The design of an ERT system for 3D data acquisition and a quantitative evaluation of its performance

This paper describes a multi-plane implementation of a current-pulse electrical resistance tomography (ERT) data capture system. This is achieved by extending a single plane system, with 16 electrodes and 16 parallel measurement channels, to a one capable of acquiring data in a specified sequence across multiple planes (up to eight) by inserting multiplexer modules in parallel between the instrument and the electrode array. This approach allows high-speed capture systems to be configured for applications such as dual plane cross-correlation velocity measurements or more complex current injection and measurement sequences yielding 3D data sets. The measurement timing and multiplexer measurement sequences are implemented by an embedded processor. Both the executable code and the measurement sequence tables are downloaded to the instrument at start-up. This allows flexibility in specifying the data acquisition sequences and timing required for specific applications without modification of the hardware or embedded code. The effect of measurement noise on the estimated conductivity is quantified and spatial resolution discussed for the case of a 2D online imaging algorithm. Example reconstructions from recorded data sets are presented which verify the operation of the instrument.