JP2784340B2 - Ultrasound diagnostic method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic method and apparatus particularly suitable for measuring the degree of decay of a standing tree or the like.

[0002]

2. Description of the Related Art Relatively low frequency (50 KHz to 100 KH)
It is widely known that the ultrasonic wave of z) does not propagate linearly due to the physical properties of the propagating medium, but propagates in a bypass direction in a uniform direction of the medium. Due to this property, the propagation time of the ultrasonic wave propagating in the wooden pillar is longer in the case where the decay portion exists inside than in the case where the decay portion does not exist inside. Also, an ultrasonic diagnostic apparatus that measures the decay state of a wooden pillar using this property is disclosed in
No. 3,257, or Japanese Utility Model Laid-Open No. 60-33653.

FIG. 6 is a view for explaining a method of measuring decay generated on a wooden pole by an ultrasonic diagnostic apparatus described in Japanese Utility Model Application Laid-Open No. 60-33653. In the figure, reference numeral 1 denotes a power pole to be measured, 2 denotes a ground on which the power pole 1 is attached, and Q1 and Q2 denote circular virtual measurement cross sections centered on the O1 point and the O2 point, respectively.

The ultrasonic diagnostic apparatus described above targets the utility pole 1 and the like that have undergone physical measures such as decay prevention after being cut down. The decay of telephone pole 1
After the installation, most of the water is generated from the surface near the ground 2 due to the infiltration of rainwater or groundwater. Therefore, the decay state of the utility pole 1 can be defined as a decay portion near the ground 2 and a healthy portion having only a healthy portion inside a portion away from the ground 2. Utilizing this, the ultrasonic diagnostic apparatus first sets a measurement cross section P1 at a sound portion 1 m or more from the ground 2 to measure the propagation time (reference propagation time) of the ultrasonic wave in the sound portion, and then By measuring the propagation time of the ultrasonic wave including the decay portion (decay propagation time) by setting the measurement section P2 to the decay portion of 1 m or less, the size of the decay portion generated on the utility pole 1 is measured.

FIG. 7 is a view for explaining a method of measuring the reference propagation time and the decay propagation time in the measurement section.
In the figure, reference numeral 3 denotes an ultrasonic transmitter for radiating ultrasonic waves into a telephone pole, and reference numeral 4 denotes an ultrasonic receiver for receiving ultrasonic waves propagated in the telephone pole.

When measuring the reference propagation time, the ultrasonic transmitter 3 is installed at the point P1 on the outer periphery of the measurement section Q1, and the ultrasonic receiver 4 is 180 ° from the point P1 around the point O1. Installed at point P1 '. In this state, the ultrasonic wave radiated from the ultrasonic wave transmitter 3 is received by the ultrasonic wave receiver 4, and the reference propagation time is measured.

Next, when measuring the decay propagation time, the ultrasonic transmitter 3 is installed at the point P1 and the ultrasonic receiver 4 is installed at the point P1 'for the measurement section Q2 including the decayed part. One decay propagation time is measured. Then, the installation point of the ultrasonic transmitter 3 is set along the outer periphery of the measurement section Q2 from the point P2 to the point P2.
The decay propagation time is shifted by 22.5 ° from the O2 point to the center at 8 points while the installation point of the ultrasonic receiver 4 is shifted by 22.5 ° in the opposite direction from P2 ′ to P8 ′. Is measured.

[0008] The ultrasonic diagnostic apparatus measures the size of the decay portion existing in the utility pole based on the one reference propagation time and the eight decay propagation times thus measured.

[0009]

By the way, the present inventor measured the decay state of a standing tree or a wooden pillar immediately after felling by using the above-mentioned ultrasonic diagnostic apparatus. Impossibility occurred frequently. This is because the corrosion pattern is different from that of materials such as utility poles. That is, many decay in the central part of standing trees or wooden poles immediately after felling is found, and the decay of these central parts extends more than 1 m from the ground, and the part more than 1 m from the ground is not necessarily healthy. Was.

