JP7352912B2 - Fresh concrete determination method and fresh concrete determination device - Google Patents

Description

The present disclosure relates to a fresh concrete determining method and a fresh concrete determining device for determining the properties of fresh concrete.

Various methods and devices for determining fresh concrete have been known. Patent Document 1 states that when concrete in the setting process is subjected to a penetration resistance test according to JIS A 1147 and the penetration resistance value is plotted for each elapsed time, the relationship between the penetration resistance value P and the elapsed time t is t = It is described that it is expressed by the logarithmic approximation formula A×Ln(P)+B.

The above slope A has a high correlation with the temperature of concrete. On the other hand, although the conductivity of concrete initially increases with time, it gradually decreases after the conductivity decrease time, and there is a correlation between the conductivity decrease time and the slope A described above. The time when the conductivity decreases coincides with the time when the penetration resistance value of 0.1 (N/mm ² ) appears. In the prediction method of Patent Document 1, using the above correlation, the above slope A is calculated from the expected temperature on the day of construction of fresh concrete, and the time from slope A to the time when the conductivity decreases, and the leveling work is possible. Predict the timing before construction begins.

Patent Document 2 describes a concrete leveling timing determining method and a leveling timing determining device. This leveling timing determination device includes a construction management device that manages concrete construction. The construction management device includes a plurality of measurement rods for measuring electrical resistance that are inserted into each of a plurality of measurement points provided in a concrete frame, and an electrical resistance measurement device that is electrically connected to each of the plurality of measurement rods. Equipped with The construction management device evaluates the solidification state of the concrete by measuring and managing the electrical resistance values measured by each of the multiple measuring rods, and determines and instructs the optimal timing for leveling the concrete frame at each measurement point. .

JP 2019-73962 Publication Japanese Patent Application Publication No. 5-340938

In the above-mentioned Patent Document 1, it is necessary to measure the time at which the conductivity of fresh concrete decreases. However, the electrical conductivity of fresh concrete tends to vary depending on not only the temperature of the fresh concrete but also the constituent materials and formulation of the fresh concrete. Therefore, the current situation is that it is difficult to accurately measure the properties of fresh concrete using conductivity.

The leveling time determination method and leveling time determination device described in Patent Document 2 described above require measurement of the electrical resistance value of fresh concrete. However, the electrical resistance value of fresh concrete varies depending on various conditions such as the temperature of fresh concrete, constituent materials, and formulation. Therefore, it is difficult to accurately determine the properties of fresh concrete. Furthermore, since a plurality of measuring rods must be inserted into each measuring point of the fresh concrete, there is a problem in that the properties of the fresh concrete cannot be easily determined.

An object of the present disclosure is to provide a fresh concrete determining method and a fresh concrete determining device that can accurately and easily determine the properties of fresh concrete.

The fresh concrete determination method according to the present disclosure includes a step of irradiating the surface of fresh concrete with ultraviolet rays, a step of photographing the surface of the fresh concrete irradiated with ultraviolet rays with a camera, and a plurality of images constituting the image photographed with the camera. , and a step of performing the digitizing step multiple times to obtain time-series data of the numerical values of the plurality of pixels.

In this fresh concrete determination method, the surface of fresh concrete is irradiated with ultraviolet rays, and a camera photographs the surface of the fresh concrete that has been irradiated with ultraviolet rays. An image photographed by a camera is digitized multiple times for each pixel, and time-series data of the numerical values of the pixels that have been digitized multiple times is calculated. As a result, time-series data of pixel values is calculated from an image of the surface of fresh concrete irradiated with ultraviolet rays, so it is possible to understand time-series changes in the properties of fresh concrete by photographing the surface of fresh concrete. Therefore, by understanding the properties of fresh concrete from time-series data of pixels of photographed images, it is possible to perform measurements that are less affected by conditions such as constituent materials and formulation of fresh concrete. can be determined with high accuracy. Furthermore, since there is no need to insert the aforementioned measuring rod or the like into the fresh concrete, the properties of the fresh concrete can be easily determined.

