JPH05307013A - Inspecting method using thermographic device - Google Patents

Abstract

PURPOSE:To provide an inspecting method which can make accurate sensing even though a wall surface is contaminated, by the use of a thermographic device. CONSTITUTION:The camera part 2 of a thermographic device is installed at a position where the exterior wall of a building 1 can be seen. The camera part 2 can photograph an infrared image or a visible image selectively by arranging an infrared ray sensor and a visible ray sensor selectively on the optical path. An infrared ray video signal and visible ray video signal obtained by this camera part 2 are sent to a processing device 3 to undergo processing and stored in image memories 4a, 4b as the infrared image data and visible image data. An image processing device 5 to read these stored pieces of data to subject them to image processing is equipped with a display device 6 which displays the results from processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method suitable for use in, for example, inspecting a building exterior wall for peeling by a thermography device.

[0002]

2. Description of the Related Art Recently, it has become widespread to inspect a mortar on an outer wall of a building or a peeling point of a tile by using a thermography device. This inspection method utilizes the fact that the peeled portion has a smaller heat capacity than the sound portion, and therefore has a quick response to an external load. For example, before the morning sunlight hits the wall surface, the sound part and the exfoliation part had almost the same temperature, but when the sunlight starts to hit, the exfoliation part suddenly rises in temperature, while the central part of the building Since the healthy part that is in close contact with the robot slowly rises, if you take an infrared image (temperature distribution image) with a thermography device at an appropriate timing, only the peeled part will be hot and you can distinguish it from the healthy part. is there.

On the contrary, when the wall surface whose temperature has risen due to sunlight during the day goes down in the evening, the temperature of the peeling part drops sharply, while the temperature of the healthy part drops slowly. Only the part becomes cold and it is possible to distinguish it from the healthy part.

[0004]

When performing a peeling inspection using such a thermographic device, there is no problem if the light absorption rate and the emissivity of the wall surface are uniform, but the wall surface is partially black or white. If the absorptivity of sunlight partially changes or the emissivity in the infrared wavelength band measured by the thermography device partially changes due to dirt, that part is displayed as higher or lower temperature than other parts. Therefore, even if it is not actually peeled off, it may be erroneously judged as a peeled portion.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an inspection method using a thermography device which can perform an accurate inspection even if a wall surface is contaminated.

[0006]

In order to achieve this object, a first inspection method using a thermographic device of the present invention is (a) a step of acquiring infrared image data and visible image data for the same visual field. And (b) a step of obtaining contour image data based on a spatial intensity change for both image data, and (c) a step of comparing and displaying two contour images based on the obtained two contour image data. It is characterized by

Further, the second inspection method using the thermographic device of the present invention is such that (a) a step of acquiring infrared image data and visible image data for the same field of view, and (b) both image data are appropriately selected. Binarization based on the threshold level to obtain binarized infrared image data and binarized visible image data, and (c) binarized infrared image data and binarized visible image data. And a step of comparing and displaying the binarized infrared image and the binarized visible image.

Furthermore, the third inspection method using the thermographic device of the present invention is such that (a) a step of acquiring infrared image data and visible image data for the same visual field, and (b) both image data are appropriately selected. A step of obtaining binarized infrared image data and binarized visible image data by binarizing based on the threshold level; (c) binarized infrared image data and binarized visible image data And a step of obtaining image data obtained by logically calculating.

[0009]

In the first inspection method using the thermographic device of the present invention, the contour image data obtained by connecting the pixels showing a large intensity change is obtained and obtained for each of the acquired infrared image data and visible image data. Since the two contour images are compared and displayed on the basis of the two contour image data, whether the temperature change caused by peeling is caused by comparing the contour shapes and sizes.
It is possible to determine whether the temperature change is due to dirt.

Further, in the second inspection method using the thermographic device of the present invention, the obtained infrared image data and visible image data are binarized based on appropriate threshold levels, and the binarized infrared image is obtained. Data and binarized visible image data are obtained, and in order to compare and display the binarized infrared image and the binarized visible image based on the obtained binarized infrared image data and the binarized visible image data, By comparing the shapes of the binarized regions, it is possible to determine whether the temperature change is caused by peeling or the temperature change is caused by stains.

Further, in the third inspection method using the thermographic device of the present invention, image data obtained by logically operating the binarized infrared image data and the binarized visible image data is obtained. It is possible to determine whether the temperature change is caused by the peeling or the temperature change is caused by the stain based on the.

An embodiment of the present invention will be described in detail below with reference to the drawings.

[0013]

1 shows an example of an apparatus configuration for carrying out the method of the present invention. In FIG. 1, a camera section 2 of a thermography apparatus is arranged at a position where the outer wall of a building 1 can be seen. The camera unit 2 includes an optical scanning mechanism that scans and collects infrared rays and visible rays from the field of view, and an infrared detector and a visible ray detector that detect the infrared rays and visible rays that are scanned and condensed. For example, an infrared image or a visible image can be selectively taken by selectively disposing two detectors on the optical path.

The infrared image signal and the visible ray image signal obtained from the camera unit 2 are sent to the processing unit 3 and processed, and then stored in the image memories 4a and 4b as infrared image data and visible image data, respectively. It Reference numeral 5 denotes an image processing device for reading out the stored infrared image data and visible image data and performing image processing, and includes a display device 6 for displaying a processing result. Reference numeral 7 is a display device for displaying an image based on the infrared image data and the visible image data stored in the image memories 4a and 4b.

