Bayesian approaches to data analysis are popular in machine vision, and yet the main advantage of Bayes theory, the ability to incorporate prior knowledge in the form of the prior probabilities, may lead to problems i...
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Bayesian approaches to data analysis are popular in machine vision, and yet the main advantage of Bayes theory, the ability to incorporate prior knowledge in the form of the prior probabilities, may lead to problems in some quantitative tasks. In this paper we demonstrate examples of Bayesian and non-Bayesian techniques from the area of magnetic resonance image (MRI) analysis. Issues raised by these examples are used to illustrate difficulties in Bayesian methods and to motivate an approach based on frequentist methods. We believe this approach to be more suited to quantitative data analysis, and provide a general theory for the use of these methods in learning (Bayes risk) systems and for data fusion. Proofs are given for the more novel aspects of the theory. We conclude with a discussion of the strengths and weaknesses, and the fundamental suitability, of Bayesian and non-Bayesian approaches for MRI analysis in particular, and for machine vision systems in general. (C) 2003 Elsevier B.V. All rights reserved.
To evaluate the robustness of non-classifier models, we propose probabilistic local equivalence, based on the notion of randomized smoothing, as a way to quantitatively evaluate the robustness of an arbitrary function...
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ISBN:
(纸本)9783031479687;9783031479694
To evaluate the robustness of non-classifier models, we propose probabilistic local equivalence, based on the notion of randomized smoothing, as a way to quantitatively evaluate the robustness of an arbitrary function. For a given function f, probabilistic local equivalence evaluates whether, when sampling a normally-distributed point x' in a neighborhood of a point x, there is a probability > 0.5 that f(x') is equivalent to f(x), according to a user-defined notion of equivalence. We use probabilistic local equivalence to evaluate the effect of data augmentation methods for improving robustness, including adversarial training, on a model's performance. We also use probabilistic local equivalence to evaluate the effect on robustness of model architecture, number of parameters, pre-training, quantization, and other model properties.
Bayesian approaches to data analysis are popular in machine vision, and yet the main advantage of Bayes theory, the ability to incorporate prior knowledge in the form of the prior probabilities, may lead to problems i...
详细信息
Bayesian approaches to data analysis are popular in machine vision, and yet the main advantage of Bayes theory, the ability to incorporate prior knowledge in the form of the prior probabilities, may lead to problems in some quantitative tasks. In this paper we demonstrate examples of Bayesian and non-Bayesian techniques from the area of magnetic resonance image (MRI) analysis. Issues raised by these examples are used to illustrate difficulties in Bayesian methods and to motivate an approach based on frequentist methods. We believe this approach to be more suited to quantitative data analysis, and provide a general theory for the use of these methods in learning (Bayes risk) systems and for data fusion. Proofs are given for the more novel aspects of the theory. We conclude with a discussion of the strengths and weaknesses, and the fundamental suitability, of Bayesian and non-Bayesian approaches for MRI analysis in particular, and for machine vision systems in general. (C) 2003 Elsevier B.V. All rights reserved.
We propose a practical application of wearable computing and augmented reality which enhances the game of billiards. A vision algorithm is implemented which operates in interactive-time with the user to assist plannin...
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ISBN:
(纸本)0818681926
We propose a practical application of wearable computing and augmented reality which enhances the game of billiards. A vision algorithm is implemented which operates in interactive-time with the user to assist planning and aiming. probabilistic color models and symmetry operations are used to localize the table, pockets and balls through a video camera near the user's eye. Classification of the objects of interest is performed and each possible shot is ranked in order to determine its relative usefulness. The system allows the user to proceed through a regular pool game while it automatically determines strategic shots. The resulting trajectories are rendered as graphical overlays on a head mounted live video display. The wearable video output and the computervision system provide an integration of real and virtual environments which enhances the experience of playing and learning the game of billiards without encumbering the player.
This paper presents a new technique for planar object recognition based on Hidden Markov models. First, the contour of the object is processed to extract a sequence of high curvature points. These points are extracted...
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This paper presents a new technique for planar object recognition based on Hidden Markov models. First, the contour of the object is processed to extract a sequence of high curvature points. These points are extracted from a new adaptively extracted curvature function which is resistant against noise and transformations. Each corner is characterized by its subtended angle and its distance to the next corner. Then, corner sequences are analyzed by using HMMs. The method has been successfully tested for different databases. Its main advantage is that it can deal with incomplete and distorted corner sequences. (C) 2003 Elsevier B.V. All rights reserved.
Data from satellite and aerial images are now widely used by everyone. These images contain information from different frequency bands that help to characterize areas of interest. In this paper we study a framework fo...
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ISBN:
(纸本)9781479957750
Data from satellite and aerial images are now widely used by everyone. These images contain information from different frequency bands that help to characterize areas of interest. In this paper we study a framework for object detection in aerial image based on discriminatively-trained models trained on multimodal data. Specifically, we investigate a method to merge outputs of large margin classifiers trained on images from different sensors: we use the ranking ability of these classifiers to learn a probabilistic model.
Reasoning with probabilisticmodels is a widespread and successful technique in areas ranging from computervision, to natural language processing, to bioinformatics. Currently, these reasoning systems are either code...
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A novel technique to classify time series with imprecise hidden Markov models is presented. The learning of these models is achieved by coupling the EM algorithm with the imprecise Dirichlet model. In the stationarity...
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A novel technique to classify time series with imprecise hidden Markov models is presented. The learning of these models is achieved by coupling the EM algorithm with the imprecise Dirichlet model. In the stationarity limit, each model corresponds to an imprecise mixture of Gaussian densities, this reducing the problem to the classification of static, imprecise-probabilistic, information. Two classifiers, one based on the expected value of the mixture, the other on the Bhattacharyya distance between pairs of mixtures, are developed. The computation of the bounds of these descriptors with respect to the imprecise quantification of the parameters is reduced to, respectively, linear and quadratic optimization tasks, and hence efficiently solved. Classification is performed by extending the k-nearest neighbors approach to interval-valued data. The classifiers are credal, meaning that multiple class labels can be returned in the output. Experiments on benchmark datasets for computervision show that these methods achieve the required robustness whilst outperforming other precise and imprecise methods. (C) 2014 Elsevier Inc. All rights reserved.
Analysing cracking behaviour is essential for assessing damage and durability of reinforced concrete (RC) structures. The cracking behaviour of RC elements is probabilistic, making it challenging to mathematically mod...
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Recently, computervision has focused on denoising diffusion models, which have produced amazing outcomes for generative modeling. The idea of modeling the joint probability distribution of input and output data is th...
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