Human body area extraction system, human body area extraction method, and program

Abstract

To provide a human body area extraction system that can correctly extract the contour of a human body in a thermal image.SOLUTION: A human body area extraction system 10 comprises: a thermal image acquisition unit 11 that acquires temperature distribution data of a space; a body area detection unit 13 that detects a body area including a human body area on the basis of the temperature distribution data; a threshold setting unit 14 that sets a threshold temperature in the body area; and a human body determination unit 15 that determines an area at the threshold temperature or more in the body area as the human body area. The threshold setting unit 14 executes re-setting of the threshold temperature according to a result of the determination made by the human body determination unit 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a human body region extraction system and the like. [Background technology]

[0002] Patent Document 1 discloses a technology for extracting a human body region in a thermal image. Specifically, the technology discloses an air conditioner having a first extraction means for extracting a pixel group that exceeds a first threshold in a first temperature distribution acquired from a sensor by a first extraction means, and a second extraction means for extracting, as a human body region, a pixel group that exceeds a second threshold in a second temperature distribution with higher resolution than the first temperature distribution from the pixel group extracted by the first extraction means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 029762 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology disclosed in Patent Document 1, if a human body is included in some of the low-resolution pixels extracted by the first extraction means, most of the pixels may be in the background region, and the pixels may not exceed the first threshold and may not be targeted for extraction of the human body region by the second extraction means. In this case, the outer edge of the human body region extracted by the second extraction means will be missing, making it impossible to correctly extract the outline of the human body.

[0005] Therefore, the present disclosure provides a human body region extraction system that can correctly extract the outline of a human body in a thermal image. [Means for solving the problem]

[0006] The human body region extraction system according to the present disclosure includes a thermal image acquisition unit that acquires temperature distribution data in space, a body region detection unit that detects a body region including a human body region based on the temperature distribution data, a threshold setting unit that sets a threshold temperature within the body region, and a human body determination unit that determines an area within the body region that has a temperature equal to or higher than the threshold temperature as a human body region, and the threshold setting unit resets the threshold temperature according to the determination result of the human body determination unit.

[0007] The human body region extraction system according to the present disclosure comprises a thermal image acquisition unit that acquires temperature distribution data in space, a body region detection unit that detects a body region including a human body region based on the temperature distribution data, a threshold setting unit that sets a threshold temperature gradient for the temperature gradient with adjacent pixels within the body region, and a human body determination unit that determines, as a human body region, an area sandwiched between pixels whose absolute value of the temperature gradient with adjacent pixels exceeds the threshold temperature gradient, and the threshold setting unit resets the threshold temperature gradient according to the determination result of the human body determination unit.

[0008] The human body region extraction method according to the present disclosure includes a thermal image acquisition step of acquiring temperature distribution data in space, a body region detection step of detecting a body region including a human body region based on the temperature distribution data, a threshold setting step of setting a threshold temperature within the body region, and a human body determination step of determining that a region within the body region having a temperature equal to or higher than the threshold temperature is a human body region, and in the threshold setting step, the threshold temperature is reset depending on the determination result in the human body determination step.

[0009] The human body region extraction method according to the present disclosure includes a thermal image acquisition step of acquiring temperature distribution data in space, a body region detection step of detecting a body region including a human body region based on the temperature distribution data, a threshold setting step of setting a threshold temperature gradient for a temperature gradient with adjacent pixels within the body region, and a human body determination step of determining, as a human body region, a region sandwiched between pixels whose absolute values ​​of the temperature gradient with adjacent pixels exceed the threshold temperature gradient, wherein in the threshold setting step, the threshold temperature gradient is reset depending on the determination result in the human body determination step.

[0010] A program according to the present disclosure is a program for causing a computer to execute the above-described human body region extraction method.

[0011] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0012] According to the human body region extraction system and the like of the present disclosure, the outline of a human body can be correctly extracted from a thermal image. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating an example of a configuration of a human body region extraction system according to an embodiment. [Figure 2] FIG. 10 is a diagram illustrating an example of temperature distribution data. [Figure 3] 10 is a flowchart illustrating an example of the operation of the human body region extraction system according to the embodiment. [Figure 4] FIG. 10 is a diagram showing an example of a moving heat source in temperature distribution data. [Figure 5] 10 is a flowchart illustrating an example of a method for determining a body region according to an embodiment. [Figure 6]FIG. 10 is a diagram showing an example of a face region and a provisional region in temperature distribution data. [Figure 7] FIG. 10 is a diagram showing an example of a body region in temperature distribution data. [Figure 8] 10 is a flowchart illustrating an example of a method for resetting a threshold temperature according to an embodiment. [Figure 9] FIG. 10 is a diagram showing an example of a region determined to be a human body region after resetting the threshold temperature in the temperature distribution data. [Figure 10] FIG. 10 is a diagram showing an example of a human body region after an OR operation in temperature distribution data. [Figure 11] FIG. 10 is a diagram illustrating an example of a human body region extraction method according to another embodiment. [Figure 12] FIG. 10 is a diagram illustrating an example of a human body region extraction method according to another embodiment. [Figure 13] FIG. 10 is a diagram illustrating an example of a human body region extraction method according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, more detailed description than necessary may be omitted. For example, detailed description of well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

[0015] The inventors have provided the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and do not intend for them to limit the subject matter described in the claims.