As described above, the conventional ultrasonic diagnostic apparatus described above has the following problems. (A) The reference propagation time cannot be measured unless there is a healthy part in the wooden pillar, so that the size and position of the decayed part cannot be measured. (B) Since the measurement cross section of the wooden pillar including the decayed portion is different from the measurement cross section of the sound portion for measuring the reference propagation time, the measurement error increases. (C) Since there are many measurement points for decay propagation time, the workability of decay measurement is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide an ultrasonic diagnostic method and apparatus capable of easily measuring the size of a decayed part of a standing tree or a wooden pillar immediately after cutting. I do.

[0012]

In order to solve the above-mentioned problems, an ultrasonic diagnostic method according to the first aspect of the present invention comprises: The ultrasonic wave is emitted toward the object to be measured at the second point where the angle between the first point on the outer circumference and the center point of the measurement cross section and the second point on the outer circumference is a predetermined propagation angle. In the ultrasonic diagnostic method of receiving an ultrasonic wave that has propagated through and measuring the propagation time of the ultrasonic wave of the object to be measured to perform an internal inspection of the object to be measured, the main propagation path of the ultrasonic wave is the object to be measured. A first propagation angle that does not pass through the measurement target portion in the inside is obtained, and a first ultrasonic propagation time is measured at the first propagation angle, and a main propagation path of the ultrasonic wave is measured in the measurement target portion in the object to be measured. At the second propagation angle, and determine the second propagation angle at the second propagation angle. The measured ultrasonic wave propagation time, on the basis of the first ultrasonic propagation time and the second ratio of the ultrasonic wave propagation time, characterized in that the internal inspection of the object to be measured.

According to a second aspect of the present invention, there is provided an ultrasonic diagnostic apparatus which radiates ultrasonic waves from a first point on an outer periphery of a measurement section of an object to the inside of the object to solve the above problem. An ultrasonic wave radiating means, an ultrasonic wave receiving means for receiving an ultrasonic wave at a second point on the outer circumference of the measurement section of the object to be measured, the first point, the center of the measurement section, and the second
A first ultrasonic wave propagation time when the angle formed by the point is 90 ° or less, a second ultrasonic wave propagation time when the angle is 180 °, and a first and a second ultrasonic wave propagation means; Based on the ultrasonic propagation time ratio of, the calculating means for calculating the ratio of the dimension of the measurement target portion in the virtual measurement cross section to the dimension of the virtual measurement cross section in the virtual measurement cross section of the measurement target, by a predetermined calculation, Display means for displaying the calculation result;
It is characterized by comprising.

[0014]

According to the ultrasonic diagnostic method and apparatus of the present invention,
The angle at which the main propagation path of the ultrasonic wave does not pass through the measurement target part,
For example, by setting the measurement angle to 90 ° or less in the measurement section of the object to be measured, the first ultrasonic propagation time not including the influence of the measurement target part is measured, and the measurement angle is set to 180 °. , The second ultrasonic propagation time including the influence of the measurement target part is measured. Then, the dimensions of the measurement target portion are calculated based on the ratio between the first and second ultrasonic propagation times. In this case, it is desirable that the measurement angle of the first ultrasonic wave propagation time is 45 °.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIGS. 1 to 5, an embodiment in which an ultrasonic diagnostic method and apparatus according to the present invention are used for measuring a decayed part of a wooden pole immediately after standing or cutting is described.

1. Configuration of Ultrasound Diagnostic Apparatus FIG. 2 is a diagram illustrating a configuration of the ultrasound diagnostic apparatus according to the present embodiment. As shown in the drawing, the ultrasonic diagnostic apparatus of the present embodiment includes a main body Y, an ultrasonic transmitter 3, and an ultrasonic receiver 4.
And an ultrasonic transmitter 3 and an ultrasonic receiver 4
Is connected to the main body Y by a connection cord. The transmission unit 6 transmits a signal corresponding to low-frequency ultrasonic waves in synchronization with a signal output from the synchronization signal generation unit 5 provided in the main body Y, and drives the ultrasonic transmitter 3. Similarly, the reference clock generator 7 continuously generates a clock pulse having a constant cycle in synchronization with the signal output from the synchronization signal generator 5 and supplies the clock pulse to the counter 8. The counter 8 counts the clock pulses simultaneously with the input of the clock pulses, and ends the counting upon receiving the control pulse output from the receiving unit 9. When the ultrasonic wave emitted from the ultrasonic transmitter 3 and propagated through the wooden pole is detected by the ultrasonic receiver 4, the receiving unit 9 outputs the control pulse.

