Methods and apparatus for monitoring the content of a chamber of a container via electrical capacitive tomography (ECT) or acoustic imaging are presented. The three-dimensional volume of the chamber and its content are imaged by developing a map of permittivity or acoustic impedance by (1) applying a stimulus signal between each of a plurality of electrode pairs of a plurality of electrodes that is arranged about the chamber and (2), for each stimulus signal applied, measuring a response signal at each of the remaining electrodes of the plurality. Once the map of permittivity or acoustic impedance is established, the number and type of tablets (or liquid) within the chamber is determined.