Luca Di Angelo - Academia.edu (original) (raw)
Papers by Luca Di Angelo
Journal of Marine Science and Engineering
In this paper, an efficient and robust Cartesian Mesh Generation with Local Refinement for an Imm... more In this paper, an efficient and robust Cartesian Mesh Generation with Local Refinement for an Immersed Boundary Approach is proposed, whose key feature is the capability of high Reynolds number simulations by the use of wall function models, bypassing the need for accurate boundary layer discretization. Starting from the discrete manifold model of the object to be analyzed, the proposed model generates Cartesian adaptive grids for a CFD simulation, with minimal user interactions; the most innovative aspect of this approach is that the automatic generation is based on the segmentation of the surfaces enveloping the object to be analyzed. The aim of this paper is to show that this automatic workflow is robust and enables to get quantitative results on geometrically complex configurations such as marine vehicles. To this purpose, the proposed methodology has been applied to the simulation of the flow past a BB2 submarine, discretized by non-uniform grid density. The obtained results ar...
2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium
Journal of Manufacturing and Materials Processing
By additive manufacturing technologies, an object is produced deposing material layer by layer. T... more By additive manufacturing technologies, an object is produced deposing material layer by layer. The piece grows along the build direction, which is one of the main manufacturing parameters of Additive Manufacturing (AM) technologies to be set-up. This process parameter affects the cost, quality, and other important properties of the manufactured object. In this paper, the Objective Functions (OFs), presented in the literature for the search of the optimal build direction, are considered and reviewed. The following OFs are discussed: part quality, surface quality, support structure, build time, manufacturing cost, and mechanical properties. All of them are distinguished factors that are affected by build direction. In the first part of the paper, a collection of the most significant published methods for the estimation of the factors that most influence the build direction is presented. In the second part, a summary of the optimization techniques adopted from the reviewed papers is p...
Computer Methods and Programs in Biomedicine
The International Journal of Advanced Manufacturing Technology
Heritage
The problem of matching fragments of three-dimensional (3D) objects has gained increasing attenti... more The problem of matching fragments of three-dimensional (3D) objects has gained increasing attention, and several approaches have been developed to solve this problem. To date, however, to the best knowledge of the authors, there is no computer-based method supporting archaeologists in this activity. For this purpose, in this paper, a semi-automatic approach is proposed for the reconstruction of archaeological pottery fragments based on two-dimensional (2D) images. Firstly, the method, considering the curves as features, involves the extraction of edge curves by applying the Canny filter algorithm to the fragments’ image. Next, the wavelet transformation method is used to fit the edge curves and obtain the approximation coefficients. Then, the correlation coefficients between fragments are computed and the matching of fragments is done by comparing their values. The proposed approach is tested on some real cases. The results of the experimentation show, if compared with the state-of-...
Virtual Archaeology Review
Potteries are the most numerous finds found in archaeological excavations; they are often used to... more Potteries are the most numerous finds found in archaeological excavations; they are often used to get information about the history, economy, and art of a site. Archaeologists rarely find complete vases but, generally, damaged and in fragments, often mixed with other pottery groups. By using the traditional manual method, the analysis and reconstruction of sherds are performed by a skilled operator. Reviewed papers provided evidence that the traditional method is not reproducible, not repeatable, time-consuming and its results have great uncertainties. To overcome the aforementioned limits, in the last years, researchers have made efforts to develop computer-based methods for archaeological ceramic sherds analysis, aimed at their reconstruction. To contribute to this field of study, in this paper, a comprehensive analysis of the most important available publications until the end of 2019 is presented. This study, focused on pottery fragments only, is performed by collecting papers i...
Journal on Computing and Cultural Heritage
Pattern Recognition Letters
Lecture Notes in Mechanical Engineering
Sensors
The construction of the artificial emissary of Fucino Lake is one of the most ambitious engineeri... more The construction of the artificial emissary of Fucino Lake is one of the most ambitious engineering buildings of antiquity. It was the longest tunnel ever made until the 19th century and, due to the depth of the adduction inlet, it required a monumental and complex incile, which, for functionality, cannot be compared to other ancient emissaries. The Roman emissary and its "incile" (Latin name of the inlet structure) were almost completely destroyed in the 19th century, when Fucino Lake was finally dried. Today, only few auxiliary structures such as wells, tunnels, and winzes remain of this ancient work. As evidence of the ancient incile remains a description made by those who also destroyed it and some drawings made by travelers who, on various occasions, visited the site. This paper presents a virtual reconstruction of the Roman incile, obtained both through the philological study of the known documentation, interpreting iconographic sources that represent the last eviden...