[0016] (Embodiment) Hereinafter, a human body region extraction system according to an embodiment will be described with reference to FIGS.

[0017] The human body region extraction system 10 is a system for extracting a human body region in a thermal image, and is installed in an air conditioner, etc. The human body region extraction system 10 extracts the human body region of a person who is standing upright.

[0018] The human body region extraction system 10 is a computer having a processor, memory, etc. The memory may be a read-only memory (ROM) or a random access memory (RAM), and may store a program executed by the processor. The human body region extraction system 10 includes a thermal image acquisition unit 11, a one-part detection unit 12, a body region detection unit 13, a threshold setting unit 14, and a human body determination unit 15. The thermal image acquisition unit 11, the one-part detection unit 12, the body region detection unit 13, the threshold setting unit 14, and the human body determination unit 15 are realized by a processor or the like that executes a program stored in memory. The human body region extraction system 10 may be a device in which its components are provided within a single housing, or a system in which its components are distributed across multiple housings. Furthermore, the human body region extraction system 10 does not have to be installed in an air conditioner or the like, and may be realized by a server, etc. In this case, the components of the human body region extraction system 10 may be distributed across multiple servers.

[0019] The thermal image acquisition unit 11 acquires a thermal image. For example, a thermal image is temperature distribution data of a space, such as a room, acquired by a thermosensor or the like. Therefore, the thermal image acquisition unit 11 acquires temperature distribution data of the space as a thermal image. For example, a thermosensor generates temperature distribution data of the space by scanning the space. In the temperature distribution data, pixels are arranged in a matrix, and each pixel is associated with a temperature. For example, the row direction in the temperature distribution data corresponds to the horizontal direction, and the column direction corresponds to the vertical direction. In the following, the row direction will also be referred to as the horizontal direction, and the column direction will also be referred to as the vertical direction. As described above, the human body region extraction system 10 extracts the human body region of a person standing upright, so in the temperature distribution data, the human body region is basically a region that is long in the vertical direction.

[0020] FIG. 2 is a diagram showing an example of temperature distribution data.

[0021] In Figure 2, low-temperature pixels in the temperature distribution data are colored black and high-temperature pixels are colored white so that people can visually recognize the temperature distribution data. For example, by identifying pixels whose temperature corresponds to the temperature of a human body, those pixels can be extracted as a human body region. However, the clothing parts of the human body region or the outer edges, such as the feet, are easily affected by the ambient temperature and may be missing. In response to this, the human body region extraction system 10 includes a part detection unit 12 and a body region detection unit 13, which enable it to detect a body region for accurately extracting the outline of a human body in a thermal image. Furthermore, the system includes a threshold setting unit 14 and a human body determination unit 15, which enable it to accurately extract the outline of a human body from the detected body region.

[0022] The one-part detection unit 12 detects at least one region of the human body in the temperature distribution data. The at least one region of the human body includes, for example, a face region. The operation of the one-part detection unit 12 will be described in detail later.

[0023] The body region detection unit 13 detects a body region including a human body region based on the temperature distribution data. For example, the body region detection unit 13 detects a body region including at least a human body region other than the one-part region based on the detection result of the one-part detection unit 12 in the temperature distribution data. The operation of the body region detection unit 13 will be described in detail later.

[0024] The threshold setting unit 14 sets a threshold temperature within the body region. Alternatively, the threshold setting unit 14 sets a threshold temperature gradient relative to the temperature gradient between adjacent pixels within the body region. The operation of the threshold setting unit 14 will be described in detail later.

[0025] The human body determination unit 15 determines a region within the body region that has a temperature equal to or higher than the threshold temperature as a human body region. Alternatively, the human body determination unit 15 determines a region within the body region that is sandwiched between pixels whose absolute values ​​of the temperature gradients between adjacent pixels exceed the threshold temperature gradient as a human body region. The operation of the human body determination unit 15 will be described in detail later.

[0026] Next, the operation of the human body region extraction system 10 will be described with reference to FIG.

[0027] Fig. 3 is a flowchart showing an example of the operation of the human body region extraction system 10 according to the embodiment. Fig. 3 shows the operation after the thermal image acquisition unit 11 acquires temperature distribution data.

