Method for measuring joint range of motion

Abstract

An embodiment of the present invention discloses a method for measuring joint range of motion, belonging to the technical field of body measurement and evaluation. The method includes: obtaining a frontal human body image of a tester completing a preset test action collected by a 2D camera; extracting spatial coordinate data of joint marker points of the tester from the frontal human body image; according to the spatial coordinate data, calculating the average value of the absolute value of the length of the body part related to the joint to be measured of the tester from the initial state to the state where the preset test action is completed, and multiplying the average value by a preset coefficient to obtain a first length value; and recording the length of the body part in the state where the preset test action is completed as a second length value; dividing the second length value by the first length value and performing an inverse trigonometric function operation to obtain joint angle data; calculating a joint range of motion score according to the joint angle data. The embodiment of the present invention has high accuracy, low cost, simple operation, and saves time and effort.

Description

Technical Field

[0001] The present invention relates to the technical field of body measurement and evaluation, and particularly to a method for measuring joint range of motion. Background Art

[0002] Measuring the joint range of motion is a key content in the evaluation of human motor function. In the prior art, conventional joint range of motion measurement schemes all use a joint range of motion measuring ruler for detection, with relatively low measurement accuracy, and it requires medical staff to personally detect the person to be measured, which is time-consuming and laborious, and not easy to operate.

[0003] Patent CN107320108B discloses a method for measuring joint range of motion, including steps of establishing a space coordinate system; initializing human body parameters; selecting a detection item; and detecting the range of motion. This invention combines a position detection module, a space coordinate system, and human body parameters together. Through the three-dimensional coordinate data transmitted by the position detection module assembled on the joint to be measured, the upper computer can simultaneously implement the function of identifying the joint to be measured and the function of detecting the joint range of motion of the joint to be measured. The calculation of the joint range of motion is accurate, realizing the intelligent detection of the joint range of motion, and it is operated by medical staff personally, making the detection simpler and faster.

[0004] Patent application CN114663463A discloses a method, system, device, electronic device, and storage medium for measuring joint range of motion. The method for measuring joint range of motion includes: obtaining motion image data of a target joint, where the motion image data includes the starting pixel point coordinates and the ending pixel point coordinates representing the motion amplitude of the target joint in a target coordinate system; mapping both the starting pixel point coordinates and the ending pixel point coordinates to the joint coordinate system corresponding to the target joint in a preset human joint standard model to respectively obtain joint range of motion data corresponding to the starting pixel point coordinates and the ending pixel point coordinates in the joint coordinate system; and determining the joint range of motion of the target joint according to the joint range of motion data. The method for measuring joint range of motion provided by this invention maps the pixel point coordinates corresponding to the starting and ending points of the spatial motion of the target joint to the corresponding joint coordinate system in the human joint standard model to represent the joint range of motion of the target joint, effectively maintaining the consistency of the measurement results.

[0005] For measuring the joint range of motion, the above patent documents all require the use of a depth camera for three-dimensional recognition, with relatively high requirements for the camera and the backend processing ability. Summary of the Invention

[0006] In view of this, an embodiment of the present invention provides a method for measuring joint range of motion with high accuracy, low cost, and simple operation.

[0007] A method for measuring joint range of motion includes:

[0008] Obtain a front human body image of a tester who has completed a preset test action collected by a 2D camera;

[0009] Extract the spatial coordinate data of the joint marker points of the tester from the front human body image;

[0010] According to the spatial coordinate data, calculate the average value of the absolute value of the length of the body part related to the joint to be measured of the tester from the initial state to the completed state of the preset test action, and multiply the average value by a preset coefficient to obtain a first length value; and record the length of the body part in the completed state of the preset test action as a second length value;

[0011] Divide the second length value by the first length value and perform an inverse trigonometric operation to obtain joint angle data;

[0012] Calculate the joint range of motion score according to the joint angle data.

