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First estimates of fumarolic SO₂ fluxes from Putana volcano, Chile, using an ultraviolet imaging camera

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH 2015年第Jul.15期300卷 112-120页

作者： Stebel, K. Amigo, A. Thomas, H. Prata, A. J. Norwegian Inst Air Res N-2007 Kjeller Norway SERNAGEOMIN Santiago Chile Nicarnica Aviat AS N-2007 Kjeller Norway

Putana is a stratovolcano in the central Andes volcanic zone in northern Chile on the border with Bolivia. Fumarolic activiy has been visible at its summit crater at 5890 m altitude from long distances since the early 1800s. However, due to its remote location neither detailed geological studies have been made nor gas fluxes have been monitored and therefore its evolution remains unknown. On November 28, 2012 an ultraviolet (UV) imaging camera was transported to Putana and for about 30 min images of the fumaroles were recorded at 12 Hz. These observations provide the first measurements of SO2 fluxes from the fumarolic field of Putana and demonstrate the applicability of the UV camera to detect such emissions. The measurement series was used to assess whether the sampling rate of the data influences the estimate of the gas flux. The results suggest that measurements made at 10 s and 1 min intervals capture the inherent (turbulent) variability in both the plume/wind speed and SO2 flux. Relatively high SO2 fluxes varying between 03 kg s(-1) and 1.4 kg s(-1), which translates to 26 t/day and 121 t/day assuming constant degassing throughout the day, were observed on November 28, 2012. Furthermore, we demonstrate how an optical flow algorithm can be integrated with the SO2 retrieval to calculate SO2 fluxes at pixel level. Average values of 0.64 kg s(-1) 020 kg s(-1) and 0.70 kg s(-1) 0.53 kg s(-1) were retrieved from a "classical" transect method and the "advanced" optical flow based retrieval, respectively. Assuming constant emissions throughout all times, these values would results in an average annual SO2 burden of 20-22 kT. (C) 2015 The Authors. Published by Elsevier B.V.

关键词： Ultraviolet imaging camera Sulfur dioxide Fumarolic gas emissions Remote sensing optical flow algorithm

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Monitoring Sea Surface Currents Based on China GF-4 Multispectral Data

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MARINE GEODESY 2021年第6期44卷 531-553页

作者： Sun, Hequan Li, Zeyu Shao, Ruoli Dalian Naval Acad Dept Mil Oceanog & Hydrog Dalian 116018 Peoples R China Dalian Univ Technol Design Inst Civil Engn & Architecture Dalian Peoples R China

The seawater tracing index that characterizes the sea surface feature can be calculated using the optimal band combination of China GF-4 high-resolution multispectral data, and the distribution of sea surface currents can be retrieved from the sequential band combination data. In this paper, the methods of monitoring sea surface currents are presented in detail by processing multispectral remote sensing images generated by China GF-4 Earth Observation satellite. The sea surface currents obtained from GF-4 imagery data are compared with the sea surface currents derived from FES2014 global ocean tide model, providing a validation of the proposed methods.

关键词： FES2014 tide model GF-4 satellite maximum cross-correlation optical flow algorithm remote sensing sea surface currents

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Evaluating a potential technique with local optical flow vectors for automatic organ-at-risk (OAR) intrusion detection and avoidance during radiotherapy

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PHYSICS IN MEDICINE AND BIOLOGY 2019年第14期64卷 145008-145008页

作者： Teo, P. Troy Guo, Kaiming Ahmed, Bilal Alayoubi, Nadia Kehler, Katherine Fontaine, Gabrielle Sasaki, David Pistorius, Stephen Univ Manitoba Dept Phys & Astron Winnipeg MB R3T 2N2 Canada CancerCare Manitoba Med Phys 675 McDermot Ave Tuti Peg MB R3E 0V9 Canada Univ Manitoba Dept Radiol Winnipeg MB R3T 2N2 Canada Univ Manitoba Biomed Engn Grad Program Winnipeg MB R3T 2N2 Canada

Various techniques of deep inspiration breath hold (DIBH) have been used to mitigate the likelihood and risk of exposing the heart, an organ-at-risk (OAR) for unintended radiation during left breast radiotherapy. However, issues of reproducibility of these techniques warrant further investigation into the feasibility of detecting the intrusion of an OAR into the treatment field during intrafractional treatment delivery. The increase of high-dose, low-fraction radiotherapy treatments makes it important to immediately adapt treatment once an OAR is detected in the treatment field. This proof-of-concept implementation includes an algorithm that detects and tracks the motion at the edges of a treatment field and a control algorithm that adapts the treatment aperture according to the motion detected. In accordance to the AAPM Task-Group (TG-132) report, image registration techniques should be verified with virtual and physical phantoms prior to clinical application. Since most OARs move as a result of respiration-induced motion, we have used a lung phantom to generate images of a generic OAR intruding into a treatment field with known velocity. The phantom was programmed to move with sinusoidal and lung patient tumor motion patterns and the accuracy of intrusion tracking and MLC adaptation were benchmarked with the ground truth-programmed motion of the OAR. The motions were recorded with an electronic portal imaging device (EPID). An optimal cluster size of 9 x 9 motion vectors was found to provide the smallest average absolute position error of 0.3 mm. A strong linear correlation between the adapted MLC leaves and the actual OAR position was observed. The algorithm had a mean position tracking error of -0.4 +/- 0.3 mm and a precision of 1.1 mm. It is possible to adapt MLC leaves based on the motion detected at the edges of the irradiated field, and it would be feasible to shield an unplanned intrusion of an OAR into the treatment field.

