JP6234044B2 - Exterior material deterioration judging method and judging device - Google Patents

Description

  The present invention relates to an exterior material deterioration determination method and determination apparatus for determining the degree of deterioration of an exterior material that is a member facing the outside such as an outer wall material or a roof material in a house or other building, determining the remaining life, etc. About.

  Exterior materials such as outer wall materials in a building are subject to deterioration of the surface layer such as color change of the coating film, cracking of the coating film, choking, dirt, etc. due to deterioration over time, leading to a life such as cracking of the base material. By grasping this state and quantifying it, you can know what stage the outer wall material is in, and what kind of situation it will be in the future, and determine the remaining life Is possible.

In general, the deterioration evaluation of the outer wall material is performed by using a color difference meter to digitize the color with an L ^* a ^* b ^* value or the like and obtaining the color difference. For cracks, the degree of deterioration is quantified by using another device such as a microscope and binarizing the image. In other words, colors and cracks are diagnosed using devices suitable for those physical property values. In addition, many of the inspection diagnoses are performed visually or at best with images from a digital camera or the like without relying on such devices.

JP 2011-99709 A JP 2002-298134 A JP 2010-117259 A

Regarding the color change that occurs in the early stage, a color state such as L ^* a ^* b ^* value can be grasped quantitatively by using a color difference meter. However, the color difference meter makes the color of the contact portion numerical by bringing a sensing portion of about φ8 into direct contact with the outer wall or the like. Since the measurement range is small, when multiple colors are included, there is a problem that the variation of the numerical value of the stain for each part becomes large and the stain evaluation is difficult. In addition, since it is expensive and requires a wired connection between the main body and the detection unit, there are disadvantages such as poor operability and limited measurement in the realization field.

  When diagnosing dirt using an image from a digital camera or the like, accurate images are difficult to diagnose because the image changes depending on the surrounding environment during shooting, such as the weather, and the characteristics of the camera.

  An object of the present invention is to provide an exterior material that can accurately determine the degree of contamination without using a dedicated measuring instrument, and by appropriately correcting changes in the surrounding environment such as sunlight and weather, and the influence of the model of the photographing means. It is providing the degradation determination method and determination apparatus.

The method for determining the deterioration of the exterior material of this invention is:
A preparation step (S0) for preparing a known color body (1) having a known color surface with known color values;
A photographing process (S1) for photographing the exterior material (4) to be subjected to deterioration judgment in the building and the color known surface of the known color body (1) by the color digital photographing means (2);
A color correction step (S2) for color-correcting the color of the image of the captured digital data using the color of the image of the color known surface in the image and quantifying the corrected color;
A stain determination that obtains a color difference including at least a brightness difference value, which is a difference between a color value of the color-corrected exterior material (4) and a predetermined color value, and determines the degree of stain from the color difference. Process (S3).
The “exterior material (4)” refers to a member arranged outside the building, such as an outer wall material or a roof material. The “color known body (1)” is, for example, a color chart.

According to this method, since the color known surface having a known color value is photographed by the digital photographing means (2) together with the exterior material (4), the environment changes at the time of photographing such as sunlight and weather, and the digital photographing means Even if there is a difference in characteristics depending on the model of (2), the color of the image of the exterior material (4) is corrected according to the change in the color appearance of the portion of the known color surface in the image, so that the exterior material ( The color of 4) can be appropriately color-corrected and digitized. In order to determine the color difference between the appropriately digitized color value and a predetermined color value, for example, the initial color value of the exterior material (4) before deterioration or discoloration, and to determine the degree of contamination from this color difference The degree of dirt can be determined with high accuracy. Further, even the exterior material (4) containing multiple colors can be determined.
As described above, the degree of contamination is determined based on the color difference. Since the degree of contamination can be determined based on the black bias, it can be determined with a certain degree of accuracy by using only the brightness difference among the color differences. By determining only by the brightness difference, each process of color correction, digitization, and determination becomes easy.
The equipment used for the deterioration determination may be a digital photographing means (2) and an information processing device (3) for processing the data. The digital photographing means (2) includes a digital camera and a mobile phone terminal with a camera function. Etc. can be used. As the information processing apparatus (3), a personal computer, a multifunction telephone terminal such as a so-called smartphone, a tablet terminal, or the like can be used. Therefore, it is possible to appropriately correct the influence of changes in the surrounding environment such as sunshine and weather without using expensive dedicated measuring equipment, and to determine the degree of contamination with high accuracy.

