Recent Developments Involving the Application of Infrared Thermal Imaging in Agriculture

( Jun-soo Lee ),( Gwang-wook Hong ),( Kyeongho Shin ),( Dongsoo Jung ),( Joo-hyung Kim ) 한국센서학회 2018 센서학회지 Vol.27 No.5

The conversion of an invisible thermal radiation pattern of an object into a visible image using infrared (IR) thermal technology is very useful to understand phenomena what we are interested in. Although IR thermal images were originally developed for military and space applications, they are currently employed to determine thermal properties and heat features in various applications, such as the non-destructive evaluation of industrial equipment, power plants, electricity, military or drive-assisted night vision, and medical applications to monitor heat generation or loss. Recently, IR imaging-based monitoring systems have been considered for application in agricultural, including crop care, plant-disease detection, bruise detection of fruits, and the evaluation of fruit maturity. This paper reviews recent progress in the development of IR thermal imaging techniques and suggests possible applications of thermal imaging techniques in agriculture.

SR Thermal GAN: 초해상화 적외선 이미지 생성 기법

이인호(In Ho Lee),정원영(Won Yeung Chung),박찬국(Chan Gook Park) 제어로봇시스템학회 2022 제어·로봇·시스템학회 논문지 Vol.28 No.2

Thermal infrared cameras create IR (infrared) images, thus enabling the recognition of objects regardless of weather, illuminance, or ambient color. With the recent development of deep learning, research interest in image conversion and super-resolution techniques has increased. This paper proposes an algorithm that converts electro-optical (EO) images to IR images using super-resolution techniques based on generative adversarial networks. ThermalWorld data were used as the learning data. Additionally, drones of EO and IR images were added using thermal infrared cameras. The proposed super-resolution technique adapts the loss function and neural network structure to generate a high-resolution IR image. The loss function learns the neural network by utilizing the difference between the actual image and the generated image, thereby generating an image while maintaining the shape of the object on the image. The resolution is further improved by densely connecting the generator neural network structure and removing batch normalization. Finally, the structure of the discriminator is changed, and the stability of learning improved using the spectral norm. Images are generated according to each change item and quantitatively verified through performance indicators of improved image quality. This study analyzes images made with super-resolution techniques by considering the results of performance indicators and discusses the possibility of using IR images; and presents future research directions.

Human Detection in a Paddy Field by using Thermal Images

( Kazuya Arai ),( Ryohei Masuda ),( Masahiko Suguri ),( Michihisa Iida ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

At present, agriculture in Japan is facing with the problem of labor shortage and aging. In order to realize stable food supply in the future, it is necessary to reduce the workload, expand the scale of management, secure new farmers. In the field of high efficiency and labor saving technology development for paddy field work, robotization of various agricultural machines has been studied. In Kyoto University, research on robotic combine harvester which determine its traveling route by navigation data acquired from GNSS and GPS compass is being studied. However, since this robotic combine harvester merely runs on a predetermined route, there is a safety problem that it cannot be stopped if humans intrude in the traveling direction. So as to solve the problem, several human detection methods have been studied. In this study, we propose a method using thermal images as a new approach to human detection method in paddy field using image processing. The thermal image has an advantageous property to human detection as compared with the visible image. It is not affected by ambient light, and human temperature often lies within a certain range so it is relatively easy to extract human area. Therefore, it is used in the traffic and security fields. This time, we examined whether it can be applied to the agricultural field. We focused on human detection during harvesting by combine harvester in paddy field. We mounted a thermographic camera on a combine harvester, shot a video showing crops and humans, and captured images from there. Then, we performed image processing, and extracted regions with high temperature as regions of interest (ROIs). Finally, feature values were calculated for each ROI, and judgement whether each ROI includes humans or not was made by an artificial neural network (ANN) classifier. We generated a confusion matrix from the judgment results for all the acquired images, and calculated the accuracy rate. By setting the temperature range and the classification categories in the output of the ANN classifier appropriately, the accuracy rate was 99.3% for the images a human exists, 94.9% for the images a human does not exist, and 97.1% on average. As such a high accuracy rate is obtained, it can be said that our proposing human detection by thermal images is effective. This time, we shot a movie in the field and conducted human detection later. In the future, we plan to detect humans who intrude during harvesting by combine harvester in real time. It is also a future subject to formulate a measure for determining the temperature range.

광열분광법을 이용한 공여기판의 표면 조사

이광원,이강인,임영주,곽진석,권진혁,이종훈 한국물리학회 2010 새물리 Vol.60 No.2

Photo-thermal spectrometry was applied to analyze the organic transfer mechanism in laser-induced thermal imaging. A photo multiplier tube was used to detect variations in the He-Ne probe beam. A fiber-coupled laser diode (910 nm) was used as the source for thermal imaging. The temporal variation of probe beam signal reflected from the donor plate was measured. The variation of the temporal profile of probe beam was measured as a function of the diode laser power incident on the donor plate. The result showed that the probe laser signal linearly depended on the thermal laser power. 레이저 열전사법(laser induced thermal imaging)에서 사용하는공여기판(donor plate)에서 유기물이 분리되는 메커니즘을 해석하기 위해광열분광법(photo-thermal spectrometry)을 적용하였다. 탐지광으로는He-Ne 레이저, 광 검출기로는 광증배관(photo-multiplier tube)을사용하였다. 열전사용 레이저는 파장이 910 nm인 다이오드 레이저를사용하였다. 시간적 분포가 사각 펄스인 다이오드 레이저를 공여기판에조사하여 탐지광 신호의 시간에 따른 변화를 관측하였다. 또한 열전사용다이오드 레이저빔의 출력에 따른 탐지광 신호의 변화를 관측한 결과,공여기판에서의 표면변형은 입력한 다이오드 레이저의 세기에 비례함을알 수 있었다.