In the step of digitizing, a density histogram may be generated from the image, and in the step of obtaining time series data, time series data of peak values of the density histogram may be obtained. In this case, a density histogram of an image of fresh concrete irradiated with ultraviolet rays is generated, and time series data of peak values of this density histogram is obtained. By the way, ultraviolet rays have the property of being easily absorbed by water. Fresh concrete contains a lot of water in its initial state. Therefore, when fresh concrete is irradiated with ultraviolet rays in the initial state, the ultraviolet rays are easily absorbed, so that the pixel density in the density histogram has a high peak value at a low density. On the other hand, fresh concrete reacts with water and hardens to develop strength, so as hardening progresses, the water content in fresh concrete decreases. Therefore, when fresh concrete is irradiated with ultraviolet rays, the ultraviolet rays are more likely to be reflected, so that the pixel density in the density histogram has a low peak value at a high density. It is presumed that one reason why the peak value decreases is that the scattering of ultraviolet rays increases with curing. Therefore, the properties of fresh concrete can be determined by obtaining time-series data of the peak values of the concentration histogram, so the properties of fresh concrete can be accurately and easily grasped.

In the digitization step, the magnitude of the change in density between one pixel and the pixel adjacent to the other pixel in the image is calculated, and in the step of obtaining time series data, the time series data of the magnitude of the change in density is calculated. You can ask for it. In this case, the properties of fresh concrete can be easily determined by calculating the rate of change (differential value) in density for each pixel from an image of the surface of fresh concrete that has been irradiated with ultraviolet rays, and obtaining time series data of the rate of change. can be done.

The above-described method for determining fresh concrete may include a step of determining the finishing start point of fresh concrete from numerical time series data. Note that finishing fresh concrete means leveling work, pressing work, etc. In this case, by understanding the progress of hardening of the fresh concrete from time-series data of numerical values for each pixel of the image of the fresh concrete irradiated with ultraviolet rays, it is possible to understand the time point at which finishing of the fresh concrete starts. Incidentally, heretofore, the point at which finishing of fresh concrete should start has been determined based on the senses based on the experience of a plasterer. In this case, the determination of when to start finishing fresh concrete must rely on the senses of the plasterer, and there is a problem in that only a skilled plasterer can accurately determine when to start finishing fresh concrete. On the other hand, in the fresh concrete determination method described above, the finishing start point of fresh concrete is determined from the numerical time series data obtained by digitizing multiple pixels of the image, so the finishing start point can be determined. It can be done automatically. Therefore, the finishing start point can be accurately and easily determined without relying on the skill level of the plasterer.

A fresh concrete determination device according to the present disclosure includes an ultraviolet irradiation device that irradiates the surface of fresh concrete with ultraviolet rays, a camera that photographs the surface of the fresh concrete irradiated with ultraviolet rays, and a plurality of images that constitute images photographed by the camera. and an image analysis unit that converts each pixel into numerical values and performs the numerical conversion multiple times to obtain time-series data of the numerical values of the plurality of pixels.

In this fresh concrete determination device, an ultraviolet irradiation device irradiates the surface of fresh concrete with ultraviolet rays, and a camera photographs the surface of fresh concrete. Then, the image analysis unit digitizes each of the plurality of pixels constituting the photographed image, and obtains time series data of the digitized numerical values. As with the fresh concrete determination method described above, time series data of pixel values is created from the image of the surface of fresh concrete irradiated with ultraviolet rays, so the properties of fresh concrete can be determined from the image of the surface of fresh concrete. It is possible to grasp series changes. Therefore, by understanding the properties of fresh concrete from time-series data of pixel values, it is possible to perform measurements that are less affected by conditions such as constituent materials and formulation of fresh concrete, so it is possible to judge the properties of fresh concrete. This can be done with high precision. Further, like the fresh concrete determination method described above, since there is no need to insert a measuring rod or the like into fresh concrete, the properties of fresh concrete can be easily determined.

