Measurement system and measurement method

Abstract

To provide a technology capable of obtaining random patterns without using irradiation in thermal image matching.SOLUTION: A measurement system comprises: random pattern sheets 110, 111, and 112 configured of a first member that generates heat or absorbs heat and a second member composed of a material different from that of the first member; infrared cameras 101 and 102 that photograph the random pattern sheets 110, 111, and 112 from two different viewpoints, and photograph a first thermal image and a second thermal image; and a PC 120 which is a processing device for performing stereo matching of the first thermal image and the second thermal image using random patterns of the random pattern sheets.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for determining correspondence between a plurality of thermal images. [Background technology]

[0002] Stereophotography using thermal images (also called infrared images) is known (see, for example, Patent Document 1). In stereophotography, it is necessary to match (identify the correspondence between) two paired photographs. Matching is efficient when a random pattern such as a random dot pattern is used.

[0003] Patent Document 1 describes irradiating a random dot infrared pattern and matching a pair of thermal images. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-019346 Summary of the Invention [Problem to be solved by the invention]

[0005] A method for irradiating a random dot pattern of infrared rays requires an irradiation device. In this context, the present invention aims to provide a technique for obtaining a random pattern in thermal image matching without irradiation. [Means for solving the problem]

[0006] The present invention reaction or endothermic Show a reactionThe measurement system includes a random pattern composed of a first member and a second member made of a material different from that of the first member, an infrared camera that photographs the random pattern from two different viewpoints and takes a first thermal image and a second thermal image, and a processing device that uses the random pattern to perform stereo matching of the first thermal image and the second thermal image.

[0007] In the present invention, the first member is a heat generating member. Show a reaction In one embodiment, the heat generating member is a granular material, and a large number of the granular materials are randomly scattered on the surface of the second member having a flat surface. Show a reaction In one embodiment, the granular material is iron powder in the process of oxidation. Show a reaction The particulate matter may be, for example, calcium oxide particles reacting with moisture or burning charcoal particles.

[0008] In the present invention, the endothermic Show a reaction In one embodiment, the first component is a grain containing urea and / or ammonium nitrate, and the endothermic heat is generated by a reaction between moisture and the urea and / or ammonium nitrate. Also, The present invention teeth, Ice or dry ice pellets The measurement system includes a random pattern composed of a first member and a second member made of a material different from that of the first member, an infrared camera that photographs the random pattern from two different viewpoints and takes a first thermal image and a second thermal image, and a processing device that uses the random pattern to perform stereo matching of the first thermal image and the second thermal image.

[0010] In the present invention, the first member may be iron powder, the second member may be magnetic, and the first member may be attached to the surface of the second member by magnetic force. In the present invention, the first member may include a carbon material and a coating that prevents the carbon material from coming into contact with the outside air and / or a material that prevents the carbon material from oxidizing. In the present invention, the first member may include exhibits an exothermic reaction, and the second member endothermic or the first component exhibits an endothermic reaction, and The second member generates heat Show a reaction The following aspects can be mentioned. The present invention also provides a measurement system that includes a random pattern formed at one end of an assembly in which a plurality of first rod-shaped members and second rod-shaped members having a thermal conductivity different from that of the first rod-shaped members are bundled together in a random arrangement by heating or cooling the other end of the assembly, an infrared camera that photographs the random pattern from two different viewpoints and takes a first thermal image and a second thermal image, and a processing device that uses the random pattern to perform stereo matching of the first thermal image and the second thermal image.

[0011] The present invention reaction or endothermic Show a reactionThis is a measurement method in which a random pattern consisting of a first member and a second member made of a different material from the first member is photographed from two different viewpoints to obtain a first thermal image and a second thermal image, and the random pattern is used to perform stereo matching of the first thermal image and the second thermal image.

