JP2005172664A - Method and device for determining soundness of concrete structure by infrared method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for determining a sound part and a defective part, based on a temperature distribution and a temperature change obtained from an infrared thermal image of a concrete structure picked up by an infrared camera. <P>SOLUTION: At first, an initial temperature of a surface of the concrete structure before heated is imaged by the infrared camera, then the surface of the concrete structure is heated to image a change of an infrared energy quantity radiated from the surface of the concrete structure after heated, the sum of the temperature distributions after heated obtained from respective infrared thermal images is compared with the sum of the initial temperature distributions before heated, and investigated to discriminate the sound part from the defective part to be determined. As a result thereof, the defective part and an exfoliated portion by an active method are easy to be specified accurately, so as to contribute to prevention of an exfoliation accident or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In this invention, the presence or absence of defects such as cavities, cracks, and jumpers that appear or exist in a concrete structure and the contents, size, and shape of the defects are determined by an infrared camera (or an infrared sensor, the same applies hereinafter) of the thermography apparatus. Detecting, calculating, and analyzing temperature distribution and temperature changes obtained from captured infrared thermal images to identify and determine sound and defective parts, and a method for determining the soundness level of concrete structures using the infrared method, and implementation of the method It belongs to the technical field of the soundness determination device used.

Conventionally, regular inspection of tunnel lining concrete is usually performed by visual inspection or hammering inspection. Recently, however, concrete has been identified by identifying and judging surface defects and internal defects through examination and analysis of concrete surface temperature distribution images (infrared thermal images = thermographic images) taken with a high-vision camera or with an infrared camera of a thermographic device. Inspection system technology has been researched and developed, and is disclosed in, for example, the following Patent Document 1 and is well known.
Similarly, techniques for pre-predicting the presence / absence and possibility of defects by photographing with an infrared camera of a thermography apparatus are also disclosed in the following Patent Documents 2, 3, and 4.

JP 2002-257744 A Japanese Patent Laid-Open No. 5-307013 Japanese Patent Laid-Open No. 9-311029 JP 2001-74678 A

As described above, a concrete inspection technique based on a so-called infrared method in which an infrared energy amount emitted from the surface of a concrete structure is imaged by an infrared camera of a thermography apparatus is already known. However, there are various methods for processing the captured infrared thermal image (temperature data), and there is still no technology that can satisfy the soundness determination of a concrete structure.
For example, in Patent Document 1 described above, a high-vision camera device as an imaging device and an infrared camera of a thermography device are mounted (paragraph numbers [0052] and [0053]), and an internal cavity and surface of a concrete structure Regarding the evaluation of defects and the like, paragraphs [0076] to [0079] describe that the evaluation is performed by superimposing the output (inspection result) of the electromagnetic wave radar and the temperature distribution by infrared rays.

Further, the above-mentioned Patent Document 2 has a technique for acquiring infrared image data and visible image data, obtaining contour image data for the two types of data, and comparing and displaying the obtained two contour image data. It is disclosed.
In Patent Document 3, the amount of infrared energy radiated from the surface of a concrete wall heated by a heater is imaged by an infrared camera, and the temperature distribution of the captured thermal image is analyzed by an image processing device. A technique for determining that peeling and other parts are normal is described (paragraph number 0016).
Patent Document 4 describes a technique for heating a tunnel inner wall with far infrared rays, immediately measuring a temperature deviation in a cooling process with an infrared camera, measuring a normal portion and a hollow portion of the inner wall, and predicting the possibility of peeling in advance. Has been.

  As described above, the conventional technology uses a high-definition camera device or an infrared camera of a thermography device as an imaging device, and processes the infrared thermal image data to temperature data or the like to determine the soundness of the concrete structure. However, the following serious problems are recognized.

  In other words, the infrared method is used to measure the change in temperature and the temperature of the concrete surface under a method in which the temperature of the concrete surface changes over time due to solar radiation, etc. When the change is small, it is roughly divided into a method (active method) for forcibly applying heat to the concrete surface and measuring the temperature change to identify the presence or absence of defects. However, in the latter so-called active method, the temperature of the concrete surface is imaged after the heat is applied, so the difference in the initial temperature depending on the state of the concrete before the heat is applied (whether there is dirt, water leakage, condensation, surface deterioration, etc.) However, although it is thought that it has a great influence on the accuracy of inspection and determination, the inspection and determination method considering the initial temperature has not been heard yet.

