Deterioration detection device and deterioration detection system

Abstract

Obtain more detailed information regarding the deterioration of the paint film. [Solution] The deterioration detection device comprises a filter that transmits infrared light in a specific wavelength range, and an imaging unit that captures an infrared image from the mid-infrared light that has passed through the filter, among the mid-infrared light reflected or emitted from the coating film formed on the surface of the object to be inspected. Based on the infrared image captured by the imaging unit, the deterioration state of the coating film is detected as a two-dimensional distribution.

Description

Technical Field

[0001] The present invention relates to a deterioration detection device and a deterioration detection system.

Background Art

[0002] Patent Document 1 describes a coating film deterioration detection method for detecting the consumption of a first layer by utilizing the spectral characteristics of a first layer applied to a base material and located on the outermost side and a second layer located directly below the first layer in a coating film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, a coating film made of a resin paint or the like is formed on the surface of outdoor equipment for the purpose of improving weather resistance and the like. The coating film is deteriorated by loads such as wind, rain, and solar radiation, and its performance deteriorates, so it is necessary to perform repairs such as repainting the paint. However, with conventional deterioration detection methods, it is difficult to obtain detailed information regarding the deterioration of the coating film, so it is impossible to appropriately determine the necessity of repair, and there is a risk that the maintenance and management costs will increase. An object of the present invention is to obtain more detailed information regarding the deterioration of a coating film.

Means for Solving the Problems

[0005] The invention according to claim 1 includes a filter that transmits infrared rays in a specific wavelength range, and an imaging unit that captures an infrared image from the mid-infrared rays that have passed through the filter among the mid-infrared rays reflected or radiated from a coating film formed on the surface of an inspection target, and based on the infrared image captured by the imaging unit, detects the deterioration state of the coating film as a two-dimensional distribution. It is a deterioration detection device. The invention described in claim 2 is a deterioration detection device according to claim 1, wherein the filter transmits infrared rays in a wavelength range in which the absorbance changes due to the deterioration of the coating film. The invention described in claim 3 is a degradation detection device according to claim 2, wherein the wavelength region in which the absorbance changes is determined from the infrared absorption characteristics of the coating obtained by Fourier transform infrared spectroscopy. The invention described in claim 4 is a deterioration detection device according to claim 1, which detects a change in the chemical bonding state of the coating film. The invention described in claim 5 is a deterioration detection device according to claim 1, which detects a temperature difference due to the physical deterioration of the coating film. The invention described in claim 6 is the deterioration detection device described in claim 1, wherein the filter is selected according to the type of coating film. The invention described in claim 7 is a degradation detection device according to claim 1, further comprising: an illumination that emits a reference signal including periodic fluctuations; a near-infrared camera that acquires the reference signal emitted by the illumination; and a processing unit that performs a process to extract a reflected component from the mid-infrared light transmitted through the filter based on the reference signal acquired by the near-infrared camera. The invention described in claim 8 is a deterioration detection device according to claim 1, further comprising: a calculation unit that calculates the degree of deterioration of the coating film from the two-dimensional distribution; and a determination unit that determines whether or not repair is appropriate based on the degree of deterioration calculated by the calculation unit. The invention described in claim 9 is a deterioration detection system comprising: a filter that transmits infrared light in a specific wavelength range; an imaging unit that captures an infrared image from mid-infrared light that has been transmitted through the filter, among the mid-infrared light reflected or emitted from a coating film formed on the surface of a target to be inspected; and a processing unit that acquires the infrared image from the imaging unit and performs processing to detect the deterioration state of the coating film as a two-dimensional distribution. The invention described in claim 10 is a degradation detection system according to claim 9, comprising an illumination that emits a reference signal including periodic fluctuations, and a near-infrared camera that acquires the reference signal emitted by the illumination, wherein the processing unit extracts a reflected component from the mid-infrared light transmitted through the filter based on the reference signal acquired by the near-infrared camera and performs a process to detect degradation. The invention described in claim 11 is the deterioration detection system according to claim 9, further comprising a display unit for displaying the two-dimensional distribution. [Effects of the Invention]

