Graphical ModelsPub Date : 2022-09-01DOI: 10.1016/j.gmod.2022.101164
Amira Chekir
{"title":"A deep architecture for log-Euclidean Fisher vector end-to-end learning with application to 3D point cloud classification","authors":"Amira Chekir","doi":"10.1016/j.gmod.2022.101164","DOIUrl":"https://doi.org/10.1016/j.gmod.2022.101164","url":null,"abstract":"<div><p>Point clouds are a widely used form of 3D data, which can be produced by depth sensors, such as RGB-D cameras. The classification of common elements of 3D point clouds remains an open research problem.</p><p><span><span>We propose a new deep network approach for the end-to-end training of log-Euclidean Fisher vectors (LE-FVs), applied to the classification of 3D point clouds. Our method uses a log-Euclidean (LE) metric in order to extend the concept of Fisher vectors (FVs) to LE-FV encoding. The LE-FV was computed on </span>covariance matrices of local 3D point cloud descriptors, representing multiple features. Our architecture is composed of two blocks. The first one aims to map the covariance matrices representing the 3D point cloud descriptors to the </span>Euclidean space<span>. The second block allows for joint and simultaneous learning of LE-FV Gaussian Mixture Model (GMM) parameters, LE-FV dimensionality reduction, and multi-label classification.</span></p><p>Our LE-FV deep learning model is more accurate than the FV deep learning architecture. Additionally, the introduction of joint learning of 3D point cloud features in the log-Euclidean space, including LE-FV GMM parameters, LE-FV dimensionality reduction, and multi-label classification greatly improves the accuracy of classification. Our method has also been compared with the most popular methods in the literature for 3D point cloud classification, and it achieved good performance. The quantitative evidence will be shown through different experiments.</p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"123 ","pages":"Article 101164"},"PeriodicalIF":1.7,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91718989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-09-01DOI: 10.1016/j.gmod.2022.101159
Yong-Xia Hao, Ting Li
{"title":"Construction of quasi-Bézier surfaces from boundary conditions","authors":"Yong-Xia Hao, Ting Li","doi":"10.1016/j.gmod.2022.101159","DOIUrl":"10.1016/j.gmod.2022.101159","url":null,"abstract":"<div><p>The quasi-Bézier surface is a kind of commonly used surfaces in CAGD/CAD systems. In this paper, we present a novel approach to construct quasi-Bézier surfaces from the boundary information based on a general second order functional. This functional includes many common functionals as special cases, such as the Dirichlet functional, the biharmonic functional and the quasi-harmonic functional etc. The problem turns into solving simple linear equations<span> about inner control points, and finally the internal control points of the resulting quasi-Bézier surface can be obtained as linear combinations of the given boundary control points. Some representative examples show the effectiveness of the presented method.</span></p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"123 ","pages":"Article 101159"},"PeriodicalIF":1.7,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75966331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-09-01DOI: 10.1016/j.gmod.2022.101163
Hui Wang , Bitao Ma , Junjie Cao , Xiuping Liu , Hui Huang
{"title":"Deep functional maps for simultaneously computing direct and symmetric correspondences of 3D shapes","authors":"Hui Wang , Bitao Ma , Junjie Cao , Xiuping Liu , Hui Huang","doi":"10.1016/j.gmod.2022.101163","DOIUrl":"https://doi.org/10.1016/j.gmod.2022.101163","url":null,"abstract":"<div><p><span>We introduce a novel method of isometric correspondences for 3D shapes, designed to address the problem of multiple solutions associated with deep functional maps when matching shapes with left-to-right reflectional intrinsic symmetries. Unlike the existing methods that only find the direct correspondences using single </span>Siamese network, our proposed method is able to detect both the direct and symmetric correspondences among shapes simultaneously. Furthermore, our method detects the reflectional intrinsic symmetry of each shape. Key to our method is the using of two Siamese networks that learn consistent direct descriptors and their symmetric ones, combined with carefully designed regularized functional maps and supervised loss. This leads to the first deep functional map capable of both producing two high-quality correspondences of shapes and detecting the left-to-right reflectional intrinsic symmetry of each shape. Extensive experiments demonstrate that the proposed method obtains more accurate results than state-of-the-art methods for shape correspondences and reflectional intrinsic symmetries detection.</p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"123 ","pages":"Article 101163"},"PeriodicalIF":1.7,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91718990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-07-01DOI: 10.1016/j.gmod.2022.101139
Xiaoqun Wu, Xiaoyun Lin, Nan Li, Haisheng Li