In the method of the present invention, in the stain determination process using the image obtained by the first photographing in the exterior material (4), the stain level is determined only by the brightness difference, and the stain level exceeds the standard from the brightness difference. Is determined,
The imaging process (S1) is performed again on a portion of the exterior material (4) different from the first imaging, or the imaging process is performed again at the same site after removing dirt. S7)
A recolor correction step (S8) for performing color correction and digitization on the image obtained by this re-shooting;
A re-stain determination process (S9) is performed in which a color difference, which is the difference between the color value of the color-corrected exterior material (4) and the predetermined color value, is obtained and the degree of stain is determined from the color difference. ,
In this re-dirt determination process (S9), the level of smudge is determined from the color difference including color elements other than the brightness difference .
In addition to the initial lightness value prepared in advance, the determination criterion may be a value of the armpit or the like with less deterioration factors such as sunlight, ultraviolet rays, and wind and rain.

  As described above, it is possible to determine the degree of dirt with a simple calculation process by determining the dirt only with the brightness difference, but if it is determined that the dirt exceeds the standard from the brightness difference, the exterior material ( By photographing another part in 4) again and determining the degree of dirt again, the degree of dirt as a whole of the exterior material (4) can be more appropriately determined. This determination is performed for the exterior material (4) that has been determined that the degree of dirt has advanced to some extent due to the difference in lightness. Therefore, the degree of dirt is determined from elements other than the lightness difference, that is, color differences including saturation differences. It is preferable to determine the degree of contamination more strictly by performing the above.

The exterior material deterioration judging device of the present invention is
An input processing means (31) for storing a color image of digital data obtained by photographing together an exterior material (4) to be subjected to deterioration determination in a building and a known color surface having a known color value in a predetermined storage area; ,
Color correction means (32) for color-correcting the color of the image using the color of the image of the color known surface in the image and digitizing the corrected color;
A stain determination that obtains a color difference including at least a brightness difference value, which is a difference between a color value of the color-corrected exterior material (4) and a predetermined color value, and determines the degree of stain from the color difference. Means (33).

  According to the deterioration determination device of this configuration, it can be realized by an information processing device (3) such as a personal computer, a smartphone, a tablet terminal, etc., as described above with respect to the deterioration determination method of the present invention. A mobile phone terminal or the like with a camera function can be used. In this way, the influence of changes in the surrounding environment such as sunlight and weather can be appropriately corrected without using a dedicated measuring instrument, and the degree of contamination can be determined with high accuracy.

In the deterioration determination device of the present invention,
The dirt judging means (33) shall judge the degree of dirt only by the brightness difference,
When it is determined that the dirt exceeds the reference in the determination based on the brightness difference, the exterior material (4) and the color-known surface of the exterior material (4) are different from the first photographing or the same part. Re-input processing means (37) for storing an image of digital data photographed together with a predetermined storage area;
The recolor correction means (38) that performs the color correction and digitization for the re-input image, and the difference between the color value of the color-corrected exterior material (4) and the determined color value Re-smudge determining means (39) for obtaining a color difference and determining the degree of stain from this color difference;
In this re-dirt determination means (39), the level of contamination is determined from the color difference including elements other than the brightness difference .

  In the case of this configuration, the degree of contamination of the exterior material (4) as a whole can be more appropriately determined in the same manner as described above for the deterioration determination method of the present invention.

