JPH07104305B2 - Defect investigation device and defect investigation 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 defect inspection apparatus and a defect inspection method, and more particularly to a technique capable of accurately recognizing a defect position of an object regardless of the influence of sunlight irradiation.

[0002]

2. Description of the Related Art For example, a part of the outer wall of a building may be lifted and a peeling phenomenon may occur due to the deterioration of the building, the influence of moisture, thermal stress and the like. If such a defect due to peeling is left as it is, a part of the wall surface may drop. Therefore, it is necessary to investigate whether the peeling phenomenon has occurred on the outer wall. As the outer wall inspection, there is a contact type inspection such as percussion. However, this contact-type inspection requires equipment such as a scaffolding, and there is a problem that the inspection takes time.

Therefore, a non-contact type inspection using an inspection device using an infrared sensor is performed. In this method, the surface temperature of the outer wall is measured by an infrared sensor, and the peeled portion is detected based on the temperature distribution.

That is, since the peeling phenomenon occurs due to the lifting of the outer wall, an air layer is formed in the wall at the peeled portion. Therefore, for example, when the wall surface of the peeled portion is heated by sunlight, the heat conduction is blocked by the air layer, and the amount of heat is retained on the outer wall surface. Therefore, the surface temperature of the peeled portion is higher than the surface temperature of the normal portion.

As described above, there is a difference in surface temperature between the peeled portion and the normal portion. Therefore, by measuring the surface temperature of the outer wall using the infrared sensor and examining the temperature distribution of the wall surface, the peeled portion and the normal portion can be distinguished.

[0006]

The conventional wall surface inspection has the following problems. As described above, the conventional inspection device using the infrared sensor measures the surface temperature of the outer wall and detects the peeled portion of the wall surface based on the temperature distribution.

However, the wall surface to be inspected may be irradiated with sun reflected light from another object. For example, when sunlight is reflected by a nearby building and the reflected light is emitted, or when the wall surface to be inspected has irregularities and the sunlight is reflected here and a part of the wall is illuminated by the reflected light. There is. In such a case, the irradiated portion of the reflected light becomes hotter than the other wall surface portions. Therefore, when the surface temperature of the wall surface is measured and the temperature distribution is examined, there is a possibility that a portion having a high temperature due to the reflected light may be erroneously recognized as a peeled portion.

The high temperature portion due to such sunlight reflection is
Conventionally, an analysis engineer has determined based on experience. Therefore, there is a problem that the inspection accuracy is greatly influenced by the skill of the analysis engineer, and the reliable and accurate inspection cannot be performed.

Therefore, an object of the present invention is to provide a defect inspection apparatus and a defect inspection method capable of accurately recognizing the position of a peeled portion of a wall surface, that is, the defect of an object, regardless of the influence of sunlight irradiation. To do.

[0010]

A defect inspection apparatus according to claim 1 is a temperature measuring unit for measuring the surface temperature of an object, wherein the surface of the object is two-dimensionally decomposed into a plurality of sections and each section is divided into a plurality of sections. After measuring the first surface temperature of each, the temperature measuring unit measuring the second surface temperature of each section at the time when a predetermined standby time has elapsed, based on the first surface temperature and the second surface temperature, A surface temperature change calculation unit for calculating the surface temperature change for each section, an average temperature change calculation section for calculating an average temperature change based on the surface temperature change for each section, the average temperature change, and for each section A relative temperature change calculation unit that calculates a relative temperature change for each section with respect to an average temperature change by comparing with the surface temperature change, and a display unit that displays the relative temperature change for each section. I am trying.

The defect inspection device according to claim 2 is the device according to claim 1.
In the defect inspection device of No. 2, the display unit is characterized in that the relative temperature change for each section is displayed in a plurality of colors.

The defect inspection device according to claim 3 is the device according to claim 1.
Alternatively, in the defect inspection device according to claim 2,
The feature is that the surface temperature for each category is also displayed.

According to a fourth aspect of the defect inspection method, the surface of the object is two-dimensionally decomposed into a plurality of sections and the first surface temperature of each section is measured. After measuring the first surface temperature, When a predetermined standby time has elapsed, a step of measuring a second surface temperature for each section, a step of calculating a surface temperature change for each section based on the first surface temperature and the second surface temperature, A step of calculating an average temperature change based on the surface temperature change for each section, comparing the average temperature change and the surface temperature change for each section, and a relative temperature for each section with respect to the average temperature change It is characterized by including a step of calculating a change and a step of discriminating a defect of an object based on the relative temperature change for each section.

The defect inspection method according to claim 5 is the method according to claim 4.
In the defect inspection method of (1), the determination of the defect of the object is performed based on the relative temperature change of each section and the surface temperature of each section.

[0015]

In the defect inspection apparatus according to the first aspect, the temperature measuring unit two-dimensionally decomposes the surface of the object into a plurality of sections,
After measuring the first surface temperature of each section, the second surface temperature of each section is measured when a predetermined waiting time has elapsed. The surface temperature change calculation unit calculates the surface temperature change for each section based on the first surface temperature and the second surface temperature.

In this way, the first surface temperature and the second surface temperature are measured, and the surface temperature change for each section is obtained. Therefore, as the standby time elapses, it is possible to know the position where the irradiation position of the sunlight has moved on the surface of the object,
It is possible to distinguish between the temperature measured due to the defect of the object and the temperature measured based on the irradiation of sunlight.

