Acoustic tree and wooden member imaging apparatus

• US 6,347,551 B1
• Filed: 11/06/2000
• Issued: 02/19/2002
• Est. Priority Date: 02/27/1998
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology, University of Alaska
• Original Assignee: Massachusetts Institute of Technology, University of Alaska
• Inventors: Matarese, Joseph R., Zhu, Zhenya, Lewis, Carol E., Turpening, Roger M.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US09/622,728
• Time in Patent Office: 470 Days
• Field of Search: 735/97, 735/98, 735/99, 736/00, 736/02, 736/34, 736/41, 736/28
• US Class Current: 73/628
• CPC Class Codes: G01N 2291/011 Velocity or travel time
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/048 Transmission, i.e. analysed material between transmitter and receiver
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 2291/2634 cylindrical from outside
• CPC Class Codes: G01N 29/0609 Display arrangements, e.g. colour displays indicating or recording in connection with measuring in general G01D
• CPC Class Codes: G01N 29/0672 by acoustic tomography medical tomography A61B8/13
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/223 Supports, positioning or alignment in fixed situation mounting transducers per se G10K11/004

Abstract

An ultrasonic computed tomography tree or log scanner has a plurality of ultrasonic transceivers carried on a belt (102) sized to encircle a tree (100). The belt includes an apparatus for engaging is tightly around the tree (104). The transceivers are strapped around the tree, and their mutual relative distances are known. Electronic circuitry energizes the transmitters in a known sequence. The signals received at each of the receivers are also collected and analyzed. Computed tomographic techniques analyze the time of arrival of the acoustic pulse that is first to arrive at each receiver. A signal processor generates a two-dimensional image of a slice of the tree (110) at the locus of the belt.

Claims

1. An ultrasound apparatus for determining the internal condition of a wooden member, said apparatus comprising:

a. a belt, sized to encircle a wooden member to be examined, which belt carries;

i. a plurality of ultrasonic transceivers, spaced along said belt; and

ii. a tightening mechanism that enables said belt to be tightened around said wooden member;

b. a controller configured to;

i. energize selected of said transceivers to transmit ultrasound energy, and others of said transceivers to receive said ultrasound energy;

ii. receive signals that are based on said transmitted energy and said received energy; and

iii. analyze said received signals to generate a signal that corresponds to the condition of a two dimensional slice surface of said wooden member; and

c. a signal channel that couples said transceivers to said controller.

2. The ultrasound apparatus of claim 1, said controller configured to identify at each receiving transceiver, a first signal to arrive that has been transmitted from a given transmitting transceiver, and to identify the time of arrival of said first signal to arrive, and, based on analyzing said times of arrival of said first signal to arrive at each receiving transceiver, generating said signal that corresponds to the condition of said two dimensional slice surface of said wooden member.

3. The ultrasound apparatus of claim 1, said controller configured to compare, at each receiving transceiver, an amplitude of a first signal to arrive that has been transmitted from a given transmitting transceiver, with an amplitude of a corresponding signal that has been transmitted by said given transmitting transceiver, and, based on analyzing said comparison of amplitudes, and any attenuation therebetween, generating said signal that corresponds to the condition of said two dimensional slice surface of said wooden member.

4. The ultrasound apparatus of claim 2, said controller configured to compare, at each receiving transceiver, an amplitude of said first signal to arrive that has been transmitted from a given transmitting transceiver, with an amplitude of a corresponding signal that has been transmitted by said given transmitting transceiver, and, based on analyzing said comparison of amplitudes, and any attenuation therebetween, as well as said times of arrival of said first signal to arrive, generating said signal that corresponds to the condition of said two dimensional slice of said wooden member.

5. The ultrasound apparatus of claim 1, said transceivers each comprising a member engagement tooth, designed to couple acoustic energy between said transceiver and a wooden member.

6. The ultrasound apparatus of claim 5, said tooth comprising a spike.

7. The ultrasound apparatus of claim 5, said tooth comprising a cup.

8. The ultrasound apparatus of claim 1, further comprising, carried upon said belt, at least one radar transmitter and a paired radar receiver, and means for coupling said radar transmitter and receiver to said controller, said controller further being configured to analyze signals received at said radar receiver to determine the relative positions of said ultrasound transceivers.

9. The ultrasound apparatus of claim 1, said controller configured to apply computer aided tomographic (CAT) techniques to analyze said received signals to generate said signal that corresponds to the condition of a two dimensional slice surface of said wooden member.

10. The ultrasound apparatus of claim 1, said signal channel that couples said transceivers to said controller comprising an infra-red frequency band channel.

11. The ultrasound apparatus of claim 1, said plurality of transceivers numbering at least ten.

12. The ultrasound apparatus of claim 1, further comprising:

a. a second belt, sized to encircle said wooden member to be examined, which second belt carries;

i. a second plurality of ultrasonic transceivers, spaced along said belt; and

ii. a tightening mechanism that enables said belt to be tightened around said wooden member;

b. a signal channel that couples said second plurality of transceivers to said controller; and

c. said controller further being configured to;

i. energize said second plurality of transceivers to receive said ultrasound energy transmitted by said selected transceivers of said first plurality;

ii. energize selected of said second plurality of transceivers to transmit ultrasound energy, and others of said second plurality of transceivers to receive said ultrasound energy transmitted by selected of said second plurality of transceivers;

iii. energize said first plurality of transceivers to receive said ultrasound energy transmitted by said selected transceivers of said second plurality;

iv. receive signals that are based on said transmitted energy and said received energy at said second plurality of transceivers; and

v. analyze said received signals from said first and second plurality of transceivers to generate a signal that corresponds to the condition of a three dimensional volume of said wooden member.