Symmetry
The accurate location of the mid-sagittal plane is fundamental for the assessment of craniofacial... more The accurate location of the mid-sagittal plane is fundamental for the assessment of craniofacial dysmorphisms and for a proper corrective surgery planning. To date, these elaborations are carried out by skilled operators within specific software environments. Since the whole procedure is based on the manual selection of specific landmarks, it is time-consuming, and the results depend on the operators’ professional experience. This work aims to propose a new automatic and landmark-independent technique which is able to extract a reliable mid-sagittal plane from 3D CT images. The algorithm has been designed to perform a robust evaluation, also in the case of large defect areas. The presented method is an upgraded version of a mirroring-and registration technique for the automatic symmetry plane detection of 3D asymmetrically scanned human faces, previously published by the authors. With respect to the published algorithm, the improvements here introduced concern both the objective fu...
Journal of Cultural Heritage
Computer-Aided Design and Applications
The photogrammetry procedure is introduced as a cheap and-effective alternative to 3D scanning fo... more The photogrammetry procedure is introduced as a cheap and-effective alternative to 3D scanning for constructing 3D point cloud data for reverse engineering applications. The data is then manipulated to generate CAD-ready models for FEA simulations or 3D printing purposes. A practical demonstration using model cars is conducted to show the effectiveness of the procedure in generating point cloud data, and various improvements are introduced. In particular, and innovative to this research work, a feature segmentation algorithm based on color information captured from photographs is implemented. This program, embedded within the photogrammetry process, allows for automatic selection of parts and features from an assembly model, providing a leading advantage over current 3D scanners, which capture spatial data only. Moreover, an intuitive method of enhancing the selection of required features of a triangular mesh during the segmentation process is introduced. This is achieved by manually marking the boundaries on the part of the object to be selected prior to taking photos. This has been proved to be more effective where areas of the object parts have similar colors.
International Journal on Interactive Design and Manufacturing (IJIDeM)
ABSTRACT In this work, a new technique for symmetry line detection for non-erected postures, whic... more ABSTRACT In this work, a new technique for symmetry line detection for non-erected postures, which can not be investigated with the other methods presented in the literature, is proposed. It evaluates the symmetry line by means an adaptive process in which a first attempt is modified step by step until the solution converges to the best estimation. The method here proposed is validated by analysing four different non-erected postures in which the spine does not lie onto sagittal plane, by the comparison with the traditional approach to symmetry line detection, having as reference the cutaneous marking. Results are analysed and critically discussed.
International Journal on Interactive Design and Manufacturing (IJIDeM)
In this work, a new technique for symmetry line detection for asymmetric postures, which can not ... more In this work, a new technique for symmetry line detection for asymmetric postures, which can not be investigated with the other methods presented in the literature, is proposed. It evaluates the symmetry line by means an adaptive process in which a first attempt is modified step by step until the solution converges to the best estimation. The method here proposed is validated by analysing four different asymmetric postures in which the spine lies far outside the sagittal plane, having as reference the cutaneous marking. Results are analysed and critically discussed.
Journal of Cultural Heritage, 2017
Journal of Engineering Design, 2017
A correct prediction of build time is essential to calculate the accurate cost of a layer manufac... more A correct prediction of build time is essential to calculate the accurate cost of a layer manufactured object. The methods presented in literature are of two types: detailed-analysis-and parametric-based approaches. The former require that a lot of data, related to the kinematic and dynamic performance of the machine, should be known. Parametric models, on the other hand, are of general use and relatively simple to implement; however, the parametric methods presented in literature only provide a few of the components of the total build time. Therefore, their performances are not properly suited in any case. In order to overcome these limitations, this paper proposes a parametric approach which uses a more complete set of build-time driving factors. Furthermore, considering the complexity of the parametric build time function, an artificial neural network is used so as to improve the method flexibility. The analysis of the test cases shows that the proposed approach provides a quite accurate estimation of build time even in critical cases and when supports are required.
Shape recognition of geometric models described by triangular meshes is affected by some problems... more Shape recognition of geometric models described by triangular meshes is affected by some problems which made it difficult to be performed without errors. Some factors, such as the location errors of points due to acquisition process and the coarse representation of continuous surfaces due to triangular approximation, introduce uncertainty in the recognition process of the geometric shape. This paper introduces some original fuzzy sets suited to recognize geometric form. The membership functions of the fuzzy sets are dynamically defined so that they can be adapted to take into account those properties of the geometric model that affect the uncertainty of the recognition process. The proposed approach is intrinsically very robust and achieves good results also in recognising form features in geometric models affected by point location errors.
