In this paper we present four types of classifier combinations determined by the numbers of trained combining functions and their input parameters. We discuss the usage of these combination types in biometric applicat...
详细信息
In this paper we present four types of classifier combinations determined by the numbers of trained combining functions and their input parameters. We discuss the usage of these combination types in biometric applications and give an example of suboptimal combination as a result of choosing non-appropriate combination type. Finally, we present results of combinations in biometric identification systems utilizing similar methods, but related to different combination types.
The adaptive mesh model is extended in several ways. Open adaptive meshes and closed adaptive shells based on triangular and rectangular elements are developed. A discontinuity detection and preservation algorithm sui...
详细信息
The adaptive mesh model is extended in several ways. Open adaptive meshes and closed adaptive shells based on triangular and rectangular elements are developed. A discontinuity detection and preservation algorithm suitable for the model is proposed. Techniques for adaptive hierarchical subdivision of adaptive meshes and shells are also developed. The extended model is applied to image and 3D surface data.< >
A family of structure from motion algorithms called the factorization method has been recently developed from the orthographic projection model to the affine camera model. All these algorithms are limited to handling ...
详细信息
A family of structure from motion algorithms called the factorization method has been recently developed from the orthographic projection model to the affine camera model. All these algorithms are limited to handling only point features of the image stream. We propose in this paper an algorithm for the recovery of shape and motion from line correspondences by the factorization method with the affine camera. Instead of one step factorization for points, a multi-step factorization method is developed for lines based on the decomposition of the whole shape and motion into three separate substructures. Each of these substructures can then be linearly solved by factorizing the appropriate measurement matrices. It is also established that affine shape and motion with uncalibrated affine cameras can be achieved with at least seven lines over three views, which extends the previous results of Koenderink and Van Doorn (1989) for points to lines.
The problem of automatic sports video classification is considered. We develop a multistage decision making system that is founded on the concept of cues, i.e. pieces of visual evidence, characteristic of certain cate...
详细信息
The problem of automatic sports video classification is considered. We develop a multistage decision making system that is founded on the concept of cues, i.e. pieces of visual evidence, characteristic of certain categories of sports that are extracted from key frames. The main decision making mechanism is a decision tree which generate hypotheses concerning the semantics of the sports video content. The final stage of the decision making process is a hidden Markov model system which bridges the gap between the semantic content categorisation defined by the user and the actual visual content categories. The latter is often ambiguous, as the same visual content may be attributed to different sport categories, depending on the context. We demonstrate experimentally that the contextual post-processing of the decision tree outputs by HMMs significantly improves the performance of the sports video classification system.
This paper describes a new method for estimating optical flow that strikes a balance between the flexibility of local dense computations and the robustness and accuracy of global parameterized flow models. An affine m...
详细信息
This paper describes a new method for estimating optical flow that strikes a balance between the flexibility of local dense computations and the robustness and accuracy of global parameterized flow models. An affine model of image motion is used within local image patches while a spatial smoothness constraint on the affine flow parameters of neighboring patches enforces continuity of the motion. We refer to this as a "Skin and Bones" model in which the affine patches can be thought of as rigid "bones" connected by a flexible "skin". Since local image patches may contain multiple motions we use a layered representation for the affine bones. To regularize this layered motion representation we develop a new framework for regularization with transparency.
A homogeneous approach for acquisition, storage, and recognition of nonparametric shapes from images, using a novel shape representation based on shape autocorrelation operators is presented. A theoretical and experim...
详细信息
A homogeneous approach for acquisition, storage, and recognition of nonparametric shapes from images, using a novel shape representation based on shape autocorrelation operators is presented. A theoretical and experimental analysis of the computational complexity, recognition performance with increasing database size, and fault tolerance of the approach is presented. The system has been tested extensively with more than 300 arbitrary shapes in the database. Using a set of complex shapes, the recognition behavior with respect to occlusion, geometric transformation, and cluttered environments is studied. Unsupervised shape and subpart acquisition is demonstrated.< >
The authors describe a technique for inference of 3-D shape from 2-D contours that utilizes not only the shapes of individual surfaces but also the interactions between them. The analysis applies to objects made of ze...
详细信息
The authors describe a technique for inference of 3-D shape from 2-D contours that utilizes not only the shapes of individual surfaces but also the interactions between them. The analysis applies to objects made of zero-Gaussian curvature surfaces viewed under orthographic projection.< >
Subspace representations have been a popular way to model appearance in computervision. In Jepson and Black's influential paper on EigenTracking, they were successfully applied in tracking. For noisy targets, opt...
详细信息
Subspace representations have been a popular way to model appearance in computervision. In Jepson and Black's influential paper on EigenTracking, they were successfully applied in tracking. For noisy targets, optimization-based algorithms (including EigenTracking) often fail catastrophically after losing track. Particle filters have recently emerged as a robust method for tracking in the presence of multi-modal distributions. To use subspace representations in a particle filter, the number of samples increases exponentially as the state vector includes the subspace coefficients. We introduce an efficient method for using subspace representations in a particle filter by applying Rao-Blackwellization to integrate out the subspace coefficients in the state vector. Fewer samples are needed since part of the posterior over the state vector is analytically calculated. We use probabilistic principal component analysis to obtain analytically tractable integrals. We show experimental results in a scenario in which we track a target in clutter.
In this paper we investigate the benefits of using a local appearance-based face recognition scheme against the problem of facial occlusion. We proposed two separate automatic block selection approaches to select the ...
详细信息
In this paper we investigate the benefits of using a local appearance-based face recognition scheme against the problem of facial occlusion. We proposed two separate automatic block selection approaches to select the local image blocks that could be used for classification. Proposed approaches are tested against both upper and lower facial occlusions using the AR face database. Significant improvements are observed in the face recognition performance.
We present a new method for synthesizing novel views of a 3D scene from few model images in full correspondence. The core of this work is the derivation of a tensorial operator that describes the transformation from a...
详细信息
We present a new method for synthesizing novel views of a 3D scene from few model images in full correspondence. The core of this work is the derivation of a tensorial operator that describes the transformation from a given tensor of three views to a novel tensor of a new configuration of three views. By repeated application of the operator on a seed tensor with a sequence of desired virtual camera positions we obtain a chain of warping functions (tensors) from the set of model images to create the desired virtual views.
暂无评论