JP2002083283A - Crack damage measuring method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively and easily measure cracks which are generated in a wood face, such as flooring or wall. SOLUTION: In this method, light parallel to the surface of the measured wood face is irradiated in a direction perpendicular to the direction of the cracks. The light scattered on the surface is photographed, nearly linear line segments in equal direction are extracted as the cracks by image processing, and the crack length total or the area total inside a prescribed area is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for measuring and evaluating damage to a wooden surface such as a wooden floor or a wooden wall. The present invention relates to measurement and evaluation of cracks (cracks) on a wooden surface, and particularly relates to a technique for measuring cracks on a flooring surface.

[0002]

2. Description of the Related Art In a multi-family house or a private house, the floor of a living room is often finished with flooring (finishing the floor with a board). Flooring has the advantages of less generation of dust and mites as compared to carpeting and the like, easy maintenance of a clean state, and easy cleaning.

[0003] Since this flooring uses a plate material, cracks (cracks) gradually occur on the surface. Cracks are less noticeable than scratches, which are referred to as life scratches that have been dented by hitting an object, but are important indicators of deterioration of the plate material. Such flooring cracks, for example, near windows that are susceptible to sunlight,
Heat or dryness that may damage the plate material such as the side of the heating equipment,
It is likely to occur in places where there is a lot of contact with water,
Conventionally, no method has been proposed for measuring the extent to which cracks occur on the flooring surface.
In addition, the occurrence of cracks occurs after many years have passed since construction, and no method has been proposed to quantitatively measure the extent to which cracks have actually occurred at the site where they occurred. .

Furthermore, quantitative analysis of cracks is required to analyze the relationship between cleaning and crack generation and the relationship between environmental effects and the like. Quantitative crack measurement methods have been proposed. I didn't.

[0005]

As a conventional method for measuring cracks, there is a method for visually measuring cracks. This is a method of performing a qualitative judgment such as more or less depending on the degree of occurrence of cracks by the visual inspection of a skilled person.In this method, cracks cannot be measured objectively and quantitatively. It cannot be measured. Further, as a method of quantitatively measuring cracks, a method of measuring a crack within a standardized area by a person can be considered. In this method, a certain area of a certain flooring is sectioned, all the cracks generated therein are copied, and the amount of the copied cracks is evaluated. In fact, the inventors worked on applying a transparent sheet from above to a 15 × 15 cm square area and copying the cracks, but it required a great deal of time and concentration. For this reason, it is practically impossible to copy and measure and evaluate cracks generated on the flooring surface at many locations actually used to evaluate the degree of deterioration and damage of the flooring.

Further, the flooring surface is divided into certain sections, and chalk is rubbed into cracks in the sections,
It is also possible to measure the length of cracks that appear white with a ruler and add all the crack lengths,
All of these methods are manually performed, and require much time and effort for the measurement as well as copying the crack.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a method and an apparatus for measuring cracks, which can facilitate quantitative measurement of cracks. Also,
An object of the present invention is to provide a method and an apparatus capable of measuring a crack in a field where the apparatus is actually used. Further, the present invention provides a method and an apparatus capable of calculating the sum of crack lengths generated in a predetermined area or the sum of scattered light areas coming out of cracks, and thereby evaluating the degree of damage or deterioration of a wooden surface. The purpose is to provide.

[0008]

According to the present invention, light parallel to the surface of a wooden surface is output from a lateral direction of a crack, and scattered light scattered on the surface is photographed. The method is characterized in that a component scattered by the existing crack is extracted and a crack amount in a predetermined area is obtained.

Here, when calculating the amount of cracks, it is preferable to obtain the sum of crack lengths or the sum of crack areas.

Further, according to the present invention, there are provided a light source for emitting light parallel to a wooden surface from a lateral direction of a crack, and a photographing means for photographing scattered light in which the parallel light is scattered on the wooden surface. And an information processing apparatus for extracting a component scattered by a crack generated on a wooden surface from the image and obtaining a crack amount in a predetermined area.