Further, the surface temperature change for each section is taken into the average temperature change calculating section, and the average temperature change of each surface temperature change is calculated. Then, the relative temperature change calculation unit compares the average temperature change with the surface temperature change for each section, and calculates the relative temperature change for each section with respect to the average temperature change. The relative temperature change thus obtained is
It is displayed on the display unit for each section.

Therefore, it is possible to visually recognize the relative temperature change for each section, and to detect the temperature location measured due to the defect of the object and the temperature location measured based on the irradiation of sunlight. It becomes possible to know clearly.

In the defect inspection apparatus according to claim 2,
The display unit displays the relative temperature change for each section in a plurality of colors.

Therefore, it is possible to more easily recognize the relative temperature change in each section. In the defect inspection apparatus according to the third aspect, the display unit also displays the surface temperature of each section.

Therefore, the relative temperature change in each section,
It is possible to determine the defect of the object based on both the surface temperature of each section and the surface temperature of each section.

In the defect investigation method according to claim 4,
First, the surface of the object is two-dimensionally decomposed into a plurality of sections, and the first surface temperature of each section is measured. Then, after measuring the first surface temperature, the second surface temperature for each section is measured when a predetermined waiting time has elapsed. Next, the surface temperature change for each section is calculated based on the first surface temperature and the second surface temperature.

In this way, the first surface temperature and the second surface temperature are measured, and the surface temperature change for each section is obtained. Therefore, as the standby time elapses, it is possible to know the position where the irradiation position of the sunlight has moved on the surface of the object,
It is possible to distinguish between the temperature measured due to the defect of the object and the temperature measured based on the irradiation of sunlight.

Further, an average temperature change is calculated based on the surface temperature change of each section, and the average temperature change is compared with the surface temperature change of each section, and the average temperature change of each section is compared. Calculate relative temperature change. And
The relative temperature change for each category is displayed.

Therefore, it is possible to visually recognize the relative temperature change for each section, and to detect the temperature location measured due to the defect of the object and the temperature location measured based on the irradiation of sunlight. It becomes possible to know clearly.

In the defect investigation method according to claim 5,
The defect of the object is discriminated based on the relative temperature change in each section and the surface temperature in each section.

Therefore, the relative temperature change for each section,
It is possible to determine the defect of the target object by a comprehensive judgment based on both the surface temperature of each section and the surface temperature of each section.

[0028]

EXAMPLES <Outline of the Example> An example of the defect inspection apparatus and the defect inspection method according to the present invention will be described by taking a peeling inspection of a wall surface as an example. A part of the outer wall of the building may be lifted and a peeling phenomenon may occur due to deterioration of the building, moisture, thermal stress, or the like. Such a peeled portion is detected by using an infrared sensor. That is, since the peeling phenomenon occurs due to the lifting of the outer wall, an air layer is formed in the wall at the peeled portion. Therefore, the peeled portion and the normal portion of the wall surface have different surface temperatures, and the peeled portion can be identified based on the distribution of the surface temperature.

In this embodiment, after the first surface temperature of the wall surface to be inspected is measured, the second surface temperature is measured after a lapse of a predetermined waiting time. Then, the surface temperature change is obtained based on the first surface temperature and the second surface temperature, and the peeled portion of the wall surface is recognized. That is, the surface irradiation temperature of the wall surface is measured twice at a predetermined time interval to determine the irradiation position of sunlight moving during that time. In this way, the influence of sunlight is avoided and the peeled portion of the wall surface is accurately detected.

The details of the inspection device and the inspection method will be described below. First, the configuration of the peeling inspection apparatus according to the present embodiment will be described with reference to FIG. A scanning device is installed in the camera head 2.
An arrangement 21, a condenser 22, a detection circuit 23, an amplification circuit 24, a synchronization circuit 25, and an internal temperature sensor 26 are provided. On the other hand, the processor unit 4 includes a camera head interface 41, a memory 42, and a display processing circuit 43, which are controlled by the MPU 44. In addition,
Based on the processing of the display processing circuit 43, a predetermined display is performed on the monitor 6.

Next, the outline of the inspection will be described based on the concrete examples of FIGS. 3 and 4 and the flowchart of FIG. Now, as shown in FIG. 3, on the wall surface 10 of the building, the peeled portion (a)
Is occurring. As described above, an air layer is formed in the peeled portion (a), and the amount of heat is held on the surface portion by the air layer, and the peeled portion (a) surface has a higher temperature than the normal portion of the wall surface 10. become. Also, this wall surface 1
It is assumed that the reflected light of the sunlight is emitted from the window glass of the neighboring building to 0. The reflected sun light is applied to the reflected light irradiation portion (f). Due to the heating of the reflected light, the reflected light irradiation portion (f) also becomes higher in temperature than other portions of the wall surface 10.

When performing the peeling inspection, the camera head 2 (FIG. 1) is installed toward the wall surface 10 and the surface temperature of the wall surface 10 is measured. The surface temperature is measured at each measurement point (section) where the wall surface 10 is two-dimensionally decomposed. That is, as shown in FIG. 5, in the image of the camera head 2, the wall surface 1
0 is decomposed into a plurality of measurement points P1 to Pn, and the surface temperature at each measurement point is measured.

