Measurement method for falling time of mortar and flowability test device for mortar

Abstract

To accurately measure the falling time of mortar.SOLUTION: A test device 10 which tests flowability of mortar M consists of: a test container 11 which contains the mortar M; a camera 14 which captures a moving image from when the mortar M contained in the test container 11 starts falling from a discharge port 11n of the test container 11 until when the mortar finishes falling; a partition plate 15 which is provided on the opposite side of the test container 11 from the camera 14, and differs in lightness from the mortar M; and falling time calculation means 16 which calculates the falling time T from when the mortar M starts falling from the discharge port until when the mortar finishes falling from the captured moving image.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to quality control testing of mortar, and more particularly to a method for measuring the drop time of mortar and an apparatus for testing the fluidity of mortar. [Background technology]

[0002] Conventionally, in quality control tests for mortar, mortar is poured into a funnel-shaped test container up to the level, then dropped from an outlet provided at the bottom of the test container, and the falling time, which is the time it takes for the mortar in the test container to be discharged outside the test container, is measured and used as an index of the fluidity of the mortar (see, for example, Patent Document 1). In reality, a worker at the work site removed his hand, which was blocking the bottom of the drain, to open the drain and used a stopwatch to measure the time it took for the mortar to fall. In addition, the measured fall time was recorded by the worker in a record called a field book, either by hand or on a computer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-323538 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when measuring with a stopwatch, whether the measurement is performed by the worker who was covering the outlet with his hand or by a different worker than the one covering the outlet with his hand, it is difficult to determine the timing when the fall begins, and there is a problem in that the fall time cannot be measured accurately. In addition, because workers had to enter the fall time into the report, not only was there the risk of mistakes (input errors) but it also took a lot of time to create the report.

[0005] The present invention has been made in consideration of the problems in the prior art, and has an object to provide a method for accurately measuring the drop time of mortar and a mortar fluidity tester for use therein. [Means for solving the problem]

[0006] The present invention is a method for measuring the fall time of mortar, which comprises placing a partition plate having a different brightness from that of the mortar in the background of a test container that contains the mortar, taking a video of the mortar from when it starts to fall from the discharge outlet of the test container to when the mortar stops falling, and calculating the fall time of the mortar from the taken video. This allows the drop time of the mortar to be accurately determined, and therefore the fluidity of the mortar can be evaluated with high precision. In addition, a partition plate is provided on the opposite side of the test container from the photographing means to prevent any moving objects other than the falling mortar from being photographed in the background of the falling mortar, so that the time it takes for the mortar to fall can be obtained accurately. In addition, because the brightness of the partition plate and the brightness of the mortar are different, the partition plate and the mortar can be clearly distinguished on the image. Therefore, the falling state of the mortar can be accurately photographed, and the time it takes for the mortar to fall can be accurately calculated. In addition, a recovery container for recovering the fallen mortar is placed directly below the test container, and a mark is placed on the side of the recovery container at the position of the surface of the mortar when it is assumed that all of the mortar has fallen.When the height of the mortar in the recovery container reaches the position of the mark, it is determined that all of the mortar in the test container has fallen, so that it is possible to determine whether or not any mortar remains in the test container.

[0007] In addition, the present invention provides a mortar fluidity testing device that includes a test container for storing mortar, a photographing means for photographing a video of the mortar stored in the test container from when it starts to fall from the discharge outlet of the test container to when it stops falling, a partition plate having a different brightness from the mortar and provided on the opposite side of the test container from the photographing means, and a fall time calculation means for calculating, from the photographed video, a fall time that is the time from when the mortar starts to fall from the discharge outlet to when it stops falling, so that the fall time of the mortar can be accurately determined. In addition, a lid member is provided on the discharge outlet side of the test container to open the discharge outlet in conjunction with the start of imaging by the imaging device, so that the mortar falls automatically, thereby reducing the burden on workers. In addition, since a storage means is provided for storing a management table in which the name of the mortar for which the fall time has been calculated and the calculated fall time are recorded, data management can be performed efficiently and errors in entering data can be eliminated. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a mortar fluidity test device according to the present embodiment. [Diagram 2] FIG. 4 is a diagram showing an example of a lid member. [Diagram 3] FIG. 13 is a diagram for explaining a background subtraction method. [Figure 4] 11 is a flowchart showing a method for measuring a fall time. [Diagram 5] FIG. 13 illustrates a method for extracting frames showing a falling mortar. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1 is a diagram showing a mortar fluidity test device (hereinafter referred to as test device 10) according to this embodiment, and test device 10 comprises a test container 11, a cover member 12, a collection container 13, a camera 14 as a video capture means, a partition plate 15, a drop time calculation means 16, a display means 17, and a storage means 18. Drop time calculation means 16 is constituted, for example, by software of a computer equipped with a CPU, and display means 17 is constituted by a liquid crystal display. Also, storage means 18 is constituted by RAM, ROM, etc. of the computer. It should be noted that the photographing, calculation, and data storage may be performed using a tablet or personal computer in which the camera 14 and the fall time calculation means 16 to the storage means 18 are integrated.

