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Thin Cloud Detection of All-Sky Images Using Markov Random Fields

Qingyong Li, Weitao Lu, Jun Yang, James Z. Wang
2012 IEEE Geoscience and Remote Sensing Letters  
Index Terms-All-sky cloud image, cloud detection, Markov random fields (MRFs).  ...  Thin cloud detection for all-sky images is a challenge in ground-based sky-imaging systems because of low contrast and vague boundaries between cloud and sky regions.  ...  Sky imager and all-sky cloud images. (a) WSC used in this study. (b) All-sky image produced by the WSC. (c) Cropped thin cloud image.  ... 
doi:10.1109/lgrs.2011.2170953 fatcat:fztv3refbzdwreeerb63ajfyny

Daytime Cloud Detection Method Using the All-Sky Imager over PERMATApintar Observatory

Mohammad Afiq Dzuan Mohd Azhar, Nurul Shazana Abdul Hamid, Wan Mohd Aimran Wan Mohd Kamil, Nor Sakinah Mohamad
2021 Universe  
Both methods were applied to all three images and compared in terms of cloud coverage detection.  ...  The objective of this study was to test the effectiveness of these two methods in detecting daytime clouds. Three all-sky images were selected from a database system at PERMATApintar Observatory.  ...  Conflicts of Interest: The authors declare no conflict of interest. Universe 2021, 7, 41  ... 
doi:10.3390/universe7020041 fatcat:2gu6vn2gqzayzlar57nvnyqj64

Cloud detection methodologies: variants and development—a review

Seema Mahajan, Bhavin Fataniya
2019 Complex & Intelligent Systems  
Researchers explored various forms of Cloud detection like Cloud/ No cloud, Snow/Cloud, and Thin Cloud/Thick Cloud using various approaches of machine learning and classical algorithms.  ...  Authors of [6] studied the deep learning method for cloud detection using the SPOT 6 image database.  ...  Author [45] presented a conditional random field (CRF) model for cloud detection on groundbased sky.  ... 
doi:10.1007/s40747-019-00128-0 fatcat:ftol5w36vzdwzpuqeijsz2dct4

Onboard Spectral and Spatial Cloud Detection for Hyperspectral Remote Sensing Images

Haoyang Li, Hong Zheng, Chuanzhao Han, Haibo Wang, Min Miao
2018 Remote Sensing  
angle map (TESAM), adaptive Markov random field (aMRF) and dynamic stochastic resonance (DSR).  ...  The accurate onboard detection of clouds in hyperspectral images before lossless compression is beneficial.  ...  ., represented spatial dependency using a prior probabilistic Markov random field [36] .  ... 
doi:10.3390/rs10010152 fatcat:ss75rfkrmfbb5l2u7ghixamahu

Incorporating Cloud Distribution in Sky Representation

Kuan-Chuan Peng, Tsuhan Chen
2013 2013 IEEE International Conference on Computer Vision  
To capture variable cloudiness, we extend the concept of sky index to a random field indicating the level of cloudiness of each sky pixel in our proposed sky representation based on the Igawa sky model  ...  Potential applications of our proposed sky model include sky image rendering, where sky images can be generated with an arbitrary cloud distribution at any time and any location, previously impossible  ...  [13] proposed a thin cloud detection algorithm using Markov random fields, but their binary labeling algorithm can only handle images with thin clouds.  ... 
doi:10.1109/iccv.2013.267 dblp:conf/iccv/PengC13 fatcat:mxtnsmtwsngphhrkobwgzywwxu

Cloud Detection Methodology Based on a Sky-imaging System

R. Chauvin, J. Nou, S. Thil, A. Traoré, S. Grieu
2015 Energy Procedia  
First, an overview of the existing sky-imaging systems and the current cloud detection algorithms is presented. Next, the experimental setup is introduced.  ...  This paper deals with an image processing methodology based on a sky-imaging system developed at the PROMES-CNRS laboratory.  ...  As a consequence, the cloud detection algorithm must be as robust as possible for all kinds of sky conditions. Cloud detection consists in classifying pixels either as cloud or sky.  ... 
doi:10.1016/j.egypro.2015.03.198 fatcat:zgxe7zevpzhjxiuutuz3hu7kny

A cloud and cloud shadow detection method based on fuzzy c-means algorithm

Bo Ping, Fenzhen Su, Yunshan Meng
2020 IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing  
Cloud and cloud shadow detection is an important preprocess before using satellite images for different applications.  ...  The detected results demonstrate that the thick and thin clouds along with their associated cloud shadows can be precisely extracted by using the FCM.  ...  ACKNOWLEDGMENT The authors would like to thank the Institute of Geographic Sciences and Natural Resources Research, University of the Chinese Academy of Sciences, the National Marine Data and Information  ... 
doi:10.1109/jstars.2020.2987844 fatcat:qlwcjpx7vjdx3ea35bq7azfcym

Multi-Visual Feature Saliency Detection for Sea-Surface Targets through Improved Sea-Sky-Line Detection

Chang Lin, Wu Chen, Haifeng Zhou
2020 Journal of Marine Science and Engineering  
The gradient edges of the sea-surface images are enhanced using a Gaussian low-pass filter to eliminate the effect of the image gradients pertaining to the clouds, wave points, and illumination.  ...  To visually detect sea-surface targets, the objects of interest must be effectively and rapidly isolated from the background of sea-surface images.  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/jmse8100799 fatcat:jqrcrfq3pzeuhksed3ssm5bqkq