[0006] According to the present invention, more detailed information regarding the deterioration of the coating film can be obtained. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example configuration of the degradation detection system according to this embodiment. [Figure 2] This figure shows an example of a computer hardware configuration used as a server. [Figure 3] This figure shows an example of the server's functional configuration. [Figure 4] This figure shows an example of the relationship between paint film deterioration and absorbance. [Figure 5] This figure shows the relationship between the degradation of polyurethane coatings and their absorbance. [Figure 6] This figure shows the detection results of polyurethane coating degradation using a wide-band filter. (a) shows the relationship between the UV irradiation period and the reflectance lock-in value, and (b) shows the relationship between the infrared absorption integral value and the reflectance lock-in value. [Figure 7] This figure shows the detection results of polyurethane coating degradation using a narrow-band filter. (a) shows the relationship between the UV irradiation period and the reflectance lock-in value, and (b) shows the relationship between the infrared absorption integral value and the reflectance lock-in value. [Figure 8] This figure shows an example of the degradation detection process performed on the server. [Figure 9] This figure shows an example of displaying an infrared image and the judgment result. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described in detail below with reference to the attached drawings. <Configuration of the deterioration detection system> FIG. 1 is a diagram showing a configuration example of a deterioration detection system 1 according to the present embodiment. The deterioration detection system 1 detects the deterioration state of a coating film formed on the surface of a subject 200 that is the inspection target. The deterioration detection system 1 includes a mid-infrared camera 10, a filter 30, an active illumination 40, a near-infrared camera 50, a server 80, and a user terminal 90. The mid-infrared camera 10, the active illumination 40, and the near-infrared camera 50 are connected to the server 80 and the user terminal 90 via a network 70.

[0009] The mid-infrared camera 10 senses light in the mid-infrared region, captures an image of the subject 200 that is the inspection target, and generates an infrared image. The light in the mid-infrared region is generally light in a wavelength region of 2.5 to 5.0 μm. In the present embodiment, a filter 30 is attached to the mid-infrared camera 10, and an infrared image is generated from the light transmitted through the filter 30. In the mid-infrared region, in addition to the reflected infrared rays from the surface of the subject 200, the infrared rays radiated according to the temperature of the subject 200 also enter the mid-infrared camera 10.

[0010] The mid-infrared camera 10 converts the amount of energy of the infrared rays reflected and radiated by the subject 200 into luminance to generate an infrared image. The generated infrared image includes information on the amount of energy of the infrared rays reflected and radiated by the subject 200. Note that the infrared image according to the present embodiment may be an image captured as a still image or an image corresponding to one frame of a video captured as a moving image. The mid-infrared camera is an example of an imaging unit.

[0011] The filter 30 selectively transmits infrared rays in a specific wavelength region. The filter 30 is attached to, for example, the lens portion of the mid-infrared camera 10. The mid-infrared camera 10 generates an infrared image from the infrared rays in a specific wavelength region transmitted through the filter 30. The filter 30 is selected according to the type of the coating film formed on the surface of the subject 200. The filter 30 is selected to have the property of transmitting infrared rays in the wavelength region where the absorbance changes due to the deterioration of the coating film. The selection of the filter will be described in detail later.

[0012] The active illumination 40 emits a reference signal including periodic fluctuations. As the active illumination 40, for example, a video lamp using a halogen lamp is used. The irradiation time of the active illumination 40 is controlled using, for example, a device including a solid-state relay, and the illuminance fluctuates periodically. For example, the blinking period of the active illumination 40 is set to repeat a lighting time of 1.0 seconds and a lighting-off time of 1.5 seconds.

[0013] The near-infrared camera 50 senses light in the near-infrared region. The light in the near-infrared region is light in the wavelength region of 0.7 to 2.5 μm. In the near-infrared region, the infrared rays radiated from an object are minute. Therefore, the infrared rays reflected from the subject 200 are incident on the near-infrared camera 50. The near-infrared camera 50 acquires the reference signal emitted from the active illumination 40 and reflected by the subject 200.

[0014] The network 70 is an information communication network that undertakes communication among the mid-infrared camera 10, the active illumination 40, the near-infrared camera 50, the server 80, and the user terminal 90. The type of the network 70 is not particularly limited as long as data can be transmitted and received, and for example, it may be the Internet, a LAN (Local Area Network), a WAN (Wide Area Network), or the like. The communication line used for data communication may be wired or wireless. Also, a configuration in which each device is connected via a plurality of networks or communication lines may be adopted.