[0028] The human body region extraction system 10 detects the background temperature in the temperature distribution data (step S11). The method for detecting the background temperature is not particularly limited, but the most frequent temperature in the temperature distribution data can be detected as the background temperature. For example, the human body region extraction system 10 detects the background temperature as 24°C.

[0029] Next, the human body region extraction system 10 sets the temperature range of the human body (step S12). For example, the human body region extraction system 10 sets the temperature range of the human body to 26°C to 40°C. The order of detecting the background temperature (step S11) and setting the temperature range of the human body (step S12) may be reversed. For example, after the temperature range of the human body is set, the temperature that is the most frequent value in the temperature distribution data excluding the temperature range of the human body may be detected as the background temperature.

[0030] Next, the human body region extraction system 10 extracts moving heat sources in the temperature range of the human body (step S13). The method for extracting the moving heat sources is not particularly limited, but for example, the method described in International Publication No. 2022 / 176732 can be used to extract moving heat sources as shown in FIG.

[0031] FIG. 4 is a diagram showing an example of a moving heat source in temperature distribution data.

[0032] As shown in Figure 4, areas such as the lower body of a person are affected by clothing and other factors, resulting in temperatures outside the set human body temperature range (for example, temperatures between 24°C and 26°C), and are therefore not extracted as human body areas.

[0033] 3, next, the one part detection unit 12 detects a face area as an area of ​​at least one part of the human body (step S14). There are no particular limitations on the method for detecting the face area, but for example, since the shoulder width is approximately twice the size of the face width, the face area can be detected based on the relationship between the shoulder width and the face width.

[0034] Next, the body region detection unit 13 detects the body region (step S15). Here, a method for detecting the body region will be described with reference to FIG.

[0035] 5 is a flowchart showing an example of a body region determination method according to the embodiment. As shown in FIG. 1, body region detection unit 13 includes first setting unit 13a and second setting unit 13b for detecting the body region.

[0036] First, the first setting unit 13a sets a provisional region including a human body region different from at least the one part region based on the detection result of the one part detection unit 12 (step S21). For example, the at least one part region includes a face region, and the human body region different from the at least one part region (face region) is a human body region below the face.

[0037] FIG. 6 is a diagram showing an example of a face region and a provisional region in temperature distribution data.

[0038] For example, the first setting unit 13a sets a provisional region below the face region detected by the one part detection unit 12. For example, as shown in Fig. 6, the first setting unit 13a sets the horizontal width of the provisional region to twice the horizontal width of the face region, sets the position of the provisional region so that the horizontal center of the provisional region and the horizontal center of the face region are in the same column, and the lower end of the face region is adjacent to and above the upper end of the provisional region, and sets the lower end of the provisional region to the lower end of the temperature distribution data.

[0039] Next, the second setting unit 13b determines a body region from the provisional region based on the temperature distribution in the provisional region set by the first setting unit 13a in the temperature distribution data. Since the human body region in the provisional region often has a temperature distribution different from that of the background region, the body region can be determined from the provisional region based on the temperature distribution in the provisional region.

[0040] Specifically, the second setting unit 13b determines the body region by performing the processes from step S22 to step S25 shown in FIG.

[0041] First, the second setting unit 13b sets n to 1 (step S22). n indicates the number of rows from the top of the provisional region in the temperature distribution data, and the second setting unit 13b first performs the process in step S23 on the first row of the provisional region.

[0042] The second setting unit 13b determines whether the temperature variance (degree of variation) of the nth row in the provisional region is smaller than a threshold value (step S23). The threshold value is not particularly limited, but is set to, for example, a variance value that is expected when a human body region exists in one row. If a human body region does not exist in the nth row, the nth row becomes entirely a background region, and the temperature variance value becomes smaller and is smaller than the threshold value. On the other hand, if a human body region exists in the nth row, the nth row contains a mixture of human body regions and background regions, and the temperature variance value becomes larger and is larger than the threshold value.

[0043] If the temperature variance value of the nth row in the provisional region is equal to or greater than the threshold value (No in step S23), the second setting unit 13b increments n by 1 (step S24). That is, the second setting unit 13b performs the process of step S23 for the next row. For example, if the temperature variance value of the first row in the provisional region is equal to or greater than the threshold value, the second setting unit 13b determines whether the temperature variance value of the second row in the provisional region is smaller than the threshold value. In this way, the second setting unit 13b repeats the process of step S23 while shifting the rows down one by one in the provisional region until the temperature variance value becomes smaller than the threshold value.

[0044] If the variance value of the temperature of the nth row in the provisional region is smaller than the threshold value (Yes in step S23), the second setting unit 13b determines the nth row as the lower end of the body region (step S25). For example, the lower end of the body region can be determined as shown in FIG.