In this way, the counter 8 sets the time between the emission of the ultrasonic wave by the ultrasonic transmitter 3 and the reception of the ultrasonic wave by the ultrasonic receiver 4, that is, the propagation time during which the ultrasonic wave propagates through the wooden pole. The calculation unit 1 calculates the count value of the corresponding clock pulse.
Output to 0. When the measurement mode set by the operation unit 11 is a mode for measuring the reference propagation time, the calculation unit 10 temporarily stores the count value of the clock pulse corresponding to the input reference propagation time. Further, in the mode for measuring the decay propagation time, when the count value corresponding to the decay propagation time is input, the calculation unit 10 corresponds to the count value corresponding to the previously stored reference propagation time and the decay propagation time. Propagation time ratio from count value (rot propagation time / reference propagation time)
Is calculated. The arithmetic unit 10 calculates the decay length ratio (dimension of the decay portion / dimension of the wooden column) in the measured cross section of the wooden column by a predetermined arithmetic method described later based on the propagation time ratio. The display unit 12 displays measurement data such as the decay length ratio measured in accordance with an instruction from the control unit 13, operation comments, and the like. The control unit 13 controls the above-described units according to the operation of the operation unit 11 including buttons and the like.

2. Measurement Method of Reference Propagation Time FIG. 1 is a diagram showing a propagation model of an ultrasonic wave propagating in a wooden pole. In the figure, reference numeral 20 denotes a circular measurement section centered on the point O in a wooden pillar whose decay state is to be measured,
Reference numeral 21 denotes a circular rotting portion as a measurement target portion centered on the point O in the measurement section 20. The decayed portion 21 often exists continuously in a pipe shape from the root to the tip of the wooden pillar. L1 is the diameter of the wooden pillar and the diameter of the decay portion 21 in the measurement section 20. At point A on the outer circumference of the measurement cross section 20, an ultrasonic transmitter 3 that emits ultrasonic waves into the interior of the wooden pillar is in contact. The ultrasonic receiver 4 that receives the signal is contacted.

If the decay portion 21 does not exist in the measurement section 20, the ultrasonic wave radiated at the point A propagates linearly in the wooden pole and passes through the point O which is the center of the measurement section 20. To the point D. The propagation time of the ultrasonic wave in this case is the shortest since the propagation distance through the wooden pole is the shortest. On the other hand, when the decay portion 21 exists at the center of the measurement section 20, the ultrasonic wave radiated at the point A is
It propagates to the point B in the radial direction of the wooden pillar, propagates from the point B along the outer periphery of the rotting part 2 and bypasses as shown by the arrow R, propagates to the point C, and returns from the point C to the radial direction of the wooden pillar again. And reaches the point D. Therefore, the propagation distance is increased by the amount of detour along the arrow R from the point B to the point C.
The propagation time is longer than in the case where the rotting part 21 does not exist at the center of the zero.

In this embodiment, as shown in FIG. 1, in order to measure the reference propagation time in the measurement section 20 in which the rotting portion 21 is present, a point A at which the ultrasonic wave is emitted and the measurement section measuring a reference propagation time in point 'angle (the reference propagation angle) D on the outer periphery of a ₁ is 45 ° and point' O point and D is the center of 20. Hereinafter, the measurement principle of the reference propagation time according to the present embodiment will be described.