[0015] The server 80 acquires the time-series data photographed by the mid-infrared camera 10 and the near-infrared camera 50. Then, multi-wavelength lock-in processing is performed based on the acquired time-series data to detect the deterioration of the coating film that is the inspection target. Multi-wavelength lock-in processing is a lock-in process that uses time-series data measured by infrared cameras with different sensitivity wavelengths as a reference signal. Multi-wavelength lock-in processing is performed using reference signals in various wavelength bands that match the degradation being detected.

[0016] Lock-in processing is a process that extracts the variable component with reduced random noise by integrating it with a reference signal related to the variation in variable data that contains random noise. For example, by applying forced infrared energy to the object being inspected by irradiating it with infrared light, it is possible to evaluate coating degradation even in environments affected by ambient light. However, if there are areas within the measurement area that are affected by ambient light and areas that are not, simply irradiating the entire measurement area with infrared light will not cancel out the effects of differences in lighting conditions.

[0017] When infrared illumination is repeatedly applied, a similar degree of fluctuation in infrared intensity occurs within the illuminated area, regardless of whether or not ambient light is present. By extracting the waveform of the flashing period of the infrared illumination from a specific area within the infrared measurement field of view, it is possible to detect only the fluctuations in infrared intensity caused by the infrared illumination. In this embodiment, the subject 200 is illuminated by an active light source 40 with a reference signal that includes periodic fluctuations. The server 80 acquires the reference signal from the near-infrared camera 50 and performs lock-in processing, thereby extracting the reflected component from the infrared time-series data, which includes the reflected and emitted components, measured by the mid-infrared camera 10.

[0018] Furthermore, when extracting the radiation component from the infrared time-series data measured by the mid-infrared camera 10, a lock-in process is performed using a far-infrared camera that senses light in the far-infrared region. The far-infrared region light used here refers to, for example, light in the wavelength range of 8.0 to 1000 μm, and the far-infrared camera senses light in the wavelength range of, for example, 8.0 to 20 μm. The server 80 performs a lock-in process using the time-series data measured by the far-infrared camera as a reference signal and extracts the radiation component from the infrared time-series data measured by the mid-infrared camera 10.

[0019] When detecting chemical degradation such as changes in chemical bonding states, the server 80 extracts the reflective component from the time-series infrared data measured by the mid-infrared camera 10. The server 80 then detects the change in chemical bonding states. When detecting physical deterioration such as peeling or cracking of the paint film or rust beneath the paint film, the server 80 extracts the radiation component from the infrared time-series data measured by the mid-infrared camera 10. The server 80 also detects temperature differences caused by physical changes. By separating and extracting either the reflective or radiant component from measurement data that captures both reflective and radiant components, the state of degradation can be detected in more detail.

[0020] Server 80 uses multi-wavelength time-series data and performs lock-in processing to separate and extract the reflected and emitted components of infrared intensity fluctuations caused by the active illumination 40 from the time-series data of the mid-infrared camera 10. It then quantitatively evaluates the degree of paint deterioration in the mid-wavelength infrared region. Server 80 also outputs the deterioration detection results to the user terminal 90. Server 80 is an example of a processing unit. The functional configuration of Server 80 will be described in detail later.

[0021] The user terminal 90 is a terminal operated by a user using the degradation detection system 1. The user terminal 90 obtains the degradation detection results from the server 80 and displays them on the screen of the user terminal 90. The screen of the user terminal 90 is an example of a display unit. The user terminal 90 may also have a function to give instructions regarding the operation of the mid-infrared camera 10, active illumination 40, and near-infrared camera 50.

[0022] Figure 2 shows an example of the hardware configuration of computer 800 used as server 80. The computer 800 comprises a CPU (Central Processing Unit) 801, RAM (Random Access Memory) 802, and ROM (Read Only Memory) 803. RAM 802 is volatile memory used as a work area when the CPU 801 executes programs. ROM 803 is non-volatile memory that stores programs and other data executed by the CPU 801. The CPU 801 uses RAM 802 as a work area and executes programs read from ROM 803.

[0023] Furthermore, the computer 800 includes a network interface 804 for communication over the network and a display mechanism 805 for displaying output to the user terminal 90. The CPU 801 is a processor that controls the functions of the measuring device 1 through the execution of various software such as the OS (operating system) and application software. In this embodiment, each process is executed on an arbitrary computer.