[0011] A housing having a rectangular opening to be brought into contact with the wooden surface to be measured is provided. A camera is mounted on the housing so as to face the opening of the housing, and one side of the opening of the housing has a wooden surface to be measured. The light source that emits light parallel to the surface of the light source may be provided.

Further, the information processing apparatus preferably includes means for Hough transforming the image, and means for extracting a line segment that is substantially linear and substantially in the same direction in the image as a crack.

[0013] The information processing apparatus may include means for calculating a sum of crack lengths or a sum of crack areas, and means for outputting an evaluation value of a wooden surface measured by comparing with a predetermined comparison standard. .

The cracks on the wooden surface are fine cracks and can be made substantially linear along the grain direction. For this reason, the crack appears as a line segment in the same direction. Cracks often turn up on the surface, so if you shine parallel light on the surface of the wooden surface, the light will scatter at the crack ridges. This scattered light is photographed, and image analysis is performed using a portion of a bright line in a straight line along the grain in the same direction as a crack, and its length and area are calculated, whereby the amount of crack formed on the wood surface can be measured. Further, by calculating the sum of the crack lengths and the sum of the crack areas in the predetermined area and comparing the sum with the comparison standard, the crack on the measured wooden surface can be evaluated, and the degree of damage can be evaluated.

When measuring a crack, a photographing housing provided with a camera device is applied to the surface of a measured wooden surface to photograph a predetermined section. At this time, light with a length (width) that is parallel to the surface from the side of the wood grain and is almost equal to the side length is applied from one side of the case so that it is scattered linearly by cracks on the surface,
Capture scattered light. At this time, external light is blocked. In the captured image, the scattered light scattered by the crack appears as a linear bright line. Therefore, the information processing apparatus performs a Hough transform on the image data to extract a linear crack portion. This crack portion appears almost linearly and in almost the same direction. Since the length h (length in the grain direction) and the width w can be extracted as the characteristic amount of the crack, the sum of the lengths of the cracks in the measurement area is obtained, and the area (h × w) of each crack is calculated. The sum of the crack areas in the measurement area can be obtained. The value of the sum of the crack lengths and the sum of the areas can be used to evaluate the wooden surface to be measured. At this time, a point other than a crack, for example, scattered by dust appears as a point having no length, and the point having no length is removed as noise.

[0016]

FIG. 1 shows a configuration example. A crack measuring apparatus according to an embodiment of the present invention includes a parallel light source 1 that emits light parallel to the surface of the flooring surface to be measured and perpendicular to the grain direction, and a digital camera that photographs the flooring surface to be measured. 2, an information processing device 3 for performing image processing of a captured image, and an LCD 4 as a display device for displaying the image processing result and the like. The information processing device 3 and the LCD 4 are realized by one portable personal computer, a so-called notebook personal computer.

FIG. 2 illustrates the measurement principle of the present invention.

The cracks on the flooring surface are formed so as to be turned up on the surface when viewed in cross section. For this reason, when parallel light is applied along the flooring surface (wood surface) from the lateral direction, the light is scattered at the ridgeline of the portion turned up on this surface. Since the cracks are formed along the grain of the flooring, if light having a certain length (width) is applied parallel to the surface from a lateral direction of the crack, preferably a direction substantially perpendicular to the grain, the light scattered by the cracks becomes a grain of the grain. And appear as substantially linear bright lines arranged in the same direction.
If the scattered light appearing as bright lines is photographed by the digital camera 2 and the photographed image is subjected to image processing to extract straight line segments as cracks, the cracks appearing on the flooring surface can be measured. The present invention radiates light that is scattered at a raised portion along the surface so that a minute uneven portion of the surface can be observed, rather than reflecting and photographing the light over the entire surface of the flooring. It is characterized by shooting.

If the light is scattered by dust other than cracks, the scattered light is not linear, so that scattering caused by points having no length may be removed as dust in image processing. Also, the part that is depressed when hit by an object does not appear as a straight line segment along the grain of wood, but appears as having a much larger width due to cracks, so the area that can not be said to be such a crack is What is necessary is just to perform the process which excludes as something other than a crack. This processing can be automated as image processing, or the Hough transformed image of the flooring surface can be displayed on the LCD 4 and removed by designating by the operator.