[0013] In the joint range of motion measurement method of the embodiment of the present invention, first, a front human body image of a tester who has completed a preset test action is obtained by a 2D camera, then the spatial coordinate data of the joint marker points of the tester is extracted from the front human body image, and then according to the spatial coordinate data, the average value of the absolute value of the length of the body part related to the joint to be measured of the tester from the initial state to the completed state of the preset test action is calculated, and the average value is multiplied by a preset coefficient to obtain a first length value; and the length of the body part in the completed state of the preset test action is recorded as a second length value. After that, the second length value is divided by the first length value and an inverse trigonometric operation is performed to obtain joint angle data. Finally, the joint range of motion score is calculated according to the joint angle data. In this way, on the one hand, the embodiment of the present invention uses the method of visual recognition to collect the joint points of the subject, uses the front human body image of the subject, calculates the first length value (which can be understood as the length of the hypotenuse in a right triangle) and the second length value (which can be understood as the length of a straight side in a right triangle), divides the second length value by the first length value, and performs an inverse trigonometric operation, so as to obtain the joint angle data and indirectly calculate the joint angle with high accuracy; on the other hand, the embodiment of the present invention uses a 2D camera to replace the conventional 3D camera, which can reduce the hardware requirements, reduce the computing power, and use the front human body image of the subject to calculate the joint angle data at one time, without collecting human body images in multiple directions, with low cost, simple operation, and time and labor saving. Description of the Drawings

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0015] Figure 1 It is a schematic flowchart of the joint range of motion measurement method of the present invention;

[0016] Figure 2 It is a schematic diagram of the principle of the joint range of motion measurement method of the present invention;

[0017] Figure 3 It is a schematic diagram of the position of the joint marking points in the present invention;

[0018] Figure 4 It is a schematic diagram of the change of the joint angle in the sagittal plane of the neck during the test process of the present invention;

[0019] Figure 5 It is a schematic diagram of the change of the joint angle in the sagittal plane of the shoulder during the test process of the present invention;

[0020] Figure 6 It is a schematic diagram of the change of the joint angle in the sagittal plane of the hip joint during the test process of the present invention;

[0021] Figure 7 It is a schematic diagram of the change of the spinal rotation angle during the test process of the present invention;

[0022] Figure 8 It is a schematic diagram of the result of the auxiliary line difference calculation during the test process of the present invention. Specific embodiments

[0023] The following will describe the embodiments of the present invention in detail with reference to the drawings.

[0024] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] The embodiments of the present invention provide a joint range of motion measurement method, as Figure 1 shown, including:

[0026] Step 101: Obtain a frontal human body image of the tester completing a preset test action collected by a 2D camera;

[0027] Step 102: Extract the spatial coordinate data of the joint marking points of the tester from the frontal human body image;

[0028] In this step, a visual recognition system can be used to extract the spatial coordinate data corresponding to the time series of the joint marker points of the tester from the frontal human body image. The specific extraction method can adopt the conventional techniques in this field and will not be elaborated here.

[0029] As an alternative embodiment, the joint marker points may include at least 16 marker points, including: head, neck, spinal shoulder position, left / right shoulder, left / right elbow, left / right wrist, sacrum, left / right hip, left / right knee, left / right ankle.

[0030] The extracted spatial coordinate data can be, for example, as follows:

[0031] ι i =(x i , y i ), representing the coordinates of the i-th joint marker point. The set of joint marker points of the tester is denoted as R(x, y). During the test, the spatial coordinate data of 16 joint marker points in each time series of the frontal human body image are collected.

[0032] The joint marker points and their numbers of the tester can be as shown in Table 1 and Figure 3 as follows.

[0033] Table 1 Joint Marker Points and Their Numbers

[0034] Number Marking point Number Marking point 0 Head 8 Right wrist 1 Neck 9 Sacrum 2 Spinal shoulder position 10 Left hip 3 Left shoulder 11 Left knee 4 Left elbow 12 Left ankle 5 Left wrist 13 Right hip 6 Right shoulder 14 Right knee 7 Right elbow 15 Right ankle

[0035] The joint marker points defined in the present invention generally correspond to the definitions of joints or body surface bony markers with a certain degree of freedom on the human body. By calculating the relative positions of human joint points in three-dimensional space, the current state of the human body is estimated. Due to the particularity of the human body structure, the connecting lines between the marker points are only connected by the human body structure.

[0036] Here, to improve the accuracy of subsequent evaluation, the extracted spatial coordinate data can also be preprocessed. The preprocessing can be specifically as follows:

[0037] Preprocessing of Spatial Coordinate Data:

[0038] When training the system to automatically recognize joint marker points, in addition to using the source data set, the system can also train the recognition system based on the company's own motion exercise action library. Different from the open-source action library, this action library includes a large number of test actions and exercise actions, which can improve the recognition accuracy of the marker points of this system.

[0039] After the marker points are recognized, data noise reduction processing can be performed first. After noise reduction using the wavelet threshold method, according to the marker point coordinates and time series, the acceleration of the marker points is obtained. Based on the upper limit of the acceleration that the human body can reach and the results of expert discussions, the data limit value is set again. If the limit value is exceeded, the data is deleted. After these two processes, a marker point sequence that is more in line with the human body is obtained.