[0033] First, the first round of the measurement process of the surface temperature of each measuring point of the wall 10 (FIG. 2, step S2). In this case, in order to eliminate noise and detect the accurate surface temperature,
Measurement is performed multiple times continuously. The specific measurement processing operation will be described below. As shown in FIG. 1, the light ray L1 from the wall surface 10 is reflected by the scanning device 21 in the camera head 2.
Reflect on the mirror . The reflection mirror inside the scanning device 21 is
The angle changes corresponding to the measurement points P1 to Pn on the wall surface 10.
Adapted to reduction, the light L1 from the measurement point sequence
The next reflection. The scanning device 21 uses a synchronization circuit during scanning.
The sync signal is output to 25.

The light beam L captured by the scanning device 21
1 is condensed by the condensing unit 22 and further taken into the detection circuit 23. The detection circuit 23 detects, among the received light rays L1,
An element that outputs an electrical signal corresponding to the intensity of infrared rays
For example, infrared using indium antimonide (InSb)
Line detection element). Thus , an electric signal corresponding to infrared rays can be obtained from the light ray L1 . The amplifier circuit 24 amplifies this electric signal and outputs it as an infrared image signal to the processor unit 4.

The infrared video signal is taken into the camera head interface 41 in the processor section 4. A synchronization signal from the synchronization circuit 25 is also given to the camera head interface 41. The camera head interface 41 recognizes which measurement point the captured infrared video signal corresponds to based on this synchronization signal. A correction signal is given to the camera head interface 41 from the internal temperature sensor 26 that measures the temperature inside the camera head 2, and the infrared image signal is corrected.

The infrared image signal output from the camera head interface 41 is taken into the memory 42 and stored at the address corresponding to the measuring point. Thus each measurement point P
Surface temperature from 1 to Pn (Fig. 5) is measured and stored in memory 4
Stored in 2. At the measurement points corresponding to the peeled portion (a) and the reflected light irradiation portion (f) shown in FIG. 3, the high temperature is measured and stored as compared with the other measurement points. In addition, as described above, in order to eliminate noise, the measurement process is repeated a plurality of times for each measurement point.

First measurement process (FIG. 2, step S
2) After the end, wait for elapse of t time (waiting time), for example, 5 minutes (step S4). It is assumed that after 5 minutes, the state of the wall surface 10 shown in FIG. 3A changes as shown in FIG. 3B. In other words, with the passage of time t, the reflection position of the sunlight from the neighboring building changes from the reflected light irradiation part (F) to (K).
Have moved to. Due to the positional relationship of the buildings, the movement of the reflection position of the sun is usually remarkable even in a short time. After a lapse of t time, the same operation as the first time is executed and the second measurement process is performed (step S6). In addition, the second measurement is also performed a plurality of times continuously at each measurement point.

Next, the MPU 44 (FIG. 1) averages a plurality of first measurement temperatures (step S2) for each measurement point (step S8) and stores the averaged first temperature in the memory 42. The second measurement temperature (step S6) is also averaged for each measurement point (step S6).
10), memorize as the second surface temperature. In this way, the first surface temperature at each measurement point and the second surface temperature after elapse of t time are obtained.

Thereafter, the first surface temperature is subtracted from the second surface temperature to calculate the surface temperature change at each measurement point (step S12). That is, how much the surface temperature at each measurement point changed during the time t is obtained. Then, the surface temperature change at each measurement point is averaged to calculate the average temperature change (step S13).

The MPU 44 (FIG. 1) has a display processing circuit 43.
Through, the histogram of the surface temperature change of each measurement point obtained in step S12 is displayed on the monitor 6, and the average temperature change obtained in step S13 is displayed (step S13).
14). Then, the average temperature change amount range is determined and input based on this display (step S16). The average temperature change amount range is set to an average value by setting a width of, for example, "2 degrees" in consideration of the measurement error of the average temperature change obtained in step S13.

After the average temperature change amount range is input, the relative temperature change at each measurement point with respect to the average temperature change amount range is calculated (step S18). Specifically, subtract the average temperature change amount range from the surface temperature change at each measurement point,
Determine the relative temperature change at each measurement point.

Therefore, at the measurement point where the temperature is remarkably increased as compared with the other measurement points, that is, at the measurement point where the surface temperature change exceeds the average temperature change amount range, the relative temperature change having a positive value is calculated. It Note that when the average temperature change range is set as a negative value (when the temperature of the entire wall surface has dropped), the measurement point where the temperature did not drop significantly was a relatively positive value. The relative temperature change of is calculated.

Further, at a measurement point where the temperature is remarkably lowered as compared with the other measurement points, that is, at a measurement point where the surface temperature change is below the average temperature change amount range, a negative relative temperature change is calculated. Note that when the average temperature change range is set as a positive value (when the temperature of the entire wall surface has risen), the measurement point where the temperature did not rise so much has a relatively negative value. The relative temperature change of is calculated.

Regarding the surface temperature change within the average temperature change amount range, the relative temperature change is set to "0". That is, such a surface temperature change is only an average temperature change in the entire wall surface.

