Forward-looking sonar image compression by integrating keypoint clustering and morphological skeleton

Forward-Looking Sonar (FLS) is one of the most effective devices for underwater exploration which provides high-resolution images that can be used for several tasks in marine research, oceanographic, and deep-sea exploration. The limitation of current underwater acoustic channels does not allow transmitting these images in real-time, therefore image compression is required. Since acoustic images are characterized by speckle noise, an important challenge, in this area, is how to perform the compression while preserving relevant information. In this paper, a novel lossy forward-looking acoustic image compression method based on the combination between keypoint clustering and Morphological Skeleton (MS) is proposed. Keypoints are extracted by using A-KAZE feature extractor, while Density-Based Spatial Clustering of Application with Noise (DBSCAN) is used to find keypoint clusters representing a region-of-interest (ROI). Then, MS is executed to compact the ROI. The rest of the image is down-sampled and quantized through K-Means Clustering and represented via colour indexing. Finally, the information is compressed by using Brotli data compression. The experimental results on real FLS images demonstrate that our method achieves good outcomes in terms of quality metrics and compression ratio.

     

A partitional clustering algorithm validated by a clustering tendency index based on graph theory

Applying graph theory to clustering, we propose a partitional clustering method and a clustering tendency index. No initial assumptions about the data set are requested by the method. The number of clusters and the partition that best fits the data set, are selected according to the optimal clustering tendency index value.     

Protein classification by matching and clustering surface graphs

In this paper, we address the problem of comparing and classifying protein surfaces with graph-based methods. Comparison relies on matching surface graphs, extracted from the surfaces by considering concave and convex patches, through a kernelized version of the Softassign graph-matching algorithm. On the other hand, classification is performed by clustering the surface graphs with an EM-like algorithm, also relying on kernelized Softassign, and then calculating the distance of an input surface graph to the closest prototype. We present experiments showing the suitability of kernelized Softassign for both comparing and classifying surface graphs.     

Semi-supervised clustering with deep metric learning and graph embedding

World Wide Web - As a common technology in social network, clustering has attracted lots of research interest due to its high performance, and many clustering methods have been presented. The most...     

On improvability of hash clustering data from different sources by bipartite graph

Pattern Analysis and Applications - Clustering is a long-standing challenging task in pattern recognition and computer vision. In recent years, with development of multimedia technologies and...     

A hybrid clustering and graph based algorithm for tagSNP selection

TagSNP selection, which aims to select a small subset of informative single nucleotide polymorphisms (SNPs) to represent the whole large SNP set, has played an important role in current genomic research. Not only can this cut down the cost of genotyping by filtering a large number of redundant SNPs, but also it can accelerate the study of genome-wide disease association. In this paper, we propose a new hybrid method called CMDStagger that combines the ideas of the clustering and the graph algorithm, to find the minimum set of tagSNPs. The proposed algorithm uses the information of the linkage disequilibrium association and the haplotype diversity to reduce the information loss in tagSNP selection, and has no limit of block partition. The approach is tested on eight benchmark datasets from Hapmap and chromosome 5q31. Experimental results show that the algorithm in this paper can reduce the selection time and obtain less tagSNPs with high prediction accuracy. It indicates that this method has better performance than previous ones.     

基于图聚类和序列信息的蛋白质远同源性探测

远同源蛋白间的序列相似性很低,处于随机涨落区域边缘,很难区分通过比对获得的序列特征是进化过程中功能约束还是随机突变导致的结果。为了从具有高度噪音的比对分数中提取关于同源性的微弱信号,本文将基于模块度优化的图聚类算法应用于蛋白质相似性网络来探测远同源性,并与已有的性能表现较好的方法进行比较,实验结果表明,该方法能较好地探测到蛋白质远同源性,输出的集团在很大程度上对应着蛋白质超家族,输出的集团数目接近数据集中超家族的个数,得到的结果明显优于其他方法。     

Efficient nonparametric and asymptotic Bayesian model selection methods for attributed graph clustering

Attributed graph clustering, also known as community detection on attributed graphs, attracts much interests recently due to the ubiquity of attributed graphs in real life. Many existing algorithms have been proposed for this problem, which are either distance based or model based. However, model selection in attributed graph clustering has not been well addressed, that is, most existing algorithms assume the cluster number to be known a priori. In this paper, we propose two efficient approaches for attributed graph clustering with automatic model selection. The first approach is a popular Bayesian nonparametric method, while the second approach is an asymptotic method based on a recently proposed model selection criterion, factorized information criterion. Experimental results on both synthetic and real datasets demonstrate that our approaches for attributed graph clustering with automatic model selection significantly outperform the state-of-the-art algorithm.     

