Temperature boundary identification system

Abstract

This invention provides a temperature boundary identification system that can identify temperature boundaries more efficiently and accurately than conventional systems. [Solution] The thermal camera 11 is capable of capturing thermal images of a material, and the thermal image analysis means 12 acquires the thermal images captured by the thermal camera 11 and analyzes the thermal images. The thermal image analysis means 12 calculates the average temperature for each pixel column or row of pixels based on the detected temperature of each pixel in the captured thermal image, calculates the temperature difference for each pixel column or row of pixels based on the average temperature for each pixel column or row of pixels, and identifies the pixel column or row of pixels with the largest temperature difference as a temperature boundary.

Description

Technical Field

[0001] The present invention relates to a temperature boundary discrimination system capable of discriminating temperature boundaries in asphalt mixtures and the like.

Background Art

[0002] Conventionally, in the construction of asphalt pavement, the temperature of the asphalt mixture spread by an asphalt finisher has been measured and managed by a portable contact thermometer or a non-contact thermometer, and joint rolling, initial rolling, secondary rolling, and finishing rolling by a roller have been carried out step by step. That is, during the construction of asphalt pavement, a quality control person carried a thermometer and measured the temperature at each location, and repeatedly instructed the roller operator about the start timing and rolling range of rolling, or clearly indicated the rolling range with a cone or the like.

[0003] Also, in the production of asphalt mixtures in an asphalt plant, materials (sand, crushed stone, etc.) stored in an outdoor stockyard are supplied to a cold hopper by a wheel loader. The supplied materials are dried and heated by a dryer facility and stored in a hot bin. At this time, if a material with a high water content ratio is supplied, the fuel cost required for drying and heating increases. To suppress such an increase in fuel cost, conventionally, the operator of the wheel loader visually checks the water content ratio of the materials stored in the stockyard, and scoops up the materials with a low water content ratio with a bucket and supplies them to the cold hopper.

[0004] Also, in relation to temperature, Patent Document 1 discloses an invention configured to discriminate the laying boundary between a newly laid pavement and an existing pavement or a formwork from a thermal image photographed by a thermo camera for the purpose of reducing the adjustment labor of a screed widener provided in an asphalt finisher, and automatically moving the widener.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, in the conventional method of asphalt paving construction described above, where a quality control officer carries a thermometer to measure the temperature at each location and instructs the roller operator on the timing and area of ​​compaction each time, the quality control officer had to constantly walk around and measure the temperature. Furthermore, since the measurements were taken at specific points, it was a significant burden to determine and instruct on the appropriate compaction area.

[0007] Furthermore, the visual inspection of moisture content in the stockyard, as described above, relies on the subjective judgment of the operator performing the inspection, making it difficult to effectively reduce fuel costs required for heating and drying.

[0008] Furthermore, the invention disclosed in Patent Document 1, as described in paragraph 0029 and Figure 6 of Patent Document 1, identifies the laying boundary of new pavement based on thermal images of wooden formwork with very low thermal conductivity. However, when two asphalt finishers are operated in parallel, simultaneously at a predetermined distance in the direction of travel, and the joints between adjacent pavements are made into hot joints, the ambient temperatures around the pavement joints become very similar. In addition, once the hot joints are compacted, it becomes very difficult to visually identify the laying boundary, unlike with wooden formwork. Consequently, it is not possible to obtain a thermal image showing a clear, straight line like that in Figure 6 of Patent Document 1, and therefore, it is difficult to accurately detect the pavement laying boundary using the thermal image recognition method disclosed in Patent Document 1.

[0009] Therefore, in view of the various problems described above, the present invention aims to provide a temperature boundary identification system that can identify temperature boundaries more efficiently and with higher accuracy than conventional systems. [Means for solving the problem]

[0010] The present invention relates to a temperature boundary identification system comprising a thermal camera capable of capturing thermal images of a material, and a thermal image analysis means for acquiring and analyzing the thermal images captured by the thermal camera, wherein the thermal image analysis means calculates the average temperature for each pixel column or row of pixels based on the detected temperature of each pixel in the captured thermal image, calculates the temperature difference for each pixel column or row of pixels based on the average temperature for each pixel column or row of pixels, and identifies the pixel column or row of pixels with the largest temperature difference as a temperature boundary.

