Posture evaluation device, posture evaluation method and program

Abstract

To provide a posture evaluation device and the like which evaluates the posture more properly.SOLUTION: A posture evaluation device 200 includes: a camera (imaging device 201) for imaging an object person 11 and outputting an image; a body position estimation part 105a for estimating the information regarding the position of a body portion of the object person 11 from the image; a posture feature amount calculation part 105b for calculating the posture feature amount of the object person 11 from the information regarding the estimated position of the body portion; a feature amount conversion part 105c for, by converting the calculated posture feature amount, outputting the feature amount which is the feature amount for a predetermined evaluation reference used for the evaluation of the posture of the object person 11 and which is related to the position of the body portion that cannot be estimated by the body position estimation part 105a; and a posture evaluation part (evaluation part 108) for evaluating the posture of the object person by the predetermined evaluation reference by using the feature amount after conversion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a posture evaluation device, a posture evaluation method, and a program for evaluating the posture of a subject. [Background technology]

[0002] In recent years, there have been many cases where accumulated fatigue has led to poor health, injuries, accidents, etc. In response to this, attention has been drawn to technology that can prevent poor health, injuries, accidents, etc. by estimating the level of fatigue. For example, Patent Document 1 discloses a fatigue determination device as a fatigue estimation system for estimating the level of fatigue, which determines the presence or absence of fatigue and the type of fatigue based on force measurement and bioelectrical impedance measurement. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-023311 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when an estimated posture is used in a fatigue determination device, etc., it may not be possible to appropriately evaluate the posture. Therefore, the present disclosure provides a posture evaluation device, etc. that can more appropriately evaluate the posture. [Means for solving the problem]

[0005] A posture evaluation device according to one aspect of the present disclosure includes a camera that captures an image of a subject and outputs an image; a body position estimation unit that estimates information related to the positions of the subject's body parts from the image; a posture feature calculation unit that calculates posture feature amounts of the subject from the information related to the estimated positions of the body parts; a feature conversion unit that converts the calculated posture feature amounts to output feature amounts for a predetermined evaluation criterion used in evaluating the posture of the subject, the feature amounts being related to the positions of body parts that cannot be estimated by the body position estimation unit; and a posture evaluation unit that uses the converted feature amounts to evaluate the posture of the subject according to the predetermined evaluation criterion.

[0006] Furthermore, a posture evaluation method according to one aspect of the present disclosure is a posture evaluation method executed by a computer, and includes the steps of acquiring an image of a subject, estimating information relating to the positions of body parts of the subject from the image, calculating posture features of the subject from the information relating to the estimated positions of the body parts, converting the calculated posture features to output features for a predetermined evaluation criterion used in evaluating the posture of the subject, the features being related to the positions of body parts that cannot be estimated in the estimating step, and evaluating the posture of the subject using the converted features according to the predetermined evaluation criterion.

[0007] Furthermore, a program according to one aspect of the present disclosure is a program for causing a computer to execute the posture evaluation method described above. [Effects of the Invention]

[0008] According to the posture evaluation device and the like according to one aspect of the present disclosure, posture can be evaluated more appropriately. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1A is a first diagram illustrating posture estimation according to an embodiment. [Figure 1B]FIG. 1B is a second diagram illustrating posture estimation according to the embodiment. [Figure 2] FIG. 2 is a block diagram illustrating a functional configuration of the posture evaluation device according to the embodiment. [Figure 3] FIG. 3 is a flowchart illustrating an example of the operation of the posture evaluation device according to the embodiment. [Figure 4] FIG. 4 is a diagram for explaining symmetry of subjects according to the embodiment. [Figure 5] FIG. 5 is a diagram for explaining symmetry of subjects according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating the conversion of feature amounts according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of determining whether or not there is a risk associated with a posture according to the embodiment. [Figure 8A] FIG. 8A shows a subject standing still in posture A. [Figure 8B] FIG. 8B shows a subject standing still in posture B. [Figure 9A] FIG. 9A is a first diagram illustrating an estimated accumulation of a subject's fatigue level according to an embodiment. [Figure 9B] FIG. 9B is a second diagram illustrating the estimated accumulation of the subject's fatigue level according to the embodiment. [Figure 10] FIG. 10 is a diagram showing an example of displaying an estimation result according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection forms, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0011] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

[0012] (Embodiment) [Posture evaluation device] The overall configuration of a posture evaluation device according to an embodiment will be described below. Fig. 1A is a first diagram for explaining posture estimation according to an embodiment. Fig. 1B is a second diagram for explaining posture estimation according to an embodiment.

[0013] In an embodiment, the analysis device 100 (see FIG. 2 described later) in the present disclosure is a system that estimates the posture of the subject 11 using an image output by capturing an image of the subject 11 using an imaging device 201, and issues an alert accompanied by a stimulus as feedback if there is a risk in the posture. The imaging device 201 is not limited to any particular form as long as it is a camera that captures an image of the subject 11 and outputs an image, and may be a fixed camera installed on a wall or ceiling of a building or the like, as shown in FIG. 1A, or may be a camera mounted on a PC, smartphone, tablet terminal, or the like operated by the subject 11.