Next, the relative temperature change at each measurement point is ternarized into plus, minus, and 0 values (step S20). Then, each value is given a color and displayed on the monitor 6 (step S22). For example, red is displayed for a measurement point of positive relative temperature change, blue is displayed for a measurement point of negative relative temperature change, and transparent is displayed for a measurement point where relative temperature change is 0. Note that, due to the limit of the measurement capability of the infrared sensor, a measurement point where the surface temperature change is not clear may be displayed with another color, for example, purple, and displayed as an unanalyzable portion.

When the surface temperature of the wall surface shown in FIGS. 3A and 3B is measured, the monitor display in step S22 is as shown in FIG. 4A. In the monitor display of FIG. 4A, the display portion H1 is shown in blue, and this portion indicates that the relative temperature change is minus during the time t. Further, the display portion H2 is shown in red, which indicates that the relative temperature change is positive during the time t.

That is, from the state of the wall surface 10 in FIG. 3A,
After the elapse of time t, the reflected light of sunlight has moved, and the reflected light irradiation portion has moved from (f) to (ki) as shown in FIG. 3B. Therefore, the relative temperature change becomes negative at the measurement point corresponding to the reflected light irradiation portion (F), and conversely the relative temperature change becomes positive at the measurement point corresponding to the reflected light irradiation portion (K). Therefore, the monitor display as shown in FIG. 4A is performed. The position of the peeled portion (a) in FIGS. 3A and 3B does not move regardless of the elapse of time t. For this reason,
At the measurement point corresponding to the peeled portion (a), the relative temperature change is 0 as in the other normal portions, and the monitor 6 is transparent and no color display is performed (see FIG. 4A). In addition to the display as shown in FIG. 4A, the monitor 6 also displays the absolute temperature of the wall surface 10 (see FIG. 4B). This display is also color display using, for example, a color bar. Here, the first surface temperature measured in steps S2 and S8 is displayed as an absolute temperature.

In this way, the display as shown in FIGS. 4A and 4B is performed on the monitor 6. The analyst sees this monitor display and determines the separation location on the wall surface 10. Since the peeling point is at a high temperature as described above, first, it can be determined based on the absolute temperature of the wall surface (FIG. 4B) that the peeling phenomenon may occur in the portions of the displays H3 and H4. However, looking at the display of FIG. 4A, it can be seen that the portion corresponding to display H4 (FIG. 4B) has moved with the elapse of t time. Therefore,
The peeling phenomenon does not occur in the part of the display H4,
It can be determined that the temperature is high due to the reflection of sunlight.

As described above, the display H3 is displayed on the wall surface 10.
It can be detected that the peeling phenomenon has occurred at the position corresponding to. That is, the position of the peeled portion can be accurately recognized regardless of the influence of the irradiation of sunlight. In addition,
The second surface temperature (FIG. 3B) may be used instead of the first surface temperature as the display of the absolute temperature in FIG. 4B.

In the above embodiment, the camera head section 2 and the processor section 4 shown in FIG. 1 perform the analysis process from the measurement process and display the analysis result on the monitor 6. However, as shown in another embodiment of FIG. 6, the analysis processing may be separately performed by the analysis device 80. As the analysis device 80, for example, a personal computer is used, and MP
A U81 and a hard disk 82 are provided. Further, an input operation is performed by the keyboard 83 and the mouse 84.

In the embodiment shown in FIG. 6, the camera head unit 2 and the processor unit 4 perform the measurement processing up to step S8 in FIG. Then, the memory 4 of the processor unit 4
The measurement data stored in No. 2 is taken into the analysis device 80 via the floppy disk 86. At this time, the data may be taken in online without using the floppy disk 86. Based on the given measurement data, the analysis device 80 uses the steps S10 to S20.
The processes up to are executed (FIG. 2). And the monitor 85
4A and 4B are displayed.

<Specific Details of this Embodiment> 1. Introduction The outer wall of a building suffers from various factors, such as deterioration over time due to sunlight and wind and rain, and peeling due to moisture, thermal stress, etc.
If the structural body is subjected to a large amount of external force such as deterioration or an earthquake, the outer wall finishing material will not only peel off and fall off, but it will not only damage the landscape of the building, but will also cause personal injury due to falling objects. Becomes It is desired that the outer wall be repaired by the time such a situation occurs, but there is a method for investigating the outer wall mainly for the purpose of determining the position of the repaired portion. One of the non-destructive investigation methods for building exterior wall diagnosis is an investigation method using infrared rays, but since this method can be carried out in a non-contact manner, scaffolds etc. are unnecessary at the time of investigation, and records can be recorded, and the temperature can be flat Therefore, the area can be easily calculated and the survey cost can be relatively low. However, this investigation method is susceptible to external factors, which leads to deterioration of accuracy and misdiagnosis.

Actually, the reflected light of the sun was a particular problem at the stage of the investigation. If the object to be measured is a material such as a tile having a low emissivity, the reflected light of the sun is reflected, and the measurement point is measured. It becomes impossible to measure the temperature correctly.

Further, the reflected light from the glass or the like of the nearby building hits the measurement surface, and the temperature is measured at a temperature higher than the actual temperature.

The outer wall diagnosis using infrared rays utilizes the fact that a temperature difference occurs due to the difference in thermal characteristics between the normal part and the peeled part, but the purpose of this study is one of the main causes of misdiagnosis. As a countermeasure against a certain reflection, we propose a method to determine the position of the reflection point using the relative temperature change amount.