Segmentation of color images using multiscale clustering and graph theoretic region synthesis

A multiresolution color image segmentation approach is presented that incorporates the main principles of region-based segmentation and cluster-analysis approaches. The contribution of This work may be divided into two parts. In the first part, a multiscale dissimilarity measure is proposed that makes use of a feature transformation operation to measure the interregion relations with respect to their proximity to the main clusters of the image. As a part of this process, an original approach is also presented to generate a multiscale representation of the image information using nonparametric clustering. In the second part, a graph theoretic algorithm is proposed to synthesize regions and produce the final segmentation results. The latter algorithm emerged from a brief analysis of fuzzy similarity relations in the context of clustering algorithms. This analysis indicates that the segmentation methods in general may be formulated sufficiently and concisely by means of similarity relations theory. The proposed scheme produces satisfying results and its efficiency is indicated by comparing it with: 1) the single scale version of dissimilarity measure and 2) several earlier graph theoretic merging approaches proposed in the literature. Finally, the multiscale processing and region-synthesis properties validate our method for applications, such as object recognition, image retrieval, and emulation of human visual perception.     

特征文本提取的网络社团划分聚类算法

传统的文本聚类方法都是基于簇的算法,文本聚类错误率较高,效率较低。本文提出了一种新的文本聚类算法,首先将特征文本提取,根据特征文本之间的相似度构造一个加权的复杂网络,利用加权复杂网络社团划分方法对其网络进行社团划分,实现文本聚类。将文本特征提取,实现网络稀疏性,提高聚类效率;利用网络的社团划分提高了文本的聚类效果。实验证明该方法的可行性和有效性。     

Bipartite spectral graph partitioning for clustering dialect varieties and detecting their linguistic features

In this study we use bipartite spectral graph partitioning to simultaneously cluster varieties and identify their most distinctive linguistic features in Dutch dialect data. While clustering geographical varieties with respect to their features, e.g. pronunciation, is not new, the simultaneous identification of the features which give rise to the geographical clustering presents novel opportunities in dialectometry. Earlier methods aggregated sound differences and clustered on the basis of aggregate differences. The determination of the significant features which co-vary with cluster membership was carried out on a post hoc basis. Bipartite spectral graph clustering simultaneously seeks groups of individual features which are strongly associated, even while seeking groups of sites which share subsets of these same features. We show that the application of this method results in clear and sensible geographical groupings and discuss and analyze the importance of the concomitant features.     

Automatic news-roundup generation using clustering,extraction, and presentation

Multimedia Systems - Along with the growth of the internet, the number of information published increased exponentially. This huge flow of information causes a problem called “information...     

基于聚类和关键词提取的软件缺陷分析方法

提出一种基于K-Means和主题模型的软件缺陷分析方法,对软件缺陷的类别和关键词进行研究.获取缺陷报告进行预处理,获取有效特征,利用向量空间模型进行文本表示,计算权重,根据最终特征向量进行聚类;提取每一类缺陷的主题和关键词,帮助修复人员快速找到对应的修复方式.关键词提取结果以单词形式呈现给修复人员.实验结果表明,所提方法在bugzilla、firefox和SeaM onkey这3款软件的缺陷报告共1500条缺陷信息上最终聚类平均准确率能达到81％.     

