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US-12618959-B2 - Detection system, sensor system, detection method, and recording medium

US12618959B2US 12618959 B2US12618959 B2US 12618959B2US-12618959-B2

Abstract

A detection system includes an obtainer, a generator, a classifier, a centroid calculator, associator, and combiner. The obtainer obtains a reception signal from a radio wave sensor. The generator generates a scattered point including positional information of a target, based on the reception signal. The classifier classifies a scattered point group into one or more clusters. The scattered point group is a set of scattered points generated by the generator during a predetermined length of time. The centroid calculator calculates a centroid for each of the one or more clusters classified by the classifier. The associator associates any of the one or more clusters classified by the classifier with the target. The combiner combines, as the scattered point, the centroid calculated by the centroid calculator during a preceding or earlier period with the scattered point group.

Inventors

  • Kenichi Inoue

Assignees

  • PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.

Dates

Publication Date
20260505
Application Date
20220426
Priority Date
20210525

Claims (13)

  1. 1 . A detection system comprising: a processor configured to perform operations comprising: obtaining a reception signal from a radio wave sensor, the radio wave sensor being a sensor that emits a radio wave from a transmitting antenna to a target and receives a reflected radio wave from the target via a plurality of receiving antennas; generating a scattered point including positional information of the target, defined in a coordinate system having the radio wave sensor as an origin point, based on the reception signal obtained in the obtaining; classifying a scattered point group into one or more clusters, the scattered point group being a set of scattered points each of which is the scattered point generated in the generating during a predetermined length of time; calculating a centroid for each of the one or more clusters classified in the classifying by calculating a weighted average of coordinates of the scattered points included in the cluster using, as weights, strengths of reflected radio waves of the scattered points by the classifier; associating any of the one or more clusters classified in the classifying with the target; and combining the centroid calculated in the calculating during a preceding or earlier period with the scattered point group, wherein the associating comprises associating any of the one or more clusters classified in the classifying with the target, based on whether the centroid calculated during the preceding or earlier period is included in the one or more clusters.
  2. 2 . The detection system according to claim 1 , wherein the scattered point includes information about a strength of the reflected radio wave, and information about at least one of a distance between the target and the radio wave sensor or a direction of the target relative to the radio wave sensor.
  3. 3 . The detection system according to claim 1 , wherein the associating comprises associating any of the one or more clusters classified in the classifying with the target, based on whether the centroid calculated during the preceding or earlier period is included in the one or more clusters.
  4. 4 . The detection system according to claim 1 , wherein the classifying comprises classifying classifies the scattered point group into the one or more clusters using an algorithm that eliminates an isolated point based on a density of the set of scattered points.
  5. 5 . The detection system according to claim 1 , wherein the combining comprises adjusting a combination amount or a delay amount of the centroid that was calculated during the preceding or earlier period and is to be combined with the scattered point group.
  6. 6 . The detection system according to claim 5 , wherein for each of the one or more clusters, the combining comprises incrementing a counter when the cluster does not include the scattered point other than the centroid, resetting the counter when the cluster includes the scattered point other than the centroid, and discarding the centroid when the counter reaches a threshold.
  7. 7 . The detection system according to claim 5 , wherein for each of the one or more clusters, the combining comprises reducing the combination amount of the centroid when the cluster does not include the scattered point other than the centroid, and restoring the combination amount of the centroid when the cluster includes the scattered point other than the centroid.
  8. 8 . The detection system according to claim 5 , wherein the radio wave sensor can switch an operation between a normal mode and a specific mode in which the radio wave is concentratedly emitted in a specific direction or is selectively received, and the combining comprises increasing the combination amount of the centroid when the radio wave sensor is operating in the specific mode, as compared to when the radio wave sensor is operating in the normal mode.
  9. 9 . The detection system according to claim 1 , the operations further comprising: estimating, for each of the one or more clusters classified in the classifying, a centroid to be calculated during a following or later period, wherein the combining comprises combining, as the scattered point, the centroid that is to be calculated during the following or later period and is estimated by the estimating with the scattered point group.
  10. 10 . A sensor system comprising: the detection system according to claim 1 ; and the radio wave sensor controlled by the detection system.
  11. 11 . A detection method comprising: obtaining a reception signal from a radio wave sensor disposed at a fixed position within a detection space, the radio wave sensor being a sensor that emits a radio wave from a transmitting antenna to a target and receives a reflected radio wave from the target via a plurality of receiving antennas; generating a scattered point including positional information of the target defined in a coordinate system having the radio wave sensor as an origin point, based on the reception signal obtained in the obtaining; classifying a scattered point group into one or more clusters, the scattered point group being a set of scattered points each of which is the scattered point generated in the generating during a predetermined length of time; calculating a centroid for each of the one or more clusters classified in the classifying by calculating a weighted average of coordinates of the scattered points included in the cluster using, as weights, strengths of reflected radio waves of the scattered points; associating any of the one or more clusters classified in the classifying with the target; and combining the centroid calculated in the calculating during a preceding or earlier period with the scattered point group, wherein the associating comprises associating any of the one or more clusters classified in the classifying with the target, based on whether the centroid calculated during the preceding or earlier period is included in the one or more clusters.
  12. 12 . A non-transitory computer-readable recording medium having recorded thereon a program for causing one or more processors to execute the detection method according to claim 11 .
  13. 13 . The detection system according to claim 1 , wherein in response to detecting that the centroid calculated during the preceding or earlier period is included in one cluster among the one or more clusters, the associating comprises associating the one cluster with the target.