[0012] In the above measurement method, the first member may be a large number of granular bodies, the second member may have a surface, and the random pattern may be formed by scattering the large number of granular bodies on the surface of the surface of the second member. The present invention also provides a measurement method in which one end of an assembly in which a plurality of first rod-shaped members and second rod-shaped members having a thermal conductivity different from that of the first rod-shaped members are bundled together in a random arrangement is heated or cooled, and the random pattern formed at the other end of the assembly is photographed from two different viewpoints to obtain a first thermal image and a second thermal image, and the random pattern is used to perform stereo matching of the first thermal image and the second thermal image. [Effects of the Invention]

[0013] According to the invention, random patterns are obtained in matching thermal images without illumination. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a conceptual diagram of an embodiment. [Figure 2] Photograph (A) shows a random pattern, and photograph (B) shows a granular heating element. [Figure 3] Photographs (A) and (B) are used as drawing substitutes to show a random pattern using a granular heating element. [Figure 4] FIG. 10 is a diagram showing a method for creating a random pattern using a granular heating element. [Figure 5] FIG. 2 is a cross-sectional view of a random pattern sheet. [Figure 6] 1A to 1C are cross-sectional views and a perspective view (D) showing a method for producing a random pattern sheet. [Figure 7] FIG. 10 is a diagram illustrating an example of a random dot pattern. [Figure 8] FIG. 10 is a diagram illustrating an example of a random dot pattern. [Figure 9] 1A and 1B are diagrams showing an example of a granular heating element. [Figure 10] 1A is a cross-sectional view and FIG. 1B is a perspective view of a random pattern sheet. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1. First embodiment (composition) Fig. 1 shows a measurement system using the present invention. Fig. 1 shows a case where stereo photography of a thermal image of a plant 100 is performed. The object of thermal image capture is not limited to plants. Here, an example using two infrared cameras 101 and 102 is shown. It is also possible to use three or more infrared cameras.

[0016] Infrared cameras 101 and 102 are set to capture overlapping areas and capture images of plant 100 from different viewpoints. Random pattern sheets 110, 111, and 112 made of heat-generating granular material are arranged around plant 100.

[0017] The method for creating the random pattern sheets 110, 111, and 112 will be described later. A simple method for obtaining a random dot pattern is to randomly scatter heat-generating granular material on the surface of a plate-like member, for example. A random dot pattern is one example of a random pattern. There are also random patterns that are not made up of dots. A random pattern is defined as a continuous display of a pattern with no regularity.

[0018] The positions and orientations of the infrared cameras 101 and 102 are adjusted so that they can simultaneously capture as many random patterns as possible.

[0019] The heat-generating granular material is, for example, iron powder undergoing oxidation. In this case, the heat generated by oxidation (oxidation heat) is utilized. A simple example is the contents of a disposable hand warmer. The main components of the contents of a disposable hand warmer are iron powder, water, vermulite, and activated carbon. Water accelerates the oxidation of the iron powder, vermulite retains moisture, and activated carbon promotes the supply of oxygen necessary for oxidation. When the disposable hand warmer is removed from its airtight bag, the iron powder reacts with oxygen in the air, causing an oxidation reaction and generating oxidation heat. The size of the particles that make up the granular material must be large enough to be distinguishable as particles in a thermal image. As long as there is a certain amount of heat generation, the image can be recognized in a thermal image even if the actual size of the particles is small.

[0020] Figure 2(A) shows an example of a random pattern for a visible image. Figure 2(A) shows an example of a random dot pattern in which many fine dots are randomly arranged. Figure 2(B) shows the iron powder in a disposable hand warmer. When this iron powder is applied to a surface, a random dot pattern is formed. When the iron powder generates heat in this state, a thermal image of the random dot pattern is obtained.

[0021] This random pattern also functions as a random pattern in a visible image because the iron powder is visible to the naked eye. Therefore, it can also be used for matching in visible images. A random pattern can also be formed by scattering heat-generating granular material around the subject. It is also possible to scatter a heating element on top of a printed random pattern, or conversely, place a printed pattern on top of a heating element.

[0022] Figure 3(A) is an RGB image showing the experimental situation. Heat-generating iron powder was scattered as shown in Figure 3(A) and a thermal image was taken. The thermal image taken is shown in Figure 3(B). As shown in Figure 3(B), the heat-generating iron powder is visualized as a random dot pattern in the thermal image.

[0023] Infrared cameras 101 and 102 photograph a plant 100, obtaining two thermal images. These two thermal images form a stereo thermal image. To create a stereo thermal image, the two thermal images must be matched. In this case, the random patterns (random dot patterns in the case of Figure 1) on random pattern sheets 110, 111, and 112, which are commonly seen in the two thermal images, are used.