1.1 Reflection Reflection is a phenomenon in which sunlight or the like hits an object to be measured and accurate measurement cannot be performed. This leads to a decrease in survey accuracy, misdiagnosis and the like, and the most adverse effects of external factors. It is one of the things that affect. When a certain portion of the measurement surface is a high temperature portion, the determination as to whether the portion has become a high temperature portion due to peeling or a high temperature portion due to reflection is left to the determination of the analyzing engineer. Moreover, even if it is called a reflection, it can be classified into several types based on its characteristics. The following classifications are named and used in this paper for the sake of simplicity.

The following is a list including a description of the phenomenon of reflection. The first conceivable case is that an object other than the survey target may reflect sunlight and raise the temperature of part of the survey building. In an example similar to this, there is a case where the object has irregularities and reflects sunlight on itself.

Further, the object to be investigated itself has luster, and when the temperature of the portion is examined by an infrared sensor, the amount of heat of the surroundings is reflected in addition to the amount of heat of itself, and the amount of heat is also added, resulting in accurate measurement. No temperature measurement is taken. In extreme cases,
There is a case where an object outside the survey reflects sunlight and hits the survey target, the temperature of the spot rises, and the spot is shiny and reflects the reflected heat to reach the infrared sensor. . Although all of the above phenomena are collectively referred to as reflection, their properties are obviously different and their countermeasures are also different.

Here, reflections are classified according to their properties. Actual temperature may differ from that measured by infrared sensor. This is a phenomenon different from the actual temperature because the measurement surface reflects and the amount of heat of itself and the ambient heat are added. This has to be taken into account when measuring such objects, especially as materials with lower emissivity reflect better. Such reflection is referred to as "direct reflection".

There is a case where some heat is directly reflected and hits the measurement surface, and that portion becomes hotter than other portions. Such reflection is called "indirect reflection". In addition, depending on whether or not the reflected heat source is the sun, a sunlight reflection type heat source and a non-sunlight reflection type heat source are selected.

1.2 Relative temperature change amount The temperature distribution obtained by measuring the same place at different times is
In almost the same situation, measurement error is included, and in most cases, they do not match perfectly. However, in this case, since the temperature change amount at each point is large at many measurement points, it follows almost the normal distribution. Consideration will be given to the points that do not follow the average temperature change even if the measurement error is subtracted under such circumstances.

In this paper, the relative temperature change amount is set in order to explain the method of determining the reflection point and the like.

This is the difference between the temperature change after a certain time elapses at that location and the average value of the temperature change amounts of all the measurement surfaces.

In addition, the temperature difference after a certain measurement point over time is the amount of temperature change, and the average value of the amount of temperature change of all the measurement points included in the measurement surface captured by the sensor is the average temperature change amount.

That is, since the infrared sensor measures the temperature of a plane, the measurement point becomes two-dimensional (FIG. 7), where the initial temperature is an and the temperature after a certain time is bn,
The temperature change amount dT, the average temperature change amount adT, and the relative temperature change amount rdTn are expressed by the following equations.

[0066]

[Equation 1]

This relative temperature change amount shows the sensitivity of the influence of the ambient temperature at that location, and is the difference in the temperature change at a certain measurement point after the elapse of time. The phenomenon occurring during that time is recorded. Become.

1.3 Direct Reflection Site by Solar Reflection-Type Heat Source When the average temperature change is negative, the place where the relative temperature change is negative is presumed to be the direct sunlight reflection site. Because the average temperature change is negative,
It is considered that the ambient temperature has dropped, and the main cause of this temperature drop is a phenomenon caused by a decrease in solar radiation.

As a reason for this, it is conceivable that the measurement surface is cooled by low-temperature outside air as a phenomenon that causes a temperature drop, but if the measurement interval is narrow, even if the difference in thermal conductivity is taken into consideration, each point will be extremely large. It is unlikely that there will be a difference in temperature change. Here, the temperature measured by the infrared sensor is not the temperature of the measured object itself, but the amount of radiation from the object that has been attenuated in the atmosphere and that reflected by the object from the surrounding environment and attenuated by the atmosphere. , And the amount of radiation from the atmosphere (see equation (4)).

[0070]

[Equation 2]

The influence of the atmosphere is related to the measurement distance and the temperature, but in a normal situation, the transmittance of the atmosphere is set to 1, and the influence of the atmosphere is ignored. Then, the measured temperature becomes the radiation amount of the object and the reflection from the surrounding environment. At this time, what the relative temperature change amount of each point shows is nothing but the change of the reflected light from the surrounding environment. As long as the emissivity is not 1, the reflected heat is always included in the measurement temperature, most of the reflected heat is sunlight, and when the temperature of the entire measurement surface drops on average, the sunlight is clearly radiated heat due to clouds. It is considered that the temperature has dropped due to the decrease in temperature, and the part where the temperature drops below the average temperature drop is considered to be the part that receives extra sunlight from the surroundings, and such part is the part directly reflected by the sunlight reflective heat source.

2 Relative Temperature Change Amount Quaternary Image Processing 2.1 Contents The relative temperature change amount is converted into four values, and colors are assigned to each and output as an image. (See Table 1)

[0073]

[Table 1]

At this time, the uncertain temperature zone is processed conditionally, and if it cannot be determined, it is processed as an unanalyzable part. As a condition at this time, when the temperature drops from the overflowed temperature zone, it is determined that the temperature drop amount has dropped by a simple calculation value or more. In this case, it is used only when the minimum value of the range of the average temperature change amount is larger than the simple calculation temperature drop amount, and when the temperature rises from the underflow temperature zone, the reverse process of the overflow process is performed.