Journal of Marine Science and Engineering
In this paper, an efficient and robust Cartesian Mesh Generation with Local Refinement for an Imm... more In this paper, an efficient and robust Cartesian Mesh Generation with Local Refinement for an Immersed Boundary Approach is proposed, whose key feature is the capability of high Reynolds number simulations by the use of wall function models, bypassing the need for accurate boundary layer discretization. Starting from the discrete manifold model of the object to be analyzed, the proposed model generates Cartesian adaptive grids for a CFD simulation, with minimal user interactions; the most innovative aspect of this approach is that the automatic generation is based on the segmentation of the surfaces enveloping the object to be analyzed. The aim of this paper is to show that this automatic workflow is robust and enables to get quantitative results on geometrically complex configurations such as marine vehicles. To this purpose, the proposed methodology has been applied to the simulation of the flow past a BB2 submarine, discretized by non-uniform grid density. The obtained results ar...
2021 IEEE International Joint EMC/SI/PI and EMC Europe Symposium
Journal of Manufacturing and Materials Processing
By additive manufacturing technologies, an object is produced deposing material layer by layer. T... more By additive manufacturing technologies, an object is produced deposing material layer by layer. The piece grows along the build direction, which is one of the main manufacturing parameters of Additive Manufacturing (AM) technologies to be set-up. This process parameter affects the cost, quality, and other important properties of the manufactured object. In this paper, the Objective Functions (OFs), presented in the literature for the search of the optimal build direction, are considered and reviewed. The following OFs are discussed: part quality, surface quality, support structure, build time, manufacturing cost, and mechanical properties. All of them are distinguished factors that are affected by build direction. In the first part of the paper, a collection of the most significant published methods for the estimation of the factors that most influence the build direction is presented. In the second part, a summary of the optimization techniques adopted from the reviewed papers is p...
Computer Methods and Programs in Biomedicine
The International Journal of Advanced Manufacturing Technology
Heritage
The problem of matching fragments of three-dimensional (3D) objects has gained increasing attenti... more The problem of matching fragments of three-dimensional (3D) objects has gained increasing attention, and several approaches have been developed to solve this problem. To date, however, to the best knowledge of the authors, there is no computer-based method supporting archaeologists in this activity. For this purpose, in this paper, a semi-automatic approach is proposed for the reconstruction of archaeological pottery fragments based on two-dimensional (2D) images. Firstly, the method, considering the curves as features, involves the extraction of edge curves by applying the Canny filter algorithm to the fragments’ image. Next, the wavelet transformation method is used to fit the edge curves and obtain the approximation coefficients. Then, the correlation coefficients between fragments are computed and the matching of fragments is done by comparing their values. The proposed approach is tested on some real cases. The results of the experimentation show, if compared with the state-of-...
Virtual Archaeology Review
Potteries are the most numerous finds found in archaeological excavations; they are often used to... more Potteries are the most numerous finds found in archaeological excavations; they are often used to get information about the history, economy, and art of a site. Archaeologists rarely find complete vases but, generally, damaged and in fragments, often mixed with other pottery groups. By using the traditional manual method, the analysis and reconstruction of sherds are performed by a skilled operator. Reviewed papers provided evidence that the traditional method is not reproducible, not repeatable, time-consuming and its results have great uncertainties. To overcome the aforementioned limits, in the last years, researchers have made efforts to develop computer-based methods for archaeological ceramic sherds analysis, aimed at their reconstruction. To contribute to this field of study, in this paper, a comprehensive analysis of the most important available publications until the end of 2019 is presented. This study, focused on pottery fragments only, is performed by collecting papers i...
Journal on Computing and Cultural Heritage
Pattern Recognition Letters
Lecture Notes in Mechanical Engineering
Sensors
The construction of the artificial emissary of Fucino Lake is one of the most ambitious engineeri... more The construction of the artificial emissary of Fucino Lake is one of the most ambitious engineering buildings of antiquity. It was the longest tunnel ever made until the 19th century and, due to the depth of the adduction inlet, it required a monumental and complex incile, which, for functionality, cannot be compared to other ancient emissaries. The Roman emissary and its "incile" (Latin name of the inlet structure) were almost completely destroyed in the 19th century, when Fucino Lake was finally dried. Today, only few auxiliary structures such as wells, tunnels, and winzes remain of this ancient work. As evidence of the ancient incile remains a description made by those who also destroyed it and some drawings made by travelers who, on various occasions, visited the site. This paper presents a virtual reconstruction of the Roman incile, obtained both through the philological study of the known documentation, interpreting iconographic sources that represent the last eviden...
