Scaled-based description and recognition of planar curves and two-dimensional shapes, (1986)

by F Mokhtarian, A Mackworth
Venue:IEEE Transactions on Pattern Analysis and Machine Intelligence
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Results 1 - 10 of 213

Evaluation of Interest Point Detectors

by Cordelia Schmid, Roger Mohr, Christian Bauckhage , 2000
"... Many different low-level feature detectors exist and it is widely agreed that the evaluation of detectors is important. In this paper we introduce two evaluation criteria for interest points: repeatability rate and information content. Repeatability rate evaluates the geometric stability under diff ..."
Abstract - Cited by 414 (8 self) - Add to MetaCart
Many different low-level feature detectors exist and it is widely agreed that the evaluation of detectors is important. In this paper we introduce two evaluation criteria for interest points: repeatability rate and information content. Repeatability rate evaluates the geometric stability under different transformations. Information content measures the distinctiveness of features. Different interest point detectors are compared using these two criteria. We determine which detector gives the best results and show that it satisfies the criteria well.
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A Survey of Shape Analysis Techniques

by Sven Loncaric - Pattern Recognition , 1998
"... This paper provides a review of shape analysis methods. Shape analysis methods play an important role in systems for object recognition, matching, registration, and analysis. Researchin shape analysis has been motivated, in part, by studies of human visual form perception systems. ..."
Abstract - Cited by 267 (2 self) - Add to MetaCart
This paper provides a review of shape analysis methods. Shape analysis methods play an important role in systems for object recognition, matching, registration, and analysis. Researchin shape analysis has been motivated, in part, by studies of human visual form perception systems.
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Detecting Salient Blob-Like Image Structures with a Scale-Space Primal Sketch: A Method for Focus-of-Attention

by Tony Lindeberg - INT. J. COMP. VISION , 1993
"... This article presents: (i) a multi-scale representation of grey-level shape called the scale-space primal sketch, which makes explicit both features in scale-space and the relations between structures at different scales, (ii) a methodology for extracting significant blob-like image structures from ..."
Abstract - Cited by 189 (14 self) - Add to MetaCart
This article presents: (i) a multi-scale representation of grey-level shape called the scale-space primal sketch, which makes explicit both features in scale-space and the relations between structures at different scales, (ii) a methodology for extracting significant blob-like image structures from this representations, and (iii) applications to edge detection, histogram analysis, and junction classification demonstrating how the proposed method can be used for guiding later stage visual processes. The representation gives a qualitative description of image structure, which allows for detection of stable scales and associated regions of interest in a solely bottom-up data-driven way. In other words, it generates coarse segmentation cues, and can hence be seen as preceding further processing, which can then be properly tuned. It is argued that once such information is available, many other processing tasks can become much simpler. Experiments on real imagery demonstrate that the proposed theory gives intuitive results.

A Computational Approach for Corner and Vertex Detection

by Rachid Deriche, Gerard Giraudon - International Journal of Computer Vision , 1992
"... Corners and vertices are strong and useful features in Computer Vision for scene analysis, stereo matching and motion analysis. This paper deals with the development of a computational approach to these important features. We consider first a corner model and study analytically its behavior once it ..."
Abstract - Cited by 132 (1 self) - Add to MetaCart
Corners and vertices are strong and useful features in Computer Vision for scene analysis, stereo matching and motion analysis. This paper deals with the development of a computational approach to these important features. We consider first a corner model and study analytically its behavior once it has been smoothed using the well-known Gaussian filter. This allows us to clarify the behavior of some well known cornerness measure based approaches used to detect these points of interest. Most of these classical approaches appear to detect points that do not correspond to the exact position of the corner. A new scale-space based approach that combines useful properties from the Laplacian and Beaudet's measure [Bea78] is then proposed in order to correct and detect exactly the corner position. An extension of this approach is then developed to solve the problem of trihedral vertex characterization and detection. In particular, it is shown that a trihedral vertex has two elliptic maxima on ...
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Flexible Syntactic Matching of Curves and its Application to Automatic Hierarchical Classification of Silhouettes

by Yoram Gdalyahu, Daphna Weinshall - IEEE Transactions on Pattern Analysis and Machine Intelligence
"... Curve matching is one instance of the fundamental correspondence problem. Our exible algorithm is designed to match curves under substantial deformations and arbitrary large scaling and rigid transformations. A syntactic representation is constructed for both curves, and an edit transformation which ..."
Abstract - Cited by 131 (2 self) - Add to MetaCart
Curve matching is one instance of the fundamental correspondence problem. Our exible algorithm is designed to match curves under substantial deformations and arbitrary large scaling and rigid transformations. A syntactic representation is constructed for both curves, and an edit transformation which maps one curve to the other is found using dynamic programming. We present extensive...
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From images to shape models for object detection

by Vittorio Ferrari, Cordelia Schmid, Vittorio Ferrari, Hal Id Inria, Vittorio Ferrari, Frederic Jurie, Cordelia Schmid, Projet Lear - International Journal of Computer Vision , 2009
"... HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte p ..."
Abstract - Cited by 92 (1 self) - Add to MetaCart
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et a ̀ la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. appor t de r ech er ch e
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Finding corners

