Methods and apparatus for using acoustic inspection of containers to image objects

• US 9,459,238 B1
• Filed: 03/13/2012
• Issued: 10/04/2016
• Est. Priority Date: 03/14/2011
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Konopka, Courtney, Wurzbach, James A., Silvia, Manuel T.
• Primary Examiner(s): Werner, David N
• Application Number:
  US13/418,807
• Time in Patent Office: 1,666 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: F42D 1/05 Electric circuits for blasting
• CPC Class Codes: G01N 29/36 Detecting the response signal , e.g. electronic circuits specially adapted therefor
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 15/86 Combinations of sonar systems with lidar systems; Combinations of sonar systems with systems not using wave reflection
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00
• CPC Class Codes: G01S 15/89 for mapping or imaging
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 7/521 Constructional features
• CPC Class Codes: G01S 7/539 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01V 1/001 Acoustic presence detection
• CPC Class Codes: G06V 20/59 inside of a vehicle, e.g. relating to seat occupancy, driver state or inner lighting conditions
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: G08B 13/1609 using active vibration detection systems
• CPC Class Codes: G08B 13/1654 using passive vibration detection systems
• CPC Class Codes: G08B 21/22 responsive to presence or absence of persons

Abstract

A system for generating an acoustic image of an object in a container having a first surface on which a vibration can be measure includes an acoustic source for directing acoustic energy to ensonify the container. The system additionally includes a sensor to detect acoustic energy from the acoustic source affected by the object without contacting the container, wherein the detected acoustic energy is measured at least with respect to the vibration on the first surface. The system further includes a processing module to process the detected acoustic energy from the sensor to generate an acoustic image of the object. A corresponding method is also provided.

Claims

1. A system for generating an acoustic image of at least one object in a container during an inspection of the container, the system configured to obtain measurements with respect to a recording surface on an exterior surface of the container during the inspection of the container, the system comprising:

at least one acoustic source for directing acoustic energy to penetrate at least one surface of the container and at least partially fill the container with acoustic energy during the inspection of the container, wherein a frequency of the acoustic energy directed by the at least one acoustic source is selected to achieve a desired level of ensonification of the container, and the frequency of the acoustic energy is selected, at least in part, on type of the container, and the at least one acoustic source is positioned with respect to the container to achieve the desired level of ensonification of the container;

a plurality of sensors to detect acoustic energy from the at least one acoustic source affected by the at least one object without contacting the container during the inspection of the container, wherein the sensors include one or more velocity vector sensors configured to measure temporal frequency differences of point scatterers that scatter the acoustic energy and spatially resolve the point scatterers at least in part from the measured temporal frequency differences, and at least one of the velocity vector sensors is provided as a laser vibrometer which detects a surface vibration on the recording surface; and

a processing module to process the detected acoustic energy, the detected surface vibration, and the spatially resolved point scatterers from the sensors to generate an acoustic image of the at least one object and to detect a location of the at least one object in the container, wherein at least one of the velocity vector sensors is a second-order acoustic tensor sensor configured to measure displacement, velocity and acceleration vectors of the point scatterers with respect to the recording surface and scalar acoustic pressure appearing at one or more points on the recording surface, wherein the point scatterers are further spatially resolved by the measured displacement, velocity and acceleration vectors of the point scatterers and the measured scalar acoustic pressure, wherein the location of the at least one object in the container is determined by interpolating select data from the detected acoustic energy, the detected surface vibration, and the spatially resolved point scatterers, wherein the select data is interpolated to find energy peaks which are indicative of the location of the at least one object,

wherein the at least one object includes a first object and a second, different object, and the sensors are configured to detect acoustic energy from the acoustic source affected by the first object in the container and the second object in the container without contacting the container, and

wherein the processing module is configured to process the detected acoustic energy, the detected surface vibrations and the spatially resolved point scatterers from the sensors to generate an acoustic image of the first object and to generate an acoustic image of the second object, wherein the processing module combines the acoustic image of the first object with recognized patterns of the first object which are based, at least in part, on an acoustic response profile characteristic of the first object, to identify the first object, and wherein the processing module combines the acoustic image of the second object with recognized patterns of the second object which are based, at least in part, on an acoustic profile characteristic of the second object, to identify the second object.

