Method and a device for extending the illumination of a test object

• US 9,268,018 B2
• Filed: 11/04/2011
• Issued: 02/23/2016
• Est. Priority Date: 06/08/2011
• Status: Active Grant

• Current Assignee: Rohde & Schwarz GmbH & Company KG
• Original Assignee: Rohde & Schwarz GmbH & Company KG
• Inventors: Ahmed, Sherif, Evers, Christian
• Primary Examiner(s): Bythrow, Peter
• Application Number:
  US14/124,815
• Publication Number:
  US 20140125517A1
• Time in Patent Office: 1,572 Days
• Field of Search: 342/22, 342/25.R, 342/25.A, 342/25.B, 342/25.C, 342/25.D, 342/25.E, 342/25.F, 342/179, 342/195
• US Class Current: 1/1
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons
• CPC Class Codes: G01S 13/888 through wall detection
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 13/904 SAR modes
• CPC Class Codes: G01S 7/04 Display arrangements
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G01V 8/005 operating with millimetre waves, e.g. measuring the black losey radiation

Abstract

The present disclosure provides a method and a corresponding device for extending the illumination of an object under investigation. The object under investigation is illuminated with an electromagnetic microwave signal which is transmitted from a transmission antenna. The microwave signal reflected from the object under investigation is received by at least one reception antenna. An image of the object under investigation is reconstructed through synthetic focusing of the reflected microwave signal. At least one reflector element is arranged orientated towards the object under investigation and the microwave signals reflected from the reflector element and from the object under investigation are received in a reception antenna and used for the reconstruction of the image of the object under investigation in addition to the microwave rays from a transmission antenna which strike the object under investigation without reflection on the reflector element and are received by the reception antenna without reflection on the reflector element.

Claims

1. A method for extending the illumination of an object under investigation, comprising:

illuminating the object under investigation with an electromagnetic microwave signal which is transmitted from at least one transmission antenna;

receiving by at least one reception antenna the microwave signal reflected from the object under investigation; and

reconstructing an image of the object under investigation from the reflected microwave signal in a purely computational manner by synthetic focusing,

wherein at least one reflector element is arranged orientated towards the object under investigation, and the microwave signals reflected from the reflector element and from the object under investigation are received in every reception antenna and used for the reconstruction of the image of the object under investigation in addition to microwave rays from a transmission antenna which strike the object under investigation without reflection on the reflector element and are received by the reception antenna without reflection on the reflector element, and

wherein a virtual position of a virtual transmission antenna is determined through the reflection of a real position of a real transmission antenna on the reflector element, and a virtual position of a virtual reception antenna is determined through the reflection of the real position of a real reception antenna on the reflector element.

2. The method according to claim 1, wherein the microwave signals used for the synthetic focusing, which are transmitted from a transmission antenna, are reflected from the reflector element in a direction towards the object under investigation and reflected from the object under investigation to a reception antenna, and/or

which are transmitted from a transmission antenna, are reflected from the object under investigation in a direction towards the reflector element and reflected from the reflector element to a reception antenna, and/or

which are transmitted from a transmission antenna, are reflected from the reflector element onto the object under investigation, reflected from the object under investigation to the reflector element and reflected from there to a reception antenna.

3. The method according to claim 1, wherein only the microwave signals received in a respective real reception antenna which are received within a first time-window of which limits are formed by a minimal and respectively a maximal delay time of a microwave signal which is reflected from a virtual transmission antenna via the object under investigation to the real reception antenna or respectively from a real transmission antenna via the object under investigation to a virtual reception antenna are allocated in the synthetic focusing to a respective virtual transmission antenna and the respective real reception antenna and respectively to the respective real transmission antenna and the respective virtual reception antenna.

4. The method according to claim 3, wherein the microwave signals received in the respective real reception antenna which are received within a second time-window of which the limits are formed by the minimal and respectively maximal delay time of a signal which is reflected from a real transmission antenna via a virtual object under investigation reflected on the reflector element to a real reception antenna are allocated in the synthetic focusing to a real transmission antenna and a real reception antenna.

5. The method according to claim 4, wherein the determined position of the virtual object under investigation is allocated by reflection on the reflector element to a real position of the object under investigation.

6. The method according to claim 3, wherein the microwave signals which are received in the first and/or second time window are provided with a weighting factor which compensates attenuation of the microwave signal through reflection on the reflector element and attenuation of the microwave signal through an increase in the delay time in air.

7. The method according to claim 1, wherein several reflector elements are positioned orientated towards the object under investigation, and the microwave signals reflected respectively from a reflector element and from the object under investigation and/or the microwave signals reflected via several reflector elements and from the object under investigation, are received in at least one reception antenna and used for the reconstruction of the image of the object under investigation.

8. The method according to claim 7, wherein the several reflector elements are arranged at a respectively different spacing distance from the object under investigation in such a manner that the delay times of the microwave signals capable of being used respectively for the reconstruction of the image do not overlap.

9. The method according to claim 1, wherein the reflector element comprises at least three, mutually separate regions, which each provide a diffuse reflecting surface, and the position and the distance of the reflector element is determined from microwave radiation which is reflected from these regions.

10. A device for extending the illumination of an object under investigation, comprising:

at least one transmission antenna which transmits an electromagnetic microwave signal in a direction towards the object under investigation;

at least one reception antenna which receives the microwave signal reflected from the object under investigation; and

a processing unit configured to reconstruct an image of the object under investigation from the reflected microwave signal through a purely computational, synthetic focusing,

wherein at least one reflector element is arranged orientated towards the object under investigation, and every reception antenna is embodied to receive reflected microwave signals from the reflector element and from the object under investigation, and the processing unit is embodied to use for reconstruction of the image of the object under investigation the microwave signals reflected from the reflector element and from the object under investigation in addition to microwave rays from a transmission antenna which strike the object under investigation without reflection on the reflector element and are received by the reception antenna without reflection on the reflector element, and

wherein a virtual position of a virtual transmission antenna is determinable through the reflection of a real position of a real transmission antenna on the reflector element, and a virtual position of a virtual reception antenna is determinable through the reflection of a real position of a real reception antenna on the reflector element.

11. The device according to claim 10, wherein the processing unit uses the microwave signals for the synthetic focusing which are transmitted from a transmission antenna and reflected from the reflector element in a direction towards the object under investigation and reflected from the object under investigation to a reception antenna, and/or

which are transmitted from a transmission antenna, reflected from the object under investigation in a direction towards the reflector element and reflected from the reflector element to a reception antenna, and/or

which are transmitted from a transmission antenna, are reflected from the reflector element onto the object under investigation, reflected from the object under investigation to the reflector element and reflected from there to a reception antenna.

12. The device according to claim 10, wherein the position of the reflector element is variable.

13. The device according to claim 10, wherein several reflector elements are arranged orientated towards the object under investigation.

14. The device according to claim 13, wherein the several reflector elements are positioned at a respectively different spacing distance from the object under investigation, so that delay times of the microwave signals capable of being used respectively for the reconstruction of the image do not overlap.

15. The device according to claim 10, wherein the reflector element comprises at least three, mutually separate regions, which each provide a diffuse reflecting surface, and

wherein the processing unit determines the position and distance of the reflector element from microwave radiation which is reflected from the regions.

16. The device according to claim 10, wherein the at least one transmission antenna and at least one reception antenna are embodied as an active multi-static array.