  The exterior material deterioration judgment method according to the present invention can accurately correct changes in the surrounding environment such as sunlight, weather, etc., and the influence of the model of the photographing means without using a dedicated measuring device. Judgment can be made.

It is explanatory drawing which shows the flow and content of the degradation determination method of the exterior material which concerns on 1st Embodiment of this invention. It is the graph which contrasted each calculation value of a chroma difference, a lightness difference, and a color difference with each calculation value by a color difference meter in the digital camera image used with the same degradation determination method. It is explanatory drawing which shows the relationship between the crack condition of an outer wall coating film, and its binarization image. It is a flowchart of the same degradation determination method. It is a conceptual diagram which shows the hardware structural example of the deterioration determination apparatus which enforces the determination method. It is a block diagram which shows the conceptual structure of the deterioration determination apparatus of the exterior material. It is a flowchart of the deterioration determination program of the exterior material. It is a flowchart of the deterioration determination method of the exterior material which concerns on other embodiment of this invention. It is a conceptual diagram which shows the hardware structural example of the deterioration determination apparatus which enforces the determination method.

  A first embodiment of the present invention will be described with reference to the drawings. This exterior material deterioration determination method is a method for determining deterioration of the exterior material 4 that is a member facing the outside such as an outer wall material or a roof material in a building. As shown in FIG. 4 and the contents of processing in FIG. 1, the exterior material deterioration determination method includes a preparation process S0, a photographing process S1, a color correction process S2, a dirt determination process S3, and crack detection. Process S4, deterioration determination process S5, and display process S6 are performed in this order. As shown in FIG. 5, the devices used are the color known body 1, the digital photographing means 2, and the information processing device 3.

The known color body 1 is a correction tool for photographing with the exterior material 4 for color correction, and has a known color surface with known color values. For this known color body 1, for example, a color chart in which various color display portions 1a are divided and displayed is used. The color known body 1 made of this color chart or the like has, for example, a flat plate shape or a sheet shape. The known color body 1 may be a single color as a whole.
The digital photographing means 2 is a means capable of photographing a color digital image, such as a digital camera (so-called digital camera), a mobile phone terminal having a camera function, another portable information processing terminal (PDA, tablet) or the like. Also good.
The information processing device 3 is a personal computer, a multifunctional mobile phone terminal such as a so-called smartphone, a PDA, a tablet-type mobile information processing terminal, or the like.

  In FIG. 1, a preparation process S0 is a process of preparing the known color body 1 for photographing. In the photographing process S <b> 1, the exterior material 4 to be subjected to deterioration determination in the building is photographed by the digital photographing unit 2 together with the color known surface of the color known body 1. Depending on the situation, this photographing is performed by limiting ambient light with a light shielding sheet or the like. You may shoot using a strobe. 1 is an image (color image before color correction processing) photographed by the digital photographing means 2 in the frame indicated by the photographing process S1. The exterior material portion and the color known body portion in the image are shown in FIG. Reference numerals 1 and 4 are given for the exterior material and the known color body. In addition, the vertical and horizontal pattern lines appearing in the image of FIG. 4 are joint pattern portions 4a of the exterior material 4 in which a concavo-convex pattern is provided in a brick shape.

  The image data thus captured is taken into the information processing apparatus 3 (FIGS. 5 and 6), and each process from the color correction process S2 to the display process S6 is performed by each unit of the information processing apparatus 3.

  In the color correction step S2, the entire color of the captured digital data image is color-corrected using the color of the color known surface image of the color known body 1 in this image, and the corrected color is digitized. Since the color known body 1 with known color values is photographed by the digital photographing means together with the exterior material 4, there are changes in the environment at the time of photographing such as sunlight and weather, and there are differences in characteristics depending on the model of the digital photographing means. In addition, the color of the exterior material can be appropriately color-corrected and digitized by color-correcting the image of the exterior material in accordance with a change in the color appearance of the portion of the known color body 1 in the image. When the color chart having the plurality of color display units 1a as described above is used as the color known body 1, the color correction is performed using the image portion of the display unit 1a of any one color. Alternatively, color correction may be performed using image portions of the plurality of display units 1a.

