This paper presents a technique that combines the occurrence of certain events, as observed by different sensors, in order to detect and classify objects. This technique explores the extent of dependence between features being observed by the sensors, and generates more informed probability distributions over the events. Provided some additional information about the features of the object, this fusion technique can outperform other existing decision level fusion approaches that may not take into account the relationship between different features. Furthermore, this paper also addresses the issue of dealing with damaged sensors during implementation of the model, by learning a hidden space between sensor modalities which can be exploited to safeguard detection performance.
Another approach to combining information from various sources is to use Dempster-Shafer Inference. Dempster-Shafer Inference can assign a probability to any of the original @math objects or to a union of these objects. The knowledge of the @math sensor is summarized in its report, @math . Where, @math and @math . Due to lack of evidence, the probability 1 may not be completely assigned to any object or unions of objects, bringing an uncertainty in the report. The probability, @math is therefore called the probability of uncertainty. The sensor reports, @math are fused to find the final fused report, @math , Where, Dempster-Shafer rule for fusion suffers from exponentially increasing complexity as @math and @math increase. Some applications of Dempster-Shafer fusion can be found in @cite_14 , where LIDAR data is combined with multi-spectral imagery, and in @cite_19 , where multi-sensor information like vibration, sound, pressure, and temperature is fused to detect engine faults. Furthermore, @cite_5 provides a detailed comparison between Bayesian Inference and Dempster-Shafer Theory.
@cite_19 @cite_5 @cite_14
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Engine diagnostics is a typical multi-sensor fusion problem. It involves the use of multi-sensor information such as vibration, sound, pressure and temperature, to detect and identify engine faults. From the viewpoint of evidence theory, information obtained from each sensor can be considered as a piece of evidence, and as such, multi-sensor based engine diagnosis can be viewed as a problem of evidence fusion. In this paper we investigate the use of Dempster-Shafer evidence theory as a tool for modeling and fusing multi-sensory pieces of evidence pertinent to engine quality. We present a preliminary review of Evidence Theory and explain how the multi-sensor engine diagnosis problem can be framed in the context of this theory, in terms of faults frame of discernment, mass functions and the rule for combining pieces of evidence. We introduce two new methods for enhancing the effectiveness of mass functions in modeling and combining pieces of evidence. Furthermore, we propose a rule for making rational decisions with respect to engine quality, and present a criterion to evaluate the performance of the proposed information fusion system. Finally, we report a case study to demonstrate the efficacy of this system in dealing with imprecise information cues and conflicts that may arise among the sensors. The fusion of multi-sensor information for state estimation is a well studied problem in robotics. However, the classical methods may fail to take into account the measurements validity, therefore ruining the benefits of sensor redundancy. This work addresses this problem by learning context-dependent knowledge about sensor reliability. This knowledge is later used as a decision rule in the fusion task in order to dynamically select the most appropriate subset of sensors. For this purpose we use the Mixture of Experts framework. In our application, each expert is a Kalman filter fed by a subset of sensors, and a gating network serves as a mediator between individual filters, basing its decision on sensor inputs and contextual information to reason about the operation context. The performance of this model is evaluated for altitude estimation of a UAV. This paper presents an approach to enable general tracking of extended objects of multiple sensors. Expert information in each input providing sensor module is mapped into simple model parameters and allows the fusion center to use a generalized version of such information. The model type and parameters are presented and a classical Kalman based fusion is extended with a method for integrated extent handling. By this approach the central fusion node can take into account both the track level information and extent estimate from each sensor. The proposed method is compared with a classic method of fusing the object center and the extent estimate separately. Simulated data is used to show that our proposed approach is general in the sense that it can be used on various setups without adaption. Detailed performance results are given based on estimation errors of the extended object space vector. The findings based on simulated data are completed by real world data from a front facing sensor setup. It is shown that the proposed method offers a benefit in position accuracy, especially when the measurement information does not contain a complete extent information in all directions. This paper proposes a multimodal biometric system through Gaussian Mixture Model (GMM) for face and ear biometrics with belief fusion of the estimated scores characterized by Gabor responses and the proposed fusion is accomplished by Dempster-Shafer (DS) decision theory. Face and ear images are convolved with Gabor wavelet filters to extracts spatially enhanced Gabor facial features and Gabor ear features. Further, GMM is applied to the high-dimensional Gabor face and Gabor ear responses separately for quantitive measurements. Expectation Maximization (EM) algorithm is used to estimate density parameters in GMM. This produces two sets of feature vectors which are then fused using Dempster-Shafer theory. Experiments are conducted on two multimodal databases, namely, IIT Kanpur database and virtual database. Former contains face and ear images of 400 individuals while later consist of both images of 17 subjects taken from BANCA face database and TUM ear database. It is found that use of Gabor wavelet filters along with GMM and DS theory can provide robust and efficient multimodal fusion strategy.