JP2906973B2 - Wall tile peeling determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for judging whether or not an attached state of a wall tile attached to a wall or the like of a building is good.

[0002]

2. Description of the Related Art As a technique for judging whether or not an attached state of a wall tile is good, a frequency spectrum of a reflected sound (hitting sound) from the wall when the wall tile is hit by a hitting means such as a hammer is used. In some cases, a comparison is made between a frequency spectrum of a good sound tile and a sound pressure level difference (level difference spectrum) obtained therefrom is compared with a threshold value to determine whether or not the attached state of the wall tile is good.

[0003] Such a technique is disclosed, for example, in Japanese Patent Publication No. 02-54.
No. 903 and Japanese Patent Publication No. 05-11577.

[0004] The technique described in Japanese Patent Publication No. 05-11577 will be described with reference to FIGS. First, the wall tile to be inspected is hit by a hitting means such as a hammer based on a hitting force signal which is a command signal from a computer. FIG. 6 shows an example of the sound reflected from the wall surface to be inspected (hitting sound) detected by the microphone at this time. The peak value P4 of the reflected sound shown in FIG. 6 is calculated, and if this value is smaller than a predetermined value PB, it is determined that the inspection target wall tile is a sound tile. When P4 ≧ PB, the reflected sound P3 standardized by the repulsive force F0 from the inspection target wall surface detected by the load detector is calculated.

Next, a frequency spectrum shown in FIG. 7 is calculated from the reflected sound level P3, and a maximum sound pressure level S1 and a frequency F1 with respect to S1 are calculated.

Next, the deviation between the frequency spectrum of the sound tile shown in FIG. 8 and the frequency spectrum shown in FIG. 7 is calculated, and a relative difference spectrum shown in FIG. 9 is created. From the relative difference spectrum, the maximum level S2 and the frequency F2 with respect to S2 are calculated, and when the maximum level S2 is smaller than the predetermined value SB, the inspection target wall surface tile is determined to be a sound tile. When S2 ≧ SB, the frequency F that bisects the area of the hatched portion of the relative difference spectrum of FIG.
3 is calculated.

Next, P4, F0,
From P3, S1, S2, F2, and F3, the depth DEP and the size DiA of the peeled (stripped) portion in the inspection target wall tile are calculated.

[0008]

However, in the conventional method as described above, the frequency spectrum of a sound tile is stored, and this frequency spectrum is compared with the frequency spectrum of a wall tile to be inspected. There is a problem that it takes a long time for the calculation by the computer and the size of the computer device becomes large. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for determining the separation of a wall tile in which the processing time by a computer is short and the size of the apparatus is not increased.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for measuring the peak value AP and the peak value AP of a reflected sound obtained when an inspection target wall tile is hit with a hitting means such as a hammer .
And from the effective value A (t) rms of the reflected sound
Kuta Cf, Cf = calculated as AP / A (t) rms, the crest factor Cf is a first predetermined
If the value is greater than or equal to the value, the wall tile to be inspected is a healthy tile
And the crest factor Cf is set to the first
Is smaller than the predetermined value of
The Rf is calculated by the following ^{equation, Rf = (X) 1/2,} X = ∫A (f) · f 2 df / ∫A (f) df expected frequency R of the expected frequency Rf and sound tile
When the deviation from f is smaller than a second predetermined value, the inspection target wall tile is determined to be a sound tile, and the deviation is determined as the second tile.
When the value is equal to or more than the predetermined value, it is determined that the inspection target wall tile is a peeling tile.

Further, in the above invention, the second predetermined value is determined by a property factor such as the shape, size, and material of the wall tile to be inspected.

[0011]

In the method for judging peeling of a wall tile according to the present invention, the quality of the attached state of the wall tile to be inspected is judged only by the crest factor and the expected frequency. , And it is not necessary to store the frequency spectrum of the sound tile, the processing by the computer is completed in a short time, and there is no need to increase the size of the device.

Furthermore, since the second predetermined value is determined based on the property factor of the wall tile to be inspected, it is possible to determine the adhering state of the wall tile very accurately.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for judging peeling of a wall tile according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is a flow chart for explaining an embodiment of the present invention. In FIG. 1, first, a hitting force signal, which is a command signal, is sent from a computer to a hitting means such as a hammer to hit the inspection target wall tile (step S
1). A reflected sound reflected from the wall surface to be inspected by this impact is detected by a sound receiver such as a microphone (Step S2), and a crest factor Cf is calculated (Step S3).

The calculation of the crest factor Cf is performed by the following equation (1). Cf = AP / A (t) rms (1) where AP is the peak value of the reflected sound and A (t) rms is the effective value of the reflected sound. AP is AP1 in the case of the reflected sound from the sound tile shown in FIG. 2 (the tile having a good state of adhering to the wall), and the peeling tile shown in FIG. AP2 in the case of a reflected sound in a tile with a mark). A (t) rm
s is the signal A in the appropriate periods T1 and T2 in FIGS.
This is the effective value of (t). The periods T1 and T2 may be determined so that the determination is accurate.

Crest factor C obtained in this way
The value of f is compared with the first predetermined value M (step S
4). The first predetermined value M is a known value obtained from the value of the crest factor in the healthy tile, and for example, M =
2.5.