FIG. 3 is a diagram for studying the propagation path of an ultrasonic wave in a wooden pole for measuring a reference propagation time. In the figure, a cut K1 for cutting off the propagation of ultrasonic waves is made from the center point O 'of the measurement cross section 22 of the sample wooden pole to the point G on the outer periphery. Further, the ultrasonic transmitter 3 is placed at a point E on the outer circumference where the angle is b with respect to the direction of the cut K1.
Is installed. Similarly, the ultrasonic receiver 4 is installed at a point F on the outer circumference where the angle is b with respect to the direction of the cut K1. In this way, the propagation time of the ultrasonic wave when the length of the cut K1 was gradually increased was measured.

FIG. 4 shows the angle (2 × b) formed by the ultrasonic transmitter 3, the center point O ′ of the measurement section 22 and the ultrasonic receiver 4.
Is a graph of the relationship between the length of the cut K1 and the propagation time of the ultrasonic wave propagating through the sample wooden pole, using the parameter as a parameter. From this figure, the angle (2) formed by the ultrasonic transmitter 3, the center point O ′ of the measurement section 22 and the ultrasonic receiver 4
It can be seen that as xb) becomes smaller, the propagation time of the ultrasonic wave does not change even if the cut K1 is made longer.

On the other hand, in FIG. 3, when a cut K2 for cutting off the propagation of the ultrasonic wave from the point G on the outer circumference toward the center point O 'of the measurement section 22 of the sample wooden pillar is formed, The relationship between the propagation times of the ultrasonic waves propagating through the sample wooden pole was as shown in FIG. From this figure,
When the angle (2 × b) is 45 °, the propagation time changes depending on the length of the cut K2. As the angle (2 × b) gradually increases, the propagation time does not change even if the cut K2 is lengthened. It can be read.

That is, from the measurement results shown in FIGS. 4 and 5, as the angle (2 × b) becomes smaller, the ultrasonic wave propagating in the sample wooden pole propagates through a portion closer to the surface of the sample wooden pole. You can see that

Therefore, as shown in FIG.
Even when the rotting portion 21 exists at the center of 0, the reference propagation angle is obtained by obtaining the first propagation angle such that the main propagation path of the ultrasonic wave does not pass through the rotting portion 21 which is the measurement target portion. be able to. In the present embodiment, by setting the reference propagation angle a1 (first propagation angle) to 45 °, the reference propagation time can be measured without causing the ultrasonic wave to propagate to the rotting portion 21.

3. Method for Measuring Propagation Time Including Decayed Part As shown in FIG. 1, the decay propagation time of the ultrasonic wave including the decayed part 21 is determined by installing the ultrasonic transmitter 3 at a point A on the outer periphery of the measurement section 20. The sound wave receiver 4 has a second propagation path whose main propagation path passes through the measurement target part and is affected by the existence of the measurement target part.
And is measured at a point D where the propagation angle is. That is,
Point A where the ultrasonic wave is emitted and O which is the center of the measurement section 20
The angle (rotation propagation angle) a2 between the point and the point D is 18
It is measured at the position where it becomes 0 °.

4. Calculation of decay length ratio In the ultrasonic propagation model in the wooden pillar shown in FIG. 1, the propagation velocity of the ultrasonic waves in the radial direction from point A to point B and point C to point D on the outer circumference of the measurement section 20 is represented by V1. The propagation velocity of the ultrasonic wave in the direction of the annulus from the point B to the point C along the arrow R is defined as V2. This, the radius L1 / 2 of the measurement section 20, the radius L2 / 2 of the decay part 21, and the decay length ratio d (= L2 /
From L1), the ultrasonic wave propagation time T45 when the reference propagation angle a1 is 45 ° and the ultrasonic wave propagation time T180 when the decay propagation angle a2 is 180 ° are obtained by the following equations. T45 = πL1 / 8V2 ‥‥ (1) T180 = {L1 (1-d) / V1｝ + dπL1 / 2V2 ‥‥ (2) From the above equation, the ultrasonic wave propagation time ratio is obtained as T180 / T45 (= α). Α = [{L1 (1-d) / V1} + dπL1 / 2V2] 18V2 / πL1 = {8 (1-d) / π} ｛V2 / V1 + 4d ‥‥ (3) Then, the velocity ratio of the ultrasonic waves in the radial direction and the annual ring direction is set to V1 / V2 = k, and the value of k is substituted into the above equation to solve for the decay length ratio d. Then, d = (παk−8) / (4πk) −8) 式 (4) is obtained.