The numerical value of the corrected color is, for example, a numerical value shown in the L ^* a ^* b ^* color system. In the L ^* a ^* b ^* color system, lightness is indicated by L ^* , and hue and saturation are indicated by a ^* and b ^* . In this specification, the following numerical values are used.
When the reference point color values (L ₀ ^* , a ₀ ^* , b ₀ ^* ) and the measurement point color values (L ₁ ^* , a ₁ ^* , b ₁ ^* ) are taken, the brightness difference: ΔL = √ (L ₁ ^* − L ₀ ^* ) ²
Saturation difference: Δa ^* b ^* = √ (a ₁ ^* −a ₀ ^* ) ² + (b ₁ ^* −b ₀ ^* ) ²
Color difference: ΔE = √ (L ₁ ^* −L ₀ ^* ) ² + (a ₁ ^* −a ₀ ^* ) ² + (b ₁ ^* −b ₀ ^* ) ²

In the stain determination process S3, a color difference including at least a value of brightness difference, which is a difference between the color value of the exterior material color-corrected in the color correction process S2 and a predetermined color value, is obtained, and the stain difference is determined from the color difference. Determine the degree. The “numerical value of the defined color” is an initial value of the numerical value of the color of the exterior material 4 before deterioration or discoloration, for example. For example, the degree of contamination as a determination result may be indicated as about ten levels, or may be indicated in an analog manner.
In this case, among the color-corrected images, the evaluation selection range E for performing the evaluation such as the dirt determination is selected using a selection frame or the like displayed superimposed on the image, and the selected evaluation range E is selected. The degree of dirt is evaluated for the exterior material 4 part. For example, the selection frame may be selected or set by an operator operating the input device 11 (FIG. 5) of the information processing apparatus 3 to move, enlarge / reduce, or determine the selection frame. It may be performed automatically according to the rules.

  In this example, the degree of contamination is determined only by the brightness difference. Since the degree of smearing can be determined by the black bias, it can be determined with a certain degree of accuracy by only the brightness difference among the color differences. The determination is facilitated by determining only by the brightness difference.

  In the deterioration determination process S5, the degree of deterioration of the exterior material 4 is determined using the color difference such as the brightness difference determined in the stain determination process S3. In addition to the brightness difference and the color difference, as described later, a crack detection process S4 is performed. Degradation is comprehensively determined using the degree of cracks detected in step 1.

  In the crack detection step S4, the image of the exterior material 4 is binarized into a black-and-white image to determine the state (size and occurrence site) of the crack 5 in the exterior material 4, and the degree of cracking is determined. The evaluation for obtaining the degree of cracking is also performed for the evaluation selection range E. The evaluation selection range E for detecting cracks may be a range different from the evaluation selection range E in the case of dirt determination. Further, the degree of cracking as a detection result may be a stepped value or an analog value.

  The size of the crack is the total length of the crack, maximum thickness, quantity, area ratio [%], etc., and the degree of cracking can be judged by any one of these items. You may determine comprehensively about several items. Determination of the degree of cracking by binarization can be performed by simple image processing.

  The image for obtaining the degree of cracking may be an image of the exterior material 4 input separately from the image for determining dirt. For example, an enlarged image is used by using a magnifying glass or the like depending on the state of deterioration.

  In the deterioration determination process S5, the degree of deterioration of the exterior material 4 is determined by comprehensively evaluating the degree of cracking obtained in the crack detection process and the degree of dirt obtained in the dirt determination process. Further, the remaining life of the exterior material 4 is estimated from the degree of deterioration according to a predetermined rule.