[0010] The test container 11 includes a container body 11a for storing mortar M for which a fluidity test is to be performed, a support member 11b for supporting the container body 11a, and a lid attachment member 11c for attaching a lid member 12 thereto. The container body 11a is a funnel-shaped member that opens at the top and bottom, with the top diameter being larger than the bottom diameter, and mortar M is poured from the upper opening, injection port 11m, and stored inside the container body 11a. During a drop test, the poured mortar M falls from the lower opening, discharge port 11n, to the bottom of the container body 11a. The support member 11b is a rod attached to the side of the container body 11a so that the upper end side is close to the center of the container body 11a and the lower end side is away from the center when viewed from above. In this example, three rods 111-113 are arranged symmetrically with respect to the axis of the container body 11a as the support member 11b. The three rods 111-113 form an equilateral triangle when viewed from above, and the direction perpendicular to one side of this equilateral triangle is defined as the front-rear direction, with the side side being the front side and the apex side being the rear side. In other words, the side where the injection port 11m is not hidden by the rods 113 (the side where the camera 14 is installed) is defined as the front side. As shown in FIGS. 2(a) and 2(b), the cover member 12 includes a cover portion 12a, a rotating portion 12b, and a connecting plate 12c.

[0011] The lid portion 12a is a disk-shaped member whose diameter is larger than the diameter of the discharge port 11n of the container body 11a. The connecting plate 12c is a plate-shaped member having a rectangular shape in a plan view whose width is smaller than the diameter of the lid portion 12a, and one end is connected to the side of the lid portion 12a and the other end is connected to the rotating portion 12b. The rotating portion 12b includes a rotating mechanism 12m having a rotating shaft 12j connected to the other end of the connecting plate 12c, and a fixed portion of the rotating mechanism 12m is fixed to the lower side of the lid mounting member 11c. As the rotating mechanism 12m, a well-known rotating mechanism including a well-known motor and a reducer consisting of multiple gears is preferably used. In this example, the rotation mechanism 12m is adapted to operate in synchronization with a signal from the camera 14 to start shooting. The collection container 13 is, as shown in FIG. 1, disposed directly below the container body 11a and is a transparent container with a constant cross-sectional area for collecting the mortar M that has dropped from the discharge port 11n. In this example, a beaker is used. A line L extending in the circumferential direction is displayed as a marker on the side of the recovery container 13 at a position corresponding to the height h of the mortar M when all of the mortar M injected into the container body 11a is stored within the recovery container 13. The height h of line L measured from the bottom of recovery container 13 can be expressed as h=V / S, where V is the volume of mortar M injected into container body 11a and S is the cross-sectional area of ​​recovery container 13. As a result, by determining whether the height of the mortar M in the recovery container 13 has reached the line L, it is possible to determine whether the mortar M remains in the test container 11a. In reality, a small amount of mortar M remains in the test container 11a, so when the height corresponding to the allowable value ΔV of the remaining amount of mortar M is Δh, it is preferable to make the line L a line having a width such as [h-Δh, h].

