Method and system for millimeter-wave image reconstruction

1. Method for reconstructing an image of an object, the object positioned adjacent a reflecting surface, comprising the steps of:

illuminating the object by transmitting millimeter-wave and/or micrometer-wave radiation from an array of transmitting antennas;

detecting signals of radiation reflected by the object with an array of receiving antennas and representing the detected signals by complex-numbered measurement data;

performing coherent processing of the measurement data by a first component of a central processing unit or a local processing unit including complex number computations for image reconstruction;

establishing Tx subgroups of transmitting antennas for which coherent processing is performed by the local processing unit to achieve coherent subimages, whereby the Tx subgroup comprises one or more virtual transmission antennas or virtual Tx clusters resulting from the reflecting surface;

establishing Rx subgroups of the receiving antennas, whereby the receiving antennas of each TX subgroup are located in or near the transmitting antennas of the associated TX subgroup and are configured to detect signals of radiation transmitted from the transmitting antennas of any associated Tx subgroup;

calculating magnitude values by a second component in the central processing unit each indicative of a magnitude of a complex number to obtain a magnitude subimage for each of the coherent subimages and generating the object image by adding the magnitude subimages; and

implementing multiple Tx clusters as a sparse array.

2. The method according to claim 1 ,

whereby the Tx subgroups are sequentially measured such that each Tx subgroup is measured by the local processing unit in a single, contiguous, non-overlapping time period.

3. The method according to claim 1 ,

whereby the steps of establishing for each Tx subgroup the specific Rx subgroup of receiving antennas contribute to achieve the coherent subimage of the corresponding Tx subgroup is buffered in a storage component associated with the central processing unit.

4. The method according to claim 1 , further comprising

providing phase values of the coherent subimages by a third component in the central processing unit for estimating phase values for the object image.

5. A system for reconstructing an image of an object, comprising:

an array of transmitting antennas adapted to illuminate the object by transmitting millimeter-wave and/or micrometer-wave radiation;

an array of receiving antennas adapted to detect signals of radiation reflected by the object;

a reflecting surface positioned adjacent the object;

at least one component adapted to represent the detected signals by complex-numbered measurement data;

at least one component adapted to perform coherent processing of the measurement data including complex number computations for image reconstruction;

at least one component adapted to establish Tx subgroups of transmitting antennas for which coherent processing is performed to achieve coherent subimages and adapted to establish Rx subgroups of the receiving antennas, whereby the receiving antennas of each Tx subgroup are located in or near the transmitting antenna of the associated Tx subgroup and are limited to configure signals of radiation transmitted from the transmitting antennas of any associated Tx subgroup, and whereby the Tx subgroup comprises one or more virtual transmission antennas or virtual Tx clusters resulting from the reflecting surface;

at least one component adapted to calculate magnitude values each indicative of a magnitude of a complex number to obtain a magnitude subimage for each of the coherent subimages and to generate the object image by adding the magnitude subimages; and

multiple Tx clusters are implemented as a sparse array.

6. The system according to claim 5 ,

wherein the Tx subgroups comprise each one and the same number of transmitting antennas.

7. The system according to claim 5 ,

wherein the Tx subgroups comprise mirrored transmitting antennas.

8. The system according to claim 5 ,

wherein in case a Tx subgroup has the associated Rx subgroup, the number of receiving antennas of the Rx subgroup is at least the number of antennas of the associated Tx subgroup.

9. The system according to claim 8 ,

wherein effective apertures of Tx subgroups and associated Rx subgroups fully cover an aperture of the transmitting antenna array and/or the receiving antenna array.

10. The system according to claim 5 ,

wherein multiple Rx antenna clusters comprise each a plurality of the receiving antennas and further comprising each a processing module for performing at least a part of the coherent processing.

11. The system according to claim 10 ,

wherein the central processing unit is adapted to perform the remaining of the coherent processing and to establish the object image.

12. The system according to claim 11 ,

wherein the Rx antenna cluster is adapted to perform coherent processing to generate an intermediate image for a Tx subgroup, and

wherein the central processing unit is adapted to perform a coherent processing including complex adding of multiple intermediate images to generate the coherent subimages.

13. The system according to claim 12 ,

wherein the central processing unit is adapted to perform at least one of an image interpolation and an incoherent addition of the coherent subimages.

14. The system according to claim 5 ,

wherein the system comprises tracking sensor equipment for relative positioning of the magnitude images before adding and/or volume limiting intermediate images.

15. A computer program comprising program code portions for performing the steps of:

illuminating an object by transmitting millimeter-wave and/or micrometer-wave radiation from an array of transmitting antennas, the object positioned adjacent a reflecting surface;

detecting signals of radiation reflected by the object with an array of receiving antennas and representing the detected signals by complex-numbered measurement data;

performing coherent processing of the measurement data including complex number computations for image reconstruct ion;

establishing Tx subgroups of transmitting antennas for which coherent processing is performed to achieve coherent subimages, whereby the Tx subgroup comprises one or more virtual transmission antennas or virtual Tx clusters resulting from the reflecting surface;

establishing Rx subgroups of the receiving antennas, whereby the receiving antennas of each TX subgroup are located in or near the transmitting antennas of the associated TX subgroup and are configured to detect signals of radiation transmitted from the transmitting antennas of any associated Tx subgroup;

calculating magnitude values each indicative of a magnitude of a complex number to obtain a magnitude subimage for each of the coherent subimages and generating the object image by adding the magnitude subimages; and

implementing multiple Tx clusters as a sparse array.