Abstract:The Dempster-Shafer theory of belief functions has proved to be a powerful formalism for uncertain reasoning. However, belief functions on a finite frame of discernment are usually defined in the power set 2 , resulting in exponential complexity of the operations involved in this framework, such as combination rules. When is linearly ordered, a usual trick is to work only with intervals, which drastically reduces the complexity of calculations. In this paper, we show that this trick can be extrapolated to fram… Show more
“…These authors could establish that the evidential approach was less restrictive than the MAP decision. We believe multi-sensor segmen- 30 tation methods should rely on models that take into account redundancy and conflicts between data sources. Evidence theory, also called Dempster-Shafer theory [8,7], is widely used in data fusion and pattern recognition [9] as it provides strong and native modelling of imprecision, data fusion, eventual conflictual sources and outliers rejection [10,11,12,13,14,15].…”
In this paper we introduce an evidential multi-source segmentation scheme for the extraction of prostate zonal anatomy using multi-parametric MRI. The Evidential C-Means (ECM) classifier was adapted to a segmentation scheme by introducing spatial neighbourhood-based relaxation step in its optimisation process. In order to do so, basic belief assignments on voxels membership were relaxed using distance-weighted combination of belief from spatial neighbours. For the application on prostate tissues, geometric a priori was modelled and used as an additional data source. Our method was first experimented on simulated images to prove the improvement brought to the ECM. A validation study of the segmentation method was then conducted on 31 patients MRI data. Each MRI was manually segmented by three independent expert radiologists, and an estimated truth was computed using STAPLE algorithm, for inter-observer variability was taken into account. This validation proved that segmentation obtained with our method is accurate and comparable to expert segmentation. We also show that our segmentation scheme enables to detect and highlight outliers, which could be interpreted by physicians as irregular tissues. The use of belief functions also provides additional information on borders between structures. We do believe these are sources of evidence that could help physicians/algorithms in characterising tissues and structures. 6 Courtesy of P. Puech and A. Iancu expert radiologists from University Hospital of Lille for contributing in this study.
“…These authors could establish that the evidential approach was less restrictive than the MAP decision. We believe multi-sensor segmen- 30 tation methods should rely on models that take into account redundancy and conflicts between data sources. Evidence theory, also called Dempster-Shafer theory [8,7], is widely used in data fusion and pattern recognition [9] as it provides strong and native modelling of imprecision, data fusion, eventual conflictual sources and outliers rejection [10,11,12,13,14,15].…”
In this paper we introduce an evidential multi-source segmentation scheme for the extraction of prostate zonal anatomy using multi-parametric MRI. The Evidential C-Means (ECM) classifier was adapted to a segmentation scheme by introducing spatial neighbourhood-based relaxation step in its optimisation process. In order to do so, basic belief assignments on voxels membership were relaxed using distance-weighted combination of belief from spatial neighbours. For the application on prostate tissues, geometric a priori was modelled and used as an additional data source. Our method was first experimented on simulated images to prove the improvement brought to the ECM. A validation study of the segmentation method was then conducted on 31 patients MRI data. Each MRI was manually segmented by three independent expert radiologists, and an estimated truth was computed using STAPLE algorithm, for inter-observer variability was taken into account. This validation proved that segmentation obtained with our method is accurate and comparable to expert segmentation. We also show that our segmentation scheme enables to detect and highlight outliers, which could be interpreted by physicians as irregular tissues. The use of belief functions also provides additional information on borders between structures. We do believe these are sources of evidence that could help physicians/algorithms in characterising tissues and structures. 6 Courtesy of P. Puech and A. Iancu expert radiologists from University Hospital of Lille for contributing in this study.
“…Belief function theory is a mathematical framework for representing and modeling uncertainty [10]. In [11], [12], the authors proposed a belief-functionbased model for preference fusion, allowing the expression of uncertainty over the lattice order (i.e. preference structure).…”
Section: State-of-the-artmentioning
confidence: 99%
“…However, this modeling approach does not constitute an optimal representation of preferences in the presence of uncertain and voluminous information. Based on [11], the model of uncertainty proposed by Masson, et al in [13] allows the expression of uncertainty on binary relations (i.e. preference relations).…”
Section: State-of-the-artmentioning
confidence: 99%
“…preference fusion under uncertainty). Furthermore, most of the work considering preference fusion under uncertainty [5], [11], [13] does not address the problem of Condorcet Paradox.…”
Abstract-Facing an unknown situation, a person may not be able to firmly elicit his/her preferences over different alternatives, so he/she tends to express uncertain preferences. Given a community of different persons expressing their preferences over certain alternatives under uncertainty, to get a collective representative opinion of the whole community, a preference fusion process is required. The aim of this work is to propose a preference fusion method that copes with uncertainty and escape from the Condorcet paradox. To model preferences under uncertainty, we propose to develop a model of preferences based on belief function theory that accurately describes and captures the uncertainty associated with individual or collective preferences. This work improves and extends the previous results. This work improves and extends the contribution presented in a previous work. The benefits of our contribution are twofold. On the one hand, we propose a qualitative and expressive preference modeling strategy based on belief-function theory which scales better with the number of sources. On the other hand, we propose an incremental distance-based algorithm (using Jousselme distance) for the construction of the collective preference order to avoid the Condorcet Paradox.
“…Since first proposed by Dempster [1] and then developed by Shafer [2], has been paid much attentions for a long time and continually attracted growing interests [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30].…”
Conflict management is still an open issue in the application of DempsterShafer evidence theory. A lot of works have been presented to address this issue. In this paper, a new theory, called as generalized evidence theory (GET), is proposed. Compared with existing methods, GET assumes that the general situation is in open world due to the uncertainty and incomplete knowledge. The conflicting evidence is handled under the framework of GET.It is shown that the new theory can explain and deal with the conflicting evidence in a more reasonable way.
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