[0011] In a further embodiment, the temperature boundary identification system includes a display means for displaying the analysis results obtained by the thermal image analysis means, and the display means is capable of displaying the temperature boundary.

[0012] In a further embodiment, the display means is a temperature boundary identification system characterized in that it is possible to display the temperature boundary overlaid on a thermal image or visible image of the material.

[0013] In a further embodiment, the temperature boundary identification system includes an operation control means for controlling the operation of a construction machine and / or an apparatus attached to the construction machine, wherein the operation control means is capable of controlling the operation of the construction machine and / or the apparatus attached to the construction machine based on the temperature boundary identified by the thermal image analysis means.

[0014] In another embodiment, the temperature boundary identification system is characterized in that the material is an asphalt mixture. [Effects of the Invention]

[0015] Unlike image recognition techniques using thermal images, such as those disclosed in Patent Document 1, the temperature boundary identification system of the present invention makes it possible to identify temperature boundaries more efficiently and accurately than conventional methods, based on temperature data for each pixel.

[0016] Also, when the present invention described above is applied to an asphalt finisher, a roller, a stockyard, etc., the work efficiency, safety, quality, economy, etc. can be significantly improved by automating the machine operation and the like.

Brief Description of the Drawings

[0017] [Figure 1] It is an external perspective view of a temperature boundary identification system in one embodiment of the present invention. [Figure 2] It is a block diagram showing an example of the system configuration of a temperature boundary identification system in one embodiment of the present invention. [Figure 3] It is a side perspective view of an asphalt finisher in one embodiment of the present invention. [Figure 4] It is an upper perspective view (a) and a lower perspective view (b) of an end pressing means in one embodiment of the present invention. [Figure 5] It is a perspective view of an end pressing means equipped with a temperature boundary identification device in one embodiment of the present invention. [Figure 6] It is a diagram for explaining a photographing mode by a thermo camera in one embodiment of the present invention. [Figure 7] It is a diagram for explaining an example of calculating an average temperature for each column based on temperature data of each pixel of a photographed image in one embodiment of the present invention. [Figure 8] It is a diagram for explaining a method of calculating a temperature difference for each column in one embodiment of the present invention. [Figure 9] It is a diagram for explaining a method of outputting a boundary between a newly laid pavement and an existing pavement from a photographed image in one embodiment of the present invention. [Figure 10] It is a diagram for explaining an offset function in one embodiment of the present invention. [Figure 11] In another embodiment of the present invention, it is a diagram for explaining an example in which a temperature boundary identification system is applied to a stockyard. [Figure 12] In another embodiment of the present invention, it is a diagram for explaining an example in which a temperature boundary identification system is applied to a stockyard. [Figure 13] In another embodiment of the present invention, it is a diagram for explaining an example in which a temperature boundary discrimination system is applied to a roller. [Figure 14] In another embodiment of the present invention, it is a diagram for explaining an example in which a temperature boundary discrimination system is applied to a roller. [Figure 15] In another embodiment of the present invention, it is a diagram for explaining an example in which a temperature boundary discrimination system is applied to a roller. [Figure 16] In another embodiment of the present invention, it is a diagram for explaining an example in which a temperature boundary discrimination system is applied to a roller. [Figure 17] In another embodiment of the present invention, it is a diagram for explaining an example in which a temperature boundary discrimination system is applied to a roller.

Mode for Carrying Out the Invention

[0018] Hereinafter, each embodiment of the temperature boundary discrimination system of the present invention and the temperature boundary discrimination device included therein will be described with reference to the drawings.

[0019] In FIG. 1, an external perspective view of a temperature boundary discrimination system 1 in an embodiment of the present invention is shown, and in FIG. 2, an example of the system configuration of the temperature boundary discrimination system 1 is shown in a block diagram.

