JP3316467B2 - Infrared image inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention utilizes infrared imaging techniques are those related to the infrared image inspection how to inspect cavities or fractures inherent in various structures.

[0002]

Based on the Background of the Invention FIGS. 3 to 7, an infrared imaging technique conventional infrared video inspection method utilizing the (thermography method) will be described. Incidentally, FIG. 3 shows an example of the configuration of the inspection apparatus, showing a data example by the inspection apparatus of FIG. 3 in FIG.

In FIG. 3 , reference numeral 51 denotes an infrared camera, which senses infrared rays radiated from various positions of an object and displays a voltage (or current) corresponding to the intensity of the infrared rays as a video signal as a video signal on a display unit 53 of an infrared video processor 52. Output display.

Reference numeral 72 denotes a component of a structure to be inspected, that is, an object, and reference numeral 73 denotes a cavity existing in the object 72 and to be detected as an abnormal article.

[0005] A plurality of heaters 54 are arranged at suitable positions for inspection in accordance with the size and shape of the object 72, and emit light (including infrared) energy to emit the object 72.
Heat the surface.

Reference numeral 110 denotes a controller, 20 denotes a start button mounted on a panel surface of the controller 110,
61, 62, 63 are cables for connecting the respective devices,
Reference numeral 111 denotes a table on which the object 72 is set.

In general, when a cavity 73 is present in a component (object 72) of a structure, there is a problem in the strength of the structure and the like, and it is desirable to inspect the presence or absence of this by some method. It is.

The inspection apparatus shown in FIG. 3 is an apparatus for detecting the internal cavity. In this figure, the heater 54 is provided with a predetermined time interval only when the start button 20 of the controller 110 is pressed by the operator. And supplies a signal to the infrared video signal processor 52 at an appropriate timing.

The infrared video signal processor 52 fetches an infrared video signal from the infrared camera 51 during a period in which it operates upon receiving a signal from the controller 110, and
3 displays an image.

The infrared camera 51 faces the portion of the object 72 to be inspected, and is arranged so that the portion to be inspected is displayed on the display unit 53 as an appropriate image.
It outputs a video signal of a voltage (or current) corresponding to the intensity of infrared rays radiated from the surface of each position of the target 72.

[0011] According to the law of Stefan Boltzmann,
An object always emits infrared light having an intensity corresponding to the temperature of the object from its surface, and the intensity of the emitted infrared light increases as the temperature of the object increases.

Now, when the outer surface of the object 72 is uniformly heated, each point near the surface of the object tries to uniformly increase the temperature and transfers heat toward the center of the object 72. Then, the temperature of each point near the surface starts to decrease.

[0013] Among solids and gases, solids have a higher thermal conductivity, and portions where solids are originally replaced by gas, such as cavities, have low thermal conductivity and are therefore hollow. The degree of decrease in the temperature of each point near the adjacent surface per unit time is reduced.

Therefore, when the periphery of the cavity 73 of the object 72 is to be inspected, even if the outer surface of the object 72 is uniformly heated, the cavity 73 is not heated at the moment of heating and within a short time range after heating. The temperature of the outer surface of the part close to is higher than the other parts.

When the temperature of the outer surface increases, the intensity of infrared rays radiated from each point increases, and the infrared camera 51 senses high intensity infrared rays from the outer surface of the high-temperature portion. By processing and displaying on the display unit 53, the underlying cavity 73 can be identified.

The detection sensitivity includes the magnitude of the heating energy (generally, the greater the heating energy, the better the detectability), the magnitude of the absorptivity of the outer surface of the object 72 to the light energy, the timing of heating and observation, etc. The instantaneous relationship between heating and observation (data acquisition) must also be carefully considered.

The controller 110 shown in FIG. 3 has a role of keeping the time relationship between heating and observation constant, and the operator presses the start button so that the heater 54 is pressed.
And sends a signal to the infrared video signal processor 52 to take in data and to process and display it.

When the object 72 has a cylindrical shape, it is difficult to inspect the entire surface by one observation, and the operator rotates the object 72 to perform heating and observation, and furthermore, rotates the object 72 slightly to perform heating and observation. Observation is repeated and the entire surface is inspected.

In order to improve the detectability of the cavity 73, it is necessary to heat the outer surface of the object 72 as uniformly as possible.
A plurality of units are used as shown in FIG. 3 according to the shape and the like.

[0020] FIG. 4 (a) is obtained in the periphery of the cavity 73 of the object 72, the image of the display unit 53 of the infrared image signal processor 52, (b) the temperature distribution in the vertical direction of the display unit 53 at that time And (c) show the temperature distribution in the horizontal direction.