에지 검출 방법을 이용한 열화상 카메라의 영상 개선

정민철 한국반도체디스플레이기술학회 2016 반도체디스플레이기술학회지 Vol.15 No.3

This paper proposes a new image enhancement method for an infrared thermal image. The proposed method uses both Laplacian and Prewitt edge detectors. Without a visible light, it uses an infrared image for the edge detection. The method subtracts contour images from the infrared thermal image. It results black contours of objects in the infrared thermal image. That makes the objects in the infrared thermal image distinguished clearly. The proposed method is implemented using C language in an embedded Linux system for a high-speed real-time image processing. Experiments were conducted by using various infrared thermal images. The results show that the proposed method is successful for image enhancement of an infrared thermal image.

Image-based multi-scale simulation and experimental validation of thermal conductivity of lanthanum zirconate

Guo, X.,Hu, B.,Wei, C.,Sun, J.,Jung, Y.G.,Li, L.,Knapp, J.,Zhang, J. Pergamon Press ; Elsevier Science Ltd 2016 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER - Vol.100 No.-

Lanthanum zirconate (La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB>) is a promising candidate material for thermal barrier coating (TBC) applications due to its low thermal conductivity and high-temperature phase stability. In this work, a novel image-based multi-scale simulation framework combining molecular dynamics (MD) and finite element (FE) calculations is proposed to study the thermal conductivity of La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> coatings. Since there is no experimental data of single crystal La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> thermal conductivity, a reverse non-equilibrium molecular dynamics (reverse NEMD) approach is first employed to compute the temperature-dependent thermal conductivity of single crystal La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB>. The single crystal data is then passed to a FE model which takes into account of realistic thermal barrier coating microstructures. The predicted thermal conductivities from the FE model are in good agreement with experimental validations using both flash laser technique and pulsed thermal imaging-multilayer analysis. The framework proposed in this work provides a powerful tool for future design of advanced coating systems.

열화상 카메라를 적용한 개인 맞춤형 냉각관리 시스템

이영지(Young-Ji Lee),이주현(Joo-Hyun Lee),이승호(Seung-Ho Lee) 한국전기전자학회 2021 전기전자학회논문지 Vol.25 No.4

본 논문에서는 열화상 카메라를 적용한 개인 맞춤형 냉각관리 시스템을 제안한다. 제안하는 장비는 열화상 카메라를 이용하여 사용자의 진행 전 피부 온도와 진행 후 피부온도의 차이에 따라 냉기 배출량 및 시스템을 제어한다. 피부의 온도가 비정상적으로 낮아지면 냉기공급을 차단하여 안전사고 발생 가능성을 방지한다. 피부 온도 감지센서를 열화상 카메라 온도측정으로 대체하여 경제적이고, 열화상 이미지로 온도를 확인할 수 있으므로 시각화가 가능하다. 또한, 제안하는 장비는 열화상 카메라를 적용한 개인 맞춤형 냉각관리 시스템의 안전을 위해 레이저 포인터를 듀얼로 사용하여 초점 거리를 산출하여 피부와의 거리를 측정하는 센서의 감도를 개선시킨다. 제안된 장비의 성능을 평가하기 위하여 외부공인 시험기관에서 실험하였다. 첫 번째로 측정된 온도 범위는 –100℃~-160℃로 측정되어, 현재 현장에서 사용되는 최고 수준인 -150~-160℃(cryo generation/미국) 보다 넓은 온도 범위를 나타내었다. 또한 오차는 ±3.2%~±3.5%로 측정되어 현재 현장에서 사용되는 최고 수준인 ±5% (CRYOTOP/중국) 보다 우수한 결과를 나타내었다. 두 번째로 측정된 거리 정확도는 ±4.0% 이하로 측정되어, 현재 현장에서 사용되는 최고 수준인 ±5%(CRYOTOP/중국) 보다 우수한 결과를 나타내었다. 세 번째로 질소 사용량은 최대 0.15 L/min 미만으로 확인되어, 현재 현장에서 사용되는 최고 수준인 6 L/min(POLAR BEAR/미국) 보다 우수한 결과를 나타내었다. 따라서 본 본문에서 제안한 열화상 카메라를 적용한 개인 맞춤형 냉각관리 시스템의 성능의 우수함이 판별되었다. In this paper, we propose a personalized cooling management system with thermal imaging camera. The proposed equipment uses a thermal imaging camera to control the amount of cold air and the system according to the difference between the user’s skin temperature before and after the procedure. When the skin temperature is abnormally low, the cold air supply is cut off to prevent the possibility of a safety accident. It is economical by replacing the skin temperature sensor with a thermal imaging camera temperature measurement, and it can be visualized because the temperature can be checked with the thermal image. In addition, the proposed equipment improves the sensitivity of the sensor that measures the distance to the skin by calculating the focal length by using a dual laser pointer for the safety of a personalized cooling management system to which a thermal imaging camera is applied. In order to evaluate the performance of the proposed equipment, it was tested in an externally accredited testing institute. The first measured temperature range was -100℃~-160℃, indicating a wider temperature range than -150~-160℃(cryo generation/USA), which is the highest level currently used in the field. In addition, the error was measured to be ±3.2%~±3.5%, which showed better results than ±5%(CRYOTOP/China), which is the highest level currently used in the field. The second measured distance accuracy was measured as below ±4.0%, which was superior to ±5%(CRYOTOP/China), which is the highest level currently used in the field. Third, the nitrogen consumption was confirmed to be less than 0.15 L/min at the maximum, which was superior to the highest level of 6 L/min(POLAR BEAR/USA) currently used in the field. Therefore, it was determined that the performance of the personalized cooling management system applied with the thermal imaging camera proposed in this paper was excellent.