13. The ultrasound apparatus of claim 12, further comprising:

a. a third belt, sized to encircle said wooden member to be examined, which third belt carries;

i. a third plurality of ultrasonic transceivers, spaced along said belt; and

ii. a tightening mechanism that enables said third belt to be tightened around said wooden member;

b. a signal channel that couples said third plurality of transceivers to said controller; and

c. said controller further being configured to;

i. energize said third plurality of transceivers to receive said ultrasound energy transmitted by said selected transceivers of said first and second pluralities;

ii. energize selected of said third plurality of transceivers to transmit ultrasound energy, and others of said third plurality of transceivers to receive said ultrasound energy transmitted by selected of said third plurality of transceivers;

iii. energize said first and second pluralities of transceivers to receive said ultrasound energy transmitted by said selected transceivers of said third plurality;

iv. receive signals that are based on said transmitted energy and said received energy at said third plurality of transceivers; and

v. analyze said received signals from said first and second and third pluralities of transceivers to generate a signal that corresponds to the condition of a three dimensional volume of said wooden member.

14. The ultrasound apparatus of claim 1, said belt comprising a material that does not stretch under the tension required to secure it to a wooden member and acoustically couple said transceivers to said wooden member.

15. The ultrasound apparatus of claim 14, said belt comprising fibers selected from the group consisting of Kevlar™

and carbon.

16. The ultrasound apparatus of claim 1, further comprising a battery unit, carried by said belt, which battery unit provides power to said transceivers.

17. The ultrasound apparatus of claim 1, said belt sized to encircle a tree.

18. The ultrasound apparatus of claim 1, said belt sized to encircle a utility pole.

19. The ultrasound apparatus of claim 1, further comprising a device that generates a human perceptible signal that corresponds to the condition of a two dimensional slice surface of said wooden member.

20. The ultrasound apparatus of claim 1, said belt comprising acoustic energy attenuation material, that impedes the transmission of acoustic energy from any transceiver, through said belt, to any other transceiver.

21. A method for determining the internal condition of a wooden member, said method comprising the steps of:

a. acoustically coupling a first plurality of ultrasonic transceivers to a wooden member, around its circumference, said transceivers carried by a removable belt;

b. causing each of said transceivers, in a known order, to generate acoustic energy that is coupled into said wooden member, and that is received by each other of said transceivers;

c. transmitting, to a control unit, signals that correspond to said received acoustic energy;

d. in said control unit, determining, for each transmitting transceiver, times of arrival at each receiving transceiver of the first acoustic pulse to arrive; and

e. based on said times of arrival, generating a signal that corresponds to the condition of a two dimensional slice surface of said wooden member.

22. The method of claim 21, said step of generating a signal comprising the step of using computer aided tomographic techniques to generate said signal that corresponds to the condition of a two dimensional slice surface of said wooden member.

23. The method of claim 22, further comprising the steps of:

a. in said control unit, determining, for each transmitter, amplitude attenuation at each receiver of the first acoustic pulse to arrive; and

b. based on said attenuation and said time of arrival, generating a signal that corresponds to the condition of a two dimensional slice surface of said wooden member.

24. The method of claim 21, further comprising the step of displaying on a human perceptible display, said signal that corresponds to the condition of a two dimensional slice surface of said wooden member.

25. The method of claim 21, further comprising:

a. acoustically coupling a second plurality of ultrasonic transceivers to said wooden member, around its circumference, said second plurality of transceivers carried by a second removable belt;

b. causing each of said second plurality of transceivers to receive said acoustic energy that has been transmitted by said first plurality of transceivers;

c. causing each of said second plurality of transceivers, in a known order, to generate acoustic energy that is coupled into said wooden member, and that is received by each other of said second plurality of transceivers;

d. causing each of said first plurality of transceivers to receive said acoustic energy that has been transmitted by said second plurality of transceivers;

e. transmitting, to said control unit, signals that correspond to said received acoustic energy, received at said first and said second plurality of transceivers;

f. in said control unit, determining, for each transmitting transceiver, times of arrival at each receiving transceiver of the first acoustic pulse to arrive; and

g. based said times of arrival, generating a signal that corresponds to the condition of a three dimensional volume of said wooden member.

26. The method of claim 21, further comprising the step of transmitting radar signals from a first location on said belt, and receiving said radar signals at a second location on said belt, and using said received radar signals to determine the relative positions of said ultrasound transceivers.

27. The method of claim 21, said step of coupling a first plurality of ultrasonic transceivers to a wooden member comprising the step of coupling said transceivers to a standing tree.

28. The method of claim 21, said step of coupling a first plurality of ultrasonic transceivers to a wooden member comprising the step of coupling said transceivers to a felled tree.

29. The method of claim 21, said step of coupling a first plurality of ultrasonic transceivers to a wooden member comprising the step of coupling said transceivers to a utility pole.

30. The method of claim 25, said step of generating a signal comprising the step of using computer aided tomographic techniques to generate said signal that corresponds to the condition of a three dimensional volume of said wooden member.

31. A method for determining the internal condition of a wooden member, said method comprising the steps of:

a. acoustically coupling a first plurality of ultrasonic transceivers to a wooden member, around its circumference, said transceivers carried by a removable belt;

b. causing each of said transceivers, in a known order, to generate acoustic energy that is coupled into said wooden member, and that is received by each other of said transceivers;

c. transmitting, to a control unit, signals that correspond to said received acoustic energy;

d. in said control unit, identifying, for each transmitting transceiver, a feature of acoustic energy arrival at each receiving transceiver; and

e. based on said feature, generating a signal that corresponds to the condition of a two dimensional slice surface of said wooden member.