JPS6013257A - Ultrasonic diagnosis - Google Patents

Abstract

PURPOSE:To achieve a quantitative detection of any decay defect of a wood pillar or the like accurately by measuring an ultrasonic wave propagation time at the parts on the straight line passing the imaginary center of a measuring section and divided by imaginery lines to determine the shaped and the position of a defect. CONSTITUTION:Ultrasonic probes 2a and 2b are provided at the point P1 and P1' opposite thereto or the like among intersections P1 and P1'-P8 and P8' between imagenery straight lines passing the imagenery center O of the section 5 to be measured of a wood pillar or the like and the propagation time of an ultrasonic wave propagating through the straight line P1 and P1' or the like is measured. In this case, the ultrasonic wave propagates shunting the decayed part H and the comparison between the measured time and the reference propagation time determines the length l1 of the decayed part H. On the other hand, the ultrasonic wave propagation times in parts at 90 deg. or the like divided by the imagenery lines are measured with the probes 2a and 2b provided at the points P1 and P5, P1 and P5', P1' and P5, P1' and P5' and the like and compared with the reference time to calculate the probability of presence of decayed parts thereby determinining the position of decayed parts from the maximum probability. Thus, decay defects of the wood pillar or the like can be accurately detected quantitatively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic method for diagnosing the shape and position of a defect within an object to be measured, such as a wooden pole, using ultrasonic waves.

Many wooden utility poles are still in use today, as they are easy to transport and erect. However, as these wooden pillars begin to rot from the base, it is necessary to periodically inspect the state of decay. Conventionally, methods of inspecting the decay of this water column include hitting the wooden column with a hammer or drilling a υ hole with a drill. There was a great deal of reliance on this, and there was a high risk of making incorrect decisions.

This invention was made in view of the above circumstances, and an object thereof is to provide an ultrasonic diagnostic method that can quantitatively and accurately detect defective parts (decayed parts) of objects to be measured such as wooden poles. It is said that

This invention will be explained below using the diagnosis of a rotten part of a wooden pole as an example. First, the basic principle of the diagnostic method according to the present invention will be briefly explained.

If there is a rotten part of the wooden pole, the ultrasonic waves tend to avoid that part and travel a long way before propagating. In other words, if there is a rotten part of a wooden pole, the propagation time of the ultrasonic wave is longer than in a healthy part, so it is possible to detect whether there is a rotten part between two points by measuring the propagation time between two points. can.

In addition, the propagation time of ultrasonic waves depends on the size of the decayed area.
Large decayed areas take time. Therefore, ultrasonic waves are transmitted.

This invention is a further development of the above principle, and the following:
An embodiment of the method according to the present invention will be explained step by step.

C1) Measurement and calculation of standard propagation time The standard propagation time refers to the healthy part of the wooden pole (the part without rotten parts).
In this embodiment, the following two types of reference propagation times T1. Measure and calculate T2 respectively.

■ As shown in Fig. 7 (a), the ultrasonic probe 2a is brought into contact with a relatively upper point of the wooden column 1, pointing toward the center O of the wooden column 1, and the ultrasonic probe 2a and the center 0 are connected to each other. The ultrasonic probe 2b is brought into contact with the center facing toward the center 0, and
Ultrasonic probe 2a.

Measure the ultrasonic propagation time between 2b. This measurement result is the reference propagation time tHjTt.

The reason why the above measurement is performed at a relatively upper part of the wooden pole is that the upper part of the wooden pole is rarely rotten.

Q) As shown in Figure 1 (b), place the ultrasonic probes 2a and 2 at the position Oo when viewed from the center O of the upper side of the wooden pillar 1.
Ultrasonic probe 2a when b is in contact with each other facing the center OK
, 2b is equal to the reference propagation time T2.

It is known from experience that this reference propagation time T2 is approximately the same as the reference propagation time T1 mentioned above, and therefore,
The reference propagation time T2 is calculated based on the formula: T 2 = 02TI (1).

