Ground penetrating radar system for non-invasive inspection of trees for internal decay

• US 6,496,136 B1
• Filed: 07/03/2000
• Issued: 12/17/2002
• Est. Priority Date: 05/15/2000
• Status: Expired due to Term

• Current Assignee: Treeradar, Inc.
• Original Assignee: Anthony N. Mucciardi
• Inventors: Mucciardi, Anthony N.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/609,773
• Time in Patent Office: 897 Days
• Field of Search: 342/22, 342/27, 342/28, 342/179, 342/190, 342/191, 342/195, 342/197
• US Class Current: 342/22
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005

Abstract

The method for examining trees comprises directing ground penetrating radar signals into a tree using a radar apparatus connected to a microprocessor control and data acquisition unit via an interface. The tree to be examined is scanned with the radar unit after the radar velocity for that tree is calibrated. The tree is scanned at a selected elevation either by moving a single radar unit along the bark of the tree in a circumferential manner or by moving a radar signal transmitter substantially diametrically opposed to a radar signal receiver along the bark of the tree in a circumferential manner. The microprocessor control and data acquisition unit controls the radar unit and stores and digitizes radar signals for generating a real-time radargram. A cross-sectional map of the tree, a map of the severity, shape, size and location of internal decay and a map of the thickness of remaining wood are then generated from the radargram and the ensemble of saved radar signals. The maps generated from this method may then be examined by tree diagnosticians to determine the extent of the internal damage of the tree.

Claims

1. A method of examining trees for internal decay comprising directing ground penetrating radar signals into a tree, receiving radar signals from the tree, scanning the tree with the directing and the receiving of radar signals and generating a real-time radargram, and digitizing and saving a resulting ensemble of radar waveforms for offline data analysis and generating diagrams derived from the radargram.

2. The method of claim 1, wherein the diagrams are selected from a group consisting of a cross-sectional map of a tree, a map of shape, location and size of decay, a map of thickness of remaining solid wood, a guide to severity, shape, and location of decay, and combinations thereof.

3. The method of claim 1, wherein scanning comprises moving a radar apparatus along bark of a tree in a circumferential manner at a selected elevation along the tree.

4. The method of claim 3, further comprising initially marking the tree at points selected from a group of points facing north, south, east, west, points between, and combinations thereof.

5. The method of claim 4, further comprising noting circumferential location along the tree using the selected points.

6. The method of claim 3, further comprising using a wheel encoder to note circumferential location along the tree.

7. The method of claim 3, wherein moving the radar apparatus comprises moving a single unit which functions as a transmitter and receiver of radar frequency signals.

8. A method for estimating radar velocity in a tree comprising:

a) applying a ground penetrating radar frequency transmitter diametrically opposite a ground penetrating radar frequency receiver to a decay-free section of a tree, transmitting a radar frequency signal from the transmitter to the receiver, and noting the time necessary for the radar frequency signal to pass from the transmitter to the receiver through the decay-free section of the tree,

b) holding the ground penetrating radar frequency transmitter diametrically opposed to the radar frequency receiver at the same distance as the thickness of the decay-free section of the tree in step a), transmitting a radar frequency signal from the transmitter to the receiver, noting the time necessary for a radar frequency signal to pass from the transmitter to the receiver through air, and

c) comparing the times noted in steps a) and b).

9. The method of claim 8, further comprising enhancing signal-to-noise ratio of the radargram comprising using a matched filtering process.

10. The method of claim 9, wherein the using a matched filtering process comprises measuring radar response from a known decay pocket of a tree and cross-correlating the radar response from the known decay pocket with each signal in the ensemble of signals generated while examining a tree.

11. The method of claim 9, further comprising using sliding window frequency transforms by:

a) selecting a short segment of a time waveform,

b) positioning the short segment at the origin of a waveform,

c) computing Fast Fourier Transformations of the portion of the waveform contained within the short segment,

d) sliding the short segment to another point on the waveform,

e) repeating the process for all segments on the waveform, and

f) repeating the process for all waveforms in the radargram.

12. An apparatus for detecting internal decay of a tree comprising a ground penetrating radar frequency transmitter for transmitting radar frequency input signals into a tree and a radar frequency receiver for receiving radar frequency output signals from the tree, a microprocessor controller and data acquisition unit for displaying a real-time display of a radargram and digitizing and saving an ensemble of radar waveforms for offline data analysis, an interface connected to the microprocessor, the transmitter, and the receiver for receiving control signals from a microprocessor controller and data acquisition unit, pulsing the radar frequency transmitter for providing radar input signals, and sending radar output signals to the microprocessor data acquisition unit and generating diagrams of solid wood remaining.

13. The apparatus of claim 12, further comprising a wheel encoder for marking circumferential location along a tree connected to the radar frequency receiver.

14. The apparatus of claim 12, wherein the transmitter and the receiver are mounted in a radar unit.

15. The apparatus of claim 14, wherein the radar unit comprises a single transmitter/receiver.

16. The method of determining viability of a tree comprising directing pulses of radar energy signals from a radar unit into a tree over a circumferential scan, while in contact with the tree at a center frequency of from above 500 MHz to about 1500 MHz, receiving the pulsed radar energy signals at the radar frequency at a time displaced from the directing of the pulses, using an encoder attached to the radar unit in contact with the tree for triggering automatic data acquisition at each increment, digitizing the radar energy signals, enhancing the received signals by noise reduction, determining time differentiations between the directing and receiving of signals, and presenting a radargram showing limitations of decay pockets in the tree.

17. The method claim 16, further comprising determining cross-section of sound wood at a cross-section of the tree, comparing the cross-section of sound wood to the cross-section of the tree, and determining viability of the tree.

18. The method of claim 17, further comprising determining the cross sections at multiple elevations and creating multiple cross-section maps showing sound wood at the multiple elevations.

19. The method of claim 16, wherein the circumferential scan comprises a 360°

scan, and wherein the increments comprise fine increments of about one-quarter inch spacing.

20. The method of determining viability of a tree comprising directing pulses of radar energy signals from a radar unit into a tree over a circumferential scan, while in contact with the tree at a center frequency of from above 500 MHz to about 1500 MHz, receiving the pulsed radar energy signals at the radar frequency at a time displaced from the directing of the pulses, digitizing the radar energy signals, enhancing the received signals by noise reduction, determining time differentiations between the directing and receiving of signals, and presenting a radar gram showing limitations of decay pockets in the tree.

21. The method of determining viability of a tree comprising directing pulses of radar energy signals from a radar unit into a tree over a circumferential scan, while in contact with the tree at a center frequency of from above 500 MHz to about 1500 MHz, receiving the pulsed radar energy signals at the radar frequency at a time displaced from the directing of the pulses, using an encoder attached to the radar unit in contact with the tree for triggering automatic data acquisition at each increment, digitizing the radar energy signals, determining time differentiations between the directing and receiving of signals, and presenting a radar gram showing limitations of decay pockets in the tree.