[0040] Step 103: According to the spatial coordinate data, calculate the average value of the absolute value of the length of the body part related to the joint to be measured of the tester from the initial state to the completed state of the preset test action, and multiply the average value by a preset coefficient to obtain a first length value; and record the length of the body part in the completed state of the preset test action as the second length value.

[0041] Step 104: Divide the second length value by the first length value and perform an inverse trigonometric function operation to obtain joint angle data.

[0042] In the prior art, usually, the spatial length / position of the body part related to the joint to be measured in the initial state and the spatial length / position of the body part in the completed state of the preset test action are collected at the joint part to be measured, a triangle is constructed, and the angle of one angle of the triangle is calculated, so as to calculate the joint angle. For example, taking the neck angle as an example, usually, the line connecting the head and neck when the head is upright and the line connecting the head and neck when the neck is flexed forward are collected, a triangle is constructed through these two lines, and the included angle between the two lines is calculated, so as to calculate the neck joint angle; another example is the shoulder angle, usually, the straight line segment where the arm is located when the arm is upright and downward and the straight line segment where the arm is located when the two arms are extended forward and lifted are collected, a triangle is constructed through these two straight line segments, and the included angle between the two straight line segments is calculated, so as to calculate the shoulder joint angle. However, since the front human body image of the tester is collected, the body part of the tester extends along the 3D depth direction of the camera (not completely extending in the vertical plane in front of the camera), at this time, it is difficult for the camera to accurately identify the joint marker points, that is, it is difficult to accurately identify the length / position of the body part. Even if an image recognition algorithm with high accuracy is used, it is difficult to achieve high accuracy in the calculated joint angle. To solve this problem, the present invention takes a different approach, calculates the first length value (which can be understood as the length of the hypotenuse in a right triangle) and the second length value (which can be understood as the length of one right side in a right triangle), divides the second length value by the first length value, and performs an inverse trigonometric function operation, so as to obtain the joint angle data and indirectly calculate the joint angle with high accuracy.

[0043] Step 105: Calculate the joint range of motion score according to the joint angle data.

[0044] In summary, for the joint range of motion measurement method according to the embodiments of the present invention, first, a frontal human body image of a tester performing a preset test action collected by a 2D camera is obtained. Then, the spatial coordinate data of the joint marker points of the tester is extracted from the frontal human body image. Next, according to the spatial coordinate data, the average value of the absolute value of the length of the body part related to the joint to be measured of the tester from the initial state to the state where the preset test action is completed is calculated, and this average value is multiplied by a preset coefficient to obtain a first length value. And the length of the body part in the state where the preset test action is completed is recorded as a second length value. After that, the second length value is divided by the first length value, and an inverse trigonometric function operation is performed to obtain joint angle data. Finally, according to the joint angle data, the joint range of motion score is calculated. In this way, on the one hand, the method according to the embodiments of the present invention uses the method of visual recognition to collect the joint points of the subject, and uses the frontal human body image of the subject to calculate the first length value (which can be understood as the length of the hypotenuse in a right triangle) and the second length value (which can be understood as the length of one of the right sides in a right triangle), divides the second length value by the first length value, and performs an inverse trigonometric function operation, thereby obtaining the joint angle data and indirectly calculating the joint angle with high accuracy. On the other hand, the method according to the embodiments of the present invention uses a 2D camera to replace the conventional 3D camera, which can reduce the hardware requirements, reduce the computing power, and uses the frontal human body image of the subject to calculate the joint angle data at one time without collecting human body images in multiple directions, with low cost, simple operation, and time and labor saving.

[0045] Figure 2 is a schematic diagram of the principle of the joint range of motion measurement method of the present invention. As Figure 2 shown, the preset test actions in the present invention may include neck flexion and extension, forward reaching and lifting of both arms, upright body rotation, and upright leg lifting. After that, the spatial coordinate data of the body joint marker points of the tester is extracted, and then the neck range of motion, shoulder range of motion, spinal rotation angle, and hip joint range of motion can be calculated respectively. The calculation of these several joint ranges of motion will be described separately below.

[0046] Neck sagittal plane range of motion

[0047] As an optional embodiment, the joint range of motion to be measured is the neck sagittal plane range of motion, the preset test action is neck flexion and extension; the body part related to the joint to be measured is the head and neck, and the length of this body part is the vertical distance between the head and the neck.