[0014] Here, the subject is seated in a chair 12. The evaluation device 200 in the present disclosure determines whether or not there is a risk associated with the subject's posture based on fatigue accumulated when the subject 11 maintains a fixed, static posture. In other words, the evaluation device 200 determines whether or not there is a risk of fatigue increasing due to fatigue accumulated due to strain on at least one of the muscles and joints and impaired blood flow (hereinafter also referred to as a decrease in blood flow) caused by a fixed posture. Therefore, the subject 11 maintains a static posture for at least a certain period of time. The certain period is the minimum period during which fatigue can be estimated by the analysis device 100, such as several tens of seconds or a few seconds. Such a period is determined depending on the processing capabilities of the analysis device 100 and the imaging device 201.

[0015] Examples of subjects 11 who assume such a static posture include desk workers in an office, drivers steering a moving object, people performing muscle training using loads in a static posture, residents of facilities such as hospitals, and passengers and crew members of airplanes.

[0016] The image captured and output by the imaging device 201 is processed by the analysis device 100, and the posture of the subject 11 is estimated as shown in FIG. 1B. The estimated posture of the subject 11 is output as a rigid link model, for example. Specifically, as shown in FIG. 1B, straight lines are connected by key points indicated by black dots, and the posture of the subject 11 can be reproduced by the angle between two straight lines connected by one key point. The posture is estimated by image recognition, and is output as the above-mentioned rigid link model based on the positional relationship of the key points.

[0017] Next, the functional configuration of posture evaluation device 200 in the present disclosure will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the functional configuration of the posture evaluation device according to an embodiment. In Fig. 2, (a) shows the overall configuration of posture evaluation device 200, and (b) shows a more detailed configuration of posture estimation unit 105.

[0018] 2(a), a posture assessment device 200 in the present disclosure includes an imaging device 201 and an analysis device 100, and is used in a state in which the analysis device 100 is connected to the imaging device 201. The posture assessment device 200 is also connected to a timing device 202 and a reception device 204.

[0019] The analysis device 100 includes a first acquisition unit 101, a second acquisition unit 102, a third acquisition unit 103, a posture estimation unit 105, an evaluation unit 108, and an output unit 109.

[0020] The first acquisition unit 101 is a communication module connected to the imaging device 201 and acquires an image of the subject 11 from the imaging device 201. The connection between the first acquisition unit 101 and the imaging device 201 is wired or wireless, and there are no particular limitations on the method of communication performed via this connection.

[0021] The second acquisition unit 102 is a communication module that acquires the time from the connected timing device 202. The connection between the second acquisition unit 102 and the timing device 202 is wired or wireless, and there are no particular limitations on the method of communication that is performed via this connection.

[0022] The timing device 202 is a device that measures time, and is realized by a clock. The timing device 202 is capable of transmitting time to the connected second acquisition unit 102. Here, the time measured by the timing device 202 may be absolute time, or may be the time elapsed from a relative starting point. The timing device 202 may be realized in any form as long as it can measure the time between two points in time, the point in time when the subject 11 is detected to be stationary and an arbitrary point in time (i.e., the time during which the stationary posture is maintained).

[0023] The third acquiring unit 103 is a communication module that is connected to the accepting device 204 and acquires input information from the subject, such as personal information, from the accepting device 204. The connection between the third acquiring unit 103 and the accepting device 204 is made by wire or wirelessly, and there are no particular limitations on the method of communication made through the connection.

[0024] The reception device 204 is a user interface that receives input of personal information of the subject 11, and is realized by an input device such as a touch panel or a keyboard. The personal information includes at least one of information related to the subject's fatigue, such as age, gender, height, weight, muscle mass, stress level, body fat percentage, and exercise proficiency. The reception device 204 may also receive input of information related to the shape of the chair 12 used by the subject 11. Therefore, the third acquisition unit 103 can be said to be an example of a chair shape acquisition unit that acquires information related to the shape of the chair 12. The third acquisition unit 103 registers the received information related to the shape of the chair 12 in advance by storing it in a storage unit (not shown) or the like, and then acquires the registered information related to the shape of the chair 12 again when evaluating the posture of the subject 11.

[0025] The information about the shape of the chair 12 includes at least one of whether the chair 12 has a headrest, a backrest, or armrests. Alternatively, the chair shape acquisition unit may include a processing unit that acquires information about the shape of the chair 12 by estimating the chair 12 shown in an image of the subject 11 using an image processing technique such as object recognition. The acquired information about the chair shape is used when evaluating the posture of the subject 11. When using evaluation criteria conforming to ISO 11226 in evaluating the posture of the subject 11 (described below), the evaluation criteria conforming to ISO 11226 recommend using information about the chair shape to improve estimation accuracy. Therefore, including a chair shape acquisition unit is effective in terms of posture evaluation accuracy. However, in applications where high posture evaluation accuracy is not required, the posture evaluation device 200 may be configured without including a chair shape acquisition unit.

