SEQUENTIAL FUSION OF ULTRASOUND AND ELECTRICAL CAPACITANCE TOMOGRAPHY

Tomographic imaging of multi-phase material distributions in in- dustrial processes can be based on difierent sensing modalities, e.g. ultrasound, electrical capacitance, or X-rays. Each of them is sensitive to speciflc properties of the materials to be imaged. The achievable image quality and resolution are limited in practice due to limited data and ill-posed inverse problems. For soft fleld modalities like electrical capacitance and resistance there are inherent lim- itations. To achieve a further improvement for the case of two-phase material distributions we investigate the fusion of Electrical Capacitance Tomography (ECT) with ultrasound transmission tomography. The methods ofier comple- mentary properties, making them well suited for data fusion. Sequential fusion is performed using the information from ultrasound tomography as input for ECT. A linear non-iterative algorithm and a nonlinear iterative algorithm are used for data fusion. The methods are validated using measurements of various gas-solids two-phase material distributions. The results show that the ultra- sound information only leads to minor improvements with the linear algorithm. However, the nonlinear algorithm can fruitfully exploit the available data and yields results exceeding the quality of the single-modality images.

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