[0024] Any computer may be implemented as a processor as hardware, a program as software, or a combination thereof. Any computer may be a general-purpose computer, a computer designed for a specific purpose, a workstation, or any other system capable of performing each of these processes. The processor is configured to perform various processes in cooperation with the program. The processor can function as each unit or each means in this embodiment. The execution order of the processes performed by the processor is not limited to the order described in this embodiment and can be changed as needed.

[0025] A processor can be composed of one or more hardware components. The types of hardware that make up a processor are not limited to any particular type. For example, a processor may consist of hardware such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), FPGA (Field Programmable Gate Array) or other programmable logic devices, ASIC (Application Specific Integrated Circuit) or other dedicated circuits for performing specific processing, GPU (Graphic Processing Unit), or NPU (Neural Processing Unit).

[0026] A processor can be configured not only with a combination of multiple hardware components of the same type, but also with a combination of multiple hardware components of different types. When multiple hardware components are configured to perform one or more processes of a given processor, these components may reside in physically separate devices or in the same device. Hardware is composed of electrical circuits and other components, such as semiconductor elements.

[0027] In any embodiment, the execution order of each process by the processor is not limited to the order described in each embodiment, and can be changed as necessary. The program may be firmware, or it may be software such as microcode. The program may also be, for example, a group of program modules. Each function constituting the group of program modules may be implemented by a processor configured to execute each function. The program in each embodiment may be program code or multiple code segments stored in one or more non-temporary computer-readable media (e.g., semiconductor memory, magnetic or optical storage media, or other storage).

[0028] A program may be divided and stored on multiple non-temporary computer-readable media located on devices that are physically separated from each other. Program code and multiple code segments may be represented by any combination of procedures, functions, subprograms, routines, subroutines, modules, software packages, classes, instructions, data structures, and program statements. Program code and multiple code segments may be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents.

[0029] <Server Functional Configuration> Figure 3 shows an example of the functional configuration of server 80. The server 80 includes an infrared image acquisition unit 81, a reference signal acquisition unit 82, a lock-in processing unit 83, a degradation degree calculation unit 84, a determination unit 85, and an output unit 86, all of which are functions executed by the processor CPU 801.

[0030] The infrared image acquisition unit 81 acquires time-series data of mid-infrared images of the subject 200 captured as time-series data from the mid-infrared camera 10. The mid-infrared image is, for example, an image corresponding to one frame of a video. The time-series data acquired by the infrared image acquisition unit 81 includes the reflected and emitted components of the infrared intensity fluctuations due to the influence of the active illumination 40. The reference signal acquisition unit 82 acquires a reference signal as time-series data from the near-infrared camera 50. The reference signal acquired by the reference signal acquisition unit 82 is the reference signal emitted from the active illumination 40 and reflected by the subject 200.

[0031] The lock-in processing unit 83 performs multi-wavelength lock-in processing based on the time-series data acquired by the infrared image acquisition unit 81 and the reference signal acquisition unit 82. The lock-in processing unit 83 performs lock-in processing using the reference signal acquired from the near-infrared camera 50 and separates and extracts the reflective component of the infrared intensity fluctuations due to the influence of the active illumination 40 from the time-series data of the mid-infrared camera 10. The degradation degree calculation unit 84 calculates the degree of degradation of the coating film from the infrared image from which the reflective component has been extracted. The degree of degradation is a numerical representation of the degree of degradation based on predetermined criteria. For example, the degradation degree calculation unit 84 calculates the degree of degradation based on the energy value of the infrared image. For example, the degradation degree calculation unit 84 calculates the area of ​​the portion where the energy value is greater than or equal to a predetermined value as the degree of degradation.

[0032] The determination unit 85 determines whether repairs are necessary based on the calculated degree of deterioration. For example, the determination unit 85 determines that repairs are necessary if the degree of deterioration exceeds a predetermined threshold. The output unit 86 outputs an infrared image from which the reflective component has been extracted to the user terminal 90. The infrared image is a two-dimensional distribution with different brightness levels depending on the degree of deterioration of the subject 200. The output unit 86 may also output the determination result of whether or not the repair is appropriate, as determined by the determination unit 85, along with the infrared image.