[0012] The camera 14 is installed in front of the test container 11 and captures a video of the mortar M from when it starts to fall from the discharge port 11n of the test container 11 until it stops falling. The partition plate 15 is a plate material that is arc-shaped in a plan view and is placed in the background behind the test container 11, with a height higher than the height of the discharge outlet 11n of the test container 11. In this example, the front surface of the partition plate 15 (the surface facing the test container 11) is a color (here, white) of different brightness from the color of the mortar M (here, gray). By making the background of the falling mortar M plain and of a color different in brightness from the color of the mortar M, a certain level of brightness difference will be created between the falling mortar M and the background, making it possible to determine by image analysis whether or not mortar M is falling on a frame-by-frame basis in the recorded video.

[0013] The fall time calculation means 16 is equipped with an image processing unit 16a and a fall time calculation unit 16b, and calculates the fall time, which is the time from when the mortar M starts to fall from the discharge outlet 11n of the test container 11 to when it finishes, from the video captured by the camera 14. The image processing unit 16a extracts frames in which the mortar M falls continuously from the captured video using a background subtraction method described later, and sends the extracted frames to the fall time calculation unit 16b. The extracted frames are a plurality of consecutive frames. The fall time calculation unit 16b counts the number of frames N in which the mortar M is captured, converts this number of frames N into a time T using the following formula (1), and regards the converted time T as the fall time. T = N × frame rate (fps = number of frames per second) ………(1) The fall time T is sent to the memory means 18 together with the name of the mortar M tested. The display means 17 displays a management table 18T, in which the drop time T calculated by the drop time calculation means 16 and the name of the tested mortar M are written, on a display screen 17G such as a liquid crystal display. The storage means 18 stores the drop time T calculated by the drop time calculation means 16 and a management table 18T in which the name of the mortar M tested is recorded.

[0014] Here, the background subtraction method will be described. Background subtraction is an image processing technique that compares the difference in brightness between an image in which no moving objects are present (background image) and an image (input image) taken at a different time with the same camera position and field of view. If there is an area in the input image where the difference in brightness exceeds a predetermined threshold, that area is detected as a moving object. In the background subtraction method, for example, a frame (still image G 00 ) is converted to grayscale and used as the background image G 01 As shown in Fig. 3(b), the frame after the mortar M starts to fall (still image G k ) is converted to grayscale and used as the input image G 1k Let us assume that. And background image G 01 and the input image G 1k The image consisting of the difference in brightness between 2k The difference image G 2k The result is an image that shows only the moving object, mortar M, as shown in Figure 3(c). Grayscale conversion refers to converting an image having three-dimensional color information of RGB values ​​into an image having one-dimensional information of only gray, which is an intermediate color between black and white.

[0015] Next, a method for measuring the fall time will be described with reference to the flow chart of FIG. First, in a state where the discharge port 11n of the test container 11 is closed, mortar M is poured into the container body 11a up to the level (step S10). The pouring of the mortar M is performed by an operator. Next, the camera 14 is installed in front of the test container 11, and the partition plate 15 is placed behind it (step S11). Next, video recording is started, and the lid member 12 is rotated to cause the mortar M in the container body 11a to drop from the discharge port 11n into the collection container 13 (step S12). In step S13, the number of frames N in which the continuously falling mortar M is captured, extracted using a background subtraction method, is counted, and the fall time T is calculated from the counted number of frames N (step S14). The calculation method for the fall time T is as follows. It is assumed that each frame (image) has been converted to grayscale in advance. First, as shown in FIG. 5(a), a background image G 01 After creating the input image, as shown in FIG. 5(b), an input image is created at each time interval Δt. Hereinafter, the shooting start time is denoted as t 0 At time t k =t 0 +k Δt (k=1~n) is the input image G 1k Let us assume that. In addition, Δt may be the same as the frame interval (1 / frame rate), but it is also possible to set the input image G every two or three frames. 1k may be created. Next, as shown in FIG. 5(c), at time t k For each difference image G 2k After creating the image, a series of differential images G, which show the falling mortar M, are created. 2k (For example, G 22 ~G 25 ) is extracted, and the extracted difference image G 2k Let N be the number of frames in which mortar M appears. Then, the number of frames N is converted into time T, and this converted time T is set as the fall time. Conversion formula (1) is shown below. T = N × frame rate (fps = number of frames per second) ………(1) Next, the drop time T calculated in step S14 and the name of the tested mortar M are written and stored in the management table 18T, and the management table 18T is displayed on the display screen 17G (step S15). Finally, a check is performed to see if mortar M remains in the container body 11a (step S16). Since it is not possible to determine from an image whether mortar M remains in the container body 11a, in this example, after calculating the fall time T, it is checked whether the height of mortar M in the collection container 13 reaches the line L displayed on the side of the container to check whether mortar M remains in the container body 11a. In step S16, if the height of mortar M is within the width of line L, i.e., if the difference between the height h of mortar M and the position of line L is within the allowable amount Δh, proceed to step S17 and end the test of that mortar M. On the other hand, if the height h of mortar M is below line L, write "retest" in management table 18T and end the test (step S18). In addition, if the mortar to be tested has a high viscosity, the mortar M may not fall continuously, but may fall discontinuously in drops. In this case, when the moving object mortar M is detected from the captured video, after the start of the fall, a frame in which the falling mortar M is detected will appear after a frame in which the mortar M is not detected. Therefore, if the time during which the mortar M falls discontinuously is equal to or longer than a certain value, it is determined that the fall time T cannot be calculated, and a retest is performed.