[0045] In this way, the second setting unit 13b determines the lower end of the body region based on the temperature distribution in the provisional region set by the first setting unit 13a in the temperature distribution data, thereby determining the body region. Specifically, the second setting unit 13b acquires the temperature distribution in the provisional region set by the first setting unit 13a in the temperature distribution data for each row, calculates the degree of variation in the acquired temperature distribution for each row, and determines the lower end of the body region from the calculated degree of variation. This makes it possible to determine the region (row) where the temperature distribution trend changes as the boundary between the body region and the background region (for example, the lower end of the body region), and specifically, to determine the row where the trend of the temperature distribution variation changes as the lower end of the body region.

[0046] FIG. 7 is a diagram showing an example of a body region in temperature distribution data.

[0047] As shown in FIGS. 6 and 7, the body region is the same as the provisional region except for the lower end, so by determining the lower end of the body region, the body region can be determined from the provisional region.

[0048] In steps S14 and S15, a relatively large body region can be detected that includes a human body region (e.g., a human body region below the face region) that has a certain relationship with the region of a specific part (e.g., the face) of the detected human body but is separate from the region of the specific part (e.g., the region below the face region). Since such a body region also includes the outer periphery of the human body region, the present disclosure can detect a body region whose outer periphery is not missing in the thermal image, i.e., a body region that can be used to correctly extract the outline of the human body in the thermal image. Specifically, a body region that can be used to correctly extract the outline of the human body below the face can be detected. By performing the human body region extraction process described in step S16 of FIG. 3 using such a body region that includes a human body region whose outer periphery is not missing, the outline of the human body can be correctly extracted.

[0049] Returning to the explanation in Fig. 3, human body region extraction system 10 extracts a human body region from the detected body region. Specifically, human body determination unit 15 determines that a region within the body region that has a temperature equal to or higher than the threshold temperature is a human body region, and threshold setting unit 14 resets the threshold temperature according to the determination result of human body determination unit 15. This process is repeated, and human body region extraction system 10 extracts a human body region from the detected body region. Here, a method for resetting the threshold temperature will be described with reference to Fig. 8.

[0050] FIG. 8 is a flowchart showing an example of a method for resetting the threshold temperature according to the embodiment.

[0051] The human body determination unit 15 determines whether the threshold temperature is background temperature + 0.1°C (step S31). For example, the threshold setting unit 14 resets the threshold temperature to a new threshold temperature that is a predetermined temperature (e.g., 0.1°C) lower than the current threshold temperature according to the determination result of the human body determination unit 15, but the process in step S31 is performed to terminate the process when the reset threshold temperature becomes approximately the same temperature as the background temperature (e.g., when the threshold temperature = background temperature + 0.1°C (Yes in step S31)).

[0052] If the human body determination unit 15 determines that the threshold temperature is not the background temperature + 0.1°C (No in step S31), it determines whether the human body area in the body area is less than a predetermined ratio of the body area (step S32). The predetermined ratio is not particularly limited, and may be set to, for example, 60%.

[0053] If it is determined that the human body region in the body region is less than a predetermined ratio in the body region (Yes in step S32), threshold setting unit 14 resets the threshold temperature to a temperature 0.1°C lower (step S33). As a result, the region determined as a human body region by human body determination unit 15 becomes larger. Note that 0.1°C is just an example of the predetermined temperature when setting a temperature lower than the threshold temperature by a predetermined temperature as the new threshold temperature, and is set appropriately.

[0054] Then, processing is performed again from step S31, and if it is determined in step S32 that the human body area within the body area is equal to or greater than a predetermined percentage of the body area, processing ends, and the area with a temperature equal to or greater than the threshold temperature set when it is determined that the human body area within the body area is equal to or greater than a predetermined percentage of the body area is extracted as the human body area.

[0055] Fig. 9 is a diagram showing an example of regions determined to be human body regions after resetting the threshold temperature in the temperature distribution data. For example, when the threshold temperature is high, the number of regions determined to be human body regions is small as shown in Fig. 7, but as the threshold temperature is gradually lowered, the number of regions determined to be human body regions becomes equal to or greater than a predetermined percentage as shown in Fig. 9.

[0056] In this way, the threshold setting unit 14 resets the threshold temperature when the area determined as a human body area by the human body determination unit 15 is less than a predetermined ratio of the body area. If the area determined as a human body area is small, it is considered that the human body area is missing, so the threshold temperature can be reset. Furthermore, by resetting the threshold temperature to gradually smaller temperatures, the area determined as a human body area gradually becomes larger, and the threshold temperature can be set so that the human body area is not missing.