Due to the limitation of the performance of the measuring device, if such a process is not performed, a completely meaningless result will be obtained, and the average temperature change amount must also consider the measurement error.

At this time, since the temperature change amount is large at many measurement points (25,600 locations), its distribution follows a normal distribution, and the reliability varies depending on the data, so it cannot be determined unequivocally as what percentage or more. The reliability of the average temperature change amount can be naturally limited by actually performing various processes centered on the value. If the range of the average value of the temperature change is made too narrow, the red and blue points will be disturbed on the screen, and if it is made too wide, the change point will not appear.

However, when the variance value is small, or when images that have hardly changed are processed, the change point may not appear even if the average temperature change amount is manipulated.

When the existing data was subjected to such a treatment, almost meaningless results were obtained unless the average temperature change amount was 1 ° C. or more. As of now, there is nothing that can be the basis of this process, so I have no choice but to try various parameters.

2.2 Relative temperature change amount four-valued image processing of existing data In the conventional investigation method, the same location was measured several times and averaged, so in a sense, this processing is convenient. Was good.

However, because of the efficiency of the investigation, the measurement interval is very narrow, so even if the first image and the last image are compared, there is often little change, and only images that seem to be meaningless are obtained. However, some of the treatments were effective.

The main effects are as follows: It is possible to judge the boundary between the shade and the sun-lit area.

Materials can be distinguished from each other by the difference in reflectance.

It is possible to judge the passage of other substances between the infrared sensor and the measurement surface. The above-mentioned judgment grounds will be described below.

(1) Basis of Judgment of Boundary between Shade and its Place of Existence The basis of judgment of this method is as follows on the boundary line between the place of shade and the place of sun exposure. The shaded areas move in the same way as the sun moves. For this reason, the place where the sun was normally exposed enters the shade and the temperature drops rapidly. This is unlikely to be because the temperature of the measurement object itself has entered the shaded area where sunlight does not hit, so it is unlikely that the temperature has decreased. Naturally, such a phenomenon may occur with the passage of time, but it is difficult to think in a short time, so it is considered to be probably the influence of reflected light. Obviously, the amount of reflected heat differs between the shade and the places where the sun hits.

In any case, the temperature drop is more remarkable in such a place than in other places. In other words, the relative temperature change amount is negative. In addition, since it is a boundary with the shade in terms of shape, such a point exists linearly.

(2) Judgment Basis for Distinguishing Materials from Differences in Reflectance This determination method does not always enable severe material discrimination. Moreover, only materials having apparently different reflectances can be judged. Also, since the emissivity is different even for the color of the external finish, the color can be discriminated to some extent.

This is useful as a means for recognizing an object that is difficult to recognize on a thermal image and is necessary for position confirmation, such as a joint. If the reflectivities are clearly different, the degree of reaction of the change of sunlight will be different. The difference in the degree of the reaction appears as the relative temperature change amount. Its shape is almost the same as that of the object, and if it is a peculiar object, it is possible to infer the object from its shape to some extent.

(3) Criteria for determining the passage of other substances between the infrared sensor and the measuring surface It is considered possible that other substances pass between the infrared sensor and the measuring surface, and birds and humans are likely to pass during the measurement. There are many cases where Since the temperature distribution of a passing object is clearly different from that of the measurement surface, it can be judged from the original image to some extent, but when the passing object is small or the distance of the passing object is long, it was difficult to judge. Became possible. Of course, it is not possible to judge under any condition,
Two or more thermal images are required after the passing object has passed the time (in this case, after the passing object has moved).

As a basis for judgment, when a high-temperature (low-temperature) heat source moves and the heat source existed before, there is no heat source at that place after the movement, so the temperature drops (rises).
However, at the location where the heat source exists after the movement, the temperature rises (falls) because the heat source did not exist before.

Actually, when the relative temperature change amount quaternarized image processing is performed on such a plurality of data, a pair of red and blue of almost the same type exists. These clearly indicate a situation where a high-temperature (low-temperature) heat source has moved. This made it possible to judge passing objects.

Therefore, if this method is similarly applied to the indirect reflection point by the sunlight reflection type heat source, this reflection point should be determined. Below, an explanation of this method, a proof method, and an experimental result are given.

3. Method for determining indirect reflection points by sunlight reflection type heat source using relative temperature change amount 3.1 Overview Objects other than the surveyed building reflect sunlight and apply more heat than usual to the building, and measure by that The amount of heat due to this reflection is added to the temperature of the location, and the measurement location heats up more than necessary, which causes the investigation property to be unable to receive a uniform amount of heat, causing a misdiagnosis. A method to identify such a part.

The indirect reflection by the solar reflection type heat source of this theme occurs when the direct reflection light from the sunlight reflection type heat source is applied to the object to be investigated for a long time with a large amount of heat or the thermal conductivity of the object is high. .