[0021] 34 in FIG. 4 (a) is a shape obtained displayed object as an infrared image, the portion where the temperature is displayed high 33, 53 is a display unit shown in FIG. 3, further detail speaking in FIG. 4 (b) shows the temperature distribution in the vertical direction can be read from the object 72 by the infrared image at the position Xb of FIG. 4 (a), FIG. 4 (c) likewise located Ya shown in FIG. 4 (a) 5 shows the temperature distribution in the horizontal direction.

As shown in FIGS. 4 (a), 4 (b) and 4 (c), when the heating of the object 72 and the taking in of data have been performed well, the cavity 73 is displayed on the display unit 53. 3 in which the temperature is displayed high in the displayed shape 34 of the object
3 and the display temperature of other portions is uniform, so that the cavity 73 can be clearly detected.

As described above, the conventional inspection method using infrared rays described with reference to FIGS. 3 and 4 can detect harmful cavities and the like in materials which cannot be identified by eyes and is practically effective. The situation is widely applied to the field.

[0024]

In what INVENTION Problems to be Solved] However the conventional described above, there is a possibility that a problem such as described below is generated on the basis of FIGS.

That is, in FIG. 5 , reference numeral 72 denotes an object, and reference numeral 74 denotes a surface dirt portion existing on the outer surface of the object 72. Further, 34 of FIG. 6 (a), the shape of the resulting object as an infrared image, 33 parts temperature is displayed higher by the presence of cavities 73 and 35, the surface contamination of the object 72 This is the portion where the temperature generated by 74 is displayed high.

[0026] Incidentally, other portions in FIG. 6 (a) ~ (d) is the same as FIG. 3, because the other parts of Figure 5 are the same as FIG. 4, the same reference numerals denote the same parts , And redundant description will be omitted as much as possible.

In FIG. 5 , a case where a surface dirt portion 74 is present on a part of the outer surface of the object 72 (for the sake of simplicity, a case where the absorptivity of this part is higher than other parts will be described) The temperature of the surface contaminated portion 74 is higher than that of other sound portions because of a high absorption rate for light (including infrared) energy.

The surface stains unit 74 temperature is increased by the portion, the portion in the display unit 53 of FIG. 6 (a), is displayed as a portion 35 where the temperature is displayed higher temperature due to inherent cavity 73 is displayed higher Similar to 33, it is displayed as a high temperature part.

[0029] Incidentally, 53 denotes a display unit shown in FIG. 5,
As the depicted graph FIG. 6 (b), the shows the temperature distribution in the vertical direction can be read from the object 72 by the infrared image at position Xb, the graph of FIG. 6 (c), the same position Y
graph of a (part of the cavity) and 6 (d) shows the temperature distribution in the horizontal direction in the same position Yb (site of contamination).

As described above, the rise of the temperature of the outer surface due to the presence of the cavity 73 in one display unit 53 and the surface contamination 7
If the rise in the temperature of the outer surface due to the presence of 4 is displayed, it is difficult to distinguish which is related to which temperature rise.

Here, the case where only one surface dirt portion 74 is present on the outer surface of the object 72 has been described as an example. However, when there are many surface dirt portions 74, a high temperature indicating an increase in the temperature of the outer surface is obtained. It becomes more difficult to distinguish whether the indication of the part is caused by the presence of the cavity 73 or the stain caused by the surface contamination part 74 on the outer surface.

That is, in the above-described conventional method, it is difficult to distinguish a cavity existing in an object from dirt on the outer surface. Is reduced.

In the prior art, the case where the absorptivity for light energy is high at the surface dirt portion 74 on the outer surface has been described. Conversely, the absorptivity for light energy at the surface dirt portion 74 has been described. Is low,
In this case, the temperature of this portion becomes lower, and in this case, the temperature of a sound portion without contamination becomes higher than the temperature of the portion of the surface contamination portion 74.

That is, the cavity 73 is formed in a sound portion free of dirt.
Temperature difference similar to the presence of
It is the same that it is more difficult to determine the presence or absence of the cavity 73 from the obtained data as compared to the case where there is no surface dirt 74.

As a second conventional example, an upper flange 175 is provided above the object 72 and a lower flange 176 is provided below the object 72 as shown in FIG. 7 (other components are shown in FIG. 3) . The same parts as those described above are denoted by the same reference numerals in the drawings, and duplicate description will be omitted.