FIG. 3 shows a photographing state. In the second embodiment, photographing of scattered light due to cracks is performed while blocking external light. For this reason, the digital camera 2 and the parallel light source 1 are provided in a housing 5 for photographing which has a rectangular opening and does not reflect light inside and blocks external light during photographing.

The housing 5 is provided with an opening of, for example, 15 × 15 cm so that the flooring surface to be photographed has a predetermined rectangular area, and has a width of 15 cm from one side of the opening. A parallel light source 1 that emits light parallel to the surface is provided. For this reason, the size of the portion corresponding to the flooring surface of the housing 5 becomes larger than 15 × 15 cm and becomes rectangular. Power is supplied to the parallel light source 1 by a power cord, and the digital camera 2 is mounted toward the opening of the housing 5. When measuring a crack, the opening of the housing 5 is placed in a direction in which a light beam parallel to the flooring surface to be measured is in a direction orthogonal to the grain direction, and the flooring surface is photographed.

FIG. 4 shows an example of the parallel light source 1. The parallel light source 1 includes a cold-cathode tube 11, an entrance lens 12, a slit 13, an exit lens 14, and a mirror 15 in contact with a flooring surface. The light emitted from the cold-cathode tube 11 is incident on the entrance lens 12, the slit 13, and the exit lens 1.
4, the light becomes parallel light, is reflected by the mirror 15, and is emitted as light parallel to the flooring surface.

There are various other methods for outputting parallel light. For example, a parallel light may be produced using a collimator, or a parallel light may be produced using a cylindrical Fresnel lens. The point is to give parallel light parallel to the surface to be photographed so as to be scattered by cracks on the flooring surface.

Next, crack measurement and its evaluation will be described.

First, before photographing, dust on the flooring to be measured is wiped off. Although the influence of dust can be reduced by image processing, it is preferable that the load on image processing be reduced as much as possible by processing before photographing.

The housing is placed on the flooring surface selected as the object to be measured so that the light emitted from the light source is orthogonal to the grain of the flooring surface, and external light is blocked and parallel light is applied to the flooring surface for photographing. I do. Since the housing is substantially a rectangular parallelepiped, the side where the parallel light source is provided may be placed in the direction of the grain.

It should be noted that the photographing is preferably performed by irradiating light at the same place from the opposite direction. This is because the light scattered by the cracks may not be scattered by one light depending on the state of the crack, but may be scattered by light from the opposite direction. This is because the width changes. The larger value of the length and the area of the crack measured from each direction is adopted as the measured value.

The photographed image data is taken into the information processing device 3 and subjected to image processing. The scattering part due to the crack part is extracted as a line segment by image processing. As the image processing for extracting the crack portion as a line segment, for example, a crack can be extracted by performing Hough transform on photographed image data. FIG. 4 shows an example of image data of the flooring surface after the Hough transform. It can be understood that cracks are generated side by side in the same direction. In addition, when the light is irradiated with the light inclined with respect to the direction of the crack, the crack is detected in an inclined state. However, in the image processing, the inclination of the crack can be standardized by rotating the image. The length and the area of the crack subjected to the chemical treatment can be obtained.

Here, the influence of scattering other than cracks, for example, due to dust is excluded. The part due to dust
Since it appears as a point having no length, a portion (bright point) having no length is removed as scattering due to dust. Also,
Scattered portions that are wider than the cracks and appear in directions other than the grain direction are also excluded as unevenness of the flooring surface that does not depend on the cracks. The removal of the scattering due to the large unevenness not along the crack direction may be operated by the operator while watching the LCD 5.

The cracks extracted by the image processing are substantially linear and appear in the same direction.
In the range of × 15 cm, the individual lengths h and widths w of the cracks that have appeared are extracted as feature amounts of the cracks.
The length h and the area s (= wh) are obtained. This is performed for n cracks appearing in the photographed 15 × 15 cm square area, and the sum of the n crack lengths and the sum of the areas are obtained.

The above measurement is performed on the flooring surface to be measured. Since the measuring device of the present embodiment is composed of a notebook housing and a photographing housing to which a digital camera and a parallel light source are attached, the measuring device is portable.
It can be measured in a living room of a general household where actual flooring is provided.

