Shape Analysis (Computer Science) Research Papers (original) (raw)

Prezentowany artykuł, opublikowany w 1979 roku, był jedną z pierwszych prac opisujących zastosowanie metod komputerowej analizy obrazów do rozwiązania praktycznego problemu związanego z potrzebami technologii. Badanymi obiektami były... more

Prezentowany artykuł, opublikowany w 1979 roku, był jedną z pierwszych prac opisujących zastosowanie metod komputerowej analizy obrazów do rozwiązania praktycznego problemu związanego z potrzebami technologii. Badanymi obiektami były ziarna surowców mineralnych, których rozmiary i kształty były badane w laboratorium mikromerytyki. Prace te wykonywano na potrzeby metod wzbogacania surowców mineralnych (na przykład rud miedzi) w procesach flotacji. Przebadano kilka współczynników kształtu ziaren szukając takiego współczynnika, który najlepiej determinuje rezultaty procesu wzbogacania.

In this paper, a general methodology is introduced for the determination of potential prototype curves used for the drawing of prehistoric wall paintings. The approach includes 1) preprocessing of the wall-paintings contours to properly... more

In this paper, a general methodology is introduced for the determination of potential prototype curves used for the drawing of prehistoric wall paintings. The approach includes 1) preprocessing of the wall-paintings contours to properly partition them, according to their curvature, 2) choice of prototype curves families, 3) analysis and optimization in 4-manifold for a first estimation of the form of these prototypes, 4) clustering of the contour parts and the prototypes to determine a minimal number of potential guides, and 5) further optimization in 4-manifold, applied to each cluster separately, in order to determine the exact functional form of the potential guides, together with the corresponding drawn contour parts. The methodology introduced simultaneously deals with two problems: 1) the arbitrariness in data-points orientation and 2) the determination of one proper form for a prototype curve that optimally fits the corresponding contour data. Arbitrariness in orientation has been dealt with a novel curvature based error, while the proper forms of curve prototypes have been exhaustively determined by embedding curvature deformations of the prototypes into 4--manifolds. Application of this methodology to celebrated wall paintings excavated at Tyrins, Greece, and the Greek island of Thera manifests that it is highly probable that these wall paintings were drawn by means of geometric guides that correspond to linear spirals and hyperbolae. These geometric forms fit the drawings' lines with an exceptionally low average error, less than 0.39 mm. Hence, the approach suggests the existence of accurate realizations of complicated geometric entities more than 1,000 years before their axiomatic formulation in the Classical Ages.

A statistical representation of three-dimensional shapes is introduced, based on a novel four-dimensional feature. The feature parameterizes the intrinsic geometrical relation of an oriented surface-point pair. The set of all such... more

A statistical representation of three-dimensional shapes is introduced, based on a novel four-dimensional feature. The feature parameterizes the intrinsic geometrical relation of an oriented surface-point pair. The set of all such features represents both local and global characteristics of the surface. We compress this set into a histogram. A database of histograms, one per object, is sampled in a training phase. During recognition, sensed surface data, as may be acquired by stereo vision, a laser range-scanner, etc., are processed and compared to the stored histograms. We evaluate the match quality by six different criteria that are commonly used in statistical settings. Experiments with artificial data containing varying levels of noise and occlusion of the objects show that Kullback-Leibler and likelihood matching yield robust recognition rates. The present study proposes histograms of the geometric relation between two oriented surface points (surflets) as a compact yet distinctive representation of arbitrary three-dimensional shapes.