[0016] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0017] For example, in the above embodiment, the cover 12a is rotated in conjunction with the start of shooting to open the outlet 11n, but the outlet 11n may be opened after a predetermined time or at any timing after the start of shooting by the camera 14. Also, the cover 12a may be slid horizontally to open the outlet 11n. In the above embodiment, the line L is provided in the collection container 13 to determine whether or not mortar M remains in the test container 11a. Alternatively, the weight of the collection container 13 may be measured. In addition, a light or laser light may be shone from the top of the test container 11, and whether or not mortar M remains in the test container 11a may be determined based on whether the color of the inside of the container body 11a when viewed from the injection port 11m has changed from before the mortar M was dropped. At this time, if an image is taken of the area near the line L of the collection container 13 and the test container 11 from above, and the image taken can be used to determine whether or not mortar M remains in the container body 11a, thereby reducing the burden on workers. In addition, in the above embodiment, the management table 18T displayed on the display means 17 is stored in the memory means 18, but if this stored management table 18T can be sent to a management center away from the site, the fluidity test data of mortar M can be shared. [Explanation of symbols]

[0018] 10 Mortar fluidity test equipment; 11 test container, 11a container body, 11b support member, 11c lid mounting member, 11m inlet, 11n outlet 12 cover member, 12a cover portion, 12b rotating portion, 12c connecting plate, 13 Collection container, 14 Camera, 15 Partition, 16 Fall time calculation means, 16a image processing unit, 16b fall time calculation unit, 17 display means, 17G display screen, 18 storage means, 18T management table, M Mortar.

Claims

1. A method for measuring the falling time of mortar, comprising: placing a partition plate having a different brightness from that of the mortar in the background of a test container for storing the mortar; taking a video of the mortar from when it starts to fall from the discharge port of the test container to when the mortar stops falling; and calculating the falling time of the mortar from the taken video.

2. A recovery container for recovering the dropped mortar is placed directly below the test container, and a mark is placed on the side of the recovery container at the position of the surface of the mortar when it is assumed that all of the mortar has fallen; 2. The method for measuring the mortar drop time according to claim 1, wherein it is determined that all of the mortar in the test container has fallen when the height of the mortar in the recovery container reaches the position of the mark.

3. A test vessel for containing mortar; a photographing means for photographing a video of the mortar contained in the test container from the time the mortar starts to fall from the discharge port of the test container to the time the mortar stops falling; A partition plate having a different brightness from that of the mortar, the partition plate being provided on the opposite side of the test container from the photographing means; a drop time calculation means for calculating a drop time, which is a time from when the mortar starts to drop from the discharge port to when the mortar stops to drop, from the captured video; A mortar fluidity test device equipped with a

4. 4. The mortar fluidity testing device according to claim 3, further comprising a cover member provided on the discharge port side of the test container for opening the discharge port in conjunction with the start of photography by the photography device.

5. 5. The mortar fluidity testing device according to claim 3, further comprising a storage means for storing a management table in which the name of the mortar for which the drop time has been calculated and the calculated drop time are recorded.

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