[0026] The posture estimation unit 105 is a processing unit that is realized by executing a predetermined program using a processor and a memory. Through processing by the posture estimation unit 105, the posture of the subject 11 is estimated based on the image acquired by the first acquisition unit 101. In other words, the posture estimation unit 105 executes processing for calculating a posture feature amount in the posture of the subject 11 at that time for each unit time.

[0027] As shown in FIG. 2(b), posture estimation unit 105 includes four components: body position estimation unit 105a, posture feature amount calculation unit 105b, feature amount conversion unit 105c, and switching unit 105d.

[0028] The body position estimation unit 105a is a processing unit that estimates information related to the positions of body parts of the subject 11. The body position estimation unit 105a acquires an image of the subject 11 from the imaging device 201 via the first acquisition unit 101, and estimates the position of each body part of the subject 11 based on the image. Each of the positions of the body parts corresponds to a key point of the subject 11, and a rigid link model 11b can be output based on the estimation by the body position estimation unit 105a.

[0029] The posture feature amount calculation unit 105b is a processing unit that calculates the posture feature amount of the subject 11 from the output information on the positions of the body parts of the subject 11, i.e., the rigid link model 11b. The posture feature amount calculation unit 105b calculates the angle between two or more straight lines included in the rigid link model 11b as the posture feature amount. However, the posture feature amount initially calculated by the posture feature amount calculation unit 105b may not correspond to the feature amount specified in the evaluation criteria used for posture evaluation, which will be described later. Therefore, there is a problem in that the posture of the subject 11 cannot be evaluated from the posture feature amount calculated from the image depending on the evaluation criteria. Therefore, this embodiment has a feature amount conversion unit 105c that converts the posture feature amount into the feature amount specified in the evaluation criteria.

[0030] For example, the evaluation criteria include those conforming to ISO 11226. As an example, the ISO 11226-compliant criteria require the use of angles between body parts containing keypoints that are difficult to estimate directly from an image. Therefore, the feature conversion unit 105c performs a process of converting posture features calculated from an image into features specified by the ISO 11226-compliant evaluation criteria using a predefined conversion formula. This enables computational posture evaluation using posture features calculated from an image, even for evaluation criteria that use angles between body parts containing keypoints that are difficult to estimate directly from an image. The ISO 11226-compliant evaluation criteria are only an example of a standard that specifies the converted features. Similar processing can be performed by setting a conversion formula for any evaluation criteria that use angles between body parts containing keypoints that are difficult to estimate directly from an image.

[0031] The switching unit 105d determines whether the posture of the subject 11 is symmetrical and whether the subject 11 is stationary based on the calculated posture feature amount before conversion, and switches whether to evaluate the posture of the subject depending on the determination result. For example, if the posture of the subject 11 is not symmetrical, there is a possibility that the evaluation result will vary (accuracy will decrease) even if the posture is evaluated. Therefore, the switching unit 105d switches to evaluate the posture only if the posture of the subject 11 is symmetrical. Note that the symmetry of the subject 11 is an indicator that indicates that the subject 11 is not tilted relative to the image capture device 201, and is considered to be symmetrical if it is within a range of a predetermined angle threshold from the reference posture. The symmetry of the subject 11 will be described in more detail later.

[0032] Furthermore, for example, it is difficult to evaluate the posture when the subject 11 is not standing still, so the switching unit 105d switches so that the posture is evaluated only when the subject 11 is standing still.

[0033] 2(a), the evaluation unit 108 is a processing unit that is realized by executing a predetermined program using a processor and a memory. The evaluation unit 108 evaluates the posture of the subject 11 based on the cumulative time of the estimated posture, using the posture estimated by the posture estimation unit 105 (i.e., the feature amount after conversion) and the time acquired by the second acquisition unit 102. The evaluation unit 108 outputs the evaluation result to the output unit 109.

[0034] The output unit 109 is a communication module that is connected to the display device 205 and the recovery device 206, and outputs content based on the posture evaluation results obtained by the posture evaluation device 200 to the display device 205 and the recovery device 206. The connection between the output unit 109 and the display device 205 or the recovery device 206 is made by wire or wirelessly, and there are no particular limitations on the method of communication made via this connection.

[0035] The display device 205 is a device for displaying content based on the posture evaluation result output by the output unit 109. The display device 205 displays an image showing content based on the posture evaluation result using a display panel such as a liquid crystal panel or an organic EL (Electro Luminescence) panel. The display device 205 is an example of a stimulation unit, and issues an alert to the subject 11 accompanied by a sensory stimulus that is relatively easy to perceive. For example, the alert displays an image indicating that there is a posture risk. Furthermore, instead of the display device 205, a device for issuing an alert accompanied by a stimulus to other senses, such as auditory, tactile, and olfactory stimuli other than such visual stimuli, may be provided. Furthermore, when the posture evaluation device 200 is configured to only reduce the fatigue level of the subject 11 using the recovery device 206, only the recovery device 206 may be provided, and the display device 205 is not essential.