[0024] The principle of matching using random patterns is the same as that of visible images. For example, suppose a random pattern recognizable in the thermal image above is photographed with an infrared camera from two different viewpoints, resulting in the first and second thermal images. To create a stereo thermal image from these two thermal images, it is necessary to match the two thermal images.

[0025] Specifically, a process is required to identify the correspondence between the image content of the first thermal image and the image content of the second thermal image. Simply put, a process is performed to identify where a certain part of the first thermal image corresponds to in the second thermal image. Various algorithms for the matching process are known, such as template matching.

[0026] Random patterns are used to perform the above matching efficiently. Without random patterns, problems such as increased matching errors and false matching become apparent.

[0027] 1 shows a PC (personal computer) 120, which is a processing means for processing image data of thermal images, performing the stereo matching process described above, and creating a 3D model of the photographed object (plant 100) based on the stereo thermal images. These processes can also be performed by dedicated hardware or a data processing server.

[0028] Here, we have shown an example of constructing a stereo thermal image using two thermal images, but it is also possible to use three or more thermal images. It is also possible to take thermal images while moving a single infrared camera, and obtain a set of stereo thermal images one after another. This is the same as in the case of stereoscopic photography measurement using SFM.

[0029] In addition, the infrared camera can be fixed and the object being photographed can be rotated to obtain thermal images of the object from multiple different viewpoints, and when matching these multiple thermal images, a random pattern using the above-mentioned heat-generating granular material can be used.

[0030] (How to make) Fig. 4 shows an example of a method for producing the random pattern sheets 110 to 112 shown in Fig. 1. First, a glue stamp 121 is produced on which protrusions of a random pattern are formed.

[0031] Glue (adhesive or adhesive) is applied to the protruding surface of this glue stamp 121, and it is stamped onto a mount 122, which is a member having a flat surface. Paper is used for the mount 122, but wood or resin may also be used as long as the material has low thermal conductivity.

[0032] Heat-generating granules are scattered on a mount 122 stamped with glue, and the granules in the areas where there is no glue are removed, thereby obtaining random pattern sheets 110 to 112 on which a random pattern made up of heat-generating granules 123 is formed on the surface of the mount 122.

[0033] (superiority) By forming a random pattern using heat-generating granular material, an infrared irradiation device, which is required when creating a random pattern by irradiating infrared light, is not required.Furthermore, the random pattern formed by this heat-generating granular material also functions as a random pattern in a visible image.

[0034] 2. Second embodiment 5 shows a plate-shaped random pattern plate 200. The random pattern plate 200 is composed of a sheet-shaped heating element 201 and a shielding random pattern layer 202 thereon, which is made of a material with poor thermal conductivity.

[0035] The sheet-shaped heating element 201 generates heat when electricity is applied. The shielding random pattern layer 202 is made of a material with poor thermal conductivity, such as resin or foam material. The shielding random pattern layer 202 has gaps (openings) in a random pattern, and the sheet-shaped heating element 202 is exposed in these gaps. This results in a random heat generation pattern.

[0036] The sheet-like heating element 201 may be a metal plate, which may be heated by a heater or Peltier element, or cooled by a Peltier element. In either case, a random pattern image is obtained on the thermal image.

[0037] 3. Third embodiment 6 is a cross-sectional view showing a method for producing another form of random pattern sheet 300. Here, a copper foil substrate used for electronic circuits is prepared. This copper foil substrate is composed of a resin substrate 301 and copper foil 302 provided thereon.

[0038] First, a mask pattern layer 303 is laminated on the surface of copper foil 302 (FIG. 6(A)). The mask pattern layer is used in a known method for forming a circuit pattern on a copper foil substrate, and is made of, for example, photoresist.

[0039] Here, a mask pattern layer 303 having a random pattern (see, for example, FIG. 2(A)) is formed. After the mask pattern layer 303 is formed, the copper foil in the unmasked areas is removed by a known etching method, resulting in the state shown in FIG. 6(B). Then, the mask pattern layer 303 is removed, resulting in the random pattern sheet 300 shown in FIGS. 3(C) and 3(D).