[0048] At this time, step 103 is further as follows:

[0049] According to the spatial coordinate data, calculate the average value of the absolute value of the vertical distance between the head and neck of the tester from the initial state (upright state) to the completed state of the preset test action (i.e., neck flexion and extension), and multiply this average value by a preset coefficient to obtain a first length value; and record the vertical distance between the head and neck in the completed state of the preset test action as the second length value.

[0050] In specific implementation, the initial position of the tester is to stand upright facing the instrument, 3 meters away from the instrument, and perform the action test according to the voice prompt, and the action is repeated three times. Neck flexion and extension: The tester stands upright, with the arms hanging naturally, bows the head towards the collarbone area, and tries to bring the chin as close to the chest as possible, and then tilts the head back. On the basis of not feeling uncomfortable, the range of motion of neck flexion and extension is the largest.

[0051] According to the joint marker point recognition, the coordinate data / sequence of the head and neck can be obtained. Here, according to the Y-axis coordinates of the head and neck (denoted as Y 头 、Y 颈 ), the vertical distance S between the head and neck can be calculated as S = |Y 头 - Y 颈 |.

[0052] On this basis, calculate the average value S0 of the absolute value of the vertical distance between the head and neck of the tester from the initial state (upright state) to the completed state of the preset test action (i.e., neck flexion and extension), and multiply this average value S0 by a preset coefficient k to obtain a first length value kS0; and record the vertical distance S between the head and neck in the completed state of the preset test action (i.e., when the range of motion of neck flexion and extension is the largest) as the second length value.

[0053] At this time, in step 104, divide the second length value by the first length value and perform an inverse trigonometric operation (specifically, inverse cosine) to obtain the joint angle data.

[0054] Specifically, on the basis of the above example, the calculation formula for the neck joint angle D reflecting the sagittal plane range of motion of the neck can be as follows:

[0055]

[0056] Among them, ACOS() is the inverse cosine function, and DEGREES() is to convert the inverse cosine value into an angle.

[0057] In the embodiment of the present invention, the preset coefficient k can be determined in the following manner:

[0058] Obtained by least squares fitting. Let the deviation r i of the neck joint angle data = (D i - y i ), (i = 1, 2, 3,..., m), then the fitting criteria that meet the least squares method are:

[0059]

[0060] wherein, i is the number of image frames during the test, D i is the true value of the angle, y i is the fitted value calculated by the foregoing method, and satisfies y i = f(D i ), and r i represents the error of the i-th sample.

[0061] Let That is That is to solve for the value of k when F(k) obtains the minimum value. Through formula solving and actual testing, it is solved that when the value of k is about 1.2, the fitting result is the best. That is to say, in this embodiment, the preset coefficient k can be 0.9 - 1.4, preferably 1.2.

[0062] During the test, an example of the calculation result of the cervical sagittal plane angle can be as Figure 4 and shown in Table 2.

[0063] Table 2 Cervical Sagittal Plane Angle

[0064] Angle Maximum angle 45.75802 Minimum angle 2.459379

[0065] Shoulder Sagittal Plane Mobility

[0066] As an alternative embodiment, the joint mobility to be measured is the shoulder sagittal plane mobility, and the preset test movement is to extend the arms forward and upward; the body part related to the joint to be measured is the upper arm and / or the forearm, and the length of this body part is the vertical length of the upper arm and / or the forearm.

[0067] The body part related to the joint to be measured can be only the upper arm. At this time, step 103 is further:

[0068] According to the spatial coordinate data, calculate the average value of the absolute value of the vertical length of the upper arm of the tester from the initial state (naturally hanging down) to the completion state of the preset test movement (that is, extending the arms forward and upward), and multiply this average value by a preset coefficient to obtain a first length value; and record the vertical length of the upper arm in the completion state of the preset test movement as the second length value.

[0069] The body part related to the joint to be measured can be only the forearm. At this time, step 103 is further:

[0070] According to the spatial coordinate data, calculate the average value of the absolute value of the vertical length of the tester's forearm from the initial state (naturally hanging down) to the completed state of the preset test action (i.e., both arms extended forward and lifted upward), and multiply this average value by a preset coefficient to obtain a first length value; and record the vertical length of the forearm in the completed state of the preset test action as the second length value.

[0071] The body part related to the joint to be measured can be the upper arm and the forearm. At this time, step 103 is further as follows:

[0072] According to the spatial coordinate data, calculate the average value of the absolute value of the vertical length of the tester's upper arm and forearm from the initial state (naturally hanging down) to the completed state of the preset test action (i.e., both arms extended forward and lifted upward), and multiply this average value by a preset coefficient to obtain a first length value; and record the vertical length of the upper arm and forearm in the completed state of the preset test action as the second length value.