The upper and lower flanges 175
When it is desired to inspect the lower flange 176 for the presence or absence of cavities, the thermal energy (infrared energy) generated by the heater 54 is transmitted to the upper and lower flanges 175 and 17.
6 not be effectively applied to the horizontal plane of not only effective heat against these surfaces is not performed, the angle observation is difficult from the infrared camera, the shape shown in FIG. 7 There is a problem that an effective inspection cannot be performed on the target object.

The present invention solves these problems of the prior art, and makes it possible to distinguish between the hollow portion and the surface dirt portion to obtain a good detectability, and it is difficult to apply heat energy (infrared energy). It is an object of the present invention to provide a device which can obtain good detection performance even on a surface having an angle where it is difficult to improve the inspection accuracy and the inspection performance.

[0038]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. In the inspection using infrared imaging technology, the surface of an object to be inspected has an absorptivity for light energy and a conductivity for heat. An object is to provide an infrared image inspection method in which a coating rate is high enough to remove disturbance due to dirt or the like on the surface of the object, and then the surface of the object is heated and inspected. It is.

That is, according to the present invention, the surface of the object to be inspected has a sufficiently high absorption rate for light energy and a high conductivity for heat to remove disturbances caused by dirt on the surface of the object. After applying a paint with
Since the surface of this object is heated and the inspection is performed by imaging the infrared rays generated by this, the inspection result is accurate without being affected by disturbance due to dirt on the surface of the object,
This is to improve the accuracy of the inspection .

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. In the present embodiment,
The same parts as those of the above-described conventional one are denoted by the same reference numerals in the drawings, and the characteristic configuration in the present embodiment will be mainly described, and the description overlapping with the conventional one will be limited to the necessary limit. .

In FIG. 1, reference numeral 51 denotes an infrared camera;
Is an infrared video signal processor, 53 is a display portion of the infrared video signal processor, 54 is a heater that emits light (including infrared) energy, 61, 62, and 63 are connected between these devices, A cable provided for transmitting and receiving the data, 110 is a controller, 20 is a controller 110
Start button provided on the panel surface of
Is a table on which the object 72 is placed, and these are the same as those described as the conventional example.

A paint 70 having a high absorption rate for light energy and a high thermal conductivity is applied to the outer surface of the object 72 which is to be inspected.
There is a cavity 73 inherent in the object 72 and a surface stain 74 observed on the outer surface of the object 72 before the paint 70 is applied.

FIG. 2A shows an image on the display unit 53 of the infrared image signal processor 52 obtained around the cavity 73 and the surface dirt part 74 of the object 72, and FIG. The temperature distribution in the vertical direction of the display unit 53 is shown in FIG.
(C) and FIG. 2 (d) show the temperature distribution in the horizontal direction.

In this figure, 53 is the display section shown in FIG. 1, 34 is the shape of the object displayed as an infrared image,
Reference numeral 33 denotes a portion where the temperature is displayed high.

The graph drawn as FIG.
FIG. 2B shows the vertical temperature distribution read from the target object 72 by the infrared image in FIG. 2B, and the graph of FIG. 2C shows the position Ya (the cavity portion), and FIG.
Indicates the horizontal temperature distribution at the position Yc (dirty portion).

In this embodiment, a paint (for example, a graphite release material) 70 having a high thermal conductivity and a high absorptivity for light (including infrared) energy is applied to the entire outer surface of the object 72. Since it is applied, when it is heated from its surface by the superheater 54, even if the outer surface of the object 72 has dirt or the like, and even if this portion has a different light energy absorptivity from other portions, it will not Due to the paint 70 applied to the surface, there is no difference in the absorptance of light energy between the portion of the surface soiled portion 74 and other portions.

Further, since the heat conductivity of the applied paint 70 is high, the heat converted from the light energy given to the object 72 is not only efficiently transmitted to the object 72 but also The temperature distribution on the outer surface appears favorably on the outer surface of the paint 70, whereby the temperature of the portion of the object 72 where the surface dirt 74 is present becomes the same as that of other healthy portions, and disturbance due to dirt is removed. Will be done.

This will be described with reference to FIGS. 2A to 2D showing data according to the present embodiment. The portion 33 where the temperature is displayed high corresponds to the cavity 73 inside the object 72. As a result, a high-temperature portion (a portion where the temperature is displayed higher) due to the surface contamination portion 74 is not recognized.

As described above, the surface of the paint 70 is heated, data is captured, and only the portion corresponding to the cavity 73 is clearly defined as a portion where the temperature is displayed higher in the shape 34 of the object of the display unit 53. Appearing and removing the influence of the surface dirt 74 present on the outer surface of the object 72, the cavity 73 can be clearly detected.