[0040] Here, the pattern of the mask pattern layer 303 is set so that all the remaining copper foil is connected, in order to conduct heat to the remaining copper foil, thus obtaining copper foil 302 with random turns.

[0041] When the copper foil 302 is heated by a heating element (not shown), the difference in thermal conductivity causes the remaining copper foil area to become hotter than the substrate. This results in a random pattern of temperature differences, resulting in a thermal image of the random pattern. In this case, a random dot pattern is obtained, where the dot areas without copper foil are relatively cooler and the areas with copper foil are relatively hotter. When the random pattern sheet 300 is photographed with an infrared camera, a thermal image of the random dot pattern is obtained.

[0042] A flexible resin film can also be used as the substrate, in which case the random pattern sheet 300 can be attached to a curved surface.

[0043] To increase the radiation efficiency of the copper foil, a carbon film or ceramic layer may be laminated on the surface of the copper foil. By increasing the radiation efficiency of the high-temperature areas, a clearer, more distinct random pattern thermal image can be obtained.

[0044] It is also possible to cool the copper foil 302. In this case, a random dot pattern is obtained in which dot areas without copper foil are relatively hot and dot areas with copper foil are relatively cold.

[0045] 4. Fourth Embodiment A random pattern can also be formed using two types of rods. An example of this is described below. Figure 7 shows an example in which a random pattern 603 is formed by randomly bundling metal rods 604 with relatively high thermal conductivity and resin rods 605 with relatively low thermal conductivity.

[0046] Examples of metals include copper, aluminum, brass, etc. Examples of resins include expanded polystyrene, etc. The cross-sectional shape of the rod is not limited to a circle, but may be an ellipse or various polygons.

[0047] The lower part of the bundled rod assembly is placed in a heating or cooling tank 601, which stores a heating liquid or a cooling liquid 602. Heating or cooling is performed by any known appropriate means, for example, a resistance heater or a Peltier element is used for heating, and a Peltier element is used for cooling.

[0048] For example, when heated liquid 602 is used, metal rod 604 becomes relatively hot and resin rod 603 becomes relatively cold, and the temperature difference forms a random dot pattern on the top surface that can be recognized in a thermal image. By color-coding the top surface of each rod, it is also possible to form a random dot pattern that can be recognized in an RGB image.

[0049] 5. Fifth Embodiment Granulated calcium oxide (quicklime) can also be used as the heat-generating granules. Calcium oxide generates heat when water is added. Utilizing this property, calcium oxide granules are scattered randomly on a surface, and water is sprayed onto them, causing the calcium oxide to generate heat. The random pattern can be obtained by photographing this with an infrared camera. In this case, the heat-generating reaction can be controlled by adjusting the amount of water. Also, by adding a water-retentive material, the duration of the heat-generating reaction can be adjusted.

[0050] Calcium oxide can also be sprinkled directly onto the soil, creating a random thermal pattern on the soil surface around the plants, as can charcoal, urea, ammonium nitrate, ice, and dry ice, which are discussed below.

[0051] 6. Sixth Embodiment Finely divided burning charcoal can also be used as the heat-generating granules.

[0052] 7. Sixth Embodiment It is also possible to create random patterns using materials that cool (absorb heat) rather than heat-generating granules. For example, urea and ammonium nitrate absorb heat and cool when they react with water. By using granules containing these, it is possible to create random patterns that can be recognized in thermal images. It is also possible to use a mixture of both materials.

[0053] For example, a large number of granules containing urea and / or ammonium nitrate are randomly scattered on a resin plate. Scattering them normally creates a sufficiently random distribution. By spraying water onto the mixture, the urea and / or ammonium nitrate react with the water, resulting in an endothermic reaction. This means that areas of low temperature appear in the random pattern, creating a thermally random pattern. In this case, the endothermic reaction can be controlled by adjusting the amount of water. Furthermore, adding a water-retentive material can adjust the duration of the endothermic reaction.

[0054] 8. Seventh Embodiment Ice or dry ice pellets can also be used to create random patterns that are visible in thermal images.