关键词： deep inspiration breath hold (DIBH) breast cancer treatment cardiac block image registration technique optical flow algorithm

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Foreground Segmentation Using Motion Vector for Camouflaged Surveillance Scenario 2

Foreground Segmentation Using Motion Vector for Camouflaged ...

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2nd IEEE International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET)

作者： Ratthi, K. Iyshwarya Nithya, V. Yogameena, B. Menaka, K. Thiagarajar Coll Engn Elect & Commun Engn Madurai Tamil Nadu India

ISBN: (纸本)9781509044429

Detection of moving objects is the first relevant step of information extraction in many computer vision applications. It gains focus of attention in applications such as abnormal event detection, human gait characterization, congestion analysis, person identification and fall detection for elderly people. Foreground segmentation fails due to various reasons such as presence of camouflage, shadows, slow moving objects, illumination changes etc. Detecting moving objects from similarly colored background (known as camouflage problem), has been a long-standing open question in this field. Thus, camouflage is one of the major issues where foreground and background gets occluded or merged when they are of similar color. In case of terrorist attacks, terrorist disguise themselves, by dressing similar to the environment so that they can hide themselves. Foreground segmentation by eliminating camouflage in such cases play a vital role which is one of the major issues being faced nowadays. In order to overcome this issue, the proposed work extracts motion information using optical flow algorithm to detect the moving object and Motion Assisted Matrix Restoration (MAMR) for foreground segmentation in fully camouflaged surveillance scenario. Experimental results have been shown emphasizing that the proposed methodology outperforms other state-of-the-art algorithms.

关键词： Foreground segmentation motion vector optical flow algorithm camouflage removal MAMR

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Locating object - of - interest & preventing Stampede using crowd management 3

Locating object - of - interest & preventing Stampede using ...

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3rd International Conference on Computing Methodologies and Communication (ICCMC)

作者： Suganya, P. Gaurav, Tannavi Rampuriya, Priyansh Dey, Subhadeep SRM Inst Sci & Technol Comp Sci Engn Chennai Tamil Nadu India

ISBN: (纸本)9781538678084

Congestion in urban areas is becoming a serious problem in modern society. Large scale events at locations such as movie theatres or sports stadiums, etc which attract thousands of spectators can be expected to cause more inconvenience in future as compared to the present day conditions. Crowd management is important as with the increase in number of individuals a number of problems can occur, like, the risks of people or objects getting lost and stampede in areas of high crowd density. It is essential for people to live safely and securely in such large cities. Real-time analysis and rapid response is necessary for the security and safety. Using Artificial Intelligence we will be able to track people and object of interest almost immediately. In cases of people or costly objects being lost it becomes imperative to find its location in real-time, and this is where this implementation has an upper-hand on all its predecessors. In places of high density of population it is very common for children to get separated from their parents. Even at places where CCTV cameras are installed it is very time seeking to search for a particular object in millions of objects.

关键词： Artificial Intelligence Open-CV optical flow algorithm Real-time tracking Crowd Behaviour Analysis

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Mesh resampling alignment for 3D face morphable model

Mesh resampling alignment for 3D face morphable model

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International Symposium on Intelligent Multimedia, Video and Speech Processing

作者： Hu, YL Yin, BC Sun, YF Beijing Univ Technol Multimedia & Intelligent Software Technol Lab Beijing 100022 Peoples R China

ISBN: (纸本)0780386876

Based on resampling method, we present a morphable model for 3D face synthesis. The morphable model can reconstruct 3D face automatically from facial image by the combination of aligning prototypic 3D faces. But the point-to-point alignment of 3D dense faces is a challengeable problem. The optical flow algorithm is used to compute the alignment by cylinder projective facial images. But this algorithm is a approximative and unstable method. We propose a mesh resampling method to do the alignment. Based on the resampling alignment a 3D face morpable model is constructed. And from the temporary data of mesh resampling a multi-resolution model is constructed to accelerate the model matching and improve its converging stability. The experimental results show, the resampling alignment is a contributive method for the morphable model in 3D face synthesis.

