Radar-based detection of objects while in motion

{
  "publication_number": "US11474228B2",
  "country": "US",
  "kind": "B2",
  "title": "Radar-based detection of objects while in motion",
  "abstract": "A radar-based security screening system for detecting objects is described. The screening system includes a radar transmitter, a radar receiver, and a processing unit. In use, the radar transmitter steers a radar beam across a screening volume. The radar receiver, in turn, receives a return signal from an object over time as the object moves in the screening volume to create a three-dimensional temporal signature for the object. The processing unit classifies the three-dimensional temporal signature utilizing a classification process based on a deep neural network model, and provides an alert when the object is classified as an object of interest. During screening, a screened person is not required to remain still in a confined volume and is not exposed to harmful radiation.",
  "claims": [
    "1. A method for detecting and classifying an object, the method comprising the steps of: steering a radar beam across a screening volume; receiving a return signal from the object over time as the object moves in the screening volume to create a three-dimensional temporal signature for the object; classifying the three-dimensional temporal signature utilizing a classification process based at a deep neural network model, the deep neural network model trained to process two four-dimensional tensors, each four-dimensional tensor based on a three-dimensional grid of voxels, each voxel describing the returned signal from a particular horizontal direction, a particular vertical direction and a particular depth in the screening volume; and providing an alert when the object is classified as an object of interest.",
    "2. The method of claim 1, wherein the method further comprises the step of providing a level of confidence when an object is classified as an object of interest.",
    "3. The method of claim 1, wherein the received return signal is stored in a memory device as a data structure represented by the four-dimensional tensor.",
    "4. The method of claim 1, further comprising the step of inviting feedback on the classification process.",
    "5. The method of claim 4, further comprising the step of refining the classification process based at least in part on the feedback.",
    "6. The method of claim 1, wherein classifying the three-dimensional temporal signature utilizes video data from a video camera.",
    "7. The method of claim 1, wherein the step of providing an alert comprises raising, lowering, closing, or locking an object.",
    "8. The method of claim 1, wherein the radar beam has a wavelength between about one and about ten millimeters.",
    "9. A screening system comprising: a radar transmitter operative to steer a radar beam across a screening volume; a radar receiver operative to receive a return signal from an object over time as the object moves in the screening volume to create a three-dimensional temporal signature for the object; and a processing unit operative to classify the three-dimensional temporal signature utilizing a classification process based at least in part on a deep neural network model, the deep neural network model trained to process two four-dimensional tensors, each four-dimensional tensor based on a three-dimensional grid of voxels, each voxel describing the returned signal from a particular horizontal direction, a particular vertical direction and a particular depth in the screening volume, and to provide an alert when the object is classified as an object of interest.",
    "10. The screening system of claim 9, further comprising a memory storing computer readable program code executable by the logic circuitry.",
    "11. The screening system of claim 9, wherein the radar transmitter comprises a phased-array antenna.",
    "12. The screening system of claim 9, wherein the processing unit is further operative to provide a level of confidence when an object is classified as an object of interest.",
    "13. The screening system of claim 9, wherein the processing unit is further operative to invite feedback on the classification process.",
    "14. The screening system of claim 13, wherein the processing unit is further operative to refine the classification process based at least in part on the feedback.",
    "15. The screening system of claim 9, further comprising an alarm that may be activated by the processing unit upon classifying an object of interest.",
    "16. The screening system of claim 9, wherein the radar receiver is operative to resolve one or more angles of arrival of the return signal.",
    "17. The screening system of claim 9, further comprising a video camera providing video data, wherein the processing unit is further operative to utilize the video data in the classification process.",
    "18. The screening system of claim 9, wherein the radar beam has a wavelength between about one and about ten millimeters."
  ],
  "cpc": [
    "G01S 13/426",
    "G01S 13/003",
    "G01S 13/04",
    "G01S 13/42",
    "G01S 13/886",
    "G01S 13/887",
    "G01S 13/9029",
    "G01S 7/417"
  ],
  "assignees": [
    "IBM"
  ],
  "filing_date": "2019-09-03",
  "publication_date": "2022-10-18",
  "grant_date": "2022-10-18",
  "priority_date": "2019-09-03",
  "application_number": "US-201916559603-A",
  "family_id": "74679697",
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}