  14 and 15 show the results of inspection by the active method by creating a simulated defect specimen in which the former is a junker and the latter is a cavity in the surface layer of the concrete structure to be inspected. Show. If there are defects such as junkers or cavities in the surface layer of the concrete structure to be inspected, these defects are structurally included in the air layer (defect layer, void layer), so this defect is heated. In such a case, the presence of the air layer causes the degree of heat diffusion to be lower than that of the healthy part, resulting in a phenomenon that the temperature is unlikely to decrease. As a result, as shown in FIGS. 14 and 15, specific differences appear on the chart between the defective portion and the healthy portion in the most frequent value, median value, etc. of the temperature distribution, and the soundness level can be determined.

  However, in the case of FIG. 14 and FIG. 15, since the difference between the defective part and the healthy part includes most of the overlap, it is recognized and judged after careful examination and examination by an expert. , There is a danger of overlooking if you inadvertently.

  The object of the present invention is to detect the initial temperature depending on the state of the concrete before applying heat (presence / absence of dirt, water leakage, condensation, surface degradation, etc.) with an infrared camera in advance, and then heat the concrete structure Changes in the amount of infrared energy (temperature change) radiated from the surface of the object is imaged with an infrared camera, and the temperature distribution after heating and the initial temperature distribution before heating are calculated based on the obtained infrared thermal image. By conducting a comparative study, anyone can clearly identify and determine a healthy part and a defective part. A soundness determination method using the infrared method of a concrete structure and a soundness determination device used to implement the method Is to provide.

As means for solving the above-mentioned problems, the soundness determination method by the infrared method of the concrete structure according to the invention described in claim 1 is:
The surface of the concrete structure is heated, changes in the amount of infrared energy (temperature change) radiated from the surface of the concrete structure after heating is imaged with an infrared camera, and the temperature distribution obtained from the infrared thermal image is tabulated. In the method of identifying and judging the sound part and abnormal part of the concrete structure,
First, the initial temperature of the surface of the concrete structure before heating is imaged by the infrared camera 4, then the surface of the same concrete structure is heated, and the change in the amount of infrared energy radiated from the surface of the concrete structure after heating (temperature) Change) is captured by the infrared camera 6, and the comparison of the temperature distribution after heating obtained from each infrared thermal image and the calculation of the initial temperature distribution before heating are compared and examined to identify a healthy part and a defective part. Judgment is performed.

The soundness determination device according to the infrared method of a concrete structure according to the invention of claim 2,
The vehicle body 1 moving in a certain direction images at least a heating means 2 such as a heater for heating the surface of the concrete structure and a change (temperature change) in the amount of infrared energy radiated from the surface of the concrete structure after heating. In the soundness judgment device by infrared method of concrete structure, which is equipped with infrared thermography device,
A first infrared camera 4 that images the initial temperature of the surface of the concrete structure before heating is installed at a position in front of the heating direction of the vehicle body 1 in the direction of travel. A second infrared camera 6 that images a change (temperature change) in the amount of infrared energy radiated from the surface of the concrete structure after heating at a position rearward of the traveling direction is the same as the first infrared camera. It is characterized by being installed with an angle of view.

The invention described in claim 3 is the soundness determination apparatus according to the infrared method of the concrete structure described in claim 2,
A high-vision camera 8 that images the surface of the heated concrete structure is installed at the same angle of view as the second infrared camera 6.

  According to the soundness judgment method by the infrared method of a concrete structure according to the invention described in claim 1, the initial temperature of the surface of the concrete structure before heating is imaged by the first infrared camera 4, The temperature data (Fig. 2) is compared with the temperature data (Fig. 5) obtained by imaging the change (temperature change) of the amount of infrared energy emitted from the surface of the concrete structure after heating. It is possible to remove noise caused by various environmental conditions, such as dirt on the concrete surface, water leakage, condensation, surface deterioration, etc. It is possible to identify and determine a temperature change assumed in a defective portion such as peeling or peeling with high accuracy. As a result, it is possible to easily and accurately specify the defective portion and the peeled portion by the active method, which greatly contributes to preventing a peeling accident.