According to the present embodiment as described above,
Apply a paint that has an absorptivity to light energy and a heat conductivity that is high enough to remove disturbance due to surface contamination on the outer surface of the target object, and apply the paint to the entire outer surface of the target object. In addition to removing the influence of the change in the absorptance of the surface with respect to the light energy, the absorptance of the surface with respect to the light energy can be improved to improve the detectability.

In other words, a coating material having a high absorption rate for light (including infrared) energy and a high thermal conductivity (for example, a graphite-based release material, etc.) is applied to the entire surface of the target portion on the outer surface of the target object. ) Is applied, the absorption rate of light energy used as a heating source is made uniform, the influence of dirt on the outer surface of the object is removed, the light energy applied from the heater is efficiently absorbed here, and the temperature of the outer surface is reduced. By increasing the rise and increasing the rise in temperature that appears on the outer surface due to the underlying cavities, the detectability of the underlying cavities can be improved.

Thus, according to the present embodiment, even if the surface of the object has dirt or the like and the absorptance of this portion with respect to the light energy is different from that of other portions, the influence of the dirt or the like is removed and the object is removed. Can be clearly detected, and the practical effect is extremely large .

Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to such an embodiment.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention .

[0054]

As described above, according to the present invention, at the time of inspection using infrared imaging technology, the surface of the object to be inspected has an absorptivity for light energy and a conductivity for heat, which are different from the surface of the object. Infrared image inspection method that applies a paint that is high enough to remove disturbances due to dirt etc. and then heats the surface of the object to perform the inspection, so that the inspection result is Thus, accurate results can be obtained without being affected by disturbance due to dirt on the surface of the object, and the accuracy of inspection can be greatly improved .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an outline of a layout for implementing an infrared image inspection method according to a first embodiment of the present invention.

FIG. 2 shows an outline of the inspection data in FIG.
(A) is an image on the display unit, (b) is a vertical temperature distribution at the position Xb in (a), (c) is a horizontal temperature distribution at the position Ya, and (d) is a horizontal temperature at the position Yc. It is explanatory drawing which shows a distribution.

FIG. 3 is an explanatory diagram showing an outline of a layout for implementing a conventional infrared image inspection method.

FIG. 4 shows an outline of the inspection data in FIG. 3 ;
(A) is an explanatory diagram showing an image on a display unit, (b) is a vertical temperature distribution at a position Xb in (a), and (c) is an explanatory diagram showing a horizontal temperature distribution at a position Ya.

FIG. 5 is an explanatory diagram showing an outline of a layout of an example of occurrence of a defect in a conventional infrared image inspection method.

FIG. 6 shows an overview of the inspection data in that of FIG. 5,
(A) is an image on the display unit, (b) is a vertical temperature distribution at the position Xb in (a), (c) is a horizontal temperature distribution at the position Ya, and (d) is a horizontal temperature at the position Yc. It is explanatory drawing which shows a distribution.

FIG. 7 is an explanatory diagram showing an outline of a layout of another example in which a problem occurs in the conventional infrared image inspection method.

[Explanation of symbols]

Reference Signs List 20 Start button 33/35 Part where temperature is displayed high 34 Shape of displayed object 51 Infrared camera 52 Infrared image signal processor 53 Display unit 54 Superheater 61/62/63 Cable 70 Paint 72 Target object 73 Cavity 74 surface contamination 110 controller 111 sets 175 the upper flange 176 downward flange

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuyuki Watanabe 1-1-155 Higashiko Higashiko, Seirocho, Kitakanbara-gun, Niigata Tohoku Electric Power Co., Inc. 2-1-1, Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory (72) Inventor Kenichiro Takeishi 2-1-1, Arai-machi, Niihama, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory (72) Inventor Keiichi Moriya Takasago, Hyogo Prefecture 2-1-1 Niihama, Araimachi Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Koji Takahashi 2-1-1, Niihama, Araimachi, Takasago-shi, Hyogo Prefecture, Japan Takasago Works, Mitsubishi Heavy Industries, Ltd. 2-1-1, Niihama, Arai-machi, Takasago City Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Ohara Hyogo Prefecture Takasago Araichoshinhama 2 chome No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Works (58) investigated the field (Int.Cl. ^7, DB name) G01N 25/72

Claims (1)

(57) [Claims] 1. In an inspection using infrared imaging technology,
On the surface of the object to be inspected, a paint having an absorption rate for light energy and a conductivity for heat that is high enough to remove disturbance due to dirt or the like on the surface of the object is applied. Infrared image inspection method characterized by performing inspection by heating.