[0033] The functions of server 80 may also be performed by the mid-infrared camera 10. The mid-infrared camera 10 may have a CPU with the hardware configuration shown in Figure 2 and perform the functions shown in Figure 3. Alternatively, the system may be configured to eliminate the effects of ambient light by other means. A mid-infrared camera 10 equipped with a filter 30 is an example of a degradation detection device. The degradation detection device may also include an active illumination 40 and a near-infrared camera 50, or it may include a mid-infrared camera 10 equipped with a server 80. Alternatively, the mid-infrared camera 10 and the near-infrared camera 50 may be configured as separate devices, with measurements taken by the near-infrared camera 50 followed by measurements taken by the mid-infrared camera 10.

[0034] <Select a filter> The filter 30 is selected according to the type of coating film formed on the surface of the subject 200. In this embodiment, the subject 200 to be inspected is, for example, the exterior walls of equipment at a liquefied natural gas (LNG) terminal or a steel road bridge. These subjects 200 have a coating film made of polyurethane resin or the like formed on their surface to improve weather resistance. When the coating film made of resin paint is exposed to ultraviolet light, the film thickness decreases. In addition, chemical structural changes mainly due to radical reactions occur on the ultraviolet irradiated surface. Due to these chemical structural changes, the number of molecules on the surface of the coating film increases or decreases, which causes a change in absorbance in a specific wavelength range. The filter 30 is selected to transmit infrared radiation in the wavelength range where the absorbance changes due to the deterioration of the coating film.

[0035] Figure 4 shows an example of the relationship between coating degradation and absorbance. In Figure 4, the horizontal axis represents wavelength (μm), and the vertical axis represents absorbance. The absorption characteristics shown in Figure 4 were obtained by Fourier transform infrared spectroscopy. Figure 4 shows the absorbance measurements at various wavelengths for a certain coating film in three states: (1) new, (2) moderately deteriorated, and (3) deteriorated to the point of requiring repainting. In the example shown in Figure 4, the absorbance changes significantly in the wavelength range X1 to X2 μm according to the deterioration of the coating film. More specifically, the absorbance is high for new coatings and decreases as deterioration progresses. When inspecting the deterioration of such a coating film, a filter 30 that transmits light in the wavelength range X1 to X2 μm is selected.

[0036] When a coating is photographed with a mid-infrared camera 10 using a filter 30 that transmits light in the wavelength range X1 to X2 μm, mid-infrared images with different energy levels depending on the degree of degradation are captured. As a result, image data showing an energy distribution is obtained, with low energy levels in areas with little degradation that are close to new, and high energy levels in areas with significant degradation. Since energy levels are converted into brightness, areas with little degradation appear dark, and areas with significant degradation appear bright. From the energy distribution in the image data, a two-dimensional distribution of the coating degradation state can be detected.

[0037] A method for detecting UV degradation in two dimensions will be explained using Figures 5 to 7, for example, with the case where polyurethane paint is used for the coating. For chemical degradation such as structural changes caused by ultraviolet light, a reference signal is obtained from the near-infrared camera 50 and the degradation is detected by separating the reflective component through lock-in processing.

[0038] Figure 5 shows the relationship between the degradation of a polyurethane coating and its absorbance. In Figure 5, the horizontal axis represents wavelength (μm), and the vertical axis represents absorbance. The absorption characteristics shown in Figure 5 were obtained by Fourier transform infrared spectroscopy. Figure 5 shows the absorbance of a polyurethane coating when not irradiated with ultraviolet light, and when irradiated with ultraviolet light for periods of 1 month, 3 months, 6 months, and 9 months. As shown in Figure 5, the infrared absorption due to ultraviolet degradation of the polyurethane coating decreases as the ultraviolet irradiation period increases at a wavelength of 3.4 μm. Therefore, when detecting the degradation of a polyurethane coating, a filter 30 that includes a wavelength of 3.4 μm in its transmission region is used. Below, we show the case using a wide-band filter with a center wavelength of 3390 nm and a full width at half maximum of 344 nm, and a narrow-band filter with a center wavelength of 3420 nm and a full width at half maximum of 74 nm.

[0039] Figure 6 shows the detection results of polyurethane coating degradation using a wide-band filter. Figure 6(a) shows the relationship between the ultraviolet irradiation period and the reflection separation lock-in value, and Figure 6(b) shows the relationship between the infrared absorption integral value and the reflection separation lock-in value. The reflection separation lock-in value is the energy value of the reflected component separated from the infrared radiation reflected and emitted by the coating by acquiring a reference signal from the near-infrared camera 50 and performing lock-in processing. In Figure 6(a), the horizontal axis represents the period (months).

