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EP-4713663-B1 - HIGH-RESOLUTION RADAR SCANNING SYSTEM FOR NON-INVASIVE TARGET ANALYSIS

EP4713663B1EP 4713663 B1EP4713663 B1EP 4713663B1EP-4713663-B1

Inventors

  • PERRAUD, Jean-Baptiste
  • MAURES, Matthieu
  • CASSAR, Quentin

Dates

Publication Date
20260513
Application Date
20250724

Claims (13)

  1. A scanning system (100) for the non-invasive analysis of targets (10), comprising, - at least one radar sensor (110) which comprises a plurality of transceiver radars (111) arranged in a two-dimensional configuration to generate a radar representation (20) of at least one target (10), wherein, - each transceiver radar (111) has an identical predetermined two-dimensional footprint and designed, during sequential acquisitions, to emit electromagnetic signals via its emitter and at least a first antenna (1111), and receive corresponding reflected electromagnetic signals via its receiver and at least a second antenna (1112), the electromagnetic signals having a frequency comprised between 3 GHz and 30 THz, - for an array of MxN transceiver radars (111), the system (100) is designed to perform K sequential acquisitions, each acquisition corresponding to at least one measurement performed by all or part of the array of transceiver radars (111) and contributing to a distinct segment, Ci, of the radar representation (20), for a different relative position between the radar sensor (110) and the target (10), the sequential acquisitions being obtained by moving the radar sensor (110) relative to the target (10) or vice versa, along a predetermined or adaptive direction of displacement, D, thus allowing a progressive and piecewise construction of the radar representation (20), - the transceiver radars (111) are disposed in an array with irregular geometry with a progressive offset, dc, between them, in at least one of the two dimensions of their two-dimensional footprint, this offset being less than the footprint of an individual transceiver radar (111) in at least the corresponding dimension, this arrangement being designed such that the acquisition of the distinct segments, Ci, of the radar representation (20) is carried out progressively over time, and - the arrangement of the transceiver radars (111) and the number K of sequential acquisitions are designed to obtain a predetermined spatial resolution in the radar representation (20) which is substantially improved compared to the resolution corresponding to the offset between the transceiver radars (111), this improvement being a function of the total number K of acquisitions and of the number of transceiver radars (111) in at least one dimension of the two-dimensional configuration.
  2. The system (100) according to claim 1, wherein the progressive offset, dc, between the transceiver radars (111) is either constant with an identical offset value between each pair of adjacent transceiver radars (111), or variable with different offset values between the pairs of adjacent transceiver radars (111), or a combination of constant and variable offsets between different pairs of adjacent transceiver radars (111).
  3. The system (100) according to any one of claims 1 to 2, wherein the array with irregular geometry with progressive offset, dc, of the transceiver radars (111) is designed in a geometric pattern selected among: a linear offset, a staggered pattern, a spiral pattern, a fractal arrangement, a pseudorandom arrangement or a distorted grid pattern.
  4. The system (100) according to any one of claims 1 to 3, comprising at least one optical system (120) optically coupled to the radar sensor (110), the optical system (120) comprising at least one optical element (121) for shaping the electromagnetic signals emitted and received by one or more of the transceiver radars (111).
  5. The system (100) according to any one of claims 1 to 4, further comprising: - at least one radar representation reconstruction processor (130) operatively coupled to the radar sensor (110) and designed to reconstruct the radar representation (20) from all or part of the K sequences of measurements generated during all or part of the sequential acquisitions.
  6. The system (100) according to claim 5, wherein the radar representation reconstruction processor (130) comprises or is coupled to an artificial intelligence module (140) included in the system (100), the artificial intelligence module (140) being designed to: - receive the radar representation (20) or all or part of the sequential acquisitions, called model input data, - determine, from the model input data, the contours of objects detected in the target (10), - extract, from the model input data, specific characteristics of the detected objects, - classify the detected objects by associating them with predetermined classes of objects, based on the extracted characteristics.
  7. The system (100) according to claim 6, wherein the artificial intelligence module (140) is further designed to: - generate metadata associated with each detected object, comprising at least its classification and position in the radar representation (20), and - integrate the generated metadata into the radar representation (20).
  8. The system (100) according to any one of claims 6 to 7, further comprising: - at least one network communication interface (150), and - at least one online learning module (160) coupled to the artificial intelligence module (140), the online learning module (160) being designed to: -- establish a connection with at least one remote server (200) via the network communication interface (150), -- receive from the remote server (200) update data comprising: --- new classification models, --- new classes of objects to be detected, and/or --- adjusted parameters for the extraction of characteristics, -- integrate the received update data into the artificial intelligence module (140), -- dynamically adapt the detection and classification algorithms of the artificial intelligence module (140) as a function of the received update data, -- allow the artificial intelligence module (140) to identify and classify newly detected objects in accordance with the update data, and -- transmit to the remote server (200) information on the classification performance following the update, so as to allow an iterative process of improvement of the artificial intelligence module (140).
  9. The system (100) according to any one of claims 5 to 8, wherein the radar representation reconstruction processor (130) is designed to reconstruct the radar representation (20) by performing the following steps: - preprocessing the acquired data, comprising the extraction of phase and amplitude information from the K measurement sequences and the compensation of the progressive offset, dc, between the radars, - iteratively generating distinct segments, Ci, of the radar representation (20) for each acquisition, by taking into account the irregular geometry of the radar array and by using the results of the preprocessing; - progressively merging the distinct segments, Ci, of the radar representation (20), integrating the relative position information between the radar sensor (110) and the target (10) for each acquisition, and using the results of the preceding steps to refine the merge, and - generating a final radar representation (20) by iterative synthesis, combining the information processed at each step.
  10. The system (100) according to claim 9, wherein the radar representation reconstruction processor (130) is further designed to perform the following additional steps: - applying techniques of improvement of the resolution exploiting the spatial diversity created by the progressive offset, dc, of the radars based on the merge results; - adaptively post-processing the merged radar representation (20), including the integration of metadata generated by the artificial intelligence module (140), if present, and using the information from the preceding steps to optimize the processing, and - integrating the results of these additional steps into the generation of the final radar representation (20), so as to allow for iterative improvement of the quality and accuracy of the reconstruction.
  11. A use of a system (100) according to any one of claims 1 to 10 for the non-invasive analysis of heterogeneous targets (10), comprising the following steps: - positioning the system (100) relative to a heterogeneous target, - acquiring K sequences of measurements, - reconstructing a radar representation (20) of the heterogeneous target (10), - analyzing the radar representation (20) to detect localized variations in dielectric properties within the target (10), - classifying the detected variations by using the artificial intelligence module (140), and - generating a two-dimensional or three-dimensional map of the target (10) integrating the classified variations and their associated characteristics.
  12. The use according to claim 11, wherein the heterogeneous target (10) is in relative motion relative to the system (100) during the acquisition of the K sequences of measurements, and further comprising the steps of: - compensating for the relative motion in the reconstruction of the radar representation (20), and - temporally analyzing the detected variations to identify dynamic changes within the target.
  13. The use according to any one of claims 11 to 12, wherein the artificial intelligence module (140) is dynamically adapted during the analysis via the online learning module (160) so as to allow: - the identification and classification of new categories of variations not previously recorded, - the continuous improvement in the accuracy of the classification of the detected variations, and - the real-time adaptation of the acquisition and reconstruction parameters as a function of the specific characteristics of the analyzed target (10).