[0073] Specifically, when implementing, the tester's initial position is standing upright facing the instrument, 3 meters away from the instrument, and follows the voice prompt to perform the action test, and the action is repeated three times. Both arms extended forward and lifted upward: The tester stands upright, with the arms naturally hanging down, the palms facing inward, and both arms are extended forward and lifted upward to the maximum extent, or stay in the direction where the arms are lifted vertically to the ground.

[0074] According to the joint marker point recognition, the coordinate data / sequence of the shoulder, elbow, and wrist can be obtained. Here, the length of the body part related to the joint to be measured can be calculated according to the Y-axis coordinates of the shoulder, elbow, and wrist (denoted as Y s 、Y e 、Y w ). When the body part is only the upper arm, the vertical length S u of the upper arm = Y e - Y s ; when the body part is only the forearm, the vertical length S l of the forearm = Y w - Y e ; when the body part is the entire arm (i.e., the upper arm and the forearm), the vertical length S u+l of the entire arm = Y w - Y s .

[0075] On this basis, taking the body part as the upper arm and the forearm as an example, calculate the average value S0 of the absolute value of the vertical length of the tester's upper arm and forearm from the initial state (naturally hanging down) to the completed state of the preset test action (i.e., both arms extended forward and lifted upward), and multiply this average value S0 by a preset coefficient k to obtain a first length value kS0; and record the vertical length S of the upper arm and forearm in the completed state of the preset test action (i.e., when the arms are extended forward and lifted upward to the maximum extent) as the second length value.

[0076] At this time, in step 104, divide the second length value by the first length value and perform an inverse trigonometric operation (specifically, arcsine) to obtain joint angle data.

[0077] Specifically, based on the above example, the calculation formula for the shoulder joint angle D reflecting the shoulder sagittal plane mobility can be as follows:

[0078]

[0079] where ASIN() is the arcsine function and DEGREES() is to convert the arcsine value into an angle.

[0080] In the embodiment of the present invention, the determination method of the preset coefficient k is the same as the foregoing, and will not be elaborated here.

[0081] During the test, an example of the calculation result of the shoulder sagittal plane angle can be as Figure 5 shown.

[0082] Hip joint sagittal plane mobility

[0083] As an alternative embodiment, the mobility of the joint to be measured is the hip joint sagittal plane mobility, the preset test action is straight leg raise; the local part of the body related to the joint to be measured is the femur, and the length of this local part of the body is the vertical distance between the hip and the knee.

[0084] At this time, step 103 is further as follows:

[0085] According to the spatial coordinate data, calculate the average value of the absolute value of the vertical distance between the hip and the knee during the process of the tester's femur from the initial state (standing state) to the completion state of the preset test action (i.e., straight leg raise), and multiply this average value by a preset coefficient to obtain the first length value; and record the vertical distance between the hip and the knee in the completion state of the preset test action as the second length value.

[0086] In specific implementation, the tester's initial position is standing facing the instrument, 3 meters away from the instrument, and performs the action test according to the voice prompt, and the action is repeated three times. Straight leg raise: The tester stands upright, swings one thigh forward and upward, folds the thigh and calf as much as possible, and the heel is close to the buttocks.

[0087] According to the identification of the joint point markers, the coordinate data / sequence of the hip and the knee can be obtained. Here, the vertical distance S between the hip and the knee can be calculated according to the Y-axis coordinates of the hip and the knee (denoted as Y 髋 , Y 膝 ) as S = |Y 髋 - Y 膝 |.

[0088] On this basis, calculate the average value S0 of the absolute value of the vertical distance between the hip and knee of the tester from the initial state (upright state) to the completed state of the preset test movement (i.e., straight leg raise), and multiply this average value S0 by the preset coefficient k to obtain the first length value kS0; and record the vertical distance S between the hip and knee in the completed state of the preset test movement (i.e., after straight leg raise) as the second length value.

[0089] At this time, in step 104, divide the second length value by the first length value and perform an inverse trigonometric operation (specifically, inverse cosine) to obtain joint angle data.

[0090] Specifically, based on the above example, the calculation formula for the hip joint angle D reflecting the sagittal plane mobility of the hip joint can be as follows:

[0091]

[0092] where ACOS() is the inverse cosine function and DEGREES() is to convert the inverse cosine value to an angle.

[0093] In the embodiments of the present invention, the determination method of the preset coefficient k is the same as the foregoing, and will not be elaborated here.

[0094] During the test, an example of the calculation result of the sagittal plane angle of the hip joint can be as Figure 6 and shown in Table 3.