In this equation, the propagation time ratio α can be obtained by actual measurement according to the method described above. Therefore, it can be seen that the speed ratio k of the ultrasonic wave in the radial direction and in the direction of the annual ring may be obtained in order to obtain the rot length ratio d.

By the way, the wooden pillars are classified into several classes according to the decay length ratio d according to the standard published by the Forestry Agency. In order to experimentally determine the speed ratio k, the present inventors sampled a large number of wooden pillars (stands and cut logs) visually graded according to the above standard, and set the speed ratio k to The decay length ratio d of this sample wooden pillar was measured by assuming some specific numerical values. As a result, the speed ratio k
It was confirmed that the visual grading and the grading according to the present ultrasonic diagnostic method best matched when it was assumed to be 1.4. Therefore, the speed ratio k =
The decay length ratio d can be calculated by the following equation in which 1.4 is substituted. d = (1.4πα-8) / (5.6π-8) ‥‥ (5)

The ultrasonic diagnostic method and apparatus according to the present invention are not limited to the above embodiment, and the following ones belong to the scope of the ultrasonic diagnostic method and apparatus according to the present invention.

(1) In this embodiment, the reference propagation angle is 4
5 ° and the rot propagation angle was 180 °. However, the respective propagation angles are not limited to these angles, and may vary depending on the frequency of the ultrasonic wave or the type of the device under test.

(2) In this embodiment, an ultrasonic wave propagation model as shown in FIG. 1 is assumed. However, it is possible to improve the measurement accuracy of the decay length ratio by grasping the propagation state of the ultrasonic wave in the wooden pole in more detail and assuming a propagation model closer to the actual propagation state.

(3) In the present embodiment, the speed ratio k was set to 1.4 by the experiment of the method described above. However, by conducting experiments on a large number of samples, such as the types of wooden pillars for which the dimensions of the decayed parts are to be measured and the standing trees and the wooden pillars after cutting, other figures may differ depending on the type of trees or the state of preservation. Preferred cases are conceivable.

(4) In the above embodiment, the decay length ratio is obtained as the measurement result. However, the number of decay propagation time measurement points can be increased to measure the shape of the decay portion or its position. It is possible.

[0035]

According to the ultrasonic diagnostic method and apparatus according to the present invention, the following excellent effects can be obtained. (1) Since the first ultrasonic wave propagation time can be measured by the same measurement cross section as the measurement cross section for measuring the second ultrasonic wave propagation time, even when the decay portion exists in all the measurement cross sections of the wooden pillar, The first ultrasonic wave propagation time can be reliably measured, and the error of the second ultrasonic wave propagation time with respect to the first ultrasonic wave propagation time is reduced. improves. (2) Since the dimensions of the measurement target portion can be measured by measuring the first ultrasonic propagation time and the second ultrasonic propagation time once each, the workability of the measurement operation is improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of measuring the size of a rotted part by ultrasonic waves according to the ultrasonic diagnostic method and apparatus according to the present invention.

FIG. 2 is a diagram illustrating a functional configuration of an ultrasonic diagnostic apparatus according to the ultrasonic diagnostic method and apparatus according to the present invention.

FIG. 3 is a diagram illustrating a propagation path of an ultrasonic wave in a wooden pole for measuring a reference propagation time according to the ultrasonic diagnostic method and apparatus according to the present invention.

FIG. 4 is a graph showing a relationship between an ultrasonic transmitter, a center point of a measurement section, and an angle formed by an ultrasonic receiver according to the ultrasonic diagnostic method and apparatus according to the present invention; It is the figure which graphed the relationship of the propagation time of a sound wave.