2. The system according to claim 1, further including an image acquisition module to obtain video images of the object.

3. The system according to claim 2, further including a module to register the video images with the acoustic image.

4. The system according to claim 1 further including a classifier to count human occupants in vehicles, wherein the classifier forms part of a toll system.

5. The system according to claim 1, wherein the processing module compares an actual time of arrival of acoustic energy and expected time of arrival to determine media through which the acoustic energy passes.

6. The system of claim 1, wherein the sensors are further configured to detect changes in at least one of the displacement vector, the velocity vector, and the acceleration vector of the point scatterers between at least a first time and a second time.

7. The system of claim 1, wherein the container is completely enclosed during the inspection of the container and frequency specific scattering and absorption of the acoustic energy is used to determine a shape of the at least one object in the container.

8. The system of claim 1, wherein the at least one acoustic source includes a plurality of acoustic sources, wherein the acoustic sources sequentially ensonify the container in a circular fashion so as to create a spiral of ensonification of the container.

9. The system of claim 1 wherein the container is stationary and at least a first object of the at least one object is in motion.

10. The system of claim 9 wherein the container is a vehicle and the first object is a human being.

11. The system of claim 1 wherein the container is a vehicle and the acoustic energy is directed towards the vehicle while the vehicle is in motion.

12. The system of claim 11 wherein the at least one acoustic source includes an acoustic transducer and road noise, and the frequency of the acoustic energy directed by the acoustic transducer is selected to achieve the desired level of ensonification of the container.

13. The system of claim 1 wherein magnitude of the select data is a function of proximity of the at least one object is to the recording surface.

14. The system of claim 1 wherein a first one of the sensors is positioned at a first position with respect to the container, a second one of the sensors is positioned at a second, different position with respect to the container.

15. The system of claim 1 wherein a number and a position of the sensors are selected based upon at least one of size and shape of the container.

16. The system of claim 1 wherein the detected acoustic energy, the detected surface vibrations, and the spatially resolved point scatterers are processed at predetermined time intervals.

20. The method according to claim 14, wherein a medium for the acoustic energy is a fluid.

17. A method for generating an acoustic image of at least one object in a container during an inspection of the container, comprising:

directing acoustic energy using at least one acoustic source to penetrate at least one surface of the container and at least partially fill the container with acoustic energy during the inspection of the container, wherein a frequency of the acoustic energy directed at the container by the at least one acoustic source is selected to achieve a desired level of ensonification of the container, and the frequency of the acoustic energy is selected, at least in part, on type of the container, and the at least one acoustic source is positioned with respect to the container to achieve the desired level of ensonification of the container;

detecting acoustic energy affected by the at least one object with a plurality of sensors without contacting the container during the inspection of the container, wherein the sensors are configured to obtain measurements with respect to a recording surface on an exterior surface of the container during the inspection of the container, and the sensors include one or more velocity vector sensors configured to measure temporal frequency differences of point scatterers that scatter the acoustic energy and spatially resolve the point scatterers at least in part from the measured temporal frequency differences, and at least one of the velocity vector sensors is provided as a laser vibrometer which detects a surface vibration on the recording surface; and

processing the detected acoustic energy, the detected surface vibration, and the spatially resolved point scatterers from the sensors to generate an image of the at least one object and to detect a location of the at least one object in the container, wherein at least one of the velocity vector sensors is a second-order acoustic tensor sensor configured to measure displacement, velocity and acceleration vectors of the point scatterers with respect to the recording surface and scalar acoustic pressure appearing at one or more points on the recording surface, wherein the point scatterers are further spatially resolved by the measured displacement, velocity and acceleration vectors of the point scatterers and the measured scalar acoustic pressure, wherein the location of the at least one object in the container is determined by interpolating select data from the detected acoustic energy, the detected surface vibration, and the spatially resolved point scatterers, wherein the select data is interpolated to find energy peaks which are indicative of the location of the at least one object,