[0095] Table 3 Sagittal plane angle of the hip joint

[0096] Angle Left hip maximum 108.0566 Left hip minimum 1.737794 Right hip maximum 108.155 Right hip minimum 2.203548

[0097] Spinal rotation angle

[0098] As an alternative embodiment, the mobility of the joint to be measured is the spinal rotation angle, and the preset test movement is a straight body rotation; the local part of the body related to the joint to be measured is the two shoulders and the two hips, and the length of this local part of the body is the distance between the two shoulders and the distance between the two hips.

[0099] At this time, the step of calculating the average value of the absolute value of the length of the local part of the body related to the joint to be measured of the tester from the initial state to the completed state of the preset test movement according to the spatial coordinate data, and multiplying this average value by a preset coefficient to obtain the first length value; and recording the length of this local part of the body in the completed state of the preset test movement as the second length value (step 103) may include:

[0100] Step 1031: According to the spatial coordinate data, calculate the average value of the absolute value of the distance between the two shoulders of the tester from the initial state (upright state) to the completion state of the preset test action (i.e., upright body rotation), multiply this average value by a preset coefficient to obtain the first shoulder length value, and record the distance between the two shoulders in the completion state of the preset test action as the second shoulder length value;

[0101] Step 1032: According to the spatial coordinate data, calculate the average value of the absolute value of the distance between the two hips of the tester from the initial state (upright state) to the completion state of the preset test action (i.e., upright body rotation), multiply this average value by a preset coefficient to obtain the first hip length value, and record the distance between the two hips in the completion state of the preset test action as the second hip length value.

[0102] During specific implementation, the initial position of the tester is to stand upright facing the instrument, 3 meters away from the instrument, and perform the action test according to the voice prompt, with the action repeated three times. Upright body rotation: The tester stands upright, holds hands together, straightens the arms and raises them forward to the horizontal position, and while keeping the lower body as still as possible without following the rotation of the upper body, drives the upper body to rotate to both sides to the maximum extent.

[0103] According to joint marker point recognition, the coordinate data / sequences of the left shoulder, right shoulder, left hip, and right hip can be obtained. Here, based on the left shoulder ( Figure 3 midpoint 3), right shoulder ( Figure 3 midpoint 6), left hip ( Figure 3 midpoint 10), and right hip ( Figure 3 midpoint 13) marker point sequences / coordinates, the distance S between the two shoulders 肩 and the distance S between the two hips 髋 can be calculated. The specific calculation formulas are as follows:

[0104] Distance between marker points 3 and 6 of the two shoulders

[0105] Distance between marker points 10 and 13 of the two hips

[0106] On this basis, calculate the average value S 肩0 of the absolute value of the distance between the two shoulders of the tester from the initial state (upright state) to the completion state of the preset test action (i.e., upright body rotation), multiply this average value by a preset coefficient k to obtain the first shoulder length value kS 肩0 ; and record the distance S 肩 between the two shoulders in the completion state of the preset test action as the second shoulder length value (corresponding to the above Step 1031);

[0107] Meanwhile, calculate the average value S of the absolute value of the distance between the two hips of the tester from the initial state (upright state) to the completed state of the preset test movement (i.e., upright body rotation). 髋0 Multiply this average value by the preset coefficient k to obtain the first hip length value kS. 髋0 Record the distance between the two hips in the completed state of the preset test movement as the second hip length value S 髋 (corresponding to step 1032 above).

[0108] At this time, the step of dividing the second length value by the first length value and performing an inverse trigonometric operation (specifically, inverse cosine) to obtain joint angle data (step 104) may include:

[0109] Step 1041: Divide the second shoulder length value by the first shoulder length value and take the inverse cosine to obtain the shoulder horizontal plane mobility;

[0110] In this step, the shoulder horizontal plane mobility D 肩 (i.e., Figure 7 the shoulder angle in) is calculated as follows:

[0111]

[0112] where ACOS() is the inverse cosine function and DEGREES() is to convert the inverse cosine value to an angle. It can be understood that the determination method of the preset coefficient k is the same as the foregoing and will not be elaborated here.

[0113] Step 1042: Divide the second hip length value by the first hip length value and take the inverse cosine to obtain the hip horizontal plane mobility;

[0114] In this step, the hip horizontal plane mobility D 髋 (i.e., Figure 7 the pelvic angle in) is calculated as follows:

[0115]

[0116] where ACOS() is the inverse cosine function and DEGREES() is to convert the inverse cosine value to an angle. It can be understood that the determination method of the preset coefficient k is the same as the foregoing and will not be elaborated here.

