Three Dimensional Imaging of a Mass Flow

An apparatus for determining the three dimensional conductivity distribution of a mass flow in a three dimensional target volume, the apparatus comprising

• collecting means for collecting current or voltage values generated by supplying alternating voltage or alternating current to the target volume and measuring the current or the voltage, correspondingly, thereby induced in the target volume;
• first determining means for determining a state space model which defines the relationships between the electrical conductivity, the voltage, and the current in the target volume, and the evolution of the electrical conductivity as a function of time;
• comparing means for comparing the currents and/or the voltages according to the state space model with the supplied and the measured ones;
• modifying means for modifying as needed the state space model to decrease the differences between the calculated and the measured results;
• and
• second determining means for determining the three dimensional conductivity distribution of the mass flow in the target volume according to the modified state space model,
• characterised in that
• the collecting means are arranged to select the collected current or voltage values so as to consist of results of measurements performed substantially within one plane;
• and
• the first determining means are arranged to determine the state space model so as to comprise the time-dependent flow field of the mass flow within the target volume.