Strawberry Plant Wetness Detection Using Color and Thermal Imaging

Swarup Anushka,이원석,Peres Natalia,Fraisse Clyde 한국농업기계학회 2020 바이오시스템공학 Vol.45 No.4

Purpose Leaf wetness is the presence of free water on the surface of a crop canopy. It is mainly caused due to factors such as rainfall, dew, and irrigation. The duration for which water is present on the crop surface is called the leaf wetness duration (LWD). The relationship between leaf wetness and plant disease has been studied for centuries. It has been found that the rate of infection is directly linked to the temperature of plants during the wet periods. Thus, it is imperative to detect and monitor the presence of water on the plant surface. Methods Currently, the most popular solution for this purpose is to use electronic leaf wetness sensors which are difficult to calibrate and are not user friendly. This research aimed at detecting leaf wetness in strawberry plants using noninvasive optical methods such as color and thermal imaging. Results It was found that color imaging yielded good classification results for differentiating between wet and dry leaf surfaces. However, its dependence on illumination conditions was a drawback. Thermal imaging proved to be useful when using highresolution cameras for water droplet detection but was dependent on ambient weather conditions. Conclusion The results suggested that fusing color and thermal imaging technologies could compensate for the drawbacks present when using these technologies individually and could prove to be potent in detecting leaf wetness.

아크 용접의 열화상을 이용한 용접품질 추정에 관한 연구

박주용(Ju-Yong Park),김우성(Woo-Seong Kim) 대한용접·접합학회 2018 대한용접·접합학회지 Vol.36 No.1

The thermal image of weld pool and its adjacent area contains many useful information related to the weld quality. Occurrence of weld defects such as porosity, slag inclusion, or crack or during welding causes the change of thermal distribution adjacent area where the weld defects occur. The accidental root gap change makes the different temperature distribution also. In this research the various thermal images of flux cored arc welding were obtained by use of a high-speed infrared camera. The thermal image of weld area 2㎝ behind the arc shows thermal image of bead and the corresponding signals of welding current and voltage. The 4 kinds of specimens, V-groove specimens without root gap, with changing root gap, filled partly with slag pieces and coated partly with grease at intervals of 30 ㎜ were used. The thermal images for each case were analyzed by the specific evaluation values, Wt and At, extracted from the thermal image. Wt value indicates the width over the specific thermal intensity and At indicates the area which means the summation of the thermal intensity over the specific value. The analysis result showed a meaningful change of these values when any weld defects occurred. The change of At values was more prominent than the change of Wt value. It means the weld quality can be monitored by the change of At values from the thermal image of weld area during welding.

Local transport properties of coated conductors by laser-scan imaging methods

Kim, Gracia,Jo, William,Nam, Dahyun,Cheong, Hyeonsik,Moon, Seoung Hyun The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.2

To observe the superconducting current and structural properties of high critical temperature ($T_c$) superconductors (HTS), we suggest the following imaging methods: Room temperature imaging (RTI) through thermal heating, low-temperature bolometric microscopy (LTBM) and Raman scattering imaging. RTI and LTBM images visualize thermal-electric voltages as different thermal gradients at room temperature (RT) and superconducting current dissipation at near-$T_c$, respectively. Using RTI, we can obtain structural information about the surface uniformity and positions of impurities. LTBM images show the flux flow in two dimensions as a function of the local critical currents. Raman imaging is transformed from Raman survey spectra in particular areas, and the Raman vibration modes can be combined. Raman imaging can quantify the vibration modes of the areas. Therefore, we demonstrate the spatial transport properties of superconducting materials by combining the results. In addition, this enables visualization of the effect of current flow on the distribution of impurities in a uniform superconducting crystalline material. These imaging methods facilitate direct examination of the local properties of superconducting materials and wires.