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Báo cáo hóa học: " Technique for Automated Recognition of Sunspots on Full-Disk Solar Images"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Technique for Automated Recognition of Sunspots on Full-Disk Solar Images | EURASIP Journal on Applied Signal Processing 2005 15 2573-2584 2005 S. Zharkov et al. Technique for Automated Recognition of Sunspots on Full-Disk Solar Images S. Zharkov Department of Cybernetics University of Bradford Bradford West Yorkshire BD71DP UK Email s.zharkov@bradford.ac.uk V. Zharkova Department of Cybernetics University of Bradford Bradford West Yorkshire BD71DP UK Email v.v.zharkova@brad.ac.uk S. Ipson Department of Cybernetics University of Bradford Bradford West Yorkshire BD71DP UK Email s.s.ipson@bradford.ac.uk A. Benkhalil Department of Cybernetics University of Bradford Bradford West Yorkshire BD7 1DP UK Email a.k.benkhalil@bradford.ac.uk Received 31 May 2004 Revised 22 February 2005 A new robust technique is presented for automated identification of sunspots on full-disk white-light WL solar images obtained from SOHO MDI instrument and Ca II K1 line images from the Meudon Observatory. Edge-detection methods are applied to find sunspot candidates followed by local thresholding using statistical properties of the region around sunspots. Possible initial oversegmentation of images is remedied with a median filter. The features are smoothed by using morphological closing operations and filled by applying watershed followed by dilation operator to define regions of interest containing sunspots. A number of physical and geometrical parameters of detected sunspot features are extracted and stored in a relational database along with umbra-penumbra information in the form of pixel run-length data within a bounding rectangle. The detection results reveal very good agreement with the manual synoptic maps and a very high correlation 96 with those produced manually by NOAA Observatory USA. Keywords and phrases digital solar image sunspots local threshold edge-detection morphological operators sunspot area time series. 1. INTRODUCTION Sunspot identification and characterisation including location lifetime contrast and so forth are required for a quantitative .