[0117] Step 1043: Subtract the hip horizontal plane mobility from the shoulder horizontal plane mobility to obtain the spinal rotation joint angle data.

[0118] In this step, the spinal rotation joint angle D 脊 (i.e., Figure 7 the spinal rotation angle in) is calculated as follows:

[0119] D 脊 = D 肩 -D 髋

[0120] Up to this point, the spinal rotation angle can be calculated through the above steps 1031-1032 and 1041-1043.

[0121] It can be conceived that spinal rotation includes left rotation and right rotation. Due to the human skeletal muscle structure, when the human body makes a turning movement, the rotating side trunk rotates a shorter distance compared to the contralateral trunk. Therefore, the spinal rotation direction can be calculated through the difference in the lengths of the auxiliary lines on both sides of the trunk. Thus, as an alternative embodiment, the step of dividing the second length value by the first length value and performing an inverse trigonometric operation to obtain joint angle data (step 104) may further include:

[0122] Step 1041': Denote the line connecting the left shoulder and the left hip as the left auxiliary line, and the line connecting the right shoulder and the right hip as the right auxiliary line, and calculate the lengths of the left auxiliary line and the right auxiliary line respectively;

[0123] Specifically, the left auxiliary line is Figure 3 the line connecting point 3 to point 10, and the distance between these two points (i.e., the length of the left auxiliary line) is L l , and the right auxiliary line is Figure 3 the line connecting point 6 to point 13, and the distance between these two points (i.e., the length of the right auxiliary line) is L r , and the calculation formulas are as follows respectively:

[0124]

[0125]

[0126] Step 1042': Calculate the difference between the length of the left auxiliary line and the length of the right auxiliary line;

[0127] Specifically, the calculation formula for the difference L between the length of the left auxiliary line and the length of the right auxiliary line is as follows:

[0128] L = L l -L r

[0129] Step 1043': Determine the spinal rotation direction according to the sign of the difference.

[0130] In this step, specifically, if the difference is negative, the spinal rotation direction is to the right, and if the difference is positive, the spinal rotation direction is to the left.

[0131] In this way, through the above steps 1041'-1043', the determination of the spinal rotation direction can be achieved.

[0132] During the test, an example of the calculation result of the spinal rotation angle can be as follows Figure 7 and as shown in Table 4, an example of the calculation result of the difference in the lengths of the left and right auxiliary lines involved in step 1042' can be as follows Figure 8 shown.

[0133] Table 4 Spinal Rotation Angle

[0134] Angle Spinal rotation maximum 29.409 Left spinal rotation maximum 29.409 Right spinal rotation maximum 28.850

[0135] As another alternative embodiment, calculating the joint range of motion score according to the joint angle data (step 105) may include:

[0136] Step 1051: Convert the joint angle data to a preset angle range;

[0137] From the foregoing calculation principle, it can be seen that the joint angle calculated in the present invention is not the actual angle, but an indirect / intermediate angle that can reflect the size of the joint angle. After measurement, taking the neck joint angle as an example, the range of this intermediate angle is 0 to 45 degrees (see Figure 4 ), taking the shoulder joint angle as an example, the range of this intermediate angle is -60 degrees to 40 degrees (see Figure 5 ), taking the hip joint angle as an example, the range of this intermediate angle is 0 degrees to 110 degrees (see Figure 6 ), taking the spinal rotation angle as an example, the range of this intermediate angle is -10 degrees to 30 degrees (see Figure 7 ).

[0138] Therefore, in this step, the joint angle data is proportionally converted to a preset angle range that conforms to the actual angle range (see the angle range in Table 5) for subsequent evaluation.

[0139] Step 1052: Calculate the joint range of motion score according to the converted joint angle data.

[0140] In this step, in combination with the normal joint range of motion, according to the literature and expert discussions, the segmented judgment scores of each index can be formulated for individual scoring of each index. The score evaluation rules can be as shown in Table 5 below.

[0141] Table 5 Action Angle Evaluation and Score Evaluation Range

[0142]

[0143]

[0144] In this way, through the above steps 1051-1052, the joint range of motion score can be conveniently calculated according to the joint angle data.

[0145] In summary, the embodiments of the present invention improve the calculation of joint angles. The angle recognition method used in the prior art is to extract the spatial coordinates of the marker points of the tester and directly calculate the angle through the positions of the coordinate points. Compared with the simple visual recognition of the prior art, the accuracy rate of the method of the embodiments of the present invention has been increased from 83.15±3.10% to 94.01±3.28%, proving that the joint range of motion measurement method of the embodiments of the present invention has higher accuracy.