According to the present disclosure, the properties of fresh concrete can be accurately and easily determined.

FIG. 1 is a side view showing an exemplary fresh concrete determination device according to an embodiment. 2 is a block diagram showing the functions of the fresh concrete determination device of FIG. 1. FIG. 2 is a graph showing an example of a density histogram generated by the fresh concrete determination device of FIG. 1. FIG. 4 is a graph schematically showing time series data of peak values of the concentration histogram of FIG. 3. FIG. It is a flowchart which shows each process of the exemplary fresh concrete determination method based on embodiment.

Hereinafter, embodiments of a fresh concrete determining method and a fresh concrete determining device according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and redundant description will be omitted as appropriate. Furthermore, for ease of understanding, some parts of the drawings may be simplified or exaggerated, and the dimensional ratios and the like are not limited to those shown in the drawings.

FIG. 1 is a side view showing an exemplary fresh concrete determination device 1. As shown in FIG. As shown in FIG. 1, the fresh concrete determination device 1 determines the properties of fresh concrete C poured at a site A, for example. For example, fresh concrete C is poured (placed) in an unhardened state at site A, which is a construction site.

As an example, fresh concrete C is composed of water, aggregates including fine aggregate and coarse aggregate, cement, and an admixture. The admixture may include fly ash or blast furnace slag. Admixtures such as fly ash or blast furnace slag are used to react with cement to increase strength. For example, cement and admixtures are binders that increase the strength of fresh concrete C.

The fresh concrete determining device 1 determines, for example, the time point at which finishing of fresh concrete C starts. In the present disclosure, the "finishing start point" indicates the timing at which the poured fresh concrete C begins to harden and the bleeding water on the surface recedes, allowing the surface finishing work to be started on the fresh concrete C.

The "finishing start point" may be, for example, a timing at which the finishing work is possible. "Amade" refers to sinking the coarse gravel components of fresh concrete C and floating the fine cement paste by tapping with a wooden trowel or the like. After the roughening work, for example, the fresh concrete C is finished with a trowel.

The fresh concrete determination device 1 includes an ultraviolet irradiation device 2 that irradiates the surface C1 of fresh concrete C with ultraviolet rays L1, and an image (ultraviolet image The image analysis unit 10 includes a camera 3 that captures images of fresh concrete C (also referred to as fresh concrete C), and an image analysis unit 10 that analyzes images of fresh concrete C captured by the camera 3.

In the present disclosure, "ultraviolet light" refers to light (near ultraviolet light) with a wavelength of 200 nm or more and 400 nm or less. The lower limit of the wavelength of the ultraviolet rays L1 and L2 is not limited to 200 nm, but may be 280 nm or 315 nm. The upper limit of the wavelength of the ultraviolet rays L1 and L2 is not limited to 400 nm, but may be 380 nm or 365 nm. In this way, the wavelength values of the ultraviolet rays L1 and L2 can be changed as appropriate. Note that when the wavelengths of the ultraviolet rays L1 and L2 are close to the wavelength of visible light (eg, 365 nm or more), human safety can be improved.

The ultraviolet irradiation device 2 is, for example, an LED irradiation illumination (an example is an LED linear illumination). As an example, the ultraviolet irradiation device 2 may be able to irradiate only the ultraviolet ray L1. When the ultraviolet irradiation device 2 is capable of irradiating only the ultraviolet ray L1, no heat such as infrared rays is emitted, so that the influence of heat and the like on the irradiation target can be reduced.

As an example, the peak wavelength of the ultraviolet irradiation device 2 is 365 nm, and the ultraviolet intensity of the ultraviolet irradiation device 2 is about 300 mW/cm ² . The exemplary ultraviolet irradiation device 2 has an aluminum case, the usable temperature of the ultraviolet irradiation device 2 is 0°C or more and 40°C or less, and the usable humidity of the ultraviolet irradiation device 2 is 20%RH or more and 80%RH. It is below RH.