Symmetry
The accurate location of the mid-sagittal plane is fundamental for the assessment of craniofacial... more The accurate location of the mid-sagittal plane is fundamental for the assessment of craniofacial dysmorphisms and for a proper corrective surgery planning. To date, these elaborations are carried out by skilled operators within specific software environments. Since the whole procedure is based on the manual selection of specific landmarks, it is time-consuming, and the results depend on the operators’ professional experience. This work aims to propose a new automatic and landmark-independent technique which is able to extract a reliable mid-sagittal plane from 3D CT images. The algorithm has been designed to perform a robust evaluation, also in the case of large defect areas. The presented method is an upgraded version of a mirroring-and registration technique for the automatic symmetry plane detection of 3D asymmetrically scanned human faces, previously published by the authors. With respect to the published algorithm, the improvements here introduced concern both the objective fu...
Journal of Cultural Heritage
Computer-Aided Design and Applications
The photogrammetry procedure is introduced as a cheap and-effective alternative to 3D scanning fo... more The photogrammetry procedure is introduced as a cheap and-effective alternative to 3D scanning for constructing 3D point cloud data for reverse engineering applications. The data is then manipulated to generate CAD-ready models for FEA simulations or 3D printing purposes. A practical demonstration using model cars is conducted to show the effectiveness of the procedure in generating point cloud data, and various improvements are introduced. In particular, and innovative to this research work, a feature segmentation algorithm based on color information captured from photographs is implemented. This program, embedded within the photogrammetry process, allows for automatic selection of parts and features from an assembly model, providing a leading advantage over current 3D scanners, which capture spatial data only. Moreover, an intuitive method of enhancing the selection of required features of a triangular mesh during the segmentation process is introduced. This is achieved by manually marking the boundaries on the part of the object to be selected prior to taking photos. This has been proved to be more effective where areas of the object parts have similar colors.
International Journal on Interactive Design and Manufacturing (IJIDeM)
ABSTRACT In this work, a new technique for symmetry line detection for non-erected postures, whic... more ABSTRACT In this work, a new technique for symmetry line detection for non-erected postures, which can not be investigated with the other methods presented in the literature, is proposed. It evaluates the symmetry line by means an adaptive process in which a first attempt is modified step by step until the solution converges to the best estimation. The method here proposed is validated by analysing four different non-erected postures in which the spine does not lie onto sagittal plane, by the comparison with the traditional approach to symmetry line detection, having as reference the cutaneous marking. Results are analysed and critically discussed.
International Journal on Interactive Design and Manufacturing (IJIDeM)
In this work, a new technique for symmetry line detection for asymmetric postures, which can not ... more In this work, a new technique for symmetry line detection for asymmetric postures, which can not be investigated with the other methods presented in the literature, is proposed. It evaluates the symmetry line by means an adaptive process in which a first attempt is modified step by step until the solution converges to the best estimation. The method here proposed is validated by analysing four different asymmetric postures in which the spine lies far outside the sagittal plane, having as reference the cutaneous marking. Results are analysed and critically discussed.
Journal of Cultural Heritage, 2017
Journal of Engineering Design, 2017
A correct prediction of build time is essential to calculate the accurate cost of a layer manufac... more A correct prediction of build time is essential to calculate the accurate cost of a layer manufactured object. The methods presented in literature are of two types: detailed-analysis-and parametric-based approaches. The former require that a lot of data, related to the kinematic and dynamic performance of the machine, should be known. Parametric models, on the other hand, are of general use and relatively simple to implement; however, the parametric methods presented in literature only provide a few of the components of the total build time. Therefore, their performances are not properly suited in any case. In order to overcome these limitations, this paper proposes a parametric approach which uses a more complete set of build-time driving factors. Furthermore, considering the complexity of the parametric build time function, an artificial neural network is used so as to improve the method flexibility. The analysis of the test cases shows that the proposed approach provides a quite accurate estimation of build time even in critical cases and when supports are required.
Shape recognition of geometric models described by triangular meshes is affected by some problems... more Shape recognition of geometric models described by triangular meshes is affected by some problems which made it difficult to be performed without errors. Some factors, such as the location errors of points due to acquisition process and the coarse representation of continuous surfaces due to triangular approximation, introduce uncertainty in the recognition process of the geometric shape. This paper introduces some original fuzzy sets suited to recognize geometric form. The membership functions of the fuzzy sets are dynamically defined so that they can be adapted to take into account those properties of the geometric model that affect the uncertainty of the recognition process. The proposed approach is intrinsically very robust and achieves good results also in recognising form features in geometric models affected by point location errors.