(2) Measurement of propagation time at a position fftK opposite the diameter of the wooden pole Figure 2 shows a hypothetical measurement cross section 5 horizontally cut through the part of the wooden pole where the decayed part H is estimated to be. In the figure, direct @PxP's, P2P2'...P
sP'a respectively pass through the center 0 of the wooden pillars, and each other, 2
2.5′. , and the points P1 to P s +p
/l to P'8 are the intersection points of the virtual line and the outer periphery of the measurement section 5, respectively.

In the measurement of this item (2), first, point P1. P'1
The ultrasonic probes 2a and 2b are brought into contact with each other toward the center 0 to point P1. The ultrasonic propagation time between 'P'1 is measured, then the propagation time between points P2 and P'2 is determined, and similar measurements are made at points PB and P'st. Here, each of the above measurement results is assumed to be t1 to t8 (=t).

(3) Calculation of the length of the decayed part In this (3) section, the straight line PIP'l ~ P s P
The length t(-11, C2・
...C8; see Figure 2).

First, the length t of the decayed part is determined by each straight line PIP'l~P8p/
Proportion L on s (=L1.L2...Ls
) is calculated from the measurement results of the above α) and (2) terms based on the following equation.

L (t/Tx') = COI, +C1...
- (2) In this equation, Co and CtFi are constants obtained based on experimental results. Therefore, the length t of the decayed part can be determined by multiplying the ratio obtained by equation (2) above by the diameter of the wooden pillar.

According to each of the above-mentioned processes (1) to (3), direct@PI
The length t of the decayed parts present on each of P'1-p8p's was determined. However, at this stage, for example, the straight line P
Is the decayed part on IF'l directly on @OPl?
It is not possible to determine whether it is on the straight line OP1 or on the straight line OP' as shown in FIG. Therefore, the following process is performed. (4) Measurement of propagation time at point P1 in FIG. 2. Ultrasonic probe 2a on P5,
2b toward the center OK, and then point Pi, P5
The propagation time τl' is measured between .

Similarly, between points P s e P' 1 and 271.
215 and between points 21521 and 21521. (5) Calculating the probability of existence of a decayed part. Now, for example, if the measurement result of the above item (4) is τ1 = /
J'θ τ2 = /gθ τ 3 = io.

Assume that τ4=/JO, and that the calculation result of the reference propagation time T2 in the above section (1) is T2-/θO. In this case, first, as shown in Fig.
The value ipo is set to the midpoint P7 of 't, the value 100 is set to 1 at the midpoint P'3 between points P'1 and p/, and the value 100 is set to 1 between the points P'5 and Pl.
Assign U to each intermediate point P' 7 K value. Next, the point PsK value/10 and ia.

The intermediate value /60 is assigned to the point P4, the intermediate value /70 between the numerical value iro and /1,0 is assigned to the point P6, and the intermediate value /30 between the numerical value ito and lg0 is assigned to the point P6. Other points Pg.

P' 1 + P' 2 * P' 4 * P' s
- Numerical values are assigned in the same way for P'6 and P'81P1轡P2. Next, the ratio between each numerical value assigned in this manner and the reference propagation time T2 (=10θ) is calculated. The numerical value obtained by this (hereinafter, this numerical value will be referred to as the probability value)
are shown in Figure μ.

However, the above probability is +? When IK is lθ, it means that there is no decayed part between that point (P'3 in the figure) and the center 0, and each probability value that exceeds io is It shows the probability that a decayed part exists between the point and the center 0. For example, point Pi.

The probability value corresponding to P'IK is the ratio of the length of the decayed part on the straight line OPI and the length of the decayed part on the straight line aOP':,2
It shows that.

In addition, the probability value is the numerical value (/10
, / 11.0%) and the reference propagation time T2.