关键词： mesh generation image morphing image reconstruction image registration image matching convergence image sampling mesh resampling alignment 3D face morphable model 3D face synthesis face reconstruction aligned prototypic faces combination point-to-point alignment optical flow algorithm cylinder projective facial images multiresolution model model matching acceleration convergence stability

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The Automatic Storm Recognition, the Track and the Early Warning Use the FY-2 Satellite Data

The Automatic Storm Recognition, the Track and the Early War...

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Conference on Remote Sensing of the Atmosphere and Clouds III

作者： Liu, Yuling Li, Sen Liu, Jianwen Zhou, Zhuhua Beijing Aviat Meteorol Inst Beijing 100085 Peoples R China

ISBN: (纸本)9780819483898

Based on the data from FY-2 meteorological satellite, this study investigates the potential of the satellite deep convection index and infrared multi-spectrum brightness temperature in identifying thunderstorm systems. To track the thunderstorm, we adopt the area overlap algorithm improved through the optical flow method. Based on these algorithms and continuous automatic tracking results, we seek to predict the location of thunderstorms by using linear extrapolation. It is proved that the combined usage of those algorithms is effective for thunderstorm identification, tracking and early-warning.

关键词： Storm Identification and Tracking Early warning Area Overlap algorithm optical flow algorithm

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algorithm of Detection and Tracking for Laboratory Unsafe Behavior Based on Computer Vision

Algorithm of Detection and Tracking for Laboratory Unsafe Be...

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2023 International Conference on Evolutionary algorithms and Soft Computing Techniques, EASCT 2023

作者： Gao, Lu Bohai University College of Physical Science and Technology Jinzhou China

ISBN: (纸本)9798350313413

Computer vision gives computers the ability of visual perception similar to people, so that computers can feel the environment in the field of vision, understand the content of the feeling, and take corresponding actions. Object tracking is a problem of creating corresponding matching between successive image frames based on position, speed, shape, texture and color. Many security problems in laboratories are caused by unsafe behaviors, and most laboratories have built a complete video surveillance system based on computer vision, using these video surveillance data to identify unsafe behaviors. In this paper, image denoising based on morphological filter algorithm, moving target detection based on optical flow algorithm and moving target tracking based on Mean-Shift algorithm are used to provide key technical solutions for the study of unsafe behaviors in laboratories. The results show that the optical flow algorithm has good adaptability and is suitable for both static and dynamic background. If a more accurate similarity measurement function is used, the tracking time is shorter and the speed is faster. © 2023 IEEE.

关键词： computer vision detection algorithms Mean-Shift algorithm morphological filtering optical flow algorithm tracking algorithms unsafe behavior

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Motion Compensated Compression for Event-Based Cameras

Motion Compensated Compression for Event-Based Cameras

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作者： Bairagi, Arnob Kumar University of Lethbridge (Canada)

学位级别：M.Sc., Master of Science

Event cameras detect significant changes at each pixel asynchronously and report these events in real-time. A changing scene can generate many events in a short time. Efficient storage and transmission are necessary for further processing of this event data. Inspired by this necessity, we propose a lossless Motion Compensated Compression algorithm based on optical flow (MCCOF) for event cameras. We analyzed our proposed algorithm performance compared with the lossless spike coding algorithm. We found that our MCCOF algorithm achieves a higher compression ratio on most datasets compared to the spike coding algorithm. Using a real-time event-based optical flow algorithm for motion compensation, our algorithm does not significantly increase the computational time for compression and decompression.

关键词： Event data processing Event-based cameras Log-luminance Lossless compression algorithm Motion compensated compression optical flow algorithm

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Quantitative determination of SO2 flux from industrial chimney through machine vision with plume model verification

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MEASUREMENT 2024年 238卷

作者： He, Weiwei Zhang, Huiliang Wang, Rui Guo, Jianjun Zhang, Yikang Wu, Kuijun Yantai Univ Sch Phys & Elect Informat Yantai 264005 Peoples R China

Accurate emission rate data are essential for assessing the environmental impact of industrial emissions and calibrating the effectiveness of desulphurization equipment. However, accurate calculation of SO2 emissions is difficult to realize due to the environmental conditions, the time-varying and spatial non-uniformity of pollution source emissions. In this paper, a Dual TV Plus machine vision algorithm is proposed, calculated and validated with the conventional Farneback optical flow algorithm in terms of industrial stack emission rates. In addition, the effect of turbulence on the inversion of SO2 emission under complex environmental conditions is evaluated by combining simulations and outdoor experiments. The results show that the Dual TV Plus algorithm performs better than the Farneback algorithm and the Dual TV-L1 algorithm, with 50% and 30% improvement in accuracy and 5% and 8% improvement in immunity to interference, respectively. This work is important for promoting the engineering applications of remote sensing instruments for environmental monitoring.

关键词： SO 2 flux Machine vision optical flow algorithm flow field modeling UV camera

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