[0036] As an example, the recovery device 206 is a device that reduces the subject 11's level of fatigue by promoting blood circulation in the subject 11 when the posture evaluation result is unfavorable (when a risky posture continues for a certain period of time or more). Specifically, the recovery device 206 actively changes the posture of the seated subject 11 by applying voltage, pressurizing, vibrating, or heating, or by changing the arrangement of various parts of the chair 12 using a mechanism provided in the chair 12. In this way, the recovery device 206 changes the load on at least one of the muscles and joints of the subject 11 and promotes blood circulation. In terms of blood flow, promoting blood circulation in this way reduces the impact of poor blood flow due to the subject 11 being in a stationary posture, and the subject 11 recovers from fatigue. The recovery device 206 is attached to or brought into contact with an appropriate body part of the subject 11 in advance, depending on the configuration of the device. When promoting blood circulation in subject 11 by heating, the entire space around subject 11 is heated, and in such a case, it is not necessary to attach or contact an appropriate body part of subject 11. Furthermore, when posture evaluation device 200 is configured only to display the posture evaluation result to subject 11, it is sufficient to include only display device 205, and recovery device 206 is not essential.

[0037] [Operation] Next, an example of the operation of the posture evaluation device 200 in the embodiment will be described with reference to Fig. 3 to Fig. 7. Fig. 3 is a flowchart showing an example of the operation of the posture evaluation device according to the embodiment.

[0038] As shown in FIG. 3, first, the first acquisition unit 101 acquires an image of the subject 11 (S101). Images of the subject 11 are sequentially acquired by the imaging device 201 continuously capturing images, so step S101 may be interpreted as starting acquisition of images of the subject 11. Next, the analysis device 100 determines whether the subject 11 is in a sitting position (S102). Here, the subsequent processing is performed when the subject 11 is in a sitting position. Therefore, if the subject 11 is in a position other than a sitting position, such as standing or lying down (No in S102), the process returns to step S101. However, if the subject 11 is in a position other than a sitting position, such as standing or lying down, and another posture evaluation device is provided that determines the risk of a posture other than a sitting position, the posture may be evaluated using the other posture evaluation device, and then the process may return to step S101. Whether or not the subject 11 is in a sitting position may be determined appropriately by an information processing function of either the imaging device 201 or the analysis device 100 using existing image recognition technology.

[0039] If the subject 11 is in a sitting position (Yes in S102), the switching unit 105d further uses the acquired time to determine whether the subject is in a stationary position where the subject has been stationary for a predetermined threshold time or longer (S103). If the subject 11 is not stationary (No in S103), the process returns to step S101. On the other hand, if the subject 11 is in a stationary position (Yes in S103), the switching unit 105d further determines whether the posture of the subject 11 is symmetrical (S104).

[0040] 4 and 5 are diagrams for explaining the symmetry of a subject according to an embodiment. In this embodiment, the symmetry of the subject 11 is determined using the symmetry of two locations, the neck and the waist. As shown in FIG. 4(a), the symmetry of the neck is determined using rotation angles B and C about two axes of the neck. The rotation angle B corresponds to FIG. 4(b), and the rotation angle C corresponds to FIG. 4(c). As shown in FIG. 4(b), the rotation angle B indicates the neck orientation angle of the subject 11. If the neck orientation angle is less than a first threshold, the neck orientation angle is determined to have symmetry. Furthermore, as shown in FIG. 4(c), the rotation angle C indicates the neck twist angle of the subject 11. If the neck twist angle is less than a second threshold, the neck twist angle is determined to have symmetry.

[0041] Furthermore, as shown in FIG. 5(a), rotation angles B and C around two axes for the waist are used to determine whether or not the waist is symmetrical. Rotation angle B corresponds to FIG. 5(b), and rotation angle C corresponds to FIG. 5(c). As shown in FIG. 5(b), rotation angle B indicates the waist inclination angle of subject 11. If the waist inclination angle is less than a third threshold, the waist inclination angle is determined to be symmetrical. Furthermore, as shown in FIG. 5(c), rotation angle C indicates the waist twist angle of subject 11. If the waist twist angle is less than a fourth threshold, the waist twist angle is determined to be symmetrical. Note that the first to fourth thresholds are each empirically set to a critical angle at which variations occur in posture evaluation and accurate posture evaluation cannot be performed. The first to fourth thresholds may be the same angle or different angles.