[0057] The lower body is generally cooler than the upper body, and the threshold temperature may be reset by utilizing the characteristic that, as the threshold temperature decreases, the area determined to be a human body area extends downward within the body area. Specifically, the threshold setting unit 14 may reset the threshold temperature if the number of vertical pixels in the area determined to be a human body area by the human body determination unit 15 is less than a predetermined number of pixels. The predetermined number of pixels is not particularly limited, and may be set, for example, according to the number of vertical pixels in the body area. In this way, if the number of vertical pixels in the area determined to be a human body area is small, it is considered that the human body area is missing, and therefore the threshold temperature may be reset.

[0058] Furthermore, the threshold setting unit 14 may reset the threshold temperature if the amount of change in the area determined as a human body area by the human body determination unit 15 before and after resetting the threshold temperature is less than a predetermined percentage of the area determined as a human body area by the human body determination unit 15 before resetting the threshold temperature. In this case, for example, the lowest temperature in the body area may be set as the initial value of the threshold temperature, and the threshold temperature may be gradually increased until the amount of change (decrease) becomes equal to or greater than a predetermined percentage. That is, the threshold setting unit 14 may reset the threshold temperature to a temperature that is a predetermined temperature higher than the threshold temperature according to the determination result of the human body determination unit 15. When the threshold temperature is the initial value (i.e., the threshold temperature is the lowest temperature in the body area), all pixels in the body area are determined to be a human body area. However, as the threshold temperature increases, there comes a point where background temperatures that are relatively frequent in the body area are excluded altogether from the pixels determined to be a human body area. At this timing, many pixels determined to be human body regions are excluded, the amount of change (decrease) becomes equal to or exceeds a predetermined rate, and the resetting of the threshold temperature is completed. In this way, if the amount of change in the region determined to be a human body region before and after resetting the threshold temperature is small, it is considered that the region determined to be a human body region within the body region still contains background pixels, and therefore the resetting of the threshold temperature can be further performed.

[0059] In step S16, the threshold temperature can be reset so that the human body region is not missing within a relatively large body region that includes pixels in the human body region whose outer edge is not missing. Therefore, by determining the human body region using the threshold temperature that has been reset so that the human body region is not missing, the outline of the human body can be accurately extracted from the thermal image. By accurately extracting the outline of the human body, it is possible to improve the accuracy of detecting the surface temperature of the human body and the accuracy of estimating thermal sensation.

[0060] The threshold setting unit 14 may set a threshold temperature gradient for the temperature gradient with adjacent pixels within the body region, and the human body determination unit 15 may determine, as a human body region, a region sandwiched between pixels whose absolute values ​​of the temperature gradient with adjacent pixels exceed the threshold temperature gradient. The threshold setting unit 14 may also reset the threshold temperature gradient depending on the determination result of the human body determination unit 15. Because there is a temperature difference between the human body region and the background region, a pixel with a temperature difference with its adjacent pixel can be estimated as the boundary between the human body region and the background region, and the region sandwiched between the pixels can be estimated as a human body region. In other words, a human body region can be determined even when a threshold temperature gradient is used. Therefore, the threshold temperature in the above description can be replaced with a threshold temperature gradient.

[0061] Returning to the explanation of FIG. 3, the human body region extraction system 10 performs an OR operation on the heat source extracted in step S13 and the human body region extracted in step S16 (step S17).

[0062] FIG. 10 is a diagram showing an example of a human body region after OR operation in temperature distribution data.

[0063] By combining the heat source shown in Figure 4 and the human body region shown in Figure 9, it is possible to extract a human body region that also includes at least one part of the human body (e.g., the face region), as shown in Figure 10.

[0064] (Other embodiments) As described above, the embodiments have been described as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these, and can be applied to embodiments in which appropriate modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the above embodiments to create new embodiments.

[0065] For example, in the above embodiment, an example has been described in which the region of at least one part includes a face region, but the region of at least one part does not have to include a face region. For example, the region of at least one part does not have to include a face region as long as it includes a region of a part that has a certain relationship with another human body region.

[0066] For example, in the above embodiment, an example has been described in which human body region extraction system 10 includes threshold setting unit 14 and human body determination unit 15, but human body region extraction system 10 does not have to include threshold setting unit 14 and human body determination unit 15. In this case, human body region extraction system 10 becomes a system for detecting a body region in order to correctly extract the outline of a human body.

[0067] For example, in the above embodiment, an example has been described in which human body region extraction system 10 includes one body part detection unit 12, but human body region extraction system 10 does not have to include one body part detection unit 12, and there are no particular limitations on the method by which body region detection unit 13 detects the body region. In this case, human body region extraction system 10 becomes a system for correctly extracting the outline of the human body.

[0068] For example, the present disclosure can be realized not only as a human body region extraction system 10, but also as a human body region extraction method including steps (processing) performed by the components that make up the human body region extraction system 10.

[0069] 11 to 13 are diagrams showing an example of a human body region extraction method according to another embodiment.