In the above-mentioned structure, first, the outer wall of the building 1 is photographed by using the camera unit 2 to obtain the image memory 4
Infrared image data and visible image data are stored in a and 4b, respectively. As described above, the infrared image data is acquired, for example, by selecting a timing at which the temperature of the peeling portion has risen sufficiently and the temperature of the sound portion has not risen so much since the irradiation of sunlight has started. The visible image data need only be taken in the same field of view under good illumination conditions, and it is not necessary to consider the relationship with the temperature rise. It is assumed that, by this photographing, for example, the infrared image shown in FIG. 2A and the visible image shown in FIG. 2B are stored in the image memories 4a and 4b, respectively. In the infrared image of FIG. 2 (a), high temperature portions H1 and H2 appear, and in the visible image of FIG. 2 (b), a low brightness portion h that appears to be a stain appears. ..

According to the first aspect of the present invention, in the image processing apparatus, as shown in the processing flow chart of FIG. 3, the infrared image data and the visible image data are subjected to, for example, the second derivative processing. By this second-order differentiation processing, a pixel having a large intensity change between adjacent pixels is extracted, and contour image data indicating a contour can be obtained. Then, the obtained infrared contour image data and visible contour image data are sent to the display device 6 and, for example, the infrared contour image and the visible contour image are displayed side by side on the screen of the display device as shown in FIG. If 2
The shape, size, position, etc. of two contour images can be compared. By this comparison, the contour of the high temperature portion appearing in the infrared contour image and the contour of the low brightness portion h in the visible image are shaped,
If the size and the position are substantially the same, it can be determined that the high temperature H1 is not due to peeling but due to dirt. High temperature part H2 with no corresponding in the visible image
It can be judged that there is a high possibility that it is a peeling part. It should be noted that the comparison becomes easier if not only the two images are displayed side by side but also different images are displayed in a superimposed manner.

In the second aspect of the present invention, in the image processing apparatus, as shown in the processing flow chart of FIG. 5, binarization processing is performed for each of infrared image data and visible image data. In the binarization process, in the case of an infrared image, the threshold temperature is an intermediate temperature level that can distinguish the high temperature part in the infrared image from the surrounding low temperature part, and in the case of a visible image,
A threshold level is an intermediate intensity level that can distinguish a low-luminance portion in a visible image from a high-luminance portion in the surroundings. The infrared image data and the visible image data after the binarization processing are sent to the display device 6, and for example, the binarized infrared image and the binarized visible image are displayed on the screen of the display device as shown in FIG. When displayed side by side, two binary images can be compared. In FIG. 4B, the high temperature part H of the infrared image is binarized and displayed in white (“1”) and the other part is black (“0”), and the low-luminance part h of the visible image is white (“ 1 ”), and the other part is binarized and displayed as (“ 0 ”). According to this comparison, if the high-temperature portion appearing in the infrared image and the low-luminance portion in the visible image substantially match in shape, size, and position, the high temperature H is not due to peeling but to dirt. You can judge. If they do not match, it can be determined that there is a high possibility that the high temperature portion H is due to peeling.

The comparison becomes easier by performing a logical operation based on two image data of the binarized infrared image and the binarized visible image. For example, when the logical product (AND) of the two images shown in FIG. 4B is obtained and displayed as an image, only the part where white and white overlap is displayed in white, and the logical difference (NOT) is displayed. When obtained and displayed, only the non-matching portions of the two images remain and comparison becomes easy.

In the above embodiment, the case where the temperature rises has been described, but it goes without saying that the same can be applied to the case where the temperature falls.

[0020]

As described in detail above, according to the present invention,
An inspection method using a thermography device that can accurately inspect even if the wall surface is contaminated is realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus configuration for carrying out a method of the present invention.

FIG. 2 is a diagram showing an infrared image and a visible image stored in image memories 4a and 4b.

FIG. 3 is a process flow diagram according to the present invention.

FIG. 4 is a diagram showing an image displayed on a display device 6.

FIG. 5 is a process flow diagram according to the present invention.

[Explanation of reference numerals] 1 building 2 camera unit 3 processing device 4a, 4b image memory 5 image processing device 6 display device

Claims (3)

[Claims] 1. A step of: (a) acquiring infrared image data and visible image data for the same field of view; and (b) obtaining contour image data based on a spatial intensity change for both image data, c) An inspection method using a thermography device, which comprises a step of comparing and displaying two contour images based on the obtained two contour image data. 2. Binarization by: (a) acquiring infrared image data and visible image data for the same field of view; and (b) binarizing both image data based on an appropriate threshold level. Obtaining infrared image data and binarized visible image data, and (c) binarized infrared image and binarized visible image based on the binarized infrared image data and binarized visible image data. An inspection method using a thermographic device, which comprises a step of comparing and displaying. 3. Binarization by: (a) acquiring infrared image data and visible image data for the same field of view; and (b) binarizing both image data based on an appropriate threshold level. A thermographic device comprising: a step of obtaining infrared image data and binarized visible image data; and (c) a step of obtaining image data obtained by logically operating the binarized infrared image data and the binarized visible image data. The inspection method used.