A Self-Trained Model for Cloud, Shadow and Snow Detection in Sentinel-2 Images of Snow- and Ice-Covered Regions

Kamal Gopikrishnan Nambiar, Veniamin I. Morgenshtern, Philipp Hochreuther, Thorsten Seehaus, Matthias Holger Braun
2022 Remote Sensing  
Given the unavailability of large, labeled Sentinel-2 training datasets, we present a multi-stage self-training approach that trains a model to perform semantic segmentation on Sentinel-2 L1C images using  ...  Screening clouds, shadows, and snow is a critical pre-processing step in many remote-sensing data processing pipelines that operate on satellite image data from polar and high mountain regions.  ...  We also thank the OpenStreetMap contributors for providing the background maps used in our figures, under an Open Data Commons Open Database License (ODbL) (accessed on 25 February 2022).  ... 
doi:10.3390/rs14081825 fatcat:ee6ognzd65h4pfzyyygs2owuoe

Development and Validation of Machine-Learning Clear-Sky Detection Method Using 1-Min Irradiance Data and Sky Imagers at a Polluted Suburban Site, Xianghe

Mengqi Liu, Xiangao Xia, Disong Fu, Jinqiang Zhang
2021 Remote Sensing  
Clear-sky detection (CSD) is of critical importance in solar energy applications and surface radiative budget studies.  ...  Using five-year high resolution ground-based solar radiation data and visual inspected Total Sky Imager (TSI) measurements at polluted Xianghe, a suburban site, this study validated 17 existing CSD methods  ...  Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/rs13183763 fatcat:4x7vnpdpprathjaj73el26lxva

Framework to create cloud-free remote sensing data using passenger aircraft as the platform

Chisheng Wang, Shuying Wang, Hongxing Cui
2021 IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing  
This method is intended to remove cloud contamination without the requirements of reference images and pre-determination of cloud types.  ...  To accomplish this, a processing framework is proposed, which includes four main steps: 1) multi-angle image acquisition from passenger aircraft, 2) cloud detection based on deep learning semantic segmentation  ...  A cloud removal method based on similar pixel replacement driven by a spatiotemporal Markov random field model was previously introduced [18] . Meng et al.  ... 
doi:10.1109/jstars.2021.3094586 fatcat:k4ntnovqx5ag3f63ctog35fgjq

Very short-term photovoltaic power forecasting with cloud modeling: A review

Florian Barbieri, Sumedha Rajakaruna, Arindam Ghosh
2017 Renewable & Sustainable Energy Reviews  
A combination of several sources of input data like satellite and land-based sky imaging also lead to the best results for very-short term forecasting.  ...  A combination of several sources of input data like satellite and land-based sky imaging also lead to the best results for very-short term forecasting. .  ...  To complete the flow, a time-dependent penalty term feeds a Maximum a Posteriori Markov Random Fields (MAP-MRF) algorithm used for classification.  ... 
doi:10.1016/j.rser.2016.10.068 fatcat:3vmohbasanccnpd5bhk5z4m6ee

Aeolus: A Markov--Chain Monte Carlo code for mapping ultracool atmospheres. An application on Jupiter and brown dwarf HST light curves [article]

Theodora Karalidi, Daniel Apai, Glenn Schneider, Jake R. Hanson, Jay M. Pasachoff
2015 arXiv   pre-print
Deducing the cloud cover and its temporal evolution from the observed planetary spectra and phase curves can give us major insight into the atmospheric dynamics.  ...  In this paper, we present Aeolus, a Markov-Chain Monte Carlo code that maps the structure of brown dwarf and other ultracool atmospheres.  ...  of thin clouds with large patches of cold and thick clouds.  ... 
arXiv:1510.04251v1 fatcat:f5yhqlddoze4bhfvn6tadkusyy

AWISECENSUS OF YOUNG STELLAR OBJECTS IN THE PERSEUS OB2 ASSOCIATION

Mohaddesseh Azimlu, Juan Rafael Martínez-Galarza, August A. Muench
2015 Astronomical Journal  
The spatial distribution of newly found YSOs all over the field shows an older generation of star formation which most of its massive members have evolved into main sequence stars.  ...  the age of Per OB2 association and currently star forming sites within the cloud.  ...  This research was made possible through the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund.  ... 
doi:10.1088/0004-6256/150/3/95 fatcat:l2qi2uralffsbbd7m7ngc6ra2a

Halos of Spiral Galaxies. I. The Tip of the Red Giant Branch as a Distance Indicator

M. Mouhcine, H. C. Ferguson, R. M. Rich, T. M. Brown, T. E. Smith
2005 Astrophysical Journal  
We have imaged the halo populations of a sample of nearby spiral galaxies using the Wide Field Planetary Camera 2 on broad the Hubble Space Telescope with the aim of studying the stellar population properties  ...  Using both the Sobel edge-detection technique and maximum-likelihood analysis to measure the I-band magnitude of the red giant branch tip, we determine distances to four nearby galaxies: NGC 253, NGC 4244  ...  Fig. 1 shows the locations of the observed halo fields, superimposed on the Digitized Sky Survey images of these galaxies.  ... 
doi:10.1086/468177 fatcat:qis5uun46bgvrg6bcg3mbyppca
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