In addition, the soundness determination device for the concrete structure according to the invention described in claim 2 by the infrared method makes it possible to mechanically easily perform the active method, and to identify the peeling site in the concrete structure over a wide area. Work can be done quickly and accurately, contributing to prevention of peeling accidents.
When the high-vision camera 8 is mounted as in the invention described in claim 3, it is possible to inspect all cracks and other surface defects generated on the surface of the concrete structure, and the object of soundness judgment other than cracks, etc. It is possible to efficiently perform the work narrowed down to the defects.

  For example, as in the invention described in claim 2, the first temperature of the surface of the concrete structure before heating is imaged at a position ahead of the traveling direction of the heating means 2 of the vehicle body 1 moving in a certain direction. Infrared camera 4 is installed, and a change (temperature change) in the amount of infrared energy radiated from the surface of the concrete structure after heating is provided at a position behind the heating means 2 of the vehicle body 1 in the traveling direction. A soundness determination device in which the second infrared camera 6 to be imaged is installed with the same angle of view as the first infrared camera 4 is used to travel along a surface of the concrete structure to be inspected in a certain direction. . First, the initial temperature of the surface of the concrete structure before heating is imaged by the first infrared camera 4, and then the surface of the same concrete structure is radiated from the surface of the concrete structure after being heated by the heating means 2. The change in the amount of infrared energy is imaged with the second infrared camera 6, and the total of the temperature distribution after heating obtained from each infrared thermal image and the total of the initial temperature distribution before heating are compared and examined for soundness. Identification and determination of parts and defective parts.

Next, examples of the present invention will be described.
FIG. 1 shows an embodiment of a soundness determination device for a concrete structure according to the invention according to claim 1 by the infrared method for the concrete structure according to the invention according to claim 2. Show.
The soundness determination device 10 is, for example, a vehicle having a self-propelled ability capable of speed control and a steering mechanism, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2002-257744), or known. A panel heater 2 as a heating means is installed in the center of one side surface of the vehicle body 1 of the vehicle traveling on the track so as to face the concrete wall surface of the tunnel to be inspected, for example. The infrared thermography device 3 for imaging the change (temperature change) of the amount of infrared energy radiated from the surface of the concrete structure immediately after being heated by the panel heater 2, which is equipped with all other necessary equipments, the so-called infrared method It is configured as a measuring vehicle.

  In particular, a first infrared camera 4 for imaging the initial temperature of the surface of the concrete structure before heating is installed on one side of the machine base 5 at a position on the front side in the vehicle traveling direction from the position of the panel heater 2. ing. Then, a change (temperature change) in the amount of infrared energy radiated from the surface of the concrete structure immediately after heating is imaged at a position behind the panel heater 2 on the same vehicle body 1 in the traveling direction of the vehicle. The second infrared camera 6 is installed on the machine base 7 with the same angle of view as the first infrared camera 4. Furthermore, on the same machine base 7, with the same angle of view as the second infrared camera 6, it is possible to photograph and inspect defects exposed on the surface of the concrete structure, including cracks that appear on the surface of the concrete structure. A high-definition camera 8 is also installed. Of course, the configuration is not limited to this. For example, two infrared cameras 24 and 25 can be installed as a set so that wide-angle imaging is possible.

  Accordingly, the front and rear infrared cameras 4 and 6 in the infrared thermography device 3 are caused to generate heat and cause the soundness determination device 10 to travel along the surface of the concrete structure to be inspected at a constant speed. First, the initial temperature of the surface of the concrete structure before heating is imaged by the first infrared camera 4 and then the concrete structure immediately after being heated by the panel heater 2 of the same concrete structure. The change (temperature change) of the amount of infrared energy radiated from the surface can be imaged by the second infrared camera 6.

As described above, the infrared thermal images captured by the first and second infrared cameras 4 and 6 of the soundness determination device 10 are converted into temperature data by a so-called computer processing system 100 illustrated in FIG. For example, temperature distribution data as shown in FIGS. 3 and 6 is obtained. The computer processing system 100 includes an input device 101 composed of a keyboard, a mouse and an interface for capturing captured images, an output device 102 composed of a monitor and a printer, a central processing unit 103 composed mainly of a CPU, a hard disk and a magnetic device. The storage device 104 includes a writable storage medium such as a disk and a drive device.
Therefore, the computer processing system 100 is a so-called stand-alone personal computer, and not only a custom-made computer but also a general personal computer or a general-purpose computer is preferably used.