[0055] 9. Eighth Embodiment It is also possible to use both heat-generating and heat-absorbing materials at the same time (in combination). The important thing is to form a random pattern in the area where there is a temperature difference.

[0056] 10. Tenth embodiment Figure 8 shows a random pattern pillar 800 in which unoxidized iron powder 802 is randomly attached to a magnetic cylinder 801 made of a magnetic material (e.g., iron) by magnetic force. Methods for imparting magnetism to a magnetic cylinder 801 include constructing the cylinder 801 itself out of a magnet, or attaching a magnet to the inside of the cylinder 801.

[0057] The iron powder 802 oxidizes when exposed to air, generating heat, which forms a random dot pattern on the surface of the cylinder 801 that is visualized on a thermal image.

[0058] In matching stereo thermal images, it is preferable to have random patterns distributed in three dimensions and random patterns distributed vertically in addition to random patterns distributed on a plane, from the viewpoint of three-dimensional matching. The example in Figure 8 is suitable for this purpose.

[0059] When oxidation is complete, heat generation also stops, and the iron powder 802 becomes iron oxide, weakening its magnetic properties (the ability to be attracted by magnetic force). Therefore, after oxidation (heat generation), the iron powder 802 can be easily removed from the surface of the cylinder 801.

[0060] Although a cylinder is shown as an example here, the target (base material) to which the iron powder is magnetically attached may be a magnetic cylinder, square tube, rectangular pillar, or plate-like member. For example, the mount 122 in the first embodiment may be a magnetic plate-like member.

[0061] If the cylinder 801 is made of a material in which magnetic powder is dispersed in a plastic magnet or resin, the temperature difference with the heated iron powder becomes more prominent, making the random dot pattern in the thermal image more prominent.

[0062] 11. Eleventh embodiment Another example of a granular heating element is shown in Figure 9. Figure 9 shows a granular heating element 900, which is a long, thin, linear heating element wound in a spiral shape with a diameter of several mm. The granular heating element 900 has a structure in which a long, thin, linear wire material made up of a core 901 made of a carbon material and a coating 902 that covers the core 901 is wound in a spiral shape. The diameter of the wire material is about 0.1 mm to 0.5 mm. A large number of granular heating elements 900 are prepared and used as heat-generating powder.

[0063] Wick 901 is burned to produce heat-generating powder. Wick 901 is mixed with a flame-retardant additive to prevent oxidation (combustion), and is designed to burn slowly. Additionally, the presence of coating 902 prevents contact between wick 901 and oxygen in the air, allowing combustion to proceed slowly. This allows heat to be generated for a long period of time.

[0064] Short fibers with a length of several mm to several cm can also be used as the granular heating element, instead of the spiral shape. An embodiment without the coating 902 or an embodiment without using a flame-retardant additive to suppress combustion are also possible.

[0065] 12. Twelfth embodiment A random pattern may be formed by combining heat generation and heat absorption. Matching between thermal images can be performed more efficiently and erroneous matching can be reduced if the random pattern is clearly displayed on the thermal image.

[0066] For example, in the case of a random dot pattern using heat-generating particles, the larger the temperature difference between the heat-generating particles and the surroundings and the stronger the temperature gradient, the clearer the random dot pattern will be on the thermal image.

[0067] For example, by scattering (randomly dispersing) heat-generating particles and heat-absorbing particles on a surface, a thermal random dot pattern that achieves the above-mentioned objectives can be obtained.

[0068] For example, one method is to place a resin mesh on a heat-generating surface and scatter heat-absorbing particles on the mesh, or conversely, to place a resin mesh on a cooled surface and scatter heat-generating particles on the mesh. Here, the mesh must be large enough to prevent particles from passing through. The mesh is used to prevent direct contact between the heat-generating element and the heat-absorbing element. The mesh is made of resin to reduce heat conduction and ensure the time for the heat-generating particles to generate heat or the time for the heat-absorbing particles to absorb heat.