{"title":"Patch-based mesh inpainting via low rank recovery","authors":"Xiaoqun Wu, Xiaoyun Lin, Nan Li, Haisheng Li","doi":"10.1016/j.gmod.2022.101139","DOIUrl":"10.1016/j.gmod.2022.101139","url":null,"abstract":"<div><p>Mesh inpainting aims to fill the holes or missing regions from observed incomplete meshes and keep consistent with prior knowledge. Inspired by the success of low rank in describing similarity, we formulate the mesh inpainting problem as the low rank matrix recovery problem and present a patch-based mesh inpainting algorithm. Normal patch covariance is adapted to describe the similarity between surface patches. By analyzing the similarity of patches, the most similar patches are packed into a matrix with low rank structure. An iterative diffusion strategy is first designed to recover the patch vertex normals gradually. Then, the normals are refined by low rank approximation<span> to keep the overall consistency and vertex positions are finally updated. We conduct several experiments in different 3D models to verify the proposed approach. Compared with existing algorithms, our experimental results demonstrate the superiority of our approach both visually and quantitatively in recovering the mesh with self-similarity patterns.</span></p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"122 ","pages":"Article 101139"},"PeriodicalIF":1.7,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80382421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-07-01DOI: 10.1016/j.gmod.2022.101142
Linlin Ge, Jieqing Feng
{"title":"Out-of-core outlier removal for large-scale indoor point clouds","authors":"Linlin Ge, Jieqing Feng","doi":"10.1016/j.gmod.2022.101142","DOIUrl":"10.1016/j.gmod.2022.101142","url":null,"abstract":"<div><p><span>An accurate coarse-to-fine out-of-core outlier removal method is proposed for large-scale indoor point clouds by mining the geometric shape constraints. In coarse processing stage, a low-resolution point cloud (LPC) is obtained using random downsampling. LPC has the same density distribution as the raw point clouds (RPC), which is important information for outlier removal. The correspondences from the LPC to the RPC are also recorded. The outliers in the LPC are removed via a global threshold. The outliers in the RPC are roughly removed guided by the cleaned LPC. In refinement processing stage, the cleaned LPC is segmented into planar and non-planar segments; and the </span>LPC segmentation is transferred to the RPC. Finally, the outliers in each RPC segment are removed elaborately via a local threshold by exploring the shape information. The experiments show that the proposed method improves the quality of outlier removal results.</p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"122 ","pages":"Article 101142"},"PeriodicalIF":1.7,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81058862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-05-01DOI: 10.1016/j.gmod.2022.101136
Qing Huang, Wen-Xiang Zhang, Qi Wang, Ligang Liu, Xiao-Ming Fu
{"title":"Untangling all-hex meshes via adaptive boundary optimization","authors":"Qing Huang, Wen-Xiang Zhang, Qi Wang, Ligang Liu, Xiao-Ming Fu","doi":"10.1016/j.gmod.2022.101136","DOIUrl":"https://doi.org/10.1016/j.gmod.2022.101136","url":null,"abstract":"<div><p>We propose a novel method to untangle and optimize all-hex meshes. Central to this algorithm is an adaptive boundary optimization process that significantly improves practical robustness. Given an all-hex mesh with many inverted hexahedral elements, we first optimize a high-quality quad boundary mesh with a small approximation<span> error to the input boundary. Since the boundary constraints limit the optimization space to search for the inversion-free meshes, we then relax the boundary constraints to generate an inversion-free all-hex mesh. We develop an adaptive boundary relaxation algorithm to implicitly restrict the shape difference between the relaxed and input boundaries, thereby facilitating the next step. Finally, an adaptive boundary difference minimization is developed to effectively and efficiently force the distance difference between the relaxed boundary and the optimized boundary of the first step to approach zero while avoiding inverted elements. We demonstrate the efficacy of our algorithm on a data set containing 1004 all-hex meshes. Compared to previous methods, our method achieves higher practical robustness.</span></p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"121 ","pages":"Article 101136"},"PeriodicalIF":1.7,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72219342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-05-01DOI: 10.1016/j.gmod.2022.101138
Yeying Fan , Qian Ma , Guangshun Wei , Zhiming Cui , Yuanfeng Zhou , Wenping Wang