In this paper we propose an artificial intelligence imaging solution to support archaeologists in the classification task of Roman commonware potsherds. Usually, each potsherd is represented by its sectional profile as a two dimensional... more

In this paper we propose an artificial intelligence imaging solution to support archaeologists in the classification task of Roman commonware potsherds. Usually, each potsherd is represented by its sectional profile as a two dimensional black-white image and printed in archaeological books related to specific archaeological excavations. The partiality and handcrafted variance of the fragments make their matching a challenging problem: we propose to pair similar profiles via the unsupervised hierarchical clustering of non-linear features learned in the latent space of a deep convolutional Variational Autoencoder (VAE) network. Our contribution also include the creation of a ROman COmmonware POTtery (ROCOPOT) database, with more than 4000 potsherds profiles extracted from 25 Roman pottery corpora, and a MATLAB GUI software for the easy inspection of shape similarities. Results are commented both from a mathematical and archaeological perspective so as to unlock new research directions in both communities.

This paper investigates monoscale and multiscale descriptors of planar binary shapes in content-based image retrieval (CBIR) applications. The set of monoscale features consists of fractal dimension, eccentricity, compacity, major and... more

This paper investigates monoscale and multiscale descriptors
of planar binary shapes in content-based image retrieval
(CBIR) applications. The set of monoscale features consists
of fractal dimension, eccentricity, compacity, major and minor
axis, equivalent diameter, perimeter and area whereas the
multiscale set comprises only the multiscale fractal dimension
(MFD). To assess the ability of the descriptors in characterizing
shapes, we compared the monoscale and the multiscale
approaches in CBIR experiments using the Euclidean distance
as the similarity measure. Tests were conducted on
two binary shape data sets: Kimia-216 with 216 samples
and Leaves-1600 with 1600 leaf samples. The performance
analysis has shown that the use of the multiscale fractal dimension
descriptor improved the shape retrieval Accuracy
when compared to monoscale descriptors. The results also
have also shown that the multiscale fractal dimension better
described the binary shapes and therefore improved shape retrieval.
Moreover, the Silhouette measure has confirmed that
MFD minimized the scattering within classes and maximized
it between classes.

Abstract Image fusion refers to the process of integrating complementary image sources from multiple imaging sensor such that the resulting fused image improves the performance of computational analysis tasks such as segmentation, feature... more

Abstract Image fusion refers to the process of integrating complementary image sources from multiple imaging sensor such that the resulting fused image improves the performance of computational analysis tasks such as segmentation, feature extraction and object ...

A method is presented for non-rigid alignment of a source shape to a target shape through estimating and interpolating point-wise correspondences between their surfaces given as point clouds. The resulting mapping can be non-smooth and... more

A method is presented for non-rigid alignment of a source shape to a target shape through estimating and interpolating point-wise correspondences between their surfaces given as point clouds. The resulting mapping can be non-smooth and non-isometric, relate shapes across large variations, and find partial matches. It does not require a parametric model or a prior of deformations. Results are shown for some objects from the Princeton Shape Benchmark and a range scan.

C programs that manipulate list-based dynamic data structures remain a challenging target for static verification. In this paper we employ the dynamic analysis of dsOli to locate and identify data structure operations in a program, and... more

C programs that manipulate list-based dynamic data structures remain a
challenging target for static verification. In this paper we employ the
dynamic analysis of dsOli to locate and identify data structure operations in a
program, and then use this information to automatically annotate that program with assertions in
separation logic. These annotations comprise candidate pre/post-conditions
and loop invariants suitable to statically verify memory safety with the
verification tool VeriFast. By using both textbook and real-world examples
on our prototype implementation, we show that the generated assertions are
often discharged automatically. Even when this is not the case, candidate
invariants are of great help to the verification engineer, significantly
reducing the manual verification effort.

Over the past decade, computer vision algorithms have transitioned from relying on the direct, pixel-based representation of images to the use of superpixels, small regions whose boundaries agree with image contours. This intermediate... more

Over the past decade, computer vision algorithms have transitioned from relying on the direct, pixel-based representation of images to the use of superpixels, small regions whose boundaries agree with image contours. This intermediate representation improves the tractability of image understanding because it reduces the number of primitives to be taken under consideration from several million to a few hundred. Despite the improvements yielded in the area of image segmentation, the concept of an oversegmentation as an intermediate representation has not been adopted in volumetric mesh processing. We take a first step in this direction, adapting a fast and efficient superpixel algorithm to the tetrahedral mesh case, present results which demonstrate the quality of the output oversegmentation, and illustrate its use in a semantic segmentation application.

