Timed dielectrometry surveillance method and apparatus

A timed dielectrometry surveillance method comprising:

• conveying articles in succession past a predefined location;
• interrogating a region at the predefined location through which successive articles are being conveyed, said interrogating including projecting microwave energy from plural collimated transmitters/receivers and measuring reflected energy responsive thereto, wherein said reflected energy is dependent upon the dielectric constant of material within the interrogation region, said projecting and said measuring being performed sequentially across said plural collimated transmitters/receivers, said interrogating producing timed indicia of the dielectric constant of material within the interrogation region;
• and
• comparing said dielectric constant indicia with predetermined criteria to characterize the material contents of an article passing through the interrogation region.

For use in a surveillance system having an elongate conveyor for conveying articles successively past a predefined location, article-scanning apparatus comprising:

• plural antennae stationarily array ed at the predefined location, said antennae being arrayed such that they define an interrogation region through which an article on a conveyor will pass, each of said antennae being capable of measuring the dielectric constant of the material within an article and producing a response signal indicative of the average dielectric constant of such material at successive depths therethrough;
• controller means for producing a control signal to each antenna within said antennae array, and for receiving a corresponding response signal produced by each antenna within said antennae array, said controller means including means for time-correlating said control signal with said corresponding response signal, thereby to produce depth-dependent dielectric-constant indicia of such material within said interrogation region, said controller means further including data storage means for storing predefined dielectric-constant criteria and for storing said indicia, said controller means further including comparison means for comparing said predefined criteria with said indicia to produce a comparison result;
• and
• annunciator means for indicating in real time to a user of said apparatus said comparison result.