Research on geometric features and point cloud properties for tree skeleton extraction

To solve skeleton extraction problems in the tree point cloud model, branch geometric features and local properties of point cloud are utilized to optimize tree skeleton extraction. First of all, according to the attribute information estimation and normal vector adjustment of point cloud neighbor domain, branch segmentation is made by estimated values and geometric features. Skeleton nodes are extracted in the branch subset in segmentations. Then, a graph is constructed based on skeleton node set and tree skeleton is reconstructed in this weighted directed graph. Finally, according to the tree growth characteristics, cubic Hermite curves are utilized to optimize the skeleton curve. This method is applied in the point cloud model of three-kind trees and it is compared with the skeleton extraction method based on voxel switch and point cloud contraction. The experiment results show that this method displays strong anti-interference and high-precision characteristics at branch bifurcation and crossed ending parts of fine tree branches. Thus, features of tree branches can be described more perfectly, obtaining the skeleton curve closer to the main axis.     

A skeleton and neural network-based approach for identifyingcosmetic surface flaws

This paper introduces an approach to cosmetic surface flaw identification that is essentially invariant to changes in workpiece orientation and position while being efficient in the use of computer memory. Visual binary images of workpieces are characterized according to the number of pixels in progressive subskeleton iterations. Those subskeletons are constructed using a modified Zhou skeleton transform with disk shaped structuring elements. Two coding schemes are proposed to record the pixel counts of succeeding subskeletons with and without lowpass filtering. The coded pixel counts are on-line fed to a supervised neural network that is previously trained by the backpropagation method using flawed and unflawed simulation patterns. The test workpiece is then identified as flawed or unflawed by comparing its coded pixel counts to associated training patterns. Such off-line trainings using simulated patterns avoid the problems of collecting flawed samples. Since both coding schemes tremendously reduce the representative skeleton image data, significant run time in each epoch is saved in the application of neural networks. Experimental results are reported using six different shapes of workpieces to corroborate the proposed approach.     

基于聚类和关键词提取的软件缺陷分析方法

提出一种基于K-Means和主题模型的软件缺陷分析方法,对软件缺陷的类别和关键词进行研究.获取缺陷报告进行预处理,获取有效特征,利用向量空间模型进行文本表示,计算权重,根据最终特征向量进行聚类;提取每一类缺陷的主题和关键词,帮助修复人员快速找到对应的修复方式.关键词提取结果以单词形式呈现给修复人员.实验结果表明,所提方法在bugzilla、firefox和SeaM onkey这3款软件的缺陷报告共1500条缺陷信息上最终聚类平均准确率能达到81％.     

A scalable algorithm for extraction and clustering of event-related pictures

The event detection problem, which is closely related to clustering, has gained a lot of attentions within event detection for textual documents. However, although image clustering is a problem that has been treated extensively in both Content-Based Image Retrieval (CBIR) and Text-Based Image Retrieval (TBIR) systems, event detection within image management is a relatively new area. Having this in mind, we propose a novel approach for event extraction and clustering of images, taking into account textual annotations, time and geographical positions. Our goal is to develop a clustering method based on the fact that an image may belong to an event cluster. Here, we stress the necessity of having an event clustering and cluster extraction algorithm that are both scalable and allow online applications. To achieve this, we extend a well-known clustering algorithm called Suffix Tree Clustering (STC), originally developed to cluster text documents using document snippets. The idea is that we consider an image along with its annotation as a document. Further, we extend it to also include time and geographical position so that we can capture the contextual information from each image during the clustering process. This has appeared to be particularly useful on images gathered from online photo-sharing applications such as Flickr. Hence, our STC-based approach is aimed at dealing with the challenges induced by capturing contextual information from Flickr images and extracting related events. We evaluate our algorithm using different annotated datasets mainly gathered from Flickr. As part of this evaluation we investigate the effects of using different parameters, such as time and space granularities, and compare these effects. In addition, we evaluate the performance of our algorithm with respect to mining events from image collections. Our experimental results clearly demonstrate the effectiveness of our STC-based algorithm in extracting and clustering events.     

Empowering graph segmentation methods with SOMs and CONN similarity for clustering large and complex data

Neural Computing and Applications - High-dimensional, large, and noisy data with complex structure challenge the limits of many clustering algorithms including modern graph segmentation methods....