[0042] Returning to the explanation of FIG. 3, if the posture of the subject 11 is not symmetrical (No in S104), the process returns to step S101. On the other hand, if the posture of the subject 11 is symmetrical (Yes in S104), the switching unit 105d switches to evaluating the posture of the subject 11. Then, the body position estimation unit 105a and the posture feature amount calculation unit 105b estimate key points of the subject 11 and calculate posture feature amounts as angles formed by lines between the key points (step S105). Thereafter, the feature amount conversion unit 105c converts the calculated posture feature amounts into feature amounts for evaluation reference (S106). For example, FIG. 6 is a diagram for explaining the conversion of feature amounts according to an embodiment. As shown in FIG. 6, when the posture feature amounts are converted into feature amounts for evaluation reference, a correlation between the calculated posture feature amounts (horizontal axis) and the converted feature amounts (vertical axis) is set in advance. This correlation can be calculated as an approximation (dashed line in the figure) by, for example, attaching markers to necessary keypoints in the transformed feature and plotting the relationship between values ​​calculated from coordinates read from the marker positions and values ​​calculated from keypoints estimated from the image. However, these correlation calculations are just examples, and any method can be used as long as it can obtain the correlation between keypoints that cannot be estimated from the image and keypoints that can be estimated from the image. For example, transmitters can be attached to necessary keypoints to obtain their coordinates.

[0043] Returning to FIG. 3, after the converted feature amount is obtained, it is determined whether or not there is a risk in the posture of the subject 11 (S107).

[0044] FIG. 7 is a diagram illustrating an example of determining whether or not a posture is at risk according to an embodiment. In FIG. 7, the horizontal axis represents the tilt angle, and the vertical axis represents the time spent maintaining that posture. The dotted hatched area in the graph indicates a region where the posture is determined to be at risk. The tilt angle is the angle between two straight lines that move at a specific keypoint in the estimated posture when the specific keypoint is focused on, i.e., the angle indicated by the converted feature. A reference angle range for the tilt angle that does not present a risk is set for each keypoint. When the tilt angle of the focused specific keypoint deviates from the reference angle range (exceeds (a) in the figure), the posture estimation unit 105 determines that the posture is at risk by determining whether or not the posture is at risk (Yes in S107). Otherwise, since there is no posture risk, the process returns to step S101 and continues to repeat the same process. At this time, the posture may be evaluated using the converted feature amount and information about the shape of the chair 12, based on evaluation criteria conforming to ISO 11226. The determination of whether or not there is a risk in the posture may be made in accordance with other standards, or may be made according to criteria established experimentally or empirically. After step S107 is Yes, the output unit 109 displays an image on the display device 205 to issue an alert (S108).

[0045] In this way, even if an evaluation criterion requires features including keypoints that cannot be estimated directly from an image, the necessary features can be indirectly obtained by transformation from posture features that have been calculated using keypoints that can be estimated from an image, making it possible to evaluate postures based on the evaluation criterion. This makes it possible to evaluate postures more appropriately.

[0046] [Variations] In the above description, an alert is issued when there is a risk in posture, but instead of issuing an alert, the degree of fatigue (also referred to as fatigue level) accumulated in subject 11 may be estimated based on the elapsed time in a stationary posture. That is, instead of steps S107 and S108, a step of estimating fatigue level may be performed using the converted feature amount. FIG. 8A is a diagram showing a subject standing still in posture A. FIG. 8B is a diagram showing a subject standing still in posture B.

[0047] Similar to the subject 11 shown in FIG. 1A, the subject 11 shown in FIG. 8A and FIG. 8B is in a static sitting position in a chair 12. Although a table, PC, etc. (not shown) are actually present in FIG. 8A and FIG. 8B, only the subject 11 and the chair 12 are shown here. The static posture of the subject 11 shown in FIG. 8A is posture A, which places a relatively heavy load on the shoulders. On the other hand, the static posture of the subject 11 shown in FIG. 8B is posture B, which places a relatively light load on the shoulders.

[0048] The fatigue level estimated for subject 11 standing still in posture A or posture B accumulates over time as shown in Figures 9A and 9B. Figure 9A is a first diagram illustrating the estimated accumulation of the subject's fatigue level according to the embodiment. Figure 9B is a second diagram illustrating the estimated accumulation of the subject's fatigue level according to the embodiment.

[0049] As shown in Figure 9A, when subject 11 remains stationary in posture A shown in Figure 8A or posture B shown in Figure 8B, the fatigue level of subject 11 is expressed by a linear function whose slope is the amount of load calculated from the posture.

[0050] As described above, posture A is a posture that imposes a greater load than posture B. Therefore, for example, in a certain muscle of subject 11 (here, a muscle related to shoulder movement), the load amount in posture A (the slope of the straight line in posture A) is greater than the load amount in posture B (the slope of the straight line in posture B). For this reason, subject 11 accumulates (accumulates) a greater degree of fatigue in a shorter period of time in posture A compared to when subject 11 is stationary in posture B.

[0051] On the other hand, as shown in Figure 9B, when the posture of subject 11 changes from posture A shown in Figure 8A to posture B shown in Figure 8B, the fatigue level of subject 11 is expressed by a function that combines a linear function whose slope is the amount of load calculated from the posture and a linear function whose slope is the amount of change in posture.