[0020] As shown in the figure, the temperature boundary discrimination system 1 of the present embodiment includes a thermal camera 11 capable of taking a thermal image of a material, and a thermal image analysis means 12 for acquiring the thermal image taken by the thermal camera 11 and analyzing the thermal image. The thermal image analysis means 12 calculates an average temperature for each pixel column or pixel row based on the detected temperature of each pixel of the taken thermal image, calculates a temperature difference for each pixel column or each pixel row based on the average temperature for each pixel column or each pixel row, and identifies the pixel column or pixel row where the temperature difference is maximum as the temperature boundary.

[0021] To illustrate with a specific example, Figure 3 shows a side perspective view of an asphalt finisher 1 equipped with a pavement edge finishing device 20 capable of finishing the side edges of newly laid pavement. The pavement edge finishing device 20 is provided with an edge compaction means 24 via a connecting member 21 that can compact the side edges of the newly laid pavement at the rear side end of the screed 3.

[0022] Figure 4 shows an upper perspective view (a) and a lower perspective view (b) of the end compaction means 14. As shown in the figure, it comprises a plate member 245 that is in direct contact with the side edge of the pavement and a vibrator 243 that enables compaction by the plate member 245, making it possible to properly compact the side edge of the pavement. The end compaction means 24 also includes a traverse means 241 that allows the end compaction means 24 to be moved in the transverse direction (direction of the arrow shown) at the side edge of the asphalt pavement.

[0023] The traversing mechanism 241 described above consists of an electric cylinder with a stroke of 200 mm. This makes it possible to move the end compaction mechanism 24 to an appropriate position according to the end position of the newly constructed pavement.

[0024] Furthermore, as shown in Figure 5, in this embodiment, a temperature boundary identification device 10 capable of identifying temperature boundaries by capturing thermal images of the area around the side edge of the leveled asphalt pavement is provided on the front side of the end compaction means 14.

[0025] Specifically, as shown in Figure 6, the thermal camera 11 of the temperature boundary identification device 10 is configured to photograph the vicinity of the edge of the newly constructed pavement from a predetermined height position (h). This aims to identify the temperature boundary between the existing pavement, which has a lower surface temperature, and the newly constructed pavement, which has a higher surface temperature. It should be noted that the boundary between the newly constructed pavement is not limited to the existing pavement; it is also possible to detect the boundary portion of other structures such as pavement guides, gutters, and street drains, as long as a temperature difference with the newly constructed pavement can be captured.

[0026] Figure 7 shows an example of a captured thermal image. In this embodiment, a thermal image measuring 200 mm horizontally (32 squares: 6.25 mm) and 150 mm vertically (24 squares: 6.25 mm) is captured, and temperature data can be obtained for each square (1 pixel).

[0027] In this embodiment, as shown in the illustration, the thermal image analysis means 12 calculates the average temperature for each pixel row from row No. 1 to row No. 32. Once the average temperature for each pixel row is calculated, the temperature difference is calculated as shown in Figure 8.

[0028] In other words, the column with the largest temperature difference is identified as the side edge of the new pavement (the temperature boundary between the existing pavement surface and the new pavement surface), as shown in Figure 10(a). Based on this result, the operation control means 16 controls the aforementioned traverse means 241. This makes it possible to always position and compact the edge compaction means 24 at an appropriate transverse position during pavement construction.

[0029] In other words, as shown in Figure 9, the temperature in the i-th row and j-th column is denoted as x(i,j), the average temperature Xj in the j-th column and the temperature difference Tj in the j-th column are calculated using the relationship in Figure 9, and the position in the j-th column where the temperature difference Tj is maximum is output as the side edge of the new pavement (the temperature boundary between the illustrated existing pavement surface and the new pavement surface).

[0030] The thermal image analysis described above is performed by the thermal image analysis means 12 shown in Figure 2, and can be carried out using a microcontroller or the like built into the temperature boundary identification device 10. Of course, it is also possible to perform the analysis using an externally connected PC or tablet terminal, and the analysis means are not particularly limited.

[0031] Furthermore, as shown in Figure 10(b), the thermal image analysis means 12 may also be equipped with an offset function that sets an offset line at a predetermined distance towards the new pavement from the side edge of the new pavement (the temperature boundary between the existing pavement surface and the new pavement surface shown in the figure) calculated and output as described above. Of course, this offset function can also set the offset line towards the existing pavement side or towards the wooden formwork side rather than the edge of the new pavement.