The camera 3 photographs the surface C1 of the fresh concrete C that is irradiated with ultraviolet light L1 by the ultraviolet irradiation device 2. The camera 3 is, for example, an ultraviolet CCD camera, and the ultraviolet detection wavelength band of the camera 3 is 200 nm or more and 400 nm or less. As an example, the number of pixels of the image photographed by the camera 3 may be 1.5 million, or the number of output pixels of the image photographed by the camera 3 may be 1360×1024.

The camera 3 includes, for example, an ultraviolet ray compatible lens corresponding to the wavelength of the ultraviolet ray L2 reflected from the surface C1 of the fresh concrete C. As an example, the close distance of the UV compatible lens is 0.44 m, and the aperture range of the UV compatible lens is 3.8 to 16. Further, the corresponding wavelength of the ultraviolet ray compatible lens is 365 nm. Note that the specifications of the ultraviolet irradiation device 2 and camera 3 are not limited to the above-mentioned examples, and can be changed as appropriate.

For example, the fresh concrete determination device 1 includes a support member 5 that supports the ultraviolet irradiation device 2 and the camera 3, a tripod 4 that holds the support member 5 and is placed on the ground G, and a support member 5 that supports the ultraviolet irradiation device 2 and the camera 3 from above. It further includes a covering member 6 for covering. The tripod 4 and the support member 5 correspond to support means for supporting the ultraviolet irradiation device 2 and camera 3 so that the ultraviolet irradiation device 2 and camera 3 are positioned above the fresh concrete C.

The tripod 4 and the support member 5, for example, hold the ultraviolet irradiation device 2 and the camera 3 movably in three-dimensional directions. Thereby, the respective distances and positions of the ultraviolet irradiation device 2 and the camera 3 with respect to the surface C1 of the fresh concrete C can be adjusted. In the support member 5, the ultraviolet irradiation device 2 and the camera 3 are supported at positions adjacent to each other.

For example, the covering member 6 covers the ultraviolet irradiation device 2 and the camera 3 from vertically above so that direct sunlight does not enter the irradiation area of the ultraviolet ray L1 of the ultraviolet irradiation device 2 and the photographing area of the camera 3. As an example, the covering member 6 may be a parasol or a small tent. By providing this covering member 6, it is possible to prevent direct sunlight from entering the irradiation area of the ultraviolet ray L1 and the photographing area of the camera 3, so that a clear image of the fresh concrete C can be obtained even at the outdoor site A. be able to. Note that when the site A is indoors, the covering member 6 can be omitted because the influence of direct sunlight is small.

FIG. 2 is an exemplary block diagram showing the functions of the fresh concrete determining device 1. As shown in FIG. As shown in FIGS. 1 and 2, the fresh concrete determination device 1 includes, for example, an image analysis section 10 and an output section 20 in addition to an ultraviolet irradiation device 2 and a camera 3. The image analysis unit 10 and the output unit 20 constitute, for example, a computer that performs image processing on images captured by the camera 3.

The output unit 20 is an output unit that outputs the analysis result of the image by the image analysis unit 10. For example, the output unit 20 includes a display unit (for example, a display) that displays the results of image analysis by the image analysis unit 10, and an audio output unit (for example, a speaker) that outputs the results of the image analysis by the image analysis unit 10. It may contain at least one of them.

The computer configured by the image analysis unit 10 and the output unit 20 includes, for example, a processor (e.g., CPU) that executes an operating system and application programs, a main storage unit configured by ROM or RAM, and a hard disk or flash memory. and a communication control unit configured with a network card or a wireless communication module.

Each component of the computer constituted by the image analysis section 10 and the output section 20 is realized by loading software into a processor or main storage and executing the software. The processor operates the communication control section according to the software, and reads or writes data in the main memory section or the auxiliary memory section. Data necessary for processing by the computer is stored in the main memory or auxiliary memory.