[0070] For example, as shown in FIG. 11, the human body region extraction method includes a thermal image acquisition step (step S101) for acquiring temperature distribution data in space, a one-part detection step (step S102) for detecting at least one part of the human body in the temperature distribution data, and a body region detection step (step S103) for detecting a body region including a human body region other than the at least one part based on the detection result in the one-part detection step.

[0071] For example, as shown in FIG. 12, the human body region extraction method includes a thermal image acquisition step (step S201) for acquiring temperature distribution data in space, a body region detection step (step S202) for detecting a body region including a human body region based on the temperature distribution data, a threshold setting step (step S203) for setting a threshold temperature within the body region, and a human body determination step (step S204) for determining that a region within the body region whose temperature is equal to or higher than the threshold temperature is a human body region. In the threshold setting step (step S203), the threshold temperature is reset depending on the determination result in the human body determination step.

[0072] For example, as shown in FIG. 13, the human body region extraction method includes a thermal image acquisition step (step S301) for acquiring temperature distribution data in space, a body region detection step (step S302) for detecting a body region including a human body region based on the temperature distribution data, a threshold setting step (step S303) for setting a threshold temperature gradient for the temperature gradient with adjacent pixels within the body region, and a human body determination step (step S304) for determining, as a human body region, a region sandwiched between pixels whose absolute value of the temperature gradient with adjacent pixels exceeds the threshold temperature gradient, and in the threshold setting step (step S303), the threshold temperature gradient is reset depending on the determination result in the human body determination step.

[0073] For example, the present disclosure can be realized as a program for causing a computer (processor) to execute steps included in the human body region extraction method. Furthermore, the present disclosure can be realized as a non-transitory computer-readable recording medium, such as a CD-ROM, on which the program is recorded.

[0074] For example, when the present disclosure is realized as a program (software), each step is performed by running the program using hardware resources such as a computer's CPU, memory, input / output circuits, etc. In other words, each step is performed by the CPU acquiring data from memory or input / output circuits, etc., performing calculations, and outputting the calculation results to memory or input / output circuits, etc.

[0075] In the above embodiment, each component included in the human body region extraction system 10 may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may also be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0076] Some or all of the functions of the human body region extraction system 10 according to the above embodiment are typically realized as an LSI, which is an integrated circuit. These may be implemented individually on a single chip, or some or all of them may be integrated on a single chip. Furthermore, the integrated circuit is not limited to an LSI, and may be realized using a dedicated circuit or a general-purpose processor. It is also possible to use an FPGA (Field Programmable Gate Array), which can be programmed after LSI manufacturing, or a reconfigurable processor, which can reconfigure the connections and settings of circuit cells within the LSI.

[0077] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, that technology may naturally be used to integrate the components included in the human body region extraction system 10 into integrated circuits.

[0078] In addition, this disclosure also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope that does not deviate from the intent of this disclosure.

[0079] (Addendum) The above description of the embodiments discloses the following techniques.

[0080] (Technology 1) A human body region extraction system comprising a thermal image acquisition unit that acquires temperature distribution data in space, a body region detection unit that detects a body region including a human body region based on the temperature distribution data, a threshold setting unit that sets a threshold temperature within the body region, and a human body determination unit that determines an area within the body region that has a temperature equal to or higher than the threshold temperature as a human body region, wherein the threshold setting unit resets the threshold temperature depending on the determination result of the human body determination unit.

[0081] This allows the threshold temperature to be reset so that the human body region is not missing, and by determining the human body region using the reset threshold temperature so that the human body region is not missing, the outline of the human body can be accurately extracted from the thermal image. By accurately extracting the outline of the human body, it is possible to improve the accuracy of detecting the surface temperature of the human body and the accuracy of estimating thermal sensation.

[0082] (Technology 2) The human body region extraction system according to Technology 1, wherein the threshold setting unit resets the threshold temperature when the region determined to be a human body region by the human body determination unit is less than a predetermined proportion of the body region.

[0083] According to this, if there are few areas determined to be human body areas, it is considered that there are no human body areas, and therefore the threshold temperature can be reset.

[0084] (Technology 3) The human body region extraction system described in Technology 1, wherein the threshold setting unit resets the threshold temperature when the number of vertical pixels in the region determined to be a human body region by the human body determination unit is less than a predetermined number of pixels.

[0085] According to this, if the number of pixels in the vertical direction in the area determined to be a human body area is small, it is considered that the human body area is missing, and therefore the threshold temperature can be reset.

[0086] (Technology 4) The human body region extraction system described in Technology 1, wherein the threshold setting unit resets the threshold temperature if the amount of change in the region determined to be a human body region by the human body determination unit before and after resetting the threshold temperature is less than a predetermined ratio of the region determined to be a human body region by the human body determination unit before resetting the threshold temperature.