3.2 Principle This method utilizes the difference in characteristics between the normal high temperature portion and the high temperature portion heated by the sunlight reflecting heat source. The big difference is that we focus on the point that the sun moves, and use the phenomenon that the reflected light moves as the sun moves. This reflected light is clearly hotter than the measured building temperature. This hot spot moves with the movement of the sun.

Therefore, the high-temperature heat source (reflecting point), which was developed between the infrared sensor and the measurement surface on the basis of the judgment of passage of another substance, moved, and in the place where the heat source existed before, it moved to that place. Since there is no heat source, the temperature drops, and at the location where the heat source exists after the movement, the temperature rises because there was no previous heat source, and such multiple data are converted into a relative temperature change amount quaternary image. After processing, there will be almost the same type of red and blue pairs.

This clearly shows the situation in which the high temperature heat source has moved, and it can be inferred that the location is a reflection location. Therefore, the following experiments were conducted to prove this theory.

3.3 Experimental Method As the experimental object, a building in which the reflection by the sunlight reflection type heat source was clearly visible can be selected and measured, and the experiment was conducted under the following settings.

Setting 1: Continuous measurement for 15 minutes, fixed parameters, recorded at 30 second intervals.

Parameter setting condition Low Temp
25, Senc 0.5.

Setting 2: Continuous measurement for 15 minutes, fixed parameters, recorded at 30 second intervals.

Parameter setting conditions Low Temp
27, Senc 0.3.

As a precaution, care was taken so that the temperature of the measurement object did not overflow or underflow.

As the infrared sensor used here, TVS3000 series manufactured by Nippon Avionics Co., Ltd. was used.

This device is composed of an information amount of 256 × 100 pixels, and a temperature division zone of 16 gradations is set for each, and the range is set by Senc.

Assign a color to each of the temperature categories,
Output as a two-dimensional thermal image. There is a color bar as a method to show the relationship between color and temperature, and its right end (white)
A high temperature part and a low temperature part are displayed on the left end (purple) and are output as a two-dimensional thermal image.

At this time, the lowest temperature zone (Low Temp)
Also includes temperatures below that (underflow), and the highest temperature zone also includes temperatures above that temperature (overflow).

The analyzer is ISA manufactured by Planet Co., Ltd.
AC Ver1.0 was used. In addition, this ISA is shown in FIG.
The processing process of AC is shown.

ISAAC is software that operates on a personal computer and was developed for this experiment, but since it is not functionally sufficient yet, it will be upgraded in the future.

[0109]

[Table 2]

4. The results and discussions were as expected. Clearly, it was possible to determine that the heat source was moving, and that location coincided with the indirect reflection location of the sunlight-reflecting heat source that was visually confirmed.

Also, looking at this result, the amount of movement of the vertically aligned reflection points is almost the same, because the reflected light does not affect the vertical direction even if the sun moves, so The greater the amount of movement, the more convincing considering the reflection angle.

In this experiment, the time required to determine all the reflection points was 8 minutes or more, but of course this time depends on the reflection angle. Also, although it seems that the results are not remarkable for a wide range of reflection, as a practical problem, the pin spot type reflection like this time is particularly likely to cause a misdiagnosis, and when the reflection is in a wide range, it is not so problematic.

The biggest problem of this method is that it takes time to measure.

It takes less than 15 minutes to measure at only one place as in this experiment, but it is not rare that most of the objects to be investigated reach 10 to 20 on each surface (north, east, west, and north).

When surveying at this pace, it could take one day for each side. Therefore, in order to solve this problem, the process of effectively utilizing the blank time of the measurement interval, measuring other places during the waiting time, and returning to the original position is repeated.

However, since the image processing method uses the temperature change at each measurement point, if the measurement point is out of order, it has no meaning at all.

When the position of the sensor cannot be accurately returned to the original position, a method is conceivable in which the obtained images are subjected to image conversion processing by a computer and are superposed by parallel movement on the same plane.

5. Conclusion In this study, an objective method was used to determine reflection points, which had been subject to the subjective judgment of the technician who performed the analysis up to now, or to determine reflection points of only heat without visible light. It became possible by using and proposed the method.

It has also been clarified that the method using the relative temperature change amount can be used for the analysis of other phenomena.
This research was able to discriminate the following phenomena.

-Judgment of boundary between shade and sun-lit place-Distinction of material based on difference in reflectance-Judgment of passage of substance between infrared sensor and measurement surface-Direct reflection point by sunlight reflective heat source- Indirect reflection part by sunlight reflection type heat source Also, this method seems to be applicable to other phenomena, especially the part where the temperature rise rate of the peeled part and the reflectance of dirt etc. are high,
Or, it is considered possible to determine the peeled portion in the same high temperature part due to the difference in heat quantity due to volume,
We plan to conduct research in this area in the future.

[0121]

In the defect inspection apparatus according to the first aspect, the temperature measuring unit two-dimensionally decomposes the surface of the object into a plurality of sections, measures the first surface temperature for each section, and then predetermined When the waiting time has elapsed, the second surface temperature of each section is measured. The surface temperature change calculation unit calculates the surface temperature change for each section based on the first surface temperature and the second surface temperature.