For example, the camera 3 is capable of communicating with the image analysis section 10, and the image of the surface C1 of the fresh concrete C taken by the camera 3 is output to the image analysis section 10. The image analysis section 10 includes a density identification section 11, a density histogram generation section 12, a peak pixel number identification section 13, and a curing timing determination section 14 as functional components.

For example, the density identification unit 11 assigns an integer between 0 and 255 that indicates the intensity of the ultraviolet light L2 reflected from the surface C1 to each of a plurality of pixels (1.5 million pixels as an example) of the image captured by the camera 3. do. An integer of 0 indicates that the intensity of the reflected ultraviolet light L2 is the weakest, and an integer of 255 indicates that the intensity of the reflected ultraviolet light L2 is the strongest. In this way, the density identification unit 11 assigns a numerical value indicating the intensity of the ultraviolet ray L2 to each of the plurality of pixels of the image photographed by the camera 3 in a plurality of stages (for example, 256 stages). Note that numerical values may be assigned to each pixel in steps other than 256 steps.

As shown in FIGS. 2 and 3, the density histogram generation unit 12 generates a density histogram from the numerical value assigned to each pixel by the density identification unit 11. In this disclosure, "density" refers to the intensity of ultraviolet light reflected from fresh concrete. A density histogram is a method of calculating the number of pixels having a density value in one image and creating a graph, and is expressed by a graph in which the vertical axis represents the number of pixels and the horizontal axis represents the density value.

The density histogram generation unit 12 may, for example, total the number of pixels by density, excluding 0 and 255, and generate a histogram showing the relationship between the density and the number of pixels. As a concrete example, how many pixels have a density value of 1? How many pixels have a density value of 2? How many pixels have a density value of 254? , the number of pixels may be counted and expressed as a bar graph. FIG. 3 shows a graph in which the vertices of the bar graph are connected.

The peak pixel number identification unit 13 identifies the peak value of the number of pixels in the density histogram. As shown in FIGS. 3 and 4, for example, the peak pixel number identification unit 13 obtains time series data of the peak value. It can be seen that the peak value becomes smaller as time passes, while the variation in pixel density becomes larger as time passes. This indicates that the intensity of the ultraviolet light L2 is becoming stronger and the variation in the intensity is increasing as time passes.

The reason why the variation in the intensity of ultraviolet light L2 increases over time is that fresh concrete C hardens over time and its moisture content decreases, and as the moisture content decreases, the surface of fresh concrete C It is presumed that the unevenness of C1 becomes rougher, and as a result of the rougher unevenness, the scattering of ultraviolet rays L2 becomes stronger. As the scattering of the ultraviolet light L2 becomes stronger, the variation in pixel density of the image becomes larger.

The reason why the intensity of ultraviolet L2 increases over time is that the moisture content of fresh concrete C decreases over time, and as the moisture content of fresh concrete C decreases, the reflectance of ultraviolet L2 increases. . That is, ultraviolet rays have the property of being easily absorbed by water, and as the moisture content of fresh concrete C decreases, it becomes less likely that ultraviolet rays will be absorbed and will be more likely to be reflected, so it is presumed that the intensity of ultraviolet rays L2 increases.

In this way, the present embodiment focuses on the fact that the fresh concrete C has the characteristic that the moisture content and shape (degree of unevenness) of the surface C1 change as the hardening progresses. In this embodiment, the surface C1 of the fresh concrete C is irradiated with ultraviolet rays to obtain an image of the fresh concrete C (ultraviolet image), and the image of the fresh concrete C is utilized for determining the hardening of the fresh concrete C. ing.

Moreover, when the fresh concrete C is irradiated with ultraviolet rays, the surface C1 of the fresh concrete C is clearly illuminated, so that the properties of the fresh concrete C can be grasped with high precision. Ultraviolet light has a shorter wavelength than visible light, has higher directivity, and has less distortion, so the properties of fresh concrete C can be determined by irradiating fresh concrete C with ultraviolet light L1 and obtaining the reflection state of ultraviolet light L2. Can be grasped with high precision.