Description

CROSS-REFERENCE OF RELATED APPLICATIONS This application is the U.S. National Phase under 35 U.S.C. § 371 of International Patent Application No. PCT/JP2022/018974, filed on Apr. 26, 2022, which in turn claims the benefit of Japanese Patent Application No. 2021-088002, filed on May 25, 2021, the entire disclosures of which applications are incorporated by reference herein. TECHNICAL FIELD The present invention relates to a detection system, a sensor system, a detection method, and a recording medium that detect a target based on a signal output from a radio wave sensor. BACKGROUND ART Patent Literature 1 discloses a Doppler radar system that detects the position of a target object. This Doppler radar system includes a transmitting antenna, a plurality of receiving antennas, a micro-Doppler calculation unit, a first centroid calculation unit, a second centroid calculation unit, and a centroid determination unit. The micro-Doppler calculation unit calculates measurement points indicating respective positions of reflection points included in a target object. The first centroid calculation unit calculates a first centroid of the measurement points, using a first division frame having a first interval. The second centroid calculation unit calculates second centroids of the measurement points, using a second division frame having a second interval shorter than the first interval. Among the second centroids, the centroid determination unit determines at least one of the second centroids as the position of the target object, based on a positional relationship between the second centroids and the first centroid. CITATION LIST Patent Literature [PTL 1] Japanese Unexamined Patent Application Publication No. 2013-96828 SUMMARY OF INVENTION Technical Problem The present invention provides a detection system, a sensor system, a detection method, and recording medium that readily improve the accuracy of detecting the position of a target. Solution to Problem A detection system according to one aspect of the present invention includes an obtainer, a generator, a classifier, a centroid calculator, an associator, and a combiner. The obtainer obtains a reception signal from a radio wave sensor. The radio wave sensor is a sensor that emits a radio wave from a transmitting antenna to a target and receives a reflected radio wave from the target via a plurality of receiving antennas. The generator generates a scattered point including positional information of the target, based on the reception signal obtained by the obtainer. The classifier classifies a scattered point group into one or more clusters. The scattered point group is a set of scattered points each of which is the scattered point generated by the generator during a predetermined length of time. The centroid calculator calculates a centroid for each of the one or more clusters classified by the classifier. The associator associates any of the one or more clusters classified by the classifier with the target. The combiner combines, as the scattered point, the centroid calculated by the centroid calculator during a preceding or earlier period with the scattered point group. A sensor system according to one aspect of the present invention includes the above-described detection system and the radio wave sensor controlled by the detection system. A detection method according to one aspect of the present invention includes obtaining, generating, classifying, calculating, associating, and combining. The obtaining includes obtaining a reception signal from a radio wave sensor. The radio wave sensor is a sensor that emits a radio wave from a transmitting antenna to a target and receives a reflected radio wave from the target via a plurality of receiving antennas. The generating includes generating a scattered point including positional information of the target, based on the reception signal obtained in the obtaining. The classifying includes classifying a scattered point group into one or more clusters. The scattered point group is a set of scattered points each of which is the scattered point generated in the generating during a predetermined length of time. The calculating includes calculating a centroid for each of the one or more clusters classified in the classifying. The associating includes associating any of the one or more clusters classified in the classifying with the target. The combining includes combining, as the scattered point, the centroid calculated in the calculating during a preceding or earlier period with the scattered point group. A recording medium according to one aspect of the present invention is a non-transitory computer-readable recording medium having recorded thereon a program for causing one or more processors to execute the above-described detection method. Advantageous Effects of Invention A detection system, a sensor system, a detection method, and a recording medium according to the present invention have an advantage of readily improving t