Description

technical field The present invention relates to the field of radar imaging systems, and more particularly to scanning systems for non-invasive target analysis using transceiver radar arrays with irregular geometric configuration. Similar systems are known to US2023358691A1 . Previous technique Conventional radar imaging systems typically use regular transceiver radar configurations, which limits their spatial resolution and ability to accurately analyze targets. These systems often struggle to adapt to moving targets, thus compromising the quality of the data acquired. Furthermore, the interpretation of radar data frequently relies on manual methods or rigid algorithms, making it difficult to automatically and accurately classify detected objects. Furthermore, these systems generally lack the flexibility to adapt to the different characteristics of the targets analyzed, which can lead to suboptimal results in certain situations. Finally, current techniques do not always allow for a sufficiently detailed non-invasive analysis of complex internal structures, thus limiting their applicability in certain critical areas. Thus, there is a need for an innovative radar imaging system capable of overcoming these limitations. Summary of the invention The invention aims to solve, at least partially, this need. A first aspect of the invention relates to a scanning system for the non-invasive analysis of targets. In practice, the system includes, at least one radar sensor comprising a plurality of transceiver radars arranged in a two-dimensional configuration to generate a radar representation of at least one target, in which, Each transceiver radar has an identical predetermined two-dimensional footprint and is designed to emit, during sequential acquisitions electromagnetic signals via its transmitter and at least one first antenna, and receive corresponding reflected electromagnetic signals via its receiver and at least one second antenna, the electromagnetic signals having a frequency between 3 GHz and THz, For an array of MxN transceiver radars, the system is designed to perform K sequential acquisitions, each acquisition corresponding to at least one measurement performed by all or part of the transceiver radar array and contributing to a distinct segment, Ci, of the radar representation, for a different relative position between the radar sensor and the target, the sequential acquisitions being obtained by moving the radar sensor relative to the target or vice versa, along a predetermined or adaptive direction of movement, D, thus allowing a progressive and piecemeal construction of the radar representation, the transmit-receiver radars are arranged in an irregularly shaped array with a progressive offset dc between them, in at least one of the two dimensions of their two-dimensional footprint, this offset being less than the footprint of an individual transmit-receiver radar in at least the corresponding dimension, this arrangement being designed such that the acquisition of the distinct segments, Ci, of the radar representation is carried out progressively over time, and The arrangement of the transceiver radars and the number K of sequential acquisitions are designed to obtain a predetermined spatial resolution in the radar representation which is substantially improved compared to the resolution corresponding to the offset between the transceiver radars, this improvement being a function of the total number K of acquisitions and the number of transceiver radars in at least one dimension of the two-dimensional configuration. In a first embodiment of the first aspect of the invention, the progressive DC offset between the transmit-receiver radars is either constant with an identical offset value between each pair of adjacent transmit-receiver radars, or variable with different offset values between pairs of adjacent transmit-receiver radars, or a combination of constant and variable offsets between different pairs of adjacent transmit-receiver radars. In a second embodiment of the first aspect of the invention, the irregular geometry network with progressive dc offset of the transmit-receive radars is designed according to a geometric pattern chosen from: a linear offset, a staggered pattern, a spiral pattern, a fractal arrangement, a pseudo-random arrangement, or a deformed grid pattern. In a third embodiment of the first aspect of the invention, the system comprises at least one optical system that is optically coupled to the radar sensor, the optical system comprising at least one optical element for shaping the electromagnetic signals emitted and received by one or more of the transceiver radars. In a fourth embodiment of the first aspect of the invention, the system further comprises at least one radar representation reconstruction processor which is functionally coupled to the radar sensor and which is designed to reconstruct the radar representation from all or part of the K measurement sequences gene