로 방출되며 파괴면의 온도가 급격히 상승하는 것이 감지되었다. 강도가 높고 신선한 섬록암과 현무암 시료의 온도 상승폭이 상대적으로 강도가 낮고 풍화된 암석인 응회암 시료의 온도 상승폭에 비해 더 크게 나타났다. 본 연구결과는 저온지역에 위치한 암반사면, 터널, 광산 내부의 응력 집중지점을 감지해 향후 발생 가능한 재해를 예방하는데 적용될 수 있으며, 지진예측을 위한 위성영상 분석에도 적용될 것으로 기대된다.

• 전자공학회논문지 IE
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• 제43권4호
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• pp.65-75
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• 2006

본 연구에서는, 열상장비(thermal imaging equipment)로 촬영한 적외선 영상의 화질을 저해하는 주된 요소인 임펄스 잡음(impulse noise)과 가우시안 잡음(Gaussian noise)을 제거하는 웨이브렛 변환 기반 방법을 논의한다. 효과적인 잡음제거를 위하여 잡음으로 손상된 적외선 영상에 대하여 상세 부분대역 웨이브렛 계수에 대한 미분과 중앙절대편차(median absolute deviation)를 이용한 문턱값 설정방법을 제안하였다. 특히, 임펄스성 잡음제거를 위해서 웨이브렛 계수를 미분하여 임펄스 잡음의 위치를 나타내는 이진 마스크를 생성하는 방법을 채택하였다. 이와 같은 방법에 의해, 모서리와 잡음을 구분하는 적응 문턱 값 설정을 보다 효율적으로 얻을 수 있었고, 기존 웨이브렛 수축법과 비교를 통하여 제안한 잡음제거 방법의 타당성을 확인하였다.

• Journal of Biosystems Engineering
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• 제42권3호
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• pp.163-169
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• 2017

Purpose: This study was performed to evaluate the feasibility of using an infrared thermography technique for phenotype analysis of pepper seedlings exposed to a low-temperature environment. Methods: We employed an active thermography technique to evaluate the thermal response of pepper seedlings exposed to low-temperature stress. The temperatures of pepper leaves grown in low-temperature conditions ($5^{\circ}C$, relative humidity [RH] 50%) for four periods (6, 12, 24, and 48 h) were measured in the experimental setting ($23^{\circ}C$, RH 70%) as soon as pepper seedling samples were taken out from the low-temperature environment. We also assessed the visible images of pepper seedling samples that were exposed to low-temperature stress to estimate appearance changes. Results: The greatest appearance change was observed for the low-temperature stressed pepper seedlings that were exposed for 12 h, and the temperature from these pepper seedling leaves was the highest among all samples. In addition, the thermal image of low-temperature stressed pepper seedlings for 6 h exhibited the lowest temperature. Conclusions: We demonstrated that the leaf withering owing to the water deficiency that occurred under low-temperature conditions could induce an increase in temperature in plant leaves using the infrared thermography technique. These results suggested that the time-resolved and averaged thermal signals or temperatures of plants could be significantly associated with the physiological or biochemical characteristics of plants exposed to low-temperature stress.

• 전기학회논문지P
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• 제56권3호
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• pp.142-147
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• 2007

Infrared thermography is one of the most valuable and cost-effective diagnostic techniques for predictive maintenance on electrical systems. For the electric installations, the thermographies can identify major problems, which if left unattended could lead to breakdowns. The result thermal images depend upon operator skills, inspection technique, and load and weather conditions. When the thermographer is applied to remote monitoring, the conditions of the systems are not perfectly analyzed because operators are hard to know the weather's effects of the installed place. Therefore, this paper defines the effects by weather conditions which will influence the final results. The purpose of this paper is to define the weather effects that a thermographer needs to consider for successful condition analysis.

• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.463-469
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• 2016

This paper presents a composite camera calibration method to determine thermal degradation of power distribution equipment by combining an infrared (IR) camera and a color camera. A calibration jig was first constructed to match the properties of the two cameras. Our calibration and visualization techniques allow for the display of two images, one from the color camera and the other from the IR camera with different field of views (FOVs), on the screen at the same time. To confirm its validity, several case studies have been developed to analyze thermal deterioration limits of indoor and outdoor power distribution facilities.

• 대한기계학회논문집A
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• 제37권9호
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• pp.1175-1182
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• 2013

위상잠금모드가 적용된 적외선열화상 시험법은 열전도도가 큰 재료에서 결함의 검출능력을 향상시키기 위해 개발되었으며, 기존의 적외선열화상 기법에 비해 우수한 결함 검출능력을 보이는 것으로 알려져 있다. 따라서, 본 연구에서는 원전 배관 감육결함 검출에서 위상잠금모드 기법의 적용 효과를 살펴보기 위해서, 감육결함이 가공된 배관 시편을 대상으로 위상잠금모드를 적용하여 적외선열화상 시험을 수행하였다. 시험 결과로부터 감육결함에 대한 위상이미지를 얻고, 이것을 기존의 적외선열화상시험법으로 구한 열화상이미지와 비교하였다. 비교 결과, 위상잠금모드의 적용이 감육결함에 대한 형상 결정 능력을 향상시키는 것을 확인하였다. 이러한 개선 효과는 폭과 길이가 작거나 경계가 경사진 감육결함에서 뚜렷하였다. 그러나, 깊이가 얕은 감육결함의 검출능력은 크게 향상되지 않았다.

• 대한원격탐사학회지
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• 제35권4호
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• pp.491-502
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• 2019

Distinguishing debris-covered glaciers from debris-free glaciers is difficult when using only optical remote sensing images to extract glacier boundaries.According to the features that the surface temperature of debris-covered glacier is lower than surrounding objects, and higher than clean glaciers, glacial changes in the Yigong Zangbo basin was analyzed on the basis of visible, near-infrared and thermal-infrared band images of Landsat TM and OLI/TIRS in the support of ancillary digital elevation model (DEM). The results indicated that glacier area gradually declined from $928.76km^2$ in 1990 to $918.46km^2$ in 2000 and $901.51km^2$ in 2015. However, debris-covered glacier area showed a slight increase from $63.39km^2$ in 1990 to $66.24km^2$ in 2000 and $71.16km^2$ in 2015. During 25 years, the glacier length became shorter continuously with terminus elevation rising up. The area of moraine lakes in 1990 was $1.43km^2$, which increased to $1.98km^2$ in 2000 and $3.41km^2$ in 2015. In other words, the total area of the moraine lakes in 2015 is 2.38 times of that in 1990. This increase in moraine lake area could be the result of accelerated glacier melt and retreat, which is consistent with the significant warming trend in recent decades in the basin.