[0052] Therefore, for example, while subject 11 remains stationary in posture A, the fatigue level of a certain muscle of subject 11 is estimated as an accumulation (addition) of fatigue level using an increasing function with a positive slope corresponding to the load of posture A, as in FIG. 9A , and the accumulation (addition) turns to recovery (decrease) at the change point when subject 11 begins to change posture. Subject 11's fatigue level recovers (decreases) by an amount shown as the change width in the figure during the period when the posture change continues, using a decreasing function with a negative slope corresponding to the amount of posture change. After the change point when subject 11 remains stationary again in posture B, subject 11's fatigue level is estimated as an accumulation (addition) of fatigue level using an increasing function with a positive slope corresponding to the load of posture B.

[0053] In this way, the posture evaluation device 200 in the modified example estimates the fatigue level of the subject 11 that reflects accumulation and recovery in accordance with the stillness and change of the posture of the subject 11.

[0054] In this manner, the posture estimation unit 105 estimates the fatigue level of the subject 11 using the converted feature quantities of the subject 11. FIG. 10 is a diagram showing an example of displaying an estimation result according to a modified example of the embodiment. As shown in FIG. 10, the posture evaluation device 200 according to the modified example can display and provide feedback on the estimation result of the fatigue level of the subject 11 using the display device 205. Specifically, as shown in FIG. 10, by visualizing the fatigue level of the subject 11, the subject 11 can visually understand how tired he or she is. In the figure, a doll resembling the subject 11 and the fatigue levels of the subject's shoulders, back, and main parts are displayed together on the display device 205. To make it easier for the subject 11 to intuitively understand the fatigue level, the fatigue level of the shoulders is displayed as a "stiff shoulder level," the fatigue level of the back is displayed as a "back pain level," and the fatigue level of the lower back is displayed as a "lower back pain level."

[0055] Here, in the display in the figure, fatigue levels of three parts of the subject 11 are displayed all at once, but the fatigue levels of these three parts are estimated from an image captured at the same time. That is, the posture evaluation device 200 converts posture feature amounts using key points estimated from one image of the subject 11 for the muscles and / or joints of each of a plurality of body parts including a first part (e.g., shoulders), a second part (e.g., back), and a third part (e.g., waist) of the subject 11, and estimates the fatigue levels from the converted feature amounts. Therefore, even if the posture of the subject 11 is constant, the fatigue levels accumulated in the muscles and / or joints of each body part differ, but the posture evaluation device 200 can simultaneously and individually estimate such different fatigue levels.

[0056] The posture evaluation device 200 calculates the load amount for each of multiple body parts, and for one posture of the subject 11, it is possible to estimate the fatigue level of a first part (the above-mentioned shoulder stiffness level) based on the load amount calculated for the first part, the fatigue level of a second part (the above-mentioned back pain level) based on the load amount calculated for the second part, and the fatigue level of a third part (the above-mentioned lower back pain level) based on the load amount calculated for the third part.

[0057] In the example shown in the figure, the degree of stiff shoulders is estimated from the load on the trapezius muscle, the degree of back pain is estimated from the fatigue level of the latissimus dorsi muscle, and the degree of lower back pain is estimated from the load on the lumbar paraspinal muscles. In this way, a single fatigue level may be estimated from a load calculated from a feature value corresponding to one muscle and / or joint, or a single fatigue level may be estimated from a composite load calculated from feature values ​​corresponding to multiple muscles and / or joints. For example, the degree of stiff shoulders (i.e., a single fatigue level in the shoulder region) may be estimated from the average value of the loads on the trapezius muscle, levator scapulae muscle, rhomboid muscle, and deltoid muscle. Furthermore, in estimating the fatigue level, a more realistic estimation of the fatigue level may be performed by weighting the load on the muscle and / or joint that has a particularly large influence on the fatigue level of the relevant body part, rather than simply using an average value.

[0058] The fatigue levels estimated in this way may be shown as relative positions on a reference meter with a minimum value of 0 and a maximum value of 100, as shown in the figure. Here, a reference value is set at a predetermined position on the reference meter. Such a reference value is set to a relative position (or around that position, etc.) of the fatigue level that may cause subjective symptoms such as pain in a typical subject 11, which has been quantified in advance through an epidemiological survey or the like. Therefore, different reference values ​​may be set depending on the fatigue level of each body part.

[0059] Furthermore, the display device 205 may display a warning to the subject 11 as an estimation result when the estimated fatigue level of the subject 11 reaches a reference value. In other words, the display device 205 may also have an alert issuing function. In the figure, an example of such a warning is displayed at the bottom of the display device 205, saying, "The degree of stiff shoulders exceeds the reference value." In addition, in connection with such a warning, the display device 205 may also display a specific countermeasure, such as "We recommend taking a break," as also shown in the figure.

[0060] Furthermore, in addition to the configuration described above in which the estimation result is displayed to the subject 11 to encourage the subject 11 to deal with the accumulated fatigue level, a configuration in which the posture evaluation device 200 actively recovers the fatigue level of the subject 11 can also be considered. Specifically, the fatigue level of the subject 11 is recovered by operating the recovery device 206 shown in Fig. 2. The specific configuration of the recovery device 206 is as described above and will not be described further. However, when the estimated fatigue level of the subject 11 reaches a reference value, the recovery device 206 operates to change the load on at least one of the muscles and joints of the subject 11 and promote blood circulation, thereby reducing the subject's fatigue level.