The value of the crest factor Cf is equal to the effective value A in the case of a sound tile in which the reflected sound is attenuated immediately.
(T) rms becomes relatively small, so it becomes large,
For exfoliated tiles where the vibration of the reflected sound continues for a long time,
Since the effective value A (t) rms becomes relatively large, it becomes small.

When Cf ≧ M or more, it is determined that the inspection target wall tile is a sound tile (step S5), and Cf is determined.
In the case of <M, since the quality of the attached state of the inspection target wall tile cannot be accurately determined (pseudo peeled state),
An expected frequency Rf for the next determination is calculated (step S6). The value of Rf is obtained from the following equation (2). Equation (2) A (f) in the 2, FIG obtained from the reflected sound signal A (t) shown in FIG. 4. 3, frequency spectrum A shown in FIG. 5
(F).

[0019]

(Equation 1) The expected frequency Rf in the healthy tile is Rf1 shown in FIG.
Which is the frequency previously determined and stored in the computer. As shown in FIG. 3, the expected frequency Rf1 in the sound tile is the frequency spectrum A (f).
Is substantially flat, and therefore takes a substantially intermediate value in the measurement frequency band. FIG. 5 shows the expected frequency Rf2 of the wall tile to be inspected. This is the frequency required for each wall tile. As shown in FIG. 5, the expected frequency Rf2 in the exfoliated tile
Is higher than Rf1 because the level of A (f) increases in the high frequency region (for example, 2 to 4 kHz).

Next, (Rf2-Rf1) is compared with a second predetermined value Δf (step S7). Second predetermined value Δf
Is a value experimentally obtained from the characteristic of the frequency spectrum A (f) in the peeling tile. (Rf2-Rf
1) If <f, it is determined that the wall tile to be inspected is a healthy tile (steps S7 and S5), and (Rf2-R)
If f1) ≧ Δf, it is determined that the tile is a peeled tile (step S8).

As described above, the judgment based on the expected frequency Rf2 is based on the degree of peeling of the wall tile to be inspected.
Is different in the degree of increase in the high frequency region. That is, a small level increase in the high-frequency region of A (f) means that the tile is close to a sound tile, and a large level increase means that the peeled tile has a property largely separated from the property of the sound tile. means. Next, it is determined whether or not all the wall tiles have been inspected (step S9). If not all the wall tiles have been inspected, the process proceeds to step S1 and the above-described operation is repeated. Inspection is terminated when all inspections have been performed.

[0022]

As described above, in the method for judging the separation of the wall tile according to the present invention, first, the quality of the wall tile to be inspected is judged by the crest factor, and when the judgment cannot be made by the crest factor, the judgment is made by the expected frequency. Therefore, it is sufficient to calculate only the frequency spectrum related to the inspection target wall tile, and it is not necessary to store the frequency spectrum of the sound tile, so that the calculation amount is drastically reduced as compared with the conventional method, and the processing by the computer can be completed in a short time. . Also, as a result of the calculation, the storage amount of the frequency spectrum and the like is small, and it is not necessary to increase the size of the device for storage.

Furthermore, since the second predetermined value is determined by the property factor of the wall tile to be inspected, the quality of the attached state of the wall tile can be determined more accurately as the number of property factors increases.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining one embodiment of a method for determining a separation of a wall tile according to the present invention.

FIG. 2 is a time chart showing a reflected sound in a healthy tile.

FIG. 3 is a frequency spectrum corresponding to FIG. 2;

FIG. 4 is a time chart showing a reflection sound from a peeling tile.

FIG. 5 is a frequency spectrum corresponding to FIG.

FIG. 6 is a time chart showing reflected sound in a conventional method.

FIG. 7 is a frequency spectrum corresponding to FIG. 6;

FIG. 8 is a frequency spectrum of a stored healthy tile.

FIG. 9 is a relative difference spectrum showing a difference between FIGS. 7 and 8;

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsuhiro Doyama 4-640 Shimoseito, Kiyose-shi, Tokyo Inside Obayashi Corporation Technical Research Institute (56) References JP-A-5-281202 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) G01N 29/00-29/28

Claims (2)

(57) [Claims] 1. A peak value AP and a peak value AP of a reflected sound obtained when a wall tile to be inspected is hit with a hitting means such as a hammer.
And crestfac from effective value A (t) rms of reflected sound
Cf is calculated as Cf = AP / A (t) rms , and the crest factor Cf is set to a first predetermined value.
If the value is greater than or equal to the value, the wall tile to be inspected is a healthy tile
And the crest factor Cf is set to the first
Is smaller than the predetermined value of
The Rf is calculated by the following ^{equation, Rf = (X) 1/} 2, X = ∫A (f) · f 2 df / ∫A (f) df expected frequency R of the expected frequency Rf and sound tile
When the deviation from f is smaller than a second predetermined value, the inspection target wall tile is determined to be a sound tile, and the deviation is determined as the second tile.
And determining that the inspection target wall tile is a peeling tile when the predetermined value is equal to or more than a predetermined value. 2. The method according to claim 1, wherein the second predetermined value is determined by a property factor such as a shape, a size, and a material of the inspection target wall tile.