[0032] In other words, depending on the construction conditions, the most preferable position for compaction by the end compaction means 24 is not necessarily the side edge of the new pavement (the temperature boundary between the existing pavement surface and the new pavement surface shown in the diagram). Therefore, the system is configured to output a suitable compaction position (offset line shown in the diagram) located at a predetermined distance from the side edge of the new pavement (the temperature boundary between the existing pavement surface and the new pavement surface shown in the diagram). Based on this, the operation control means 16 controls the traverse means 241, making it possible to always position the end compaction means 24 at a suitable transverse position during pavement construction. (Other embodiments) Although the temperature boundary identification system 1 of this embodiment has been described above, the present invention is not necessarily limited to the embodiments described above, and various modifications as shown below are possible.

[0033] For example, as shown in Figures 11 and 12, the temperature boundary identification system of the present invention can be applied to a stockyard for storing storage materials such as crushed stone aggregate. As shown in the figures, the temperature boundary identification device 10 is installed in the stockyard and the surface temperature of the storage material is captured by a thermal camera 11.

[0034] When the moisture content of stored material is high, the surface temperature is lower than when the moisture content is low. Because of this property, by applying the temperature boundary identification system of the present invention and identifying the temperature boundary, it becomes possible to identify the moisture content boundary line. Furthermore, as shown in Figure 12, a display means 14 can be provided in the stockyard to display the height position corresponding to the moisture content boundary line.

[0035] This allows the wheel loader operator to visually recognize the boundary line of the moisture content of the stored material by observing the height indicator of the display means 14, and for example, to efficiently scoop up aggregate with a low moisture content in the bucket in order to reduce the fuel costs of the burner required to heat the aggregate when manufacturing asphalt mixture.

[0036] Furthermore, while the above-described embodiment explains a configuration in which the temperature difference of each pixel row is calculated based on Figures 7-10 to identify a temperature boundary extending in the front-to-back direction, the invention is not necessarily limited to this configuration. For example, when identifying a temperature boundary extending in the left-to-right direction of an image, it is possible to identify the temperature boundary by calculating the temperature difference of each pixel row.

[0037] Next, as shown in Figures 13-17, the temperature boundary identification system of the present invention can be applied to the compaction process of asphalt pavement. As shown in the figures, the temperature boundary identification device 10 is installed in front of the roller, and the surface temperature of the leveled asphalt mixture is captured by the thermal camera 11.

[0038] In asphalt pavement, for example, secondary compaction using a tire roller has a predetermined compaction temperature, and it is necessary to confirm that the pavement temperature has dropped to the predetermined temperature (generally 70-90°C) before starting secondary compaction. Therefore, by setting a predetermined compaction temperature in the temperature range identification system, it can be configured to notify the timing of compaction start and the range in which compaction is possible.

[0039] The specific technical configuration includes a thermal camera 11 capable of capturing thermal images of materials, and a thermal image analysis means 12 that acquires the thermal images captured by the thermal camera 11 and analyzes the thermal images. The thermal image analysis means 12 is a temperature boundary identification system 1 that calculates the average temperature for each pixel row based on the detected temperature of each pixel in the captured thermal image, and identifies pixel rows where the average temperature for each pixel row at the frontmost side in the shooting direction is equal to or greater than a predetermined set temperature as temperature boundaries.

[0040] More specifically, Figure 14 shows a thermal image captured by a thermal camera 11 installed on a tire roller, and this range is the identification range for identifying the temperature boundary. The temperature boundary identification system 1 is provided with a boundary temperature setting means that allows setting the temperature of the temperature boundary, and for example, it is possible to set it to 90°C, which is the temperature at which compaction by the tire roller is impossible.

[0041] Furthermore, the thermal image analysis means 12 calculates the average temperature for each pixel row based on the detected temperature of each pixel in the captured thermal image, and monitors it by comparing it with the temperature set by the boundary temperature setting means (for example, set temperature: 90°C). In this embodiment, the average temperature of the top row and the average temperature of the bottom row are compared, and the higher temperature is determined to be the direction of travel of the tire roller.