An example of the remaining life analysis procedure will be described collectively.
From an initial outer wall color and L ^* a ^* b ^* values (color before use of the outer package), the L ^* a ^* b ^* values of the image after correction of the outer wall color (color of the outer package 4), brightness difference, Aya Carry out degree difference and total color difference. The comprehensive color difference referred to here is a color difference having a brightness difference and a saturation difference. The stain is determined from the brightness difference, the saturation difference, and the color difference. This stain determination is performed in the stain determination step S3.
In addition, the state of cracking (occurrence site) and the size of the crack (total length, maximum thickness, quantity, area ratio [%], etc.) are detected. This detection is performed in the crack detection process (S4).
From the value of the determination result of the dirt thus obtained and the value of the crack status, the deterioration state of the exterior material 4 is converted into a numerical value or a stepped current value, and the remaining life is estimated. The process for obtaining the current value of the deterioration state and the process for estimating the remaining life are performed in the deterioration determination step S5. In the deterioration determination process S5, an appropriate repainting time of the exterior material 4 is further estimated according to a predetermined rule.

  In the display step S6, the screen display device 12 such as the liquid crystal display device of the information processing device 3 is used to indicate the deterioration state, remaining life, and appropriate repainting time of the exterior material 4 obtained in the deterioration determination step S5 as described above. It displays on the screen of (FIG. 8, FIG. 9).

  FIG. 2 shows the relationship between the saturation difference, brightness difference, and color difference calculated values (calculated values using a digital camera) calculated by the exterior material deterioration determination method of this embodiment, and the calculated values obtained by a color difference meter. As can be seen from the figure, each calculated value calculated by the exterior material deterioration judgment method of this embodiment and each calculated value by the color difference meter have a strong positive correlation and are the same as the calculation by the color difference meter with a simple calculation. It can be seen that a degree of saturation difference, brightness difference, and color difference are obtained.

  FIG. 3 shows an example of the relationship between the progress of cracks in the coating film of the outer wall material that is the exterior material 4 and the binarized image. The crack images at the initial stage, middle stage, and late stage of the crack are shown in a column labeled “Exterior material coating film image” in FIG. The crack image at each stage becomes clear by binarization as shown next to the image. In the initial stage, the crack is thin and short, but in the middle period, the crack becomes thick and long. In the later stage, the cracks become thicker and proceed so that they can be visually identified. From the tendency of such cracks to progress, the state of cracks can be understood.

  According to this exterior material deterioration judgment method, it is possible to accurately correct the influence of changes in the surrounding environment such as sunlight and weather without using a dedicated measuring device, and to accurately judge the degree of contamination. In addition, comprehensive deterioration determination including dirt and cracks can be performed. Furthermore, the remaining life can be determined.

The actions and effects of this embodiment are summarized as follows.
・ It is possible to know the remaining life as well as the degree of dirt on the outer wall material.
・ Dirt evaluation in a wider range than color difference meter is possible.
・ Residual life estimation of roofing materials can be performed in the same way as for outer wall materials.
-Colors can be digitized even for exterior materials containing multiple colors.
・ A general-purpose digital camera can be used to diagnose the remaining life at low cost.
・ Precise diagnosis can be performed with a method close to the conventional method without taking much time.
・ Diagnosis equipment can be reduced.
-By presenting the remaining life to the user, it is possible to explain the degree of danger and urgency to the user in an easy-to-understand manner.
・ Appropriate presentation of maintenance time for outer walls, etc. is possible.
・ Advantages as a sales tool for maintenance work orders.
-By linking with the information processing device 3 such as a personal computer, it becomes possible to present the diagnosis result on the spot immediately after the inspection.