[0087] According to this, if the amount of change in the area determined to be a human body area is small before and after the threshold temperature is reset, it is considered that the human body area is still missing or that the human body area contains background pixels, so the threshold temperature can be further reset.

[0088] (Technology 5) The human body region extraction system according to any one of Technologies 1 to 4, wherein the threshold setting unit resets the threshold temperature to a temperature that is a predetermined temperature lower than the threshold temperature or a predetermined temperature higher than the threshold temperature, depending on the judgment result of the human body judgment unit.

[0089] According to this, by resetting the threshold temperature to a gradually lower or higher temperature, the area determined to be a human body area gradually becomes larger, and the threshold temperature can be set so that no human body area is missing.

[0090] (Technology 6) A human body region extraction system comprising: a thermal image acquisition unit that acquires temperature distribution data in space; a body region detection unit that detects a body region including a human body region based on the temperature distribution data; a threshold setting unit that sets a threshold temperature gradient for the temperature gradient with adjacent pixels within the body region; and a human body determination unit that determines, as a human body region, a region sandwiched between pixels whose absolute values ​​of the temperature gradient with adjacent pixels exceed the threshold temperature gradient, within the body region; wherein the threshold setting unit resets the threshold temperature gradient depending on the determination result of the human body determination unit.

[0091] This allows the threshold temperature gradient to be reset so that the human body region is not missing, and by determining the human body region using the threshold temperature gradient that has been reset so that the human body region is not missing, the outline of the human body can be accurately extracted from the thermal image. By accurately extracting the outline of the human body, it is possible to improve the accuracy of detecting the surface temperature of the human body and the accuracy of estimating thermal sensation.

[0092] (Technology 7) The human body region extraction system described in Technology 6, wherein the threshold setting unit resets the threshold temperature gradient when the region determined to be a human body region by the human body determination unit is less than a predetermined proportion of the body region.

[0093] According to this, if there are few areas determined to be human body areas, it is considered that there are no human body areas, and therefore the threshold temperature gradient can be reset.

[0094] (Technology 8) The human body region extraction system described in Technology 6, wherein the threshold setting unit resets the threshold temperature gradient when the number of vertical pixels in the region determined to be a human body region by the human body determination unit is less than a predetermined number of pixels.

[0095] According to this, if the number of pixels in the vertical direction in an area determined to be a human body area is small, it is considered that the human body area is missing, and therefore the threshold temperature gradient can be reset.

[0096] (Technology 9) The human body region extraction system described in Technology 6, wherein the threshold setting unit resets the threshold temperature gradient if the amount of change in the region determined to be a human body region by the human body determination unit before and after resetting the threshold temperature gradient is less than a predetermined percentage of the region determined to be a human body region by the human body determination unit before resetting the threshold temperature gradient.

[0097] According to this, if the amount of change in the area determined to be a human body area is small before and after the resetting of the threshold temperature gradient, it is considered that the human body area is still missing or that the human body area contains background pixels, so the threshold temperature gradient can be further reset.

[0098] (Technology 10) The human body region extraction system according to any one of technologies 6 to 9, wherein the threshold setting unit resets the threshold temperature gradient to a temperature gradient that is smaller by a predetermined temperature than the threshold temperature gradient, or a temperature gradient that is larger by a predetermined temperature than the threshold temperature gradient, depending on the judgment result of the human body judgment unit.

[0099] According to this, by gradually resetting the threshold temperature gradient to a smaller or larger temperature gradient, the area determined to be a human body area gradually becomes larger, and the threshold temperature gradient can be set so that no human body area is missing.

[0100] (Technology 11) A human body region extraction method including a thermal image acquisition step for acquiring temperature distribution data in space, a body region detection step for detecting a body region including a human body region based on the temperature distribution data, a threshold setting step for setting a threshold temperature within the body region, and a human body determination step for determining that a region within the body region having a temperature equal to or higher than the threshold temperature is a human body region, wherein in the threshold setting step, the threshold temperature is reset depending on the determination result in the human body determination step.

[0101] This provides a method for extracting a human body region that can correctly extract the outline of a human body in a thermal image.

[0102] (Technology 12) A human body region extraction method including: a thermal image acquisition step for acquiring temperature distribution data in space; a body region detection step for detecting a body region including a human body region based on the temperature distribution data; a threshold setting step for setting a threshold temperature gradient for a temperature gradient with adjacent pixels within the body region; and a human body determination step for determining, as a human body region, a region sandwiched between pixels whose absolute values ​​of the temperature gradient with adjacent pixels exceed the threshold temperature gradient, within the body region; wherein, in the threshold setting step, the threshold temperature gradient is reset depending on the determination result in the human body determination step.

[0103] This provides a method for extracting a human body region that can correctly extract the outline of a human body in a thermal image.