wherein the at least one object includes a first object and a second, different object, and the sensors are configured to detect acoustic energy from the acoustic source affected by the first object in the container and the second object in the container without contacting the container, and

wherein the detected acoustic energy, the detected surface vibrations and the spatially resolved point scatterers received from the sensors are processed to generate an acoustic image of the first object and to generate an acoustic image of the second object, wherein the acoustic image of the first object is combined with recognized patterns of the first object which are based, at least in part, on an acoustic response profile characteristic of the first object, to identify the first object, and wherein the acoustic image of the second object is combined with recognized patterns of the second object which are based, at least in part, on an acoustic profile characteristic of the second object, to identify the second object.

18. The method according to claim 17, further including performing image acquisition to obtain video images of the object.

19. The method according to claim 18, further including registering the video images with the acoustic image.

21. A system for generating an acoustic image of at least one object in a vehicle during an inspection of the vehicle, the system configured to obtain measurements with respect to a recording surface on an exterior surface of the vehicle during the inspection of the vehicle, the system comprising:

at least one acoustic source for directing acoustic energy to penetrate at least one surface of the vehicle and at least partially fill the vehicle with acoustic energy during the inspection of the vehicle, wherein a frequency of the acoustic energy directed by the at least one acoustic source is selected to achieve a desired level of ensonification of the vehicle, and the frequency of the acoustic energy is selected, at least in part, on type of the vehicle, and the at least one acoustic source is positioned with respect to the vehicle to achieve the desired level of ensonification of the vehicle;

a means to detect acoustic energy from the at least one acoustic source affected by the at least one object and from road noise affected by the at least one object when the vehicle is in motion without contacting the vehicle during the inspection of the vehicle, wherein the means to detect acoustic energy comprises one or more velocity vector sensors configured to measure temporal frequency differences of point scatterers that scatter the acoustic energy and spatially resolve the point scatterers at least in part from the measured temporal frequency differences, and at least one of the velocity vector sensors is provided as a laser vibrometer which detects a surface vibration on the recording surface; and

a processing module to process the detected acoustic energy, the detected surface vibration, and the spatially resolved point scatterers from the means to detect acoustic energy to generate an image of the at least one object and to detect a location of the at least one object in the vehicle, wherein at least one of the velocity vector sensors is a second-order acoustic tensor sensor configured to measure displacement, velocity and acceleration vectors of the point scatterers with respect to the recording surface and scalar acoustic pressure appearing at one or more points on the recording surface, wherein the point scatterers are further spatially resolved by the measured displacement, velocity and acceleration vectors of the point scatterers and the measured scalar acoustic pressure, wherein the location of the at least one object in the vehicle is determined by interpolating select data from the detected acoustic energy, the detected surface vibration, and the spatially resolved point scatterers, wherein the select data is interpolated to find energy peaks which are indicative of the location of the at least one object,

wherein the at least one object includes a first object and a second, different object, and the sensors are configured to detect acoustic energy from the acoustic source affected by the first object in the container and the second object in the container without contacting the container, and

wherein the processing module is configured to process the detected acoustic energy, the detected surface vibrations and the spatially resolved point scatterers from the means to detect acoustic energy to generate an acoustic image of the first object and to generate an acoustic image of the second object, wherein the processing module combines the acoustic image of the first object with recognized patterns of the first object which are based, at least in part, on an acoustic response profile characteristic of the first object, to identify the first object, and wherein the processing module combines the acoustic image of the second object with recognized patterns of the second object which are based, at least in part, on an acoustic profile characteristic of the second object, to identify the second object.