In this way, the first surface temperature and the second surface temperature are measured, and the surface temperature change for each section is obtained. That is, as the standby time elapses, it is possible to know the position where the irradiation position of the sunlight has moved on the surface of the object, and the temperature measured due to the defect of the object and the irradiation of the sunlight Can be distinguished from the temperature measured by

Further, the surface temperature change for each section is taken into the average temperature change calculating section, and the average temperature change of each surface temperature change is calculated. Then, the relative temperature change calculation unit compares the average temperature change with the surface temperature change for each section, and calculates the relative temperature change for each section with respect to the average temperature change. The relative temperature change thus obtained is
It is displayed on the display unit for each section.

That is, the relative temperature change for each section can be visually recognized, and the temperature location measured due to the defect of the object and the temperature location measured based on the irradiation of the sunlight are detected. It becomes possible to know clearly.

Therefore, the position of the defect of the object can be accurately recognized regardless of the influence of the irradiation of sunlight.

In the defect inspection apparatus according to claim 2,
The display unit displays the relative temperature change for each section in a plurality of colors. That is, it is possible to more easily recognize the relative temperature change for each section.

Therefore, the position of the defect of the object can be recognized more accurately.

In the defect inspection apparatus according to claim 3,
The display unit also displays the surface temperature of each section. That is, the defect determination of the object can be performed based on both the relative temperature change in each section and the surface temperature in each section.

Therefore, the position of the defect of the object can be recognized more accurately.

In the defect investigation method according to claim 4,
First, the surface of the object is two-dimensionally decomposed into a plurality of sections, and the first surface temperature of each section is measured. Then, after measuring the first surface temperature, the second surface temperature for each section is measured when a predetermined waiting time has elapsed. Next, the surface temperature change for each section is calculated based on the first surface temperature and the second surface temperature.

In this way, the first surface temperature and the second surface temperature are measured, and the surface temperature change for each section is obtained. That is, as the standby time elapses, it is possible to know the position where the irradiation position of the sunlight has moved on the surface of the object, and the temperature measured due to the defect of the object and the irradiation of the sunlight Can be distinguished from the temperature measured by

Further, the average temperature change is calculated based on the surface temperature change for each section, and this average temperature change is compared with the surface temperature change for each section, and the average temperature change for each section is calculated. Calculate relative temperature change. And
The relative temperature change for each category is displayed.

That is, the relative temperature change for each section can be visually recognized, and the temperature location measured due to the defect of the target object and the temperature location measured based on the irradiation of sunlight are detected. It becomes possible to know clearly.

Therefore, in the defect inspection method according to claim 5, the position of the defect of the object can be accurately recognized regardless of the influence of the irradiation of sunlight, and the defect of the object is discriminated in each section. It is performed based on the relative temperature change for each and the surface temperature for each category. That is, the defect of the object can be discriminated by a comprehensive judgment based on both the relative temperature change of each section and the surface temperature of each section.

Therefore, the position of the defect of the object can be recognized more accurately.

[Brief description of drawings]

FIG. 1 is a block diagram of a peeling inspection apparatus that is an embodiment of a defect inspection apparatus according to the present invention.

FIG. 2 is a flowchart showing a processing operation of the peeling inspection apparatus shown in FIG.

FIG. 3 is a diagram showing a peeled portion generated on a wall surface and an irradiation position of sun reflected light.

FIG. 4 is a diagram showing display contents on the monitor shown in FIG. 1.

FIG. 5 is a diagram showing each measurement point in a measurement image.

FIG. 6 is a block diagram of a peeling inspection apparatus which is another embodiment of the defect inspection apparatus according to the present invention.

FIG. 7 is a diagram showing a two-dimensional arrangement of measurement points in a measurement image.

FIG. 8 is a diagram showing a process of ISAAC used as an analysis device.

[Explanation of symbols]

 2 ... Camera head 4 ... Processor 6 ... Monitor 10 ... Wall 42 ... Memory 44 ... MPU

Claims (5)

[Claims] 1. A temperature measuring unit for measuring the surface temperature of an object, wherein the surface of the object is two-dimensionally decomposed into a plurality of sections, the first surface temperature of each section is measured, and then a predetermined standby A temperature measuring unit that measures the second surface temperature of each section at the time when the time has passed, based on the first surface temperature and the second surface temperature,
A surface temperature change calculation unit for calculating the surface temperature change for each section, an average temperature change calculation section for calculating an average temperature change based on the surface temperature change for each section, the average temperature change, and for each section A relative temperature change calculation unit that calculates a relative temperature change for each section with respect to an average temperature change by comparing with the surface temperature change; and a display unit that displays the relative temperature change for each section. Defect investigation device. 2. The defect inspection apparatus according to claim 1, wherein the display unit displays the relative temperature change for each section in a plurality of colors. 3. The defect inspection apparatus according to claim 1 or 2, wherein the display unit also displays the surface temperature of each section. 4. A step of two-dimensionally decomposing a surface of an object into a plurality of sections and measuring a first surface temperature of each section, a point of time when a predetermined waiting time has elapsed after measuring the first surface temperature. In the step of measuring the second surface temperature for each section, based on the first surface temperature and the second surface temperature,
Calculating a surface temperature change for each section, calculating an average temperature change based on the surface temperature change for each section, comparing the average temperature change with the surface temperature change for each section And a step of calculating a relative temperature change for each section with respect to an average temperature change, and a step of determining a defect of an object based on the relative temperature change for each section. 5. The defect inspection method according to claim 4, wherein the defect of the object is discriminated based on the relative temperature change of each section and the surface temperature of each section.