Next, the exterior material deterioration determination device and the determination program will be described with reference to FIGS.
In FIG. 5, the information processing layer device 3 is a personal computer, or a form terminal such as a smartphone or a tablet terminal as described above. The information processing layer device 3 includes a CPU (central processing unit) 5, a storage unit 6, and an input / output port 7. A deterioration determination program 9 is stored in the storage unit 6 and installed in a state that can be executed by the information processing layer device 3. The storage means 6 collectively shows a large-capacity storage device such as a hard disk or SSD and a memory. The storage means 6 stores an OS (option program) (not shown), and is provided with a data storage area 6a for storing data such as image data. The deterioration determination program 9 is an application program executed on the OS.

  In addition, an input device 11 such as a keyboard, a mouse, and a touch panel and a screen display device which is an output device capable of displaying an image such as a liquid crystal display device are connected via an input / output port 7. The input / output port 7 has an interface such as a USB standard, and an image photographed by the digital photographing means 2 is input to the information processing device 3 through the input / output port 7, for example. The image photographed by the digital photographing means 2 may be stored in a removable memory chip (not shown) and input to the information processing device 3 from the memory chip.

  As shown in the flowchart of FIG. 7, the deterioration determination program 9 includes an input processing procedure R1, a color correction procedure R2, a stain determination procedure R3, a crack detection procedure R4, a deterioration determination procedure R5, and a display procedure R6. Each procedure R2 to R6 except the input processing procedure R1 is performed by the information processing apparatus 3 in the steps S2 to S6 described with reference to FIGS. 1 and 4, that is, the color correction step S2, the stain determination step S3, and the crack detection step. This is a procedure for performing S4, the deterioration determination process S5, and the display process S6. The input processing procedure R1 is a procedure for storing data of an image photographed by the digital image photographing means 2 in a predetermined data storage area 6a in accordance with an operator operation or the like.

  When the deterioration determination program 9 is installed in the information processing apparatus 3, the information processing apparatus 3 includes an input processing means 31, which is a function achievement means, a color correction means 32, a dirt determination means 33, a crack detection means 34, and a deterioration determination means. 35 and display means 36 are configured. Each of these means 31 to 36 is composed of the procedures R1 to R6 of the deterioration determination program 9 and the hardware of the information processing apparatus 3. The color correction means 32, the dirt determination means 33, the crack detection means 34, the deterioration determination means 35, and the display means 36 are respectively the color correction process S2, the dirt determination process S3, and the crack detection process S4 in this deterioration determination method. , Means for performing the deterioration determination process S5 and the display process S6. The input processing means 30 is a means for performing the processing described for the input processing procedure R1 of the deterioration determination program 9.

8 and 9 show another embodiment of the present invention. The deterioration determination method of this embodiment is the same as that in the first embodiment described with reference to FIGS. 1 to 7, but in the stain determination process S <b> 3 using the image obtained by the first shooting of the exterior material 4, the stain is determined only by the brightness difference. This is a method of adding a re-photographing process S7, a re-correction process S8, and a re-stain determination process S9 when the determination is made and it is determined from this brightness difference that the dirt exceeds the reference. Other than the matters to be specifically described, the second embodiment is the same as the first embodiment.

The re-shooting process S7 is a process in which the same shooting as the shooting process S1 is performed again for another part of the exterior material 4 from the time of the first shooting. In the re-imaging process S7, the same image as the above-described imaging process S1 may be performed again at the same site after removing the dirt.
In the re-correction process S8, the color correction and digitization are performed on the image obtained by the re-photographing.
In the re-stain determination step S9, a color difference that is a difference between the color value of the color-corrected exterior material 4 and a predetermined color value is obtained, and the degree of stain is determined from the color difference. In this re-dirt determination step S9, the level of smudge is determined from the color difference including color elements other than the brightness difference.

As described above, it is possible to determine the degree of dirt with high accuracy by simple arithmetic processing by determining the dirt only with the brightness difference. However, when it is determined that the dirt exceeds the reference from the brightness difference, the exterior material 4 It is possible to more appropriately determine the degree of dirt as a whole of the exterior material 4 by photographing again with another part or removing the dirt and photographing again with the same part and judging the dirt again. it can. In this determination again, since the exterior material is determined to have a certain degree of contamination due to the lightness difference, the degree of contamination is determined from the elements other than the lightness difference, that is, the color difference including the chroma difference. Therefore, it is preferable to more strictly determine the degree of contamination.