The curing timing determination unit 14 determines, for example, the timing T at which the change rate of the peak value in the time-series data of the peak value becomes equal to or less than the threshold value as the time point at which finishing of the fresh concrete C is started. As a specific example, the curing timing determination unit 14 may determine the timing T at which the inclination angle θ of the graph shown in FIG. 4 becomes equal to or less than the angle threshold as the finishing start time.

The angle threshold value of the tilt angle θ can be changed as appropriate. As an example, the angle threshold value of the inclination angle θ may be determined by calculating backward from the timing T based on the plasterer's prior experience. In this case, the experience of a skilled plasterer can be effectively utilized in setting the angle threshold. Further, the angle threshold value of the inclination angle θ may be determined by the value of the penetration resistance test. As an example, the angle threshold value of the inclination angle θ may be set by calculating backward from the timing T when the penetration resistance value in the penetration resistance value test falls within the range of 0.1 MPa to 0.2 MPa.

Next, a specific example of the fresh concrete determination method according to the present embodiment will be described with reference to FIG. FIG. 5 shows exemplary steps of the fresh concrete determination method according to the present embodiment. Below, an example of a method for determining the properties of fresh concrete C using the fresh concrete determining device 1 will be described.

First, as illustrated in FIG. 1, fresh concrete C is poured at the site A, and then the surface C1 of the fresh concrete C is irradiated with ultraviolet light L1 from the ultraviolet irradiation device 2 (irradiation step, step S1). At this time, for example, the ultraviolet irradiation device 2 and the camera 3 are arranged so that the surface C1 of the fresh concrete C is orthogonal to the irradiation direction of the ultraviolet rays L1. As an example, when the surface C1 of the fresh concrete C extends in the horizontal direction, the ultraviolet irradiation device 2 and the camera 3 are arranged directly above the surface C1.

The distance between each of the ultraviolet irradiation device 2 and the camera 3 and the surface C1 of the fresh concrete C is, for example, 50 cm or less. However, as described above, if the close distance of the ultraviolet ray compatible lens of the camera 3 is 0.44 m and the aperture range of the ultraviolet ray compatible lens is 3.8 to 16, the ultraviolet ray irradiation device 2 and camera 3 It is also possible to set the distance between each and the surface C1 to be 40.2 cm or more and 60 cm or less.

As described above, while the ultraviolet irradiation device 2 and the camera 3 are installed and the ultraviolet ray L1 is being irradiated from the ultraviolet irradiation device 2 to the surface C1, the camera 3 photographs the surface C1 of the fresh concrete C (photographing step , step S2). For example, the camera 3 captures ultraviolet images of the surface C1 at regular intervals (intermittently) and outputs the captured images to the image analysis unit 10. As an example, the camera 3 photographs the surface C1 at 5 minute intervals.

In addition, in order to obtain many ultraviolet images and further improve the accuracy of character determination of the fresh concrete C, it is possible to photograph the surface C1 with the camera 3 at intervals shorter than 5 minutes (for example, 1 minute or more and 4 minutes or less). desirable. However, the interval at which the camera 3 photographs the surface C1 can be changed as appropriate. Further, the camera 3 may photograph the surface C1 continuously (or as a moving image) instead of intermittently. In this case, for example, the steps described below are executed after converting a captured moving image into a plurality of still images.

After the surface C1 of the fresh concrete C is photographed by the camera 3, the image analysis unit 10 creates time-series data of the density (intensity of ultraviolet ray L2) distribution of the image, for example. At this time, for example, the density identification unit 11 digitizes the density of pixels of the plurality of images captured by the camera 3 (numerization step), and the density histogram generation unit 12 generates a density histogram (step S3). .