[0042] Next, as shown in Figure 15, the thermal image analysis means 12 detects the range (shown by the dashed line) in which the average temperature of each pixel row is equal to or above the set temperature (90°C) as the pressure-free temperature zone, and further identifies the pixel row in the foreground of the shooting direction in which the average temperature of each pixel row is equal to or above the predetermined set temperature (90°C) as the temperature boundary.

[0043] As the tire roller progresses in compaction and approaches the preceding asphalt finisher (not shown), the temperature zone where compaction is not possible (shown by the dashed line in Figure 16) expands towards the foreground in the direction of the photograph. In other words, as compaction by the tire roller progresses, it follows the moving temperature boundary. In this embodiment, the tracking is performed finely at 8 Hz (0.125 sec).

[0044] Based on the analysis results from the thermal image analysis means 12 described above, a display means 14 as shown in Figure 17 is placed in the operator's seat of the roller, and the compaction area and other information are displayed on the display means, allowing the operator to perform compaction appropriately.

[0045] In the example shown in Figure 17, the system visually displays the area where compaction is not possible (beyond the compaction temperature) and the area where compaction is possible, separated by an identified temperature boundary. In addition, it displays the remaining distance to the temperature boundary to the operator of a moving tire roller while compacting, as shown by the message "Compaction Possible, 5.3m Remaining". The distance to the temperature boundary can be calculated based on the dimensions of each row (one cell) of the pixel row.

[0046] The notification method for the tire roller operator is not limited to a specific method; voice or alarm sounds can also be used. Furthermore, as shown in Figure 17, the non-compactionable and compactionable areas may be combined and displayed on a visible image, or an appropriately created animated image may be displayed.

[0047] Furthermore, while the temperature boundary identification system 1 of the above-described alternative embodiment was explained using the compaction work of a tire roller as an example, it is not necessarily limited to this. For example, when managing the timing of opening a road after pavement construction, the temperature boundary identification system of the present invention can be used to appropriately determine the range within which the road can be opened.

[0048] Furthermore, while Figures 7-10 and 14-16 show examples of thermal images, it is possible to arbitrarily set the shooting range, installation height, installation position, and dimensions per square of the thermal camera 11.

[0049] Although embodiments and other modifications of the present invention have been described above, the scope of the present invention is indicated by the claims rather than the above-described embodiments, and all modifications within the meaning and scope of equivalence to the claims are included. Furthermore, the specific materials, dimensions, shapes, etc., described in the above embodiments can be modified to the extent that they solve the problem of the present invention. [Explanation of symbols]

[0050] 1. Temperature boundary identification system 10. Temperature boundary identification device 11. Thermal camera 12 Thermal image analysis means 13 Communication lines 14 Display means 15 Input / Output Means 16 Operation control means 2. Asphalt finisher 3 Screede 20 Pavement edge finishing device 21 Connecting Member 24 End compaction means 241 Rampant means 243 Vibrator 245 Plate Member

Claims

1. A thermal camera capable of capturing thermal images of materials, The system includes a thermal image analysis means for acquiring the thermal image captured by the thermal camera and analyzing the thermal image, The thermal image analysis means is Based on the detected temperature of each pixel in the captured thermal image, the average temperature is calculated for each pixel column or pixel row. Based on the average temperature for each pixel column or pixel row, the temperature difference for each pixel column or pixel row is calculated, and the pixel column or pixel row with the largest temperature difference is identified as a temperature boundary. A temperature boundary identification system characterized by the following features.

2. The system has a display means for displaying the analysis results obtained by the thermal image analysis means, The display means is capable of displaying the temperature boundary. The temperature boundary identification system according to feature 1.

3. The display means is capable of displaying the temperature boundary overlaid on the thermal image or visible image of the material. The temperature boundary identification system according to claim 2.

4. It has operation control means for controlling the operation of construction machinery and / or the operation of devices attached to said construction machinery, The operation control means can control the operation of the construction machine and / or the operation of devices attached to the construction machine based on the temperature boundary identified by the thermal image analysis means. The temperature boundary identification system according to feature 1.

5. The aforementioned material is an asphalt mixture. The temperature boundary identification system according to feature 1 to 4.

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