Consensus-Based Credibility Estimation of Soft Evidence for Robust Data Fusion

Due to its subjective naturewhich can otherwise compromise the integrity of the fusion process, it is critical that

soft evidence

(generated by human sources) be validated prior to its incorporation into the fusion engine. The strategy of

discounting

evidence based on source reliability may not be applicable when dealing with soft sources because their reliability (e.g., an eye witnesses account) is often unknown beforehand. In this paper, we propose a methodology based on the notion of

consensus

to estimate the credibility of (soft) evidence in the absence of a ‘ground truth.’ This estimated credibility can then be used for source reliability estimation, discounting or appropriately ‘weighting’ evidence for fusion. The consensus procedure is set up via Dempster-Shafer belief theoretic notions. Further, the proposed procedure allows one to constrain the consensus by an estimate of the ground truth if/when it is available. We illustrate several interesting and intuitively appealing properties of the consensus procedure via a numerical example.