(5) Detection of Decayed Parts From the results of each of the above processes, the shape and position of the decayed parts present in the wooden pole are detected as follows. That is, first of all, in the above-mentioned item (3), please read @P1. Based on the length tl of the decayed part above P' and the probability value determined in the above (4), the length tla, 11k) of each decayed part on the straight line OP 1 * OP' 1 (tI B+t1 b=t1
). Next, as shown in the figure, the busy point P1
s P' 1 to the diameter of the wooden pillar! Point Q1a- inside the hole
Find each Q1a', then find the point Q i a +Q/1
A point Qlb*Q'1b in the direction of center 0, length zx a, and tl b is determined from &. Hereinafter, the other straight lines P 2 P'2 to P s P's are also marked with the same @ and point Q2a.

By finding each of these points and connecting these points as shown in FIG. 5, it is possible to detect the shape and position of the decayed part.

The above is the basic process of detecting rotten parts of wooden pillars.

Decayed parts of wooden poles usually occur along the outer periphery, and therefore, the above-mentioned process can usually detect rotted parts.

However, in some cases, the decayed part is marked H in the figure.
As shown in 1, it may occur in the center of the wooden pillar. This case will be explained below.

If the decayed part is located in the center of the wooden pillar, the measurement results in item (4) above will all be very small values6. In other words, the value is close to the reference propagation time T2. Therefore, if the presence of a rotten part is confirmed by the measurement in item (2) above, and the measurement results in item (4) above are all small, then the rotten part is located in the center of the wooden pillar. It can be determined that there is. In this case, the process of detecting rotten parts is exactly the same as in the above-mentioned case in terms of items (1) to (4), but item (5) is slightly different. That is, in item (5), instead of placing the calculated length 41a-tlb... from the outer periphery of the wooden pillar to the position of the end, the length is placed from the center 0 as shown in the figure. Deploy.

As is clear from the above explanation, the diagnosis method according to the present invention can accurately detect the position and shape of the defective part existing inside the object to be measured. In addition, it is extremely effective in detecting the state of decay of trees, house pillars, etc., and in detecting cast iron.

[Brief explanation of the drawing]

Figure 7 (A) and Oo) are the reference propagation times TI and T, respectively.
2 is a diagram showing the measurement method of 2. Figure 2 is a diagram showing a measurement cross section of a wooden pole. Figure 3 is a diagram showing an example of a decayed part that occurs on a wooden pole. Figure µ is a diagram showing the process of calculating the probability value K. Figure 3 is a diagram for explaining the process of detecting the position and shape of a decayed part in a wooden pillar. Figure 3 is a diagram showing a decayed part that occurs in the center of a wooden pillar. It is. 2a, 2b...Ultrasonic probe, 5...Measurement cross section, H, Hl...) αi rotten part. Figure 1 (b) Figure 2 pゎFigure 3 5 P'5 Figure 4 6 1.5 17 60 ++u , 1.15 1.05

Claims (1)

[Claims] A measurement cross section is set within the object to be measured, and an ultrasonic wave is transmitted from a point on the outer periphery of this measurement cross section toward the center point 0 of the measurement cross section, and the transmitted ultrasonic wave is transmitted to the In the ultrasonic diagnostic method of detecting a defective part in the object to be measured based on the ultrasonic wave propagation time between transmission and reception by receiving ultrasonic waves at another point on the measurement cross-section, (a) a center point O is placed on the measurement cross-section; Set virtual lines passing through the plane, and set the evening points (Px, Px'), ('P2.P2
')...(Pn, Pn Rimome, said intersection P1.
Between P1'. P2. A seventh process of measuring each ultrasonic propagation time between P2'... P n * P rL'; (b) From the ultrasonic propagation time measured in the seventh process, a virtual Line PtPt'*PzP2',...
A first step of calculating the length of each defective part of the upper body; (c) dividing the measurement cross section into a plurality of parts based on the virtual line and transmitting an ultrasound wave through each part; a third step of respectively measuring propagation times; (d) based on the ultrasound propagation times measured by said third step, virtual Ivj! OPx, OP2...
・OP Yu, OP'l, OP'2...op
a third step of calculating the existence probability of the defective portion on the file, and detecting the position and shape of the defective portion based on the calculation results in the first step and the second step. An ultrasonic diagnostic method characterized by: