Timed dielectrometry surveillance method and apparatus

• US 4,975,968 A
• Filed: 10/27/1989
• Issued: 12/04/1990
• Est. Priority Date: 10/27/1989
• Status: Expired due to Term

• Current Assignee: EMIT Technologies LLC
• Original Assignee: Spatial Dynamics, Ltd.
• Inventors: Yukl, Tex
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): DINH, TAN X
• Application Number:
  US07/428,209
• Time in Patent Office: 403 Days
• Field of Search: 340/505, 340/568, 342/189, 374/130, 324/636, 324/640, 324/632, 324/642, 324/643, 324/644, 324/645, 324/646, 324/647, 382/1
• US Class Current: 382/100
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: G01R 27/267 Coils or antennae arrangements, e.g. coils surrounding the sample or transmitter/receiver antennae
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons
• CPC Class Codes: G01S 13/89 for mapping or imaging

Abstract

Dielectrometry monitoring method and apparatus for three-dimensional profiling and colorable imaging of the material contents of articles carried on a conveyor through an interrogation region are disclosed. In a preferred embodiment, the apparatus includes a plural, stationary, collimated, microwave transmitter/receiver antennae array and associated electronics for measuring the dielectric constant of the materials to produce data for interpretation in real time as to the article'"'"'s dielectric material configuration and contents. High-speed, GaAs gates and switching devices, as well as microstrip delay lines, are used to perform the precisely timed, depth-wise sampling of data reflective of dielectric-constant material characteristics, with sampling periods in the sub-nanosecond range. By comparison to predefined criteria, computerized analysis determines whether the data profile of the material within the interrogation region is indicative of any of a variety of contraband or hazardous conditions, including narcotic drugs and explosives. In the preferred embodiment of the invention, one each of such collimated arrays is positioned above and below the article-carrying conveyor in order to avoid potential blind spots that may be caused by conductive structures within an article.

Claims

1. For detecting characteristics of material moving through an interrogation region, surveillance apparatus comprising:

a dielectrometry monitor that defines a generally planar interrogation region and in real time views said interrogation region and material moving therethrough generally normal to the plane of the interrogation region, and

means synchronized with such movement of the material through the interrogation region and operatively connected with said monitor for producing a three-dimensional material profile in real time of changing dielectric conditions within said interrogation region.

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

serial electromagnetic transmission/reception means defining an interrogation region for interrogating the material contents of articles successively conveyed past a predefined location and through said interrogation region, and

interpretation means coupled with said transmission/reception means, said interpretation means being responsive to serial reflections of electromagnetic energy from such articles, thereby to produce imageable profile data reflective of the material configuration and contents of such articles within said interrogation region.

3. 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.

4. 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.