Fuzzy c-means clustering algorithm for classification of sea ice and land cover from SAR images

Author(s):  
Aisheng Li ◽  
Patrik B. Dammert ◽  
Gary Smith ◽  
Jan Askne
Author(s):  
Polina Mikhaylyukova ◽  
Marina Semenova ◽  
Anastasia Shurygina ◽  
Nickolay Shabalin ◽  
Anna Antonova ◽  
...  

The paper presents the results of the first version algorithm development for sea ice binary classification by SAR images. To create training, test, and validation samples, we have used 81 images acquired with the Sentinel-1 radar for the area of the Pechora Sea (the south-western part of the Barents Sea) for the 2019–2020 ice period. We conducted the preprocessing procedure for each image aimed at better image quality, noise removal, including gradient noise, and geospatial reference. The marking images was carried out semi-automatically using the K-means clustering algorithm. The result of clustering is a bitmap file with a class number assigned to each pixel. The raster was then vectorized and the expert manually divided the resulting vector polygons into water and ice classes. Validation images were monitored using a set of metrics with the following average result achieved: 0.86 (Jaccard), 0.14 (Binary Crossentropy), 0.90 (Precision), 0.95 (Recall). Expert analysis of binary classification errors has shown that they are typical for the periods when ice is being actively formed or destructed, which results in alternating small areas of ice and open water offshore.


2020 ◽  
Vol 15 ◽  
pp. 155892502097832
Author(s):  
Jiaqin Zhang ◽  
Jingan Wang ◽  
Le Xing ◽  
Hui’e Liang

As the precious cultural heritage of the Chinese nation, traditional costumes are in urgent need of scientific research and protection. In particular, there are scanty studies on costume silhouettes, due to the reasons of the need for cultural relic protection, and the strong subjectivity of manual measurement, which limit the accuracy of quantitative research. This paper presents an automatic measurement method for traditional Chinese costume dimensions based on fuzzy C-means clustering and silhouette feature point location. The method is consisted of six steps: (1) costume image acquisition; (2) costume image preprocessing; (3) color space transformation; (4) object clustering segmentation; (5) costume silhouette feature point location; and (6) costume measurement. First, the relative total variation model was used to obtain the environmental robustness and costume color adaptability. Second, the FCM clustering algorithm was used to implement image segmentation to extract the outer silhouette of the costume. Finally, automatic measurement of costume silhouette was achieved by locating its feature points. The experimental results demonstrated that the proposed method could effectively segment the outer silhouette of a costume image and locate the feature points of the silhouette. The measurement accuracy could meet the requirements of industrial application, thus providing the dual value of costume culture research and industrial application.


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