Then, the peak pixel number identification unit 13 generates time-series data of the peak values of the density histogram (step S4, a step of obtaining time-series data). At this time, for example, time series data of peak values shown in FIG. 4 is generated. The curing timing determination unit 14 determines whether the slope (rate of change) of the time series data generated in step S4 has become equal to or less than a threshold (step S5).

For example, the curing timing determination unit 14 continues to perform the determination in step S5 at a timing when the inclination angle θ of the graph representing time-series data of peak values is not equal to or less than the angle threshold value (NO in step S5). On the other hand, the hardening timing determination unit 14 determines that the fresh concrete C has hardened when the inclination angle θ of the graph showing the time series data of peak values becomes equal to or less than the angle threshold and reaches timing T (YES in step S5). Determine (determining step, step S6). Then, the series of steps is completed.

Next, the effects obtained from the fresh concrete determining method and fresh concrete determining device 1 according to the present embodiment will be described in detail. In the fresh concrete determining method and fresh concrete determining device 1 according to the present embodiment, the surface C1 of the fresh concrete C is irradiated with ultraviolet rays L1, and the camera 3 photographs the surface C1 of the fresh concrete C that is irradiated with the ultraviolet rays L1. The image photographed by the camera 3 is digitized multiple times for each pixel, and time-series data of the numerical values of the pixels digitized multiple times is calculated, for example, in the manner shown in FIG. 4.

As a result, time-series data of pixel values is calculated from the image of surface C1 of fresh concrete C irradiated with ultraviolet rays L1, so time-series changes in the properties of fresh concrete C can be detected by photographing surface C1 of fresh concrete C. can be grasped.

Therefore, by understanding the properties of fresh concrete C from the time-series data of the pixels of the photographed image, it is possible to perform measurements that are less affected by conditions such as the constituent materials and formulation of fresh concrete C. The properties of C can be determined with high precision. Furthermore, since there is no need to insert a measuring rod or the like into the fresh concrete C, the properties of the fresh concrete C can be easily determined. That is, since fresh concrete C can be measured without contacting fresh concrete C, fresh concrete C can be easily measured.

In the step of digitizing, a density histogram may be generated from the image, and in the step of obtaining time series data, time series data of peak values of the density histogram may be obtained. In this case, a density histogram of an image of fresh concrete C irradiated with ultraviolet rays L1 is generated, and time series data of peak values of this density histogram is obtained. As described above, as time passes, the ultraviolet light L2 becomes more likely to be reflected from the fresh concrete C, so that the pixel density in the density histogram has a low peak value at a high density. Therefore, the properties of the fresh concrete C can be determined by obtaining time series data of the peak values of the concentration histogram, so the properties of the fresh concrete C can be accurately and easily grasped.

The fresh concrete determination method according to the present embodiment may include a step of determining the finishing start point of fresh concrete C from numerical time series data. In this case, by understanding the progress of hardening of fresh concrete C from the time-series data of numerical values for each pixel of the image of fresh concrete C irradiated with ultraviolet rays L1, it is possible to understand the starting point of finishing of fresh concrete. . In this way, since the finishing start point of fresh concrete C is determined from the numerical time series data obtained by digitizing multiple pixels of the image, the finishing start point can be automatically determined. . Therefore, it is possible to accurately determine the finishing start time without relying on the skill level of the plasterer, so the finishing start time can be accurately and easily determined without relying on the plasterer's skill level.

The embodiments of the fresh concrete determining method and fresh concrete determining device according to the present disclosure have been described above. However, the present invention is not limited to the embodiments described above, and may be modified or applied to other things without changing the gist of each claim. That is, the present invention can be modified in various ways without changing the gist of each claim.

For example, in the above-described embodiment, an example has been described in which a density histogram is generated from an image in the digitizing step, and time-series data of the peak value of the density histogram is obtained in the step of obtaining time-series data. However, the contents of the process of converting image pixels into numerical values and the process of obtaining time-series data can be changed as appropriate.