For this reason, the 15 × 1 obtained by photographing
The degree of occurrence of cracks on the flooring surface to be measured can be evaluated based on the sum of the crack lengths and the sum of the areas within the area of 5 cm. At this time, the values of the crack length and the area are set as standard degradation indexes, and the degradation of the flooring surface to be measured can be evaluated by comparing the values with the reference values. The value of this evaluation is printed together with the print output of the flooring surface photographed by the digital camera and the print output of the result of the Hough transform, and is printed as the value of the sum of the crack lengths and the sum of the areas.・ It can be output as an evaluation value such as

The size of the measurement area is an example, and an appropriate range may be set in consideration of the resolution of the digital camera, the size of the parallel light source, the capability of the information processing device, and the like.

In the above description, an example has been described in which the flooring surface is measured as an object to be measured for occurrence of cracks. However, even a wooden wall, furniture or the like exposed to the same environment as the flooring surface is described. Needless to say, it can be measured and evaluated similarly.

[0035]

As described above, cracks on a wooden surface can be quantitatively and easily measured. In addition, there is an advantage that it is not affected by the lighting environment. Further, since the present invention is configured as a portable device including a notebook computer and a photographing illumination device, it is possible to measure cracks in a living room of a general home, and to measure actual cracks in a special place such as a laboratory. There is an advantage that cracks can be measured at the site where the device is used. In addition, since many locations can be measured in a short time, it is possible to investigate and analyze the influence of the environment by investigating the difference in the degree of occurrence of cracks depending on the location of the flooring. Further, according to the present invention, since the sum of the crack lengths or the sum of the areas generated in a predetermined area can be calculated as a numerical value, the degree of damage or deterioration of the wooden surface can be used as an evaluation device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a crack measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a measurement principle of the present invention.

FIG. 3 is a diagram illustrating a shooting state.

FIG. 4 is a diagram showing a configuration example of a light source.

FIG. 5 is a diagram showing a result of image processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Parallel light source 2 Digital camera 3 Information processing device 4 LCD 5 Housing 11 Cold cathode tube 12 Incident-side lens 13 Slit 14 Exit-side lens 15 Mirror

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2F065 AA07 AA18 AA49 BB01 CC14 DD02 DD11 FF01 FF04 FF42 GG03 HH03 HH16 JJ03 JJ09 JJ26 LL00 LL10 LL12 LL28 QQ31 QQ34 SS13 TT07 UU01 UU05 BA04ACB DA17 EA09 EA12 EA30 EB01 5B057 AA15 DA03 DB02 DC03 DC04 DC09 DC13

Claims (5)

[Claims] 1. A method of outputting light parallel to a surface of a wooden surface from a lateral direction of a crack, photographing scattered light scattered on the surface, and calculating a component scattered by a crack generated on the wooden surface from an obtained image. A method for measuring crack damage, comprising extracting and calculating the amount of cracks in a predetermined area. 2. A light source that emits light parallel to the surface of the wooden surface from the lateral direction of the crack; an imaging unit that captures scattered light obtained by scattering the parallel light on the surface of the wooden surface; An information processing device for extracting a component scattered by a crack generated on a wooden surface and obtaining a crack amount in a predetermined area, and a damage measuring device for the wooden surface. 3. A housing having a rectangular opening to be contacted with a wooden surface to be measured, wherein a camera is mounted on the housing so as to face the opening of the housing, and one side of the opening of the housing is measured. The wooden surface damage measuring device according to claim 2, wherein the light source that emits light parallel to the surface of the wooden surface is provided. 4. The tree according to claim 2, wherein said information processing apparatus includes means for Hough-transforming the image, and means for extracting, as cracks, line segments that are substantially linear and substantially in the same direction in the image. Surface damage measuring device. 5. The information processing apparatus according to claim 1, further comprising: means for calculating a total crack length or a total crack area; and a method for comparing the calculated total crack length or the total crack area with a predetermined comparison standard. The wooden surface damage measuring device according to claim 3, further comprising: means for outputting an evaluation value.