Structure-from-motion and multiview-stereo together offer a computer vision technique for reconstructing detailed 3D models from overlapping images of anything from large landscapes to microscopic features. Because such models can be... more

Structure-from-motion and multiview-stereo together offer a computer vision technique for reconstructing detailed 3D models from overlapping images of anything from large landscapes to microscopic features. Because such models can be generated from ordinary photographs taken with standard cameras in ordinary lighting conditions, these techniques are revolutionising digital recording and analysis in archaeology and related subjects such as palaeontology, museum studies and art history. However, most published treatments so far have focused merely on this technique’s ability to produce low-cost, high quality representations, with one or two also suggesting new opportunities for citizen science. However, perhaps the major artefact scale advantage comes from significantly enhanced possibilities for 3D morphometric analysis and comparative taxonomy. We wish to stimulate further discussion of this new research domain by considering a case study using a famous and contentious set of archaeological objects: the terracotta warriors of China’s first emperor.

In this paper, a novel approach is introduced for classifying curves into proper families, according to their similarity. First, a mathematical quantity we call plane curvature is introduced and a number of propositions are stated and... more

In this paper, a novel approach is introduced for classifying curves into proper families, according to their similarity. First, a mathematical quantity we call plane curvature is introduced and a number of propositions are stated and proved. Proper similarity measures of two curves are introduced and a subsequent statistical analysis is applied. First, the efficiency of the curve fitting process has been tested on 2 shapes datasets of reference. Next, the methodology has been applied to the very important problem of classifying 23 Byzantine codices and 46 Ancient inscriptions to their writers, thus achieving correct dating of their content. The inscriptions have been attributed to ten individual hands and the Byzantine codices to four writers.

In this paper a general methodology is introduced for the determination of potential prototype curves used for the drawing of prehistoric wall-paintings. The approach includes a) preprocessing of the wall-paintings contours to properly... more

In this paper a general methodology is introduced for the determination of potential prototype curves used for the drawing of prehistoric wall-paintings. The approach includes a) preprocessing of the wall-paintings contours to properly partition them, according to their curvature, b) choice of prototype curves families, c) analysis and optimization in 4-manifold for a first estimation of the form of these prototypes, d) clustering of the contour parts and the prototypes, to determine a minimal number of potential guides, e) further optimization in 4-manifold, applied to each cluster separately, in order to determine the exact functional form of the potential guides, together with the corresponding drawn contour parts. The introduced methodology simultaneously deals with two problems: a) the arbitrariness in data-points orientation and b) the determination of one proper form for a prototype curve that optimally fits the corresponding contour data. Arbitrariness in orientation has been dealt with a novel curvature based error, while the proper forms of curve prototypes have been exhaustively determined by embedding curvature deformations of the prototypes into 4-manifolds. Application of this methodology to celebrated wall-paintings excavated at Tyrins, Greece and the Greek island of Thera, manifests it is highly probable that these wall-paintings had been drawn by means of geometric guides that correspond to linear spirals and hyperbolae. These geometric forms fit the drawings' lines with an exceptionally low average error, less than 0.39mm. Hence, the approach suggests the existence of accurate realizations of complicated geometric entities, more than 1000 years before their axiomatic formulation in Classical Ages.

This paper describes an efficient approach towards road sign detection and recognition. The proposed system is divided into three sections namely; Colour Segmentation of the road traffic signs using the HSV colour space considering... more

This paper describes an efficient approach towards road sign detection and recognition. The proposed system is divided into three sections namely; Colour Segmentation of the road traffic signs using the HSV colour space considering varying lighting conditions, Shape Classification using the Contourlet Transform considering occlusion and rotation of the candidate signs and the Recognition of the road traffic signs using features of a Local Energy based Shape Histogram (LESH). We have provided experimental results and a detailed analysis to justify that the algorithm described in this paper is robust enough to detect and recognize road signs under varying weather, occlusion, rotation and scaling conditions.