[0040] Figure 6(a) shows the reflection separation lock-in values ​​for polyurethane coatings when no ultraviolet light is irradiated, and when ultraviolet light is irradiated for periods of 1 month, 3 months, 6 months, and 9 months. As shown in Figure 6(a), a tendency was observed for the reflection separation lock-in values ​​to increase as the irradiation period lengthened. By combining the mid-infrared camera 10 with a wide-band filter, it is also possible to detect initial degradation even with an ultraviolet irradiation period of 9 months or less.

[0041] Figure 6(b) shows the relationship between the integrated infrared absorption in the transmission wavelength range of the wide-band filter and the reflection separation lock-in value in the infrared absorption spectrum shown in Figure 5. As shown in Figure 6(b), a tendency was observed where the reflection separation lock-in value decreased as the integrated value of infrared absorption increased. In the transmission wavelength range of the wide-band filter, the trends of the infrared absorption spectrum and the reflection separation lock-in value were consistent.

[0042] Figure 7 shows the detection results of polyurethane coating degradation using a narrow-band filter. Figure 7(a) shows the relationship between the UV irradiation period and the reflectance lock-in value, and Figure 7(b) shows the relationship between the infrared absorption integral value and the reflectance lock-in value. In Figure 7(a), the horizontal axis represents the period (months).

[0043] Figure 7(a) shows the reflection separation lock-in values ​​for polyurethane coatings when no ultraviolet light is irradiated, and when ultraviolet light is irradiated for periods of 1 month, 3 months, 6 months, and 9 months. Similar to the case shown in Figure 6(a), a tendency was observed for the reflection separation lock-in values ​​to increase as the irradiation period lengthened. By combining the mid-infrared camera 10 with a narrow-band filter, it is also possible to detect initial degradation even with an ultraviolet irradiation period of 9 months or less.

[0044] Figure 7(b) shows the relationship between the integrated infrared absorption in the transmission wavelength range of the narrow-band filter and the reflection separation lock-in value in the infrared absorption spectrum shown in Figure 5. As shown in Figure 7(b), a tendency was observed where the reflection separation lock-in value decreased as the integrated value of infrared absorption increased. Similar to the transmission wavelength range of the wide-band filter, the trends in the infrared absorption spectrum and the reflection separation lock-in value were consistent in the transmission wavelength range of the narrow-band filter.

[0045] The results shown in Figures 6 and 7 demonstrate that multi-wavelength lock-in processing allows for the quantitative evaluation of changes in infrared absorption due to UV degradation using the reflection separation lock-in value. Comparing wide-band filters and narrow-band filters, the narrow-band filter has a narrower transmission wavelength range. Comparing Figure 6(b) and Figure 7(b), it can be seen that initial degradation with UV irradiation periods of 6 months or less can be detected with higher accuracy when using a narrow-band filter. In other words, by focusing measurements on wavelengths where the difference in infrared absorption due to UV irradiation is large, degradation areas can be detected with high efficiency. On the other hand, when using a narrow-band filter, the amount of energy captured by the mid-infrared camera 10 is smaller.

[0046] <Degradation detection process> This section describes the degradation detection process when detecting chemical degradation caused by ultraviolet irradiation. When using the degradation detection system 1 to detect the degradation state of a coating formed on the surface of an object 200 to be inspected, a reference signal is first irradiated onto the object 200 from the active illumination 40. The reference signal reflected by the object 200 is acquired by the near-infrared camera 50, and the reflected and emitted mid-infrared light is captured by the mid-infrared camera 10. Server 80 acquires mid-infrared images captured by the mid-infrared camera 10. It also acquires a reference signal from the near-infrared camera 50. Based on the acquired mid-infrared images and reference signal, it performs a lock-in process to detect deterioration of the target coating.

[0047] The processing flow performed on server 80 will be explained using Figure 8. Figure 8 shows an example of the degradation detection process performed on server 80. In Figure 8, first, the infrared image acquisition unit 81 acquires an infrared image captured by the mid-infrared camera 10 (step 1001). Then, the reference signal acquisition unit 82 acquires a reference signal from the near-infrared camera 50 (step 1002).

[0048] Next, the lock-in processing unit 83 extracts the reflective component through lock-in processing (step 1003). The time-series data acquired from the mid-infrared camera 10 includes infrared intensity fluctuations due to the active illumination 40. The lock-in processing unit 83 separates and extracts the reflective component of the infrared intensity fluctuations by performing lock-in processing using a reference signal acquired from the near-infrared camera 50.