  When the re-stain determination process S9 is performed, in the later deterioration determination process S6, the re-stain determination process S9 is used as a result of the stain determination for the deterioration determination and the remaining life estimation, or in the first stain determination process S3. Both the result and the result of the re-stain determination step S9 are used.

  9 is the same as the first deterioration determination apparatus shown in FIG. 6 except that a re-input processing unit 37, a recolor correction unit 38, and a re-stain determination unit 39 are added. The re-input processing unit 37 is a unit that stores the image obtained in the re-shooting process S7 in a predetermined storage area. The recolor correction unit 38 and the recontamination determination unit 39 are units for performing the recorrection process S8 and the recontamination determination process S9, respectively.

DESCRIPTION OF SYMBOLS 1 ... Color known body 2 ... Digital imaging | photography means 3 ... Information processing layer apparatus 4 ... Exterior material 9 ... Deterioration determination program 31 ... Input processing means 32 ... Color correction means 33 ... Dirt determination means 34 ... Crack detection means 35 ... Deterioration determination means 36 ... Display means 37 ... Re-input processing means 38 ... Re-color correction means 39 ... Re-stain determination means

Claims (2)

Preparing a known color body having a known color surface with known color values;
A photographing process of photographing the exterior material to be subjected to deterioration determination in the building and the color known surface of the known color body with a color digital photographing means;
A color correction process in which the color of the image of the captured digital data is color-corrected using the color of the image of the color known surface in the image, and the corrected color is digitized;
A stain determination process for determining the degree of stain from this color difference by obtaining a color difference including at least a value of brightness difference, which is the difference between the color value of the color-corrected exterior material and the determined color value,
Look including a degradation determiner processes a degradation of the exterior material using the degree of soiling determination process in the determination soils,
In the stain determination process using the image obtained in the first shooting of the exterior material, the stain is determined only by the brightness difference, and when it is determined from the brightness difference that the stain level exceeds the standard,
A re-imaging process in which the imaging process is performed again for a part different from the first imaging in the exterior material or the imaging process is performed again at the same site after wiping off dirt;
Re-color correction process for color correction and quantification of the image obtained by this re-shooting;
A re-smudge determination process is performed in which a color difference that is a difference between the color value of the color-corrected exterior material and a predetermined color value is determined and the degree of stain is determined from the color difference,
In this re-stain determination process, the level of stain is determined from the color difference including color elements other than the brightness difference.
A method for judging deterioration of exterior materials. Input processing means for storing, in a predetermined storage area, a color image of digital data obtained by photographing together an exterior material to be subjected to deterioration determination in a building and a color known surface having a known color value;
Color correction means for color-correcting the color of the image using the color of the image of the color known surface in the image, and digitizing the corrected color;
A stain determination means for determining a degree of stain from this color difference by obtaining a color difference including at least a value of brightness difference, which is a difference between the color value of the color-corrected exterior material and a predetermined color value,
Look including a degradation determiner means deterioration of the exterior material using the determined degree of dirt in the dirt judging means,
The determination means determines the degree of dirt only by the brightness difference,
When it is determined that the degree of dirt exceeds the standard in the determination based on the brightness difference, the exterior material and the color known surface are combined together in a part different from or the same as the first photographing in the exterior material. Re-input processing means for storing a photographed digital data image in a predetermined storage area;
Recolor correction means for performing the color correction and digitization for the re-input image;
Re-stain determination means for determining the degree of stain from this color difference by obtaining a color difference that is the difference between the color value of the color-corrected exterior material and a predetermined color value;
In this re-stain determination unit, an exterior material deterioration determination device that determines the degree of stain from a color difference including an element other than a brightness difference .

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