[0146] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for measuring joint range of motion, characterized in that Including: Obtaining a frontal human body image of a tester completing a preset test action collected by a 2D camera; Extracting spatial coordinate data of joint marker points of the tester from the frontal human body image; According to the spatial coordinate data, calculating the average value of the absolute value of the length of the body part related to the joint to be measured of the tester from the initial state to the completed state of the preset test action, and multiplying the average value by a preset coefficient to obtain a first length value; and recording the length of the body part in the completed state of the preset test action as a second length value; Dividing the second length value by the first length value and performing an inverse trigonometric operation to obtain joint angle data; Calculating a joint mobility score according to the joint angle data; Wherein, the joint mobility to be measured is the sagittal plane mobility of the neck, and the preset test action is neck flexion and extension; the body part related to the joint to be measured is the head and neck, and the length of the body part is the vertical distance between the head and the neck; Or, the joint mobility to be measured is the sagittal plane mobility of the shoulder, and the preset test action is raising the arms forward; the body part related to the joint to be measured is the upper arm and / or the forearm, and the length of the body part is the vertical length of the upper arm and / or the forearm; Or, the joint mobility to be measured is the sagittal plane mobility of the hip joint, and the preset test action is straight leg raising; the body part related to the joint to be measured is the femur, and the length of the body part is the vertical distance between the hip and the knee; Or, the joint mobility to be measured is the spinal rotation angle, and the preset test action is standing body rotation; the body part related to the joint to be measured is the two shoulders and the two hips, and the length of the body part is the distance between the two shoulders and the distance between the two hips.

2. The joint range of motion measurement method according to claim 1, wherein The joint marker points include at least 16 marker points, including: head, neck, spinal shoulder position, left / right shoulder, left / right elbow, left / right wrist, sacrum, left / right hip, left / right knee, left / right ankle.

3. The joint range of motion measurement method according to claim 1, wherein When the joint mobility to be measured is the spinal rotation angle, the calculating the average value of the absolute value of the length of the body part related to the joint to be measured of the tester from the initial state to the completed state of the preset test action, and multiplying the average value by a preset coefficient to obtain a first length value according to the spatial coordinate data; And recording the length of the body part in the completed state of the preset test action as a second length value, including: According to the spatial coordinate data, calculating the average value of the absolute value of the distance between the two shoulders of the tester from the initial state to the completed state of the preset test action, and multiplying the average value by a preset coefficient to obtain a first length value of the two shoulders; and recording the distance between the two shoulders in the completed state of the preset test action as a second length value of the two shoulders; According to the spatial coordinate data, calculating the average value of the absolute value of the distance between the two hips of the tester from the initial state to the completed state of the preset test action, and multiplying the average value by a preset coefficient to obtain a first length value of the two hips; and recording the distance between the two hips in the completed state of the preset test action as a second length value of the two hips; The dividing the second length value by the first length value and performing an inverse trigonometric operation to obtain joint angle data includes: Divide the second shoulder length value by the first shoulder length value and take the arccosine to obtain the shoulder horizontal plane mobility; Divide the second hip length value by the first hip length value and take the arccosine to obtain the hip horizontal plane mobility; Subtract the hip horizontal plane mobility from the shoulder horizontal plane mobility to obtain the spinal rotation joint angle data.

4. The method for measuring joint range of motion according to claim 3, wherein The step of dividing the second length value by the first length value and performing an inverse trigonometric function operation to obtain joint angle data includes: Denote the line connecting the left shoulder and the left hip as the left auxiliary line, and the line connecting the right shoulder and the right hip as the right auxiliary line, and calculate the lengths of the left auxiliary line and the right auxiliary line respectively; Calculate the difference between the length of the left auxiliary line and the length of the right auxiliary line; Judge the spinal rotation direction according to the positive or negative of the difference.

5. The method for measuring joint range of motion according to claim 4, wherein The step of judging the spinal rotation direction according to the positive or negative of the difference includes: If the difference is negative, the spinal rotation direction is to the right; if the difference is positive, the spinal rotation direction is to the left.

6. The method for measuring joint range of motion according to claim 1, wherein The preset coefficient is 0.9 - 1.

4.

7. The method for measuring joint range of motion according to any one of claims 1-6, characterized in that, The step of calculating the joint mobility score according to the joint angle data includes: Convert the joint angle data to a preset angle range; Calculate the joint mobility score according to the converted joint angle data.

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