[0049] Next, the degradation degree calculation unit 84 calculates the degree of degradation from the infrared image from which the reflective component has been extracted (step 1004). The degradation degree calculation unit 84 calculates the degree of degradation based on, for example, the energy value of the infrared image. Then, the determination unit 85 determines whether repair is necessary by comparing the degree of degradation with a predetermined threshold (step 1005). The determination unit 85 determines, for example, that repair is necessary if the degree of degradation exceeds a predetermined threshold. Then, the output unit 86 outputs the infrared image and the judgment result (step 1006). The output infrared image and judgment result are displayed on the screen of the user terminal 90.

[0050] An example of the display of infrared images and judgment results on the user terminal 90 will be explained using Figure 9. Figure 9 shows an example of displaying an infrared image and the judgment result. In Figure 9, the case where the subject 200 is rectangular is shown. For simplification, in Figure 9, the subject 200 is displayed divided into two areas: an area that requires repair and an area that does not require repair.

[0051] In infrared images, areas with significant degradation appear brighter, while areas with less degradation appear darker. In the example shown in Figure 9, areas with significant degradation requiring repair are shown in white, while areas with minor degradation that do not require repair are shown in shaded areas. In the example shown in Figure 9, along with the infrared image, the date of capture "yyyy / mm / dd" and the judgment result "The area of ​​the deteriorated part exceeds XX. Paint repair is required." are displayed. Note that these displays are just examples, and other text, images, or audio notifications may also be displayed. Furthermore, the determination of whether repair is necessary is not limited to the area of ​​the deteriorated part, but is determined based on the obtained infrared image and predetermined criteria. [Explanation of Symbols]

[0052] 1…Degradation detection system, 10…Mid-infrared camera, 30…Filter, 40…Active illumination, 50…Near-infrared camera, 70…Network, 80…Server, 200…Subject

Claims

1. A filter that transmits infrared light in a specific wavelength range, The system includes an imaging unit that captures an infrared image from mid-infrared rays that have passed through the filter, among the mid-infrared rays reflected or emitted from a coating formed on the surface of the object to be inspected, Based on the infrared image captured by the aforementioned imaging unit, the deterioration state of the coating film is detected as a two-dimensional distribution. Deterioration detection device.

2. The deterioration detection device according to claim 1, wherein the filter transmits infrared rays in a wavelength range in which the absorbance changes due to the deterioration of the coating film.

3. The degradation detection device according to claim 2, wherein the wavelength region in which the absorbance changes is identified from the infrared absorption characteristics of the coating obtained by Fourier transform infrared spectroscopy.

4. A deterioration detection device according to claim 1, which detects a change in the chemical bonding state of the coating film.

5. The deterioration detection device according to claim 1, which detects temperature differences due to the physical deterioration of the coating film.

6. The deterioration detection device according to claim 1, wherein the filter is selected according to the type of coating film.

7. A light source that emits a reference signal containing periodic fluctuations, A near-infrared camera that acquires the reference signal emitted by the illumination, A processing unit that extracts a reflected component from the mid-infrared light transmitted through the filter based on the reference signal acquired by the near-infrared camera, The deterioration detection device according to claim 1, further comprising:

8. A calculation unit that calculates the degree of deterioration of the coating film from the two-dimensional distribution, A determination unit that determines whether repair is appropriate based on the degree of deterioration calculated by the calculation unit, The deterioration detection device according to claim 1, further comprising:

9. A filter that transmits infrared light in a specific wavelength range, An imaging unit captures an infrared image from mid-infrared rays that have passed through the filter, among the mid-infrared rays reflected or emitted from a coating formed on the surface of the object to be inspected. A processing unit that acquires the infrared image from the imaging unit and performs processing to detect the deterioration state of the coating as a two-dimensional distribution, A degradation detection system equipped with the following features.

10. A light source that emits a reference signal containing periodic fluctuations, The system includes a near-infrared camera that acquires the reference signal emitted by the illumination, The processing unit extracts a reflected component from the mid-infrared light transmitted through the filter based on the reference signal acquired by the near-infrared camera, and performs a process to detect degradation. The deterioration detection system according to claim 9.

11. The deterioration detection system according to claim 9, further comprising a display unit for displaying the two-dimensional distribution.

Images