[0061] [Effects, etc.] As described above, the posture evaluation device 200 according to the first aspect of the present disclosure comprises a camera (image capture device 201) that captures an image of the subject 11 and outputs the image, a body position estimation unit 105a that estimates information relating to the positions of the body parts of the subject 11 from the image, a posture feature calculation unit 105b that calculates posture feature quantities of the subject 11 from the information relating to the estimated positions of the body parts, a feature conversion unit 105c that converts the calculated posture feature quantities to output feature quantities related to the positions of body parts that cannot be estimated by the body position estimation unit 105a, which are feature quantities for a predetermined evaluation criterion used in evaluating the posture of the subject 11, and a posture evaluation unit (evaluation unit 108) that uses the converted feature quantities to evaluate the posture of the subject according to the predetermined evaluation criterion.

[0062] The body position estimation unit 105a, which estimates information about the positions of body parts of the subject 11 from an image, may be unable to estimate the position of a body part, i.e., the position of a body part that is difficult to estimate directly from an image, may be required as a feature related to a predetermined evaluation criterion used to evaluate the posture of the subject 11. With the above configuration, even in such cases, the required feature can be obtained by converting the posture feature calculated using information about the positions of body parts that can be estimated from the image using the feature conversion unit 105c. In other words, by performing conversion, the feature for the predetermined evaluation criterion can be indirectly obtained from the image, enabling appropriate posture evaluation. Therefore, the posture evaluation device 200 can more appropriately evaluate the posture of the subject 11.

[0063] Furthermore, the posture evaluation device 200 according to the second aspect of the present disclosure is the posture evaluation device 200 according to the first aspect, and further includes a switching unit 105d that switches whether or not to evaluate the posture of the subject 11 based on the calculated posture feature.

[0064] According to this, it is possible to use the posture feature values ​​before conversion to switch whether or not to evaluate the posture of the subject 11. For example, if it is found from the posture feature values ​​of the subject 11 that the posture of the subject 11 is not suitable for evaluation, it is possible to switch to not performing evaluation without conversion. In other words, since there is no need to convert unnecessary features when the evaluation is not appropriate, it is possible to save calculation resources.

[0065] Furthermore, the posture evaluation device 200 according to the third aspect of the present disclosure is the posture evaluation device 200 according to the second aspect, and the switching unit 105d determines, based on the calculated posture feature, at least one of whether the posture of the subject 11 is symmetrical or not and whether the subject 11 is stationary or not, and switches whether to evaluate the posture of the subject 11 or not depending on the determination result.

[0066] According to this, the posture feature before conversion can be used to determine at least one of whether the posture of the subject 11 is symmetrical or not and whether the subject 11 is stationary or not, and whether or not to evaluate the posture of the subject 11 can be switched depending on the determination result.

[0067] Furthermore, a posture evaluation device 200 according to a fourth aspect of the present disclosure is a posture evaluation device 200 according to any one of the first to third aspects, in which the subject 11 is a subject 11 using a chair 12, and the posture evaluation device 200 further includes a chair shape acquisition unit (a third acquisition unit 103 or a processing unit related to image processing) that acquires information regarding the shape of the chair 12 used by the subject 11, and the posture evaluation unit 108 evaluates the posture of the subject 11 according to a predetermined evaluation criterion using the converted features and the acquired information regarding the shape of the chair 12.

[0068] This allows evaluation of the posture of the subject 11 based on a predetermined evaluation criterion to include information about the shape of the chair 12.

[0069] Furthermore, the posture evaluation device 200 according to the fifth aspect of the present disclosure is the posture evaluation device 200 according to the fourth aspect, and the chair shape acquisition unit (a processing unit related to image processing) acquires information about the shape of the chair 12 by estimating it using an image.

[0070] This allows evaluation including information about the shape of the chair 12 obtained by estimating information about the shape of the chair 12 using the image.

[0071] Furthermore, the posture evaluation device 200 according to the sixth aspect of the present disclosure is the posture evaluation device 200 according to the fourth aspect, and the chair shape acquisition unit (third acquisition unit 103) acquires information about the shape of the chair 12 that has been registered in advance for the subject 11 by reading it out.

[0072] This allows evaluation of the subject 11 including information about the shape of the chair 12 acquired by reading out information about the shape of the chair 12 that has been registered in advance.

[0073] Furthermore, a posture evaluation device 200 according to a seventh aspect of the present disclosure is a posture evaluation device 200 according to any one of the fourth to sixth aspects, and the information relating to the shape of the chair 12 includes at least one of whether the chair 12 has a headrest, whether it has a backrest, and whether it has armrests.

[0074] This allows evaluation to be made including information about the shape of the chair 12, including at least one of whether the chair 12 has a headrest, whether it has a backrest, and whether it has armrests.