For example, in the process of digitizing, the magnitude of the change in density between one pixel and a pixel adjacent to that pixel in an image may be calculated, and in the step of obtaining time series data, the magnitude of the change in density may be calculated. You may also obtain time series data. For example, the finishing start time may be determined based on the result of a differential operation on pixels of the image.

An example of a differential operation is a SOBEL differential operation or a Laplacian differential operation. In the SOBEL differential operation or the Laplacian differential operation, the magnitude of change in density (differential result) in pixels adjacent to each other in an image is determined, and time-series data of the differential result is generated. Then, as time passes, the total sum of the differential results gradually becomes smaller, so the hardening timing of the fresh concrete C can be determined from this slope. Note that while SOBEL differential operation analyzes the density changes of vertically and horizontally adjacent pixels from two directions (vertical and horizontal), Laplacian differential operation analyzes the density changes of diagonally adjacent pixels two-dimensionally. The operation and the Laplacian differential operation are different from each other.

As described above, in the step of calculating the magnitude of the change in density between one pixel and the pixel adjacent to the other pixel in an image and obtaining time series data, time series data of the magnitude of the change in density is calculated. It's okay. In this case, by calculating the rate of change (differential value) in density for each pixel from the image of the surface C1 of fresh concrete C irradiated with ultraviolet rays L1, and obtaining time series data of the rate of change, the properties of fresh concrete C can be determined. can be easily determined.

Furthermore, in the embodiment described above, an example was described in which the finishing start time point is determined. However, in the fresh concrete determining method and fresh concrete determining device according to the present disclosure, the properties of fresh concrete other than at the time of starting finishing may be determined. Furthermore, the fresh concrete determining method and fresh concrete determining device according to the present disclosure are not limited to site A, but can be applied to various locations.

DESCRIPTION OF SYMBOLS 1... Fresh concrete determination device, 2... Ultraviolet irradiation device, 3... Camera, 4... Tripod, 5... Support member, 6... Covering member, 10... Image analysis section, 11... Concentration identification section, 12... Concentration histogram generation section, 13...Peak pixel number identification unit, 14...Curing timing determination unit, 20...Output unit, A...Site, C...Fresh concrete, C1...Surface, G...Ground, L1, L2...Ultraviolet rays, T...Timing, θ...Inclination angle.

Claims (4)

A step of irradiating the surface of fresh concrete with ultraviolet rays with a wavelength of 200 nm or more and 400 nm or less ,
photographing the surface of the fresh concrete irradiated with the ultraviolet rays with a camera capable of detecting the ultraviolet rays ;
digitizing each of a plurality of pixels constituting an image taken by the camera;
performing the digitizing step multiple times to obtain time-series data of the numerical values of the plurality of pixels;
Grasping the progress of hardening of the fresh concrete from the time series data of the numerical values and determining the finishing start point of the fresh concrete;
A fresh concrete determination method comprising: In the digitizing step, a density histogram is generated from the image,
In the step of obtaining the time series data, obtaining time series data of the peak value of the concentration histogram.
The method for determining fresh concrete according to claim 1. In the digitizing step, the magnitude of a change in density between one pixel and a pixel adjacent to the one pixel in the image is calculated,
In the step of obtaining the time series data, obtaining time series data of the magnitude of the change in concentration,
The method for determining fresh concrete according to claim 1 . an ultraviolet irradiation device that irradiates the surface of fresh concrete with ultraviolet light with a wavelength of 200 nm or more and 400 nm or less ;
a camera capable of detecting the ultraviolet rays and photographing the surface of the fresh concrete irradiated with the ultraviolet rays ;
an image analysis unit that digitizes each of a plurality of pixels constituting an image taken by the camera, and performs the digitization multiple times to obtain time-series data of the numerical values of the plurality of pixels;
a curing timing determination unit that determines the finishing start point of the fresh concrete from the time series data of the numerical values;
A fresh concrete determination device equipped with

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