[0069] 10, a random pattern sheet 920 can be formed by laminating a heat-generating layer 921, a randomly patterned thermal insulating layer 922 (e.g., a resin layer) on top of that, and a randomly patterned heat-absorbing layer (cooling layer) 923 on top of that. Also possible is a random pattern sheet 920 by laminating a heat-absorbing layer 921, a randomly patterned thermal insulating layer 922 on top of that, and a randomly patterned heat-generating layer 923 on top of that. In this case, the temperature difference between the dot pattern 924 and the surroundings is large, and the temperature gradient with the surroundings is steep, resulting in prominent edges in the thermal image and a clear dot pattern. [Explanation of symbols]

[0070] 100...plant to be thermally imaged, 101...infrared camera, 102...infrared camera, 110, 111, 112...random pattern sheet, 120...PC for data processing, 121...stamp, 122...backing paper, 123...heat-generating granular material (iron powder), 200...random pattern plate, 201...sheet-shaped heating element, 202...shielding random pattern layer, 300...random pattern sheet, 301...resin substrate, 302...copper foil, 601...heating or cooling bath, 602...heating liquid or cooling liquid, 603...random pattern, 604...metal rod, 605...resin rod, 800...random pattern pillar, 801...cylindrical member, 802...iron powder before oxidation.

Claims

1. a random pattern including a first member that exhibits an exothermic or endothermic reaction and a second member that is made of a material different from that of the first member; an infrared camera that captures images of the random pattern from two different viewpoints to capture a first thermal image and a second thermal image; a processing device that performs stereo matching between the first thermal image and the second thermal image using the random pattern; A measurement system comprising:

2. 2. The measurement system according to claim 1, wherein the first member is a granular material that exhibits an exothermic reaction, and a large number of the granular material are randomly scattered on the surface of the second member having a flat surface.

3. 3. The measurement system according to claim 2, wherein the granular material exhibiting an exothermic reaction is iron powder in the process of oxidation.

4. 3. The measurement system according to claim 2, wherein the granular material exhibiting an exothermic reaction is calcium oxide granules reacting with moisture or burning charcoal granules.

5. 2. The measurement system according to claim 1, wherein the first member exhibiting an endothermic reaction is a particle containing urea and / or ammonium nitrate, and the reaction of moisture with the urea and / or ammonium nitrate generates endothermic heat.

6. A random pattern composed of a first member which is ice or dry ice particles and a second member which is made of a material different from that of the first member; an infrared camera that captures images of the random pattern from two different viewpoints to capture a first thermal image and a second thermal image; a processing device that performs stereo matching between the first thermal image and the second thermal image using the random pattern; A measurement system comprising:

7. the first component is iron powder; the second member is magnetic, 2. The measurement system of claim 1, wherein the first member is magnetically attached to a surface of the second member.

8. The first member includes: A carbon material; The measurement system according to claim 1 , further comprising a coating that prevents the carbon material from coming into contact with the outside air and / or a material that prevents oxidation of the carbon material.

9. The measurement system according to claim 1 , wherein the first member exhibits an exothermic reaction and the second member exhibits an endothermic reaction, or the first member exhibits an endothermic reaction and the second member exhibits an exothermic reaction.

10. A random pattern is formed at one end of an assembly in which a plurality of first rod-shaped members and second rod-shaped members having a thermal conductivity different from that of the first rod-shaped members are bundled together in a random arrangement by heating or cooling the other end of the assembly; an infrared camera that captures images of the random pattern from two different viewpoints to capture a first thermal image and a second thermal image; a processing device that performs stereo matching between the first thermal image and the second thermal image using the random pattern; A measurement system comprising:

11. A random pattern composed of a first member that exhibits an exothermic or endothermic reaction and a second member that is made of a material different from that of the first member is photographed from two different viewpoints to obtain a first thermal image and a second thermal image; A measurement method for performing stereo matching between the first thermal image and the second thermal image by using the random pattern.

12. the first member is a large number of granular bodies, the second member has a surface; The measurement method according to claim 11 , wherein the random pattern is formed by scattering the large number of granular materials on the surface of the face of the second member.

13. A method for obtaining a first thermal image and a second thermal image by heating or cooling one end of an assembly in which a plurality of first rod-shaped members and second rod-shaped members having a thermal conductivity different from that of the first rod-shaped members are bundled together in a random arrangement, and photographing the random pattern formed at the other end of the assembly from two different viewpoints; A measurement method for performing stereo matching between the first thermal image and the second thermal image by using the random pattern.

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