Method for three-dimensional positions, orientation and mass distribution

A method of characterizing at least one property selected from mass distribution, position and orientation of an electrically conductive mass within a defined space, the method comprising the steps of:

• a. disposing a plurality of electrodes proximate to the space and with defined positions relative to each other;
• b. providing an AC source;
• c. connecting the AC source to one of the electrodes to create an electric field around the mass;
• d. measuring current levels through a plurality of the electrodes to produce a measurement set;
• and
• e. inferring, from the measurement set, the instance of the property which, according to a forward model relating a plurality of instances of the property to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes, produces expected current levels closest to the measured levels, wherein the inferring step comprises:
• i. deriving, from each measurement of the measurement set, a probability distribution characterizing the property instance responsible for the measurement;
• ii. multiplying the probability distributions together into an ensemble probability distribution;
• and
• iii. deriving, from the ensemble probability distribution, the property instance to a maximum probability level.

A method of obtaining the distribution of an electrically conductive mass within a defined space, the mass having a size within a predetermined range, the method comprising the steps of:

• a. disposing a plurality of electrodes proximate to the space and with defined positions relative to each other, the electrodes being sufficient in number to resolve the unknown parameter;
• b. providing an AC source;
• c. connecting the AC source to one of the electrodes to create an electric field around the mass;
• d. measuring current levels through a plurality of the electrodes;
• e. for each measurement, localizing the mass within a spatial region spanning first and second spatial boundaries corresponding to first and second iso-signal shells, the iso-signal shells being established by the predetermined size range of the mass and the measured current level;
• and
• f. combining the spatial regions into a representation of a composite spatial region containing the mass, the composite spatial region approximating the distribution of the mass, the iso-signal shells being established based on a forward model relating mass locations to corresponding expected current levels through a plurality of the electrodes given an AC signal through one of the electrodes.