The central processing unit 103 is operated by an image processing unit that performs operations such as capturing captured infrared images and converting them into temperature data, and an arithmetic processing unit that performs operations such as temperature data of temperature distribution. And a comparison / determination unit that compares the respective data to determine the soundness level. The storage device 104 records and stores data such as all captured and captured moving image data, all captured still image data, temperature distribution data, temperature data, and the like.
FIG. 2B shows a processing flow for implementing the soundness determination method by the infrared method according to the invention described in claim 1. Hereinafter, the processing content will be described along the processing flow.
Steps A to C are for acquiring data of a concrete structure necessary for soundness determination, and are the contents of steps performed by the soundness determination device 10 in one run.
In step A, the first infrared cameras 4 and 4 image the initial temperature of the surface of the concrete structure as the soundness determination apparatus 10 shown in FIG. 2 travels.
Immediately in step B, the surface of the concrete structure is heated by the panel heater 2 mounted at an intermediate position of the soundness level determination device 10.
Subsequently, in step C, the second infrared cameras 6 and 6 of the soundness determination apparatus 10 image changes in the amount of infrared energy radiated from the surface of the concrete structure after heating.

In step D, the image processing unit of the central processing unit 103 performs analysis / aggregation of the infrared thermal image captured in steps A to C. Hereinafter, a specific description will be given with reference to FIGS.
In short, FIG. 3 shows the temperature distribution for each mass obtained by dividing the object to be photographed into a size of 50 cm square by taking an infrared thermal image as an example. The temperature distribution data of FIG. 3 is created in a temperature distribution tabulation table as shown in FIG. 4 by counting the number of temperature distributions by further computer processing. In short, in FIG. 4, the temperature distribution data in FIG. 3 is tabulated such that there are 11 cells at a temperature of 19 ° C. and 5 cells at a temperature of 20 ° C.
The tabulation table of FIG. 4 can be further created in the temperature distribution graph of FIG. According to this graph, it is obvious that the most frequent temperature distribution before heating is 19 ° C.

  For the infrared thermal image captured by the second infrared camera 6, for example, temperature distribution data as shown in FIG. 6 is obtained by the same computer processing. In short, FIG. 6 also shows the temperature distribution for each mass obtained by dividing the infrared thermal image into, for example, a size of 50 cm. The temperature distribution data of FIG. 6 is created in a temperature distribution tabulation table as shown in FIG. 7 by counting the number of temperature distributions by further computer processing. In short, FIG. 7 is a summary in FIG. 6 where there is one mass at a temperature of 19 ° C., five masses at a temperature of 21 ° C., seven masses at a temperature of 22 ° C., and six masses at a temperature of 23 ° C. It is the result of having performed. The tabulation table of FIG. 7 can be further created in the temperature distribution graph of FIG. According to FIG. 8, it is obvious that the most frequent temperature distribution after heating is 22 ° C.

Next, in Step E, the comparison / examination of the temperature data before and after heating is performed by the comparison / examination unit of the central processing unit 103. The essence of the temperature data processing in the present invention is based on the temperature distribution data of FIG. 3 and FIG. 6 obtained by imaging the same portion of the surface of the concrete structure to be inspected. The comparison and subtraction process in which the initial temperature in FIG. 3 is subtracted from the post temperature is also performed as a computer process. The specific description is given below based on the drawings.
FIG. 9 shows a temperature data distribution obtained by subtracting the initial temperature from the post-heating temperature for each of the corresponding cells in FIGS. 3 and 6. For example, the mass in the upper left corner of FIGS. 3 and 6 will be described. Since the temperature after heating in FIG. 6 is 20 ° C. and the initial temperature in FIG. 3 is 19 ° C., the temperature after subtraction is 1 ° C. . The temperature distribution data in FIG. 9 is created in a temperature distribution tabulation table as shown in FIG. 10 by counting the number of temperature distributions by further computer processing. Further, the temperature distribution graph as shown in FIG. 11 is created as described above.

