JPH01321343A - Crack detector for concrete construction - Google Patents

Abstract

PURPOSE:To enable accurate detection of the width of a crack by arranging a black box covering the perimeter of an object desired to detect cracking and a plurality of lighting lamps to irradiating in all bearings provided therein. CONSTITUTION:A front opening of a black box 3 is made to abut the perimeter of a cracking 2 of a housing concrete wall surface 1 and the cracking 2 is taken with a camera device 5 irradiating the cracking 2 and an area in the vicinity thereof with a plurality of lighting lamps 7 in the black box 3 vertically and horizontally. Then, an image of the cracking is processed with an recorder/ processor 6. As a result, shadows due to ruggedness and fouling of the surface of the wall surface 1 otherwise caused by sunlight and natural light are vanished by a forcible lighting from all bearings of the perimeter of the cracking 2 and the shadow alone of the cracking 2 can be caught clearly with the device 5 thereby enabling accurate detection of a width of the cracking 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a crack detection device for concrete structures that detects cracks on the surface of concrete structures using an image capturing device.

[Conventional technology]

Conventionally, as a crack detection device for detecting the crack width on the surface of a concrete structure used for an architectural structure, a civil engineering structure, etc. by photographing an image, for example, as shown in the perspective view of FIG. 4 is a perspective view and FIG. 5 is a partially enlarged side view of a fixed type photographing device in which a fixed photographing device 5 such as a VTR camera or a photographic camera is directed and the images obtained are processed by an image recording processing device 6. As shown in FIG. 4, in this mobile photography method, a photographing device 5 is movably arranged on a concrete wall surface 1 of a house using a moving device 4, and images obtained while moving are processed by a fixed image recording processing device 6. The latter is usually used.

However, the images obtained by these photographing devices 5 include dirt on the concrete surface of the photographed area and sunlight shining on its uneven parts.

Shadow areas due to the influence of natural light are mixed with shadow areas of crack occurrence areas, and when this image is used for image processing or signal processing, it is virtually impossible to isolate only the crack you want to detect and detect its exact width. It is.

[Problem to be solved by the invention]

The present invention was proposed in view of these circumstances, and
To provide a crack detection device for a concrete structure that can eliminate the influence of dirt and unevenness on the concrete surface, obtain an image that clearly shows only the shadow of the crack, and thereby accurately detect the width of the crack. purpose.

[Means to solve the problem]

To be sure of this, the present invention provides a dark box that covers and abuts the surface of the concrete structure where the crack is to be detected, and a dark box that is placed spaced apart from each other in the dark box and irradiates the crack and its vicinity from different directions. multiple lighting lights,
The present invention is characterized by comprising an image photographing device installed substantially in the center of the plurality of illumination lights and directed toward the crack.

[For production]

In the device of the present invention, the area to be detected for cracks is covered with a dark box to eliminate the influence of external light irradiation such as sunlight on the unevenness of the concrete surface. By irradiating the concrete surface from all directions, it is possible to eliminate shadows on the concrete surface and clarify only the shadows of cracks leading from the surface to the lower layer, making it possible to capture images suitable for image processing or signal processing.

〔Example〕

An embodiment of the crack detection device for concrete structures according to the present invention will be explained with reference to the drawings.
Vertical sectional view of the embodiment, FIG. 2 is a vertical sectional view of the second embodiment of the fixed type.

First of all, in Fig. 1, 1 is a 4-house concrete wall surface, 2 is a crack in a 4-house concrete wall surface 1iC, and 3 is a concrete wall surface whose front opening covers the periphery of the crack 2 of the concrete wall surface 1 and is in contact with the moving device 4. 1 is a dark box mounted in a movable manner, 5 is a photographing device such as a VTR camera or a photo camera, which is attached to the center of the back plate of the dark box 3 and is oriented toward the center of the front opening; 6 is a photographic device mounted on the back plate of the dark box. The image recording and processing devices 7 mounted close to the photographing device 5 are spaced apart from each other so as to point approximately at the center of the opening from above and below and/or from the left and right inside the dark box 3. A plurality of lighting lights are arranged above and below and/or left and right.

In such a mobile photographing device, the front opening of the dark box 3 is brought into contact with the periphery of the crack 2 in the concrete wall surface 1 of the four-house concrete wall, and the crack 2 and its vicinity are viewed above, below, and around by a plurality of illumination lights 7 inside the dark box 3. (Or) The crack 2 is photographed by the photographing device 5 while being irradiated from the left and right sides, and the image is processed by the image recording processing device 6.

In this case, the forced illumination from all directions around the crack 2 eliminates the shadows caused by sunlight and natural light on the surface of the concrete wall 1 and the dirt, and only the shadow of the crack 2 is clearly visible with the camera. Caught by it5.

Further, according to this WiC device, it is possible to remotely control the moving device 4 and sequentially take pictures while moving the dark box 3 over a wide range of the concrete wall surface 1 of the building.

Next, in FIG. 2, similarly to FIG. 1, a dark box 3 with a photographing device 5 attached to its back plate and an illumination light 7 arranged inside is placed and fixed on a fixed base 4'. The image recording processing device 6 connected to the photographing device 5 is installed on the floor.

However, in this fixed type photographing device as well, as in the mobile device shown in FIG.

Only the shadow image of crack 2 is clearly captured.

〔Effect of the invention〕

In short, according to the present invention, a dark box is placed in contact with the surface of the concrete structure where the crack is to be detected, covering the periphery of the crack; This method is equipped with a plurality of illumination lights, which are installed approximately in the center of the plurality of illumination lights, and an image capturing device that points toward the crack. INDUSTRIAL APPLICABILITY The present invention is extremely useful industrially because it provides a crack detection device for concrete structures that can accurately detect the width of a crack by obtaining an image in which only the shadow of the crack is clearly defined.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a first embodiment of a mobile crack detection device for concrete structures according to the present invention, and FIG. 2 is a vertical cross-sectional view of a second embodiment of the same fixed type. Figure 3 is a perspective view of a conventional fixed crack detection device;
The figure is a perspective view of the mobile crack detection device, and FIG. 5 is an enlarged side view of part 7 of FIG. 4. 1...4 House concrete wall, 2...Crack, 3
...Dark box, 4...Moving equipment, 4...Fixed stand, 5
... Photographing device, 6... Image recording processing device, 7...
Lighting lamp. Agent: Masa Tsukamoto, Patent Attorney Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A dark box that covers and abuts the surface of the concrete structure in which the crack is to be detected, and a plurality of dark boxes that are spaced apart from each other and that illuminate the crack and its vicinity from different directions. What is claimed is: 1. A crack detection device for a concrete structure, comprising: a lighting lamp; and an image photographing device installed substantially in the center of the plurality of lighting lights and directed toward the crack.