[0075] Furthermore, a posture evaluation method according to an eighth aspect of the present disclosure is a posture evaluation method executed by a computer, and includes the steps of acquiring an image of a subject, estimating information regarding the positions of the subject's body parts from the image, calculating posture features of the subject from the information regarding the estimated positions of the body parts, converting the calculated posture features to output features for a predetermined evaluation criterion used in evaluating the subject's posture, which are related to the positions of body parts that cannot be estimated in the estimating step, and evaluating the subject's posture according to the predetermined evaluation criterion using the converted features.

[0076] This provides the same effects as those of the posture evaluation device 200 described above.

[0077] A program according to a ninth aspect of the present disclosure is a program for causing a computer to execute the posture evaluation method according to the eighth aspect.

[0078] By executing this on a computer, the same effects as those of the posture evaluation device 200 described above can be achieved.

[0079] (Other embodiments) Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments.

[0080] For example, in the above embodiment, a process executed by a specific processing unit may be executed by another processing unit, the order of multiple processes may be changed, or multiple processes may be executed in parallel.

[0081] Furthermore, the posture assessment device of the present disclosure may be realized by multiple devices each having some of the multiple components, or may be realized by a single device having all of the multiple components. Also, some of the functions of a component may be realized as the functions of another component, and each function may be distributed in any way among the components. Any form having a configuration that substantially provides all of the functions that can realize the posture assessment device of the present disclosure is included in the present disclosure.

[0082] In the above-described embodiments, each component may be realized by executing a software program suitable for that component, or 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.

[0083] Furthermore, each component may be realized by hardware. For example, each component may be a circuit (or integrated circuit). These circuits may form a single circuit as a whole, or each may be a separate circuit. Furthermore, each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0084] Furthermore, the general or specific aspects of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0085] In the above embodiment, the posture of the subject is estimated from the image using a rigid link model generated by image recognition, but the posture estimation method is not limited to this. Any existing method may be used as a method for estimating the posture of the subject from the image.

[0086] The present disclosure may also be realized as a posture evaluation method executed by a posture evaluation device, as a program for causing a computer to execute such a posture evaluation method, or as a computer-readable non-transitory recording medium on which such a program is recorded.

[0087] In addition, this disclosure also includes forms obtained by applying various modifications to the embodiments that a person skilled in the art would conceive, or forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the intent of this disclosure. [Explanation of symbols]

[0088] 11. Target Audience 11b Rigid link model 12 chairs 100 Analyzer 101 First acquisition part 102 Second acquisition part 103 Third acquisition part 105 Posture estimation section 105a Body position estimation section 105b Posture feature calculation unit 105c Feature conversion unit 105d Switching part 108 Evaluation Department 109 Output section 200 Posture evaluation device 201 Imaging device 202 Timing device 204 Reception Device 205 Display device 206 Recovery Device

Claims

1. a camera that captures an image of a subject and outputs the image; a body position estimation unit that estimates information about positions of body parts of the subject from the image; a posture feature amount calculation unit that calculates posture feature amounts of the subject from information about the estimated positions of the body parts; a feature conversion unit that converts the calculated posture feature to output a feature for a predetermined evaluation standard used in evaluating the posture of the subject, the feature being related to the position of a body part that cannot be estimated by the body position estimation unit; and a posture evaluation unit that evaluates the posture of the subject based on the predetermined evaluation criterion using the converted feature amount. Posture assessment device.

2. The posture evaluation device further includes a switching unit that switches whether or not to evaluate the posture of the subject based on the calculated posture feature amount. The posture evaluation device according to claim 1 .

3. The switching unit is determining at least one of whether the posture of the subject is symmetrical and whether the subject is stationary based on the calculated posture feature amount; Depending on the result of the determination, it is determined whether or not to evaluate the posture of the subject. The posture evaluation device according to claim 2 .

4. the subject is a subject using a chair, the posture evaluation device further includes a chair shape acquisition unit that acquires information about a shape of the chair used by the subject, The posture evaluation unit evaluates the posture of the subject based on the predetermined evaluation criterion using the converted feature amount and the acquired information about the shape of the chair. The posture evaluation device according to claim 1 .

5. The chair shape acquisition unit estimates and acquires information about the shape of the chair using the image. The posture evaluation device according to claim 4 .

6. The chair shape acquisition unit acquires information about the shape of the chair registered in advance for the subject by reading it out. The posture evaluation device according to claim 4 .

7. The information about the shape of the chair includes at least one of whether the chair has a headrest, whether the chair has a backrest, and whether the chair has armrests. The posture evaluation device according to any one of claims 4 to 6.

8. 1. A computer-implemented method for posture assessment, comprising: acquiring an image of a subject; estimating information about the position of a body part of the subject from the image; calculating posture features of the subject from information about the estimated positions of the body parts; a step of converting the calculated posture feature to output a feature for a predetermined evaluation standard used in evaluating the posture of the subject, the feature being related to the position of a body part that cannot be estimated in the estimating step; and evaluating the posture of the subject based on the predetermined evaluation criterion using the transformed feature amount. Posture assessment methods.

9. A method for causing the computer to execute the posture evaluation method according to claim 8. program.

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