As already explained in the section on the problem to be solved (paragraph 0008), if there are defects such as jumpers or cavities in the surface layer of the concrete structure to be inspected, these defects are structurally defined as an air layer (defect layer). , Void layer). Therefore, when these defective parts are heated, the air layer is present, so that the degree of heat diffusion is lower than that of the healthy part and the temperature is not easily lowered. That is, the difference in the temperature distribution between the defective portion and the healthy portion (for example, the numbers in the comparative temperature distribution data in FIG. 9) is significantly significant.
As a result, in FIG. 12 corresponding to FIG. 14, when the defective portion is “junker”, as shown in the result of processing by the soundness determination method of the present invention, the “healthy portion” where the temperature is likely to drop is shown. In comparison, the most frequent values, median values, etc., representing “defects = jumpers” that are less likely to decrease in temperature appear concentrated and rising, and appear to the right (high temperature side) with a temperature difference, so everyone At first glance, it is possible to recognize and determine the presence of the defect (see the difference from FIG. 14).

Exactly in the same manner as FIG. 13 corresponding to FIG. 15, when the defective portion is “internal cavity”, the result of processing by the soundness determination method of the present invention is shown. The most frequent value, median value, etc., which represent “defect = internal cavity”, which is less likely to decrease the temperature, appear on the right side (high temperature side) with a clear temperature difference. Thus, the presence of the defective portion can be recognized and determined (see the difference from FIG. 15).
In step F, the result of the soundness determination made in step E is visualized so that the inspector can visually check it, and is output by the monitor or printer of the output device 102. As a form of visualization, for example, the determination result may be displayed for each temperature distribution for each mass divided into the size of 50 cm described above with reference to FIGS. 3 and 6.

It is the figure which showed the concept of the structure of the soundness determination apparatus. FIG. 1A is a schematic diagram showing an entire system for carrying out the present invention. B is a processing flowchart of the soundness determination method by the infrared method of the present invention. It is a figure which shows an example of the initial temperature data before a heating. It is the figure which showed the temperature distribution totalization table | surface of the temperature data of FIG. FIG. 5 is a graph of the temperature distribution summary table shown in FIG. 4. It is the figure which showed an example of the temperature data after a heating. It is the figure which showed the temperature distribution totalization table | surface of the temperature data shown in FIG. FIG. 8 is a graph of the temperature distribution summary table shown in FIG. 7. It is the figure which showed the temperature data which deducted the temperature before a heating from the temperature after a heating. It is the figure which showed the temperature distribution totalization table | surface of the temperature data shown in FIG. It is the figure which graphed the temperature distribution totalization table shown in FIG. It is a graph which shows the healthy part and defective part in the case of the jumper which deducted the temperature data before a heating after heating. It is a graph which shows the healthy part and defective part in the case of the internal cavity which deducted the temperature data before a heating after heating. It is a graph which shows a healthy part and a defective part in the case of a jumper by the temperature data after a heating. It is a graph which shows a healthy part and a defective part in the case of an internal cavity by the temperature data after a heating.

Explanation of symbols

2 Panel heater 4, 6 Infrared camera 8 Hi-vision camera

Claims (3)

The surface of the concrete structure is heated, changes in the amount of infrared energy (temperature change) radiated from the surface of the concrete structure after heating is imaged with an infrared camera, and the temperature distribution obtained from the infrared thermal image is tabulated. In the method of analyzing and identifying and judging the sound part of the concrete structure and the abnormal part,
First, the initial temperature of the surface of the concrete structure before heating is imaged with an infrared camera, then the surface of the same concrete structure is heated, and the change in the amount of infrared energy radiated from the surface of the concrete structure after heating (temperature change) ) With an infrared camera, and compare and examine the total temperature distribution after heating obtained from each infrared thermal image and the total initial temperature distribution before heating to identify and determine healthy and defective areas. A method for determining the soundness of a concrete structure by an infrared method, characterized by Heating means such as a heater that heats at least the surface of the concrete structure on the body moving in a certain direction, and infrared thermography that images changes in the amount of infrared energy (temperature change) emitted from the surface of the concrete structure after heating In the soundness judgment device by infrared method of concrete structure, which is equipped with the device,
A first infrared camera for imaging the initial temperature of the surface of the concrete structure before heating is installed at a position in front of the heating means of the vehicle body in the direction of travel, and the traveling direction of the vehicle body from the position of the heating means of the vehicle body A second infrared camera that captures a change (temperature change) in the amount of infrared energy radiated from the surface of the concrete structure after heating is installed at the rear position with the same angle of view as the first infrared camera. A soundness determination device for a concrete structure by an infrared method.   The sound property of the concrete structure according to claim 2, characterized in that a high-definition camera is installed to image the surface of the heated concrete structure with the same angle of view as the second infrared camera. Degree determination device.

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