Abdominal Aortic Aneurysms (AAAs) are located in the abdominal segment of the aorta, the majority below the renal arteries and above the iliac artery bifurcation. The associated mortality and morbidity rates have risen concomitantly in... more

Abdominal Aortic Aneurysms (AAAs) are located in the abdominal segment of the aorta, the majority below the renal arteries and above the iliac artery bifurcation. The associated mortality and morbidity rates have risen concomitantly in the last few years, despite significant improvements in surgical procedures and technological advancements in imaging devices. AAAs are a health risk of significant importance since

In this paper, we propose a method for computing partial functional correspondence between non-rigid shapes. We use perturbation analysis to show how removal of shape parts changes the Laplace-Beltrami eigenfunctions, and exploit it as a... more

In this paper, we propose a method for computing partial functional correspondence between non-rigid shapes. We
use perturbation analysis to show how removal of shape parts changes the Laplace-Beltrami eigenfunctions, and
exploit it as a prior on the spectral representation of the correspondence. Corresponding parts are optimization
variables in our problem and are used to weight the functional correspondence; we are looking for the largest
and most regular (in the Mumford-Shah sense) parts that minimize correspondence distortion. We show that our
approach can cope with very challenging correspondence settings.

We present a novel and generic user-guided approach for the digital reconstruction of cultural heritage finds from fragments, which operates directly on generic 3D objects. Central to our approach is a three-tier geometric registration... more

We present a novel and generic user-guided approach for the digital reconstruction of cultural heritage finds from fragments, which operates directly on generic 3D objects. Central to our approach is a three-tier geometric registration approach that addresses the reassembly problem using i) the contact surface of the fractured objects, ii) feature curves on the intact surfaces and iii) partial object symmetries. In contrast to most existing methodologies, our approach is more generic and addresses even the most difficult cases, where contact surface is unusable, small or absent. We evaluate our method using digitized fragments from the Nidaros Cathedral.

We present a deformation-driven approach to topology-varying 3D shape correspondence. In this paradigm, the best correspondence between two shapes is the one that results in a minimal-energy, possibly topology-varying, deformation that... more

We present a deformation-driven approach to topology-varying 3D shape correspondence. In this paradigm, the best correspondence between two shapes is the one that results in a minimal-energy, possibly topology-varying, deformation that transforms one shape to conform to the other while respecting the correspondence. Our deformation model, called GeoTopo transform, allows both geometric and topological operations such as part split, duplication, and merging, leading to fine-grained and piecewise continuous correspondence results. The key ingredient of our correspondence scheme is a deformation energy that penalizes geometric distortion, encourages structure preservation, and simultaneously allows topology changes. This is accomplished by connecting shape parts using structural rods, which behave similarly to virtual springs but simultaneously allow the encoding of energies arising from geometric, structural, and topological shape variations. Driven by the combined deformation energy, an optimal shape correspondence is obtained via a pruned beam search. We demonstrate our deformation-driven correspondence scheme on extensive sets of man-made models with rich geometric and topological variation and compare the results to state-of-the-art approaches.

We study the effect of growth on the fingerprints of adolescents, based on which we suggest a simple method to adjust for growth when trying to retrieve an ado- lescent’s fingerprint in a database years later. Here, we focus on the... more

We study the effect of growth on the fingerprints of adolescents, based on
which we suggest a simple method to adjust for growth when trying to retrieve an ado-
lescent’s fingerprint in a database years later. Here, we focus on the statistical analyses
used to determine how fingerprints grow: Procrustes analyses allows us to establish
that fingerprints grow isotropically, an appropriate mixed effects model shows that fin-
gerprints essentially grow proportionally to body height. The resulting growth model
is validated by showing that it brings points of interest as close as if both fingerprints
were taken from an adult