FIG. 5 is a graph showing the propagation time of an ultrasonic wave with respect to the length of a cut when a cut is made from one point on the outer circumference according to the ultrasonic diagnostic method and apparatus according to the present invention toward a center point of a measurement cross section of a sample wooden pillar. It is the figure which graphed the relationship.

FIG. 6 is a diagram illustrating an example of a method for measuring decay generated on a wooden pillar by a conventional ultrasonic diagnostic apparatus.

FIG. 7 is a diagram illustrating an example of a method of measuring a reference propagation time and a decay propagation time by a conventional ultrasonic diagnostic apparatus.

[Explanation of symbols]

L1 ‥ diameter of cross section, L2 ‥ diameter of decay part, a1 伝 搬 reference propagation angle, a2 ‥ rotation propagation angle, 1 ‥ pole, 2 ‥ ground,
3 ultrasonic transmitter, 4 ultrasonic receiver, 5 synchronizing signal generator, 6 transmitter, 7 reference clock generator, 8 counter, 9 receiver, 10 arithmetic unit, 11 operation Part, 12
{Display part, 13} Control part, 20} Measurement cross section, 21} Rotting part, 22} Measurement cross section

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenzo Saeki 7-15-15 Minamiichijo Nishi, Chuo-ku, Sapporo, Hokkaido Incorporated Foundation, Hokkaido Forest Maintenance Corporation (72) Inventor Takashi Numata Minamiichijo-Nishi, Chuo-ku, Sapporo, Hokkaido 7-15-15 Hokkaido Forest Improvement Corporation (72) Inventor Takejiro Kai 7-15-15 Minami Ichijo Nishi 1-chome, Chuo-ku, Sapporo, Hokkaido Hokkaido Forest Maintenance Corporation (72) Inventor Mikio Arakawa Chiyoda, Tokyo 2-11-2, Iwamotocho, Ward Inside NTT Rental Engineering Co., Ltd. (56) References JP-A-60-13257 (JP, A) JP-A-2-251750 (JP, A) JP-A-60-165546 (JP, A) JP-A-61-200468 (JP, A) JP-A-60-202358 (JP, A) JP-A-61-20469 (JP, A) −33653 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 29/00-29/28

Claims (2)

(57) [Claims] 1. An ultrasonic wave is radiated from a first point on an outer periphery of a measurement section of an object to be measured toward an inside of the object, and a first point on the outer periphery, a center point of the measurement section, and an outer periphery. Receiving an ultrasonic wave propagating inside the object under measurement at the second point at which the angle formed by the second point is a predetermined propagation angle;
An ultrasonic diagnostic method for performing an internal inspection of an object to be measured by measuring a propagation time of an ultrasonic wave of the object to be measured, wherein an ultrasonic main propagation path does not pass through a measurement target portion in the object to be measured. 1 is measured, and the first ultrasonic wave propagation time is measured at the first propagation angle, and the main propagation path of the ultrasonic wave is determined by the second propagation angle passing through the measurement target portion in the object to be measured. And measuring a second ultrasonic propagation time at the second propagation angle, and performing an internal inspection of the device under test based on a ratio of the first ultrasonic propagation time to the second ultrasonic propagation time. An ultrasonic diagnostic method comprising: 2. An ultrasonic wave radiating means for radiating an ultrasonic wave from a first point on an outer periphery of a measurement section of an object to the inside of the object to be measured, and Ultrasonic receiving means for receiving an ultrasonic wave at a second point, a first ultrasonic propagation time when an angle formed by the first point, the center of the measurement section, and the second point is 90 ° or less; Time measuring means for measuring a second ultrasonic propagation time when the angle is 180 °; and a measuring means for measuring a virtual ultrasonic cross-section of the measured object based on the first and second ultrasonic propagation time ratios. A calculating means for calculating, by a predetermined calculation, a ratio of the dimension of the measurement target portion in the virtual measurement cross section to the dimension of the measured object; and a display means for displaying the calculation result. Ultrasound diagnostic device.