{"title":"TAD-Net: tooth axis detection network based on rotation transformation encoding","authors":"Yeying Fan , Qian Ma , Guangshun Wei , Zhiming Cui , Yuanfeng Zhou , Wenping Wang","doi":"10.1016/j.gmod.2022.101138","DOIUrl":"10.1016/j.gmod.2022.101138","url":null,"abstract":"<div><p>The tooth axes, defined on 3D tooth model, play a key role in digital orthodontics, which is usually used as an important reference in automatic tooth arrangement and anomaly detection<span>. In this paper, we propose an automatic deep learning network (TAD-Net) of tooth axis detection based on rotation transformation encoding. By utilizing quaternion transformation, we convert the geometric rotation transformation of the tooth axes into the feature encoding of the point cloud of 3D tooth models. Furthermore, the feature confidence-aware attention mechanism is adopted to generate dynamic weights for the features of each point to improve the network learning accuracy. Experimental results show that the proposed method has achieved higher detection accuracy on the constructed dental data set compared with the existing networks.</span></p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"121 ","pages":"Article 101138"},"PeriodicalIF":1.7,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83982159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-05-01DOI: 10.1016/j.gmod.2022.101135
Han Chen, Minghai Chen, Lin Lu
{"title":"3D Printed hair modeling from strand-level hairstyles","authors":"Han Chen, Minghai Chen, Lin Lu","doi":"10.1016/j.gmod.2022.101135","DOIUrl":"https://doi.org/10.1016/j.gmod.2022.101135","url":null,"abstract":"<div><p><span><span>Recent advances in the design and fabrication of personalized figurines have made the creation of high-quality figurines possible for ordinary users with the facilities of 3D printing<span> techniques. The hair plays an important role in gaining the realism of the figurines. Existing hair reconstruction methods suffer from the high demand for acquisition equipment, or the result is approximated very coarsely. Instead of creating hairs for figurines by scanning devices, we present a novel surface reconstruction method to generate a 3D printable hair model with geometric features from a strand-level hairstyle, thus converting the exiting digital hair database to a 3D printable database. Given a strand-level hair model, we filter the strands via bundle clustering, retain the main features, and reconstruct hair strands in two stages. First, our algorithm is the key to extracting the hair contour surface according to the structure of strands and calculating the normal for each vertex. Next, a close, manifold triangle mesh with </span></span>geometric details and an embedded </span>direction field is achieved with the Poisson surface reconstruction. We obtain closed-manifold hairstyles without user interactions, benefiting personalized figurine fabrication. We verify the feasibility of our method by exhibiting a wide range of examples.</p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"121 ","pages":"Article 101135"},"PeriodicalIF":1.7,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72219324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-05-01DOI: 10.1016/j.gmod.2022.101140
Lang Zhou , Guoxing Sun , Yong Li , Weiqing Li , Zhiyong Su
{"title":"Point cloud denoising review: from classical to deep learning-based approaches","authors":"Lang Zhou , Guoxing Sun , Yong Li , Weiqing Li , Zhiyong Su","doi":"10.1016/j.gmod.2022.101140","DOIUrl":"https://doi.org/10.1016/j.gmod.2022.101140","url":null,"abstract":"<div><p>Over the past decade, we have witnessed an enormous amount of research effort dedicated to the design of point cloud denoising techniques. In this article, we first provide a comprehensive survey on state-of-the-art denoising solutions, which are mainly categorized into three classes: filter-based, optimization-based, and deep learning-based techniques. Methods of each class are analyzed and discussed in detail. This is done using a benchmark on different denoising models, taking into account different aspects of denoising challenges. We also review two kinds of quality assessment methods designed for evaluating denoising quality. A comprehensive comparison is performed to cover several popular or state-of-the-art methods, together with insightful observations. Finally, we discuss open challenges and future research directions in identifying new point cloud denoising strategies.</p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"121 ","pages":"Article 101140"},"PeriodicalIF":1.7,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72219325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphical ModelsPub Date : 2022-03-01DOI: 10.1016/j.gmod.2022.101134
Chengzhi Liu, Juncheng Li, Lijuan Hu
{"title":"Jacobi–PIA algorithm for bi-cubic B-spline interpolation surfaces","authors":"Chengzhi Liu, Juncheng Li, Lijuan Hu","doi":"10.1016/j.gmod.2022.101134","DOIUrl":"10.1016/j.gmod.2022.101134","url":null,"abstract":"<div><p><span>Based on the Jacobi splitting of collocation matrices, we in this paper exploited the Jacobi–PIA format for bi-cubic B-spline surfaces. We first present the Jacobi–PIA scheme in term of matrix product<span>, which has higher computational efficiency than that in term of matrix-vector product. To analyze the convergence of Jacobi–PIA, we transform the matrix product iterative scheme into the equivalent matrix-vector product scheme by using the properties of the </span></span>Kronecker product. We showed that with the optimal relaxation factor, the Jacobi–PIA format for bi-cubic B-spline surface converges to the interpolation surface. Numerical results also demonstrated the effectiveness of the proposed method.</p></div>","PeriodicalId":55083,"journal":{"name":"Graphical Models","volume":"120 ","pages":"Article 101134"},"PeriodicalIF":1.7,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85559981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}