by J. Alison Noble - Image and Vision Computing Journal , 1988
"... Many important image cues such as 'T'-,'X'- and 'L'- junctions have a local two-dimensional structure. Conventional edge detectors are designed for one-dimensional 'events'. Even the best edge operators can not reliably detect these two-dimensional features. T ..."
Abstract - Cited by 75 (1 self) - Add to MetaCart
Many important image cues such as 'T'-,'X'- and 'L'- junctions have a local two-dimensional structure. Conventional edge detectors are designed for one-dimensional 'events'. Even the best edge operators can not reliably detect these two-dimensional features. This contribution proposes a solution to the two-dimensional problem. In this paper, I address the following: • 'L'-junction detection. Previous attempts, relying on the second differentials of the image surface have essentially measured image curvature. Recently Harris [Harris 87] implemented a 'corner ' detector that is based only on first differentials. I provide a mathematical proof to explain how this algorithm estimates image curvature. Although this algorithm will isolate image 'L'junctions, its performance cannot be predicted for T'-junctions and other higher order image structures. • Instead, an image representation is proposed that exploits the richness of the local differential geometrical 'topography ' of the intensity surface. Theoretical and experimental results are presented which demonstrate how idealised instances of two-dimensional surface features such as junctions can be characterised by the differential geometry of a simple facet model. • Preliminary results are very encouraging. Current studies are concerned with the extension to real data. I am investigating statistical noise models to provide a measure of 'confidence' in the geometric labelling. The richness and sparseness of a two-dimensional structure can be exploited in many high-level vision processes. I intend to use my representation to explore some of these fields in future work.

Silhouette-based isolated object recognition through curvature scale space

by Farzin Mokhtarian - IEEE Transactions of Pattern Analysis and Machine Intelligence , 1995
"... Abstrac-A complete, fast and practical isolated object recognition sys-tem has been developed which is very robust with respect to scale, position and orientation changes of the objects as well as noise and local deforma-tions of shape (due to perspective projection, segmentation errors and non-rigi ..."
Abstract - Cited by 60 (2 self) - Add to MetaCart
Abstrac-A complete, fast and practical isolated object recognition sys-tem has been developed which is very robust with respect to scale, position and orientation changes of the objects as well as noise and local deforma-tions of shape (due to perspective projection, segmentation errors and non-rigid material used in some objects). The system has been tested on a wide variety of three-dimensional objects with different shapes and material and surface properties. A light-box setup is used to obtain silhouette images which are segmented to obtain the physical boundaries of the objects which are classified as either convex or concave. Convex curves are recognized using their four high-scale curvature extrema points. Curvature Scale Space (CSS) Representations are computed for concave curves. The CSS represen-tation is a multi-scale organization of the natural, invariant features of a curve (curvature zero-crossings or extrema) and useful for very reliable recognition of the correct model since it places no constraints on the shape of objects. A three-stage, coarse-to-fine matching algorithm prunes the search space in stage one by applying the CSS aspect ratio test. The maxima of contours in CSS representations of the surviving models are used for fast CSS matching in stage two. Finally, stage three verifies the best match and resolves any ambiguities by determining the distance be-tween the image and model curves. Transformation parameter optimization is then used to find the best fit of the input object to the correct model. Zndex Term- Object recognition system, light-box setup, boundary contours, curvature scale space representation, maxima of curvature zero-crossing contours, coarse-to-fine matching strategy, transformation pa-rameter optimization. I.

Classical Floorplanning Harmful?

by Andrew B. Kahng
"... Classical floorplanning formulations may lead researchers to solve the wrong problems. This paper points out several examples, including (i) the preoccupation with packing-driven, as opposed to connectivity-driven, problem formulations and benchmarking standards; (ii) the preoccupation with rectangu ..."
Abstract - Cited by 43 (2 self) - Add to MetaCart
Classical floorplanning formulations may lead researchers to solve the wrong problems. This paper points out several examples, including (i) the preoccupation with packing-driven, as opposed to connectivity-driven, problem formulations and benchmarking standards; (ii) the preoccupation with rectangular (and L or T shaped) block shapes; and (iii) the lack of attention to algorithm scalability, fixed-die layout requirements, and the overall RTL-down methodology context. The right problem formulations must match the purpose and context of prevailing RTL-down design methodologies, and must be neither overconstrained nor underconstrained. The right solution ingredients are those which are scalable while delivering good solution quality according to relevant metrics. We also describe new problem formulations and solution ingredients, notably a perfect rectilinear floorplanning formulation that seeks zero-whitespace, perfectly packed rectilinear floorplans in a fixed-die regime. The paper closes with a list of questions for future research.

Integral invariants for shape matching

by Siddharth Manay, Daniel Cremers, Byung-woo Hong, Anthony J. Yezzi, Jr., Stefano Soatto - PAMI , 2006
"... For shapes represented as closed planar contours, we introduce a class of functionals which are invariant with respect to the Euclidean group and which are obtained by performing integral operations. While such integral invariants enjoy some of the desirable properties of their differential counter ..."
Abstract - Cited by 42 (1 self) - Add to MetaCart
For shapes represented as closed planar contours, we introduce a class of functionals which are invariant with respect to the Euclidean group and which are obtained by performing integral operations. While such integral invariants enjoy some of the desirable properties of their differential counterparts, such as locality of computation (which allows matching under occlusions) and uniqueness of representation (asymptotically), they do not exhibit the noise sensitivity associated with differential quantities and, therefore, do not require presmoothing of the input shape. Our formulation allows the analysis of shapes at multiple scales. Based on integral invariants, we define a notion of distance between shapes. The proposed distance measure can be computed efficiently and allows warping the shape boundaries onto each other; its computation results in optimal point correspondence as an intermediate step. Numerical results on shape matching demonstrate that this framework can match shapes despite the deformation of subparts, missing parts and noise. As a quantitative analysis, we report matching scores for shape retrieval from a database.
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