[0104] (Technology 13) A program for causing a computer to execute the human body region extraction method described in Technology 11.

[0105] This provides a program that can correctly extract the outline of a human body from a thermal image.

[0106] (Technology 14) A program for causing a computer to execute the human body region extraction method described in Technology 12.

[0107] This provides a program that can correctly extract the outline of a human body from a thermal image. [Industrial Applicability]

[0108] The present disclosure can be applied to systems that use thermal images to detect people, etc. [Explanation of symbols]

[0109] 10 Human body region extraction system 11 Thermal image acquisition unit 12 Single-site detection unit 13 Body region detection unit 13a First Setting Section 13b Second Setting Section 14 Threshold setting section 15 Human Body Identification Department

Claims

1. A thermal image acquisition unit for acquiring temperature distribution data in a space; a body region detection unit that detects a body region including a human body region based on the temperature distribution data; a threshold setting unit that sets a threshold temperature within the body region; a human body determination unit that determines an area in the body area that has a temperature equal to or higher than the threshold temperature as a human body area, The threshold setting unit resets the threshold temperature in accordance with a determination result of the human body determination unit. Human body region extraction system.

2. the threshold setting unit resets the threshold temperature when the area determined to be a human body area by the human body determination unit is less than a predetermined ratio to the body area. The human body region extraction system according to claim 1 .

3. the threshold setting unit resets the threshold temperature when the number of pixels in the vertical direction of the region determined to be a human body region by the human body determination unit is less than a predetermined number of pixels. The human body region extraction system according to claim 1 .

4. the threshold setting unit resets the threshold temperature when a change in an area determined to be a human body area by the human body determination unit before and after resetting the threshold temperature is less than a predetermined ratio to an area determined to be a human body area by the human body determination unit before resetting the threshold temperature. The human body region extraction system according to claim 1 .

5. the threshold setting unit resets the threshold temperature to a temperature that is a predetermined temperature lower than the threshold temperature or a predetermined temperature higher than the threshold temperature in accordance with a determination result of the human body determination unit. The human body region extraction system according to any one of claims 1 to 4.

6. A thermal image acquisition unit for acquiring temperature distribution data in a space; a body region detection unit that detects a body region including a human body region based on the temperature distribution data; a threshold setting unit that sets a threshold temperature gradient for a temperature gradient between adjacent pixels in the body region; a human body determination unit that determines, within the body region, a region sandwiched between pixels whose absolute values ​​of temperature gradients with adjacent pixels exceed the threshold temperature gradient as a human body region; The threshold setting unit resets the threshold temperature gradient in accordance with a determination result of the human body determination unit. Human body region extraction system.

7. the threshold setting unit resets the threshold temperature gradient when the area determined to be a human body area by the human body determination unit is less than a predetermined ratio to the body area. The human body region extraction system according to claim 6 .

8. the threshold setting unit resets the threshold temperature gradient when the number of pixels in the vertical direction of the region determined to be a human body region by the human body determination unit is less than a predetermined number of pixels. The human body region extraction system according to claim 6 .

9. the threshold setting unit resets the threshold temperature gradient when an amount of change in the area determined to be a human body area by the human body determination unit before and after resetting the threshold temperature gradient is less than a predetermined ratio to the area determined to be a human body area by the human body determination unit before resetting the threshold temperature gradient. The human body region extraction system according to claim 6 .

10. the threshold setting unit resets the threshold temperature gradient to a temperature gradient that is smaller by a predetermined temperature than the threshold temperature gradient or a temperature gradient that is larger by a predetermined temperature than the threshold temperature gradient, depending on the determination result of the human body determination unit. The human body region extraction system according to any one of claims 6 to 9.

11. A thermal image acquisition step for acquiring temperature distribution data in a space; a body region detecting step of detecting a body region including a human body region based on the temperature distribution data; a threshold setting step of setting a threshold temperature within the body region; a human body determination step of determining an area in the body area that has a temperature equal to or higher than the threshold temperature as a human body area, In the threshold setting step, the threshold temperature is reset according to a result of the determination in the human body determination step. Human body region extraction method.

12. A thermal image acquisition step for acquiring temperature distribution data in a space; a body region detecting step of detecting a body region including a human body region based on the temperature distribution data; a threshold setting step of setting a threshold temperature gradient for a temperature gradient between adjacent pixels in the body region; a human body determining step of determining, within the body region, a region sandwiched between pixels whose absolute values ​​of temperature gradients with adjacent pixels exceed the threshold temperature gradient, as a human body region; In the threshold setting step, the threshold temperature gradient is reset according to a result of the determination in the human body determination step. Human body region extraction method.

13. A program for causing a computer to execute the human body region extraction method according to claim 11.

14. A program for causing a computer to execute the human body region extraction method according to claim 12.

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