Lumbar vertebra load determination method in different spine activity modes

Abstract

The invention relates to a lumbar vertebra load determination method in different spine movement modes, which comprises the following steps: S1, image acquisition: establishing a reference object, and shooting spine movement images of a sagittal plane and a coronal plane of a human body at two camera positions by adopting a camera device; s2, image registration: establishing a space coordinate system; correcting the size of the shot image, and restoring the form and size of each body segment link of the human body in the three-dimensional space; s3, gravity center position calculation: calculating three-dimensional coordinates of the gravity center of each body section link of the human body, and further calculating three-dimensional coordinates of the gravity center of the upper half body of the human body; generating a gravity center movement curve based on the gravity center coordinates in different spine activity modes, and further calculating the gravity center position of any activity angle; s4, lumbar vertebra load calculation: loading the gravity of the upper body to L1-L5 sections of lumbar vertebra section by section, and calculating horizontal and vertical component forces; and calculating the total gravitational torque according to the gravity center offset distance, and distributing the total gravitational torque to the lumbar vertebra of each section in proportion. The method is beneficial to accurately and conveniently determining the loads borne by the lumbar vertebra of the human body in different spine movement modes.

Description

Technical Field

[0001] The present invention relates to the technical field of human force analysis, and particularly relates to a method for determining lumbar load under different spinal movement patterns. Background Art

[0002] Different spinal movement patterns will cause changes in the center of gravity of the human body, thereby changing the force-bearing pattern of the lumbar spine. In the prior art, although research on measurement methods of the human center of gravity has been published, however, the human bone and muscle system is highly flexible, and the human body is usually in a moving state, so the position of the center of gravity is also in a moving state. Currently, there is no relevant research on the method for determining lumbar load under the condition that the dynamic spinal movement pattern changes the force-bearing pattern of the lumbar spine. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for determining lumbar load under different spinal movement patterns, which is beneficial to accurately and conveniently determine the load on the human lumbar spine under different spinal movement patterns.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: a method for determining lumbar load under different spinal movement patterns, including the following steps:

[0005] S1. Image acquisition: Use two standard-sized flat plates as reference objects, and attach them adjacent to two adjacent vertical sides of a square column; Use a camera device to take spinal movement images of the human sagittal plane and coronal plane at two camera positions; The shooting plane of the camera device is parallel to the plane where the reference object is located; During the shooting process, the object to be photographed is located in front of or beside the reference object, keep the foot position fixed and complete different spinal movements;

[0006] S2. Image registration: Take one end point of the intersecting edge of the two reference objects as the origin of the coordinate system, and establish a three-dimensional rectangular coordinate system in space; Correct the size of the captured images to restore the shape and size of each body segment of the human body in three-dimensional space;

[0007] S3. Center of gravity position calculation: According to the corrected image data and the established coordinate system, obtain the coordinates of the proximal and distal joint points of each link of the human body, calculate the three-dimensional coordinates of the center of gravity of each body segment of the human body, and then calculate the three-dimensional coordinates of the center of gravity of the upper body of the human body; Based on the center of gravity coordinates under different spinal movement patterns, generate a center of gravity movement curve, and then calculate the center of gravity position at any movement angle;

[0008] S4. Lumbar load calculation: Gradually load the gravity of the upper body of the human body onto the L1-L5 lumbar segments of the human body, and calculate the horizontal and vertical component forces; Calculate the total gravity moment according to the center of gravity offset distance and distribute it proportionally to each lumbar segment.

[0009] Further, in step S1, the flat plate is a square cardboard with a set side length, and the side size of the square column is larger than the reference object; the shooting range of the imaging device is ensured to cover the object to be photographed and the reference object by adjusting the focal length of the imaging device.

[0010] Further, in step S2, a scale is established according to the proportional relationship between the size of the reference object in the captured image and the standard size of the actual reference object, and used as the scale between the sizes of each body segment link in the captured image and the actual sizes of each body segment link of the human body. The data in the captured image is corrected in size to accurately and truly restore the shape and size of each body segment link of the human body in three-dimensional space.

[0011] Further, in step S3, according to the corrected image data and the position of the origin in the established coordinate system, combined with the relative mass of the human body link and the relative position parameter of the link centroid, the proximal and distal bony joint points of each link in the image are marked, and the coordinates of the proximal and distal joint points of each link in the human body are obtained by measuring the distances from each joint point to the origin of the coordinate system.

[0012] Further, in step S3, according to the coordinates of the proximal and distal joint points of each link in the human body, the three-dimensional coordinates of the centroid of each body segment link in the human body are calculated, and the calculation formula is as follows:

[0013] X ic =X 近 -(X 远 -X 远 )L CS ,S iC =Y 近 -(Y 近 -Y 远 )L CS ,Z iC =Z 近 -(Z 近 -Z 远 )L CS (1)

[0015] Wherein, X iC 、Y iC 、Z iC are the coordinates of the link centroid, X 近 、Y 近 、Z 近 are the coordinates of the proximal joint point of the link, X 远 、Y 远 、Z 远 are the coordinates of the distal joint point of the link, and L CS is the position of the link centroid relative to the proximal joint point of the link;

[0016] Then, calculate the three-dimensional coordinates of the center of gravity of the upper body of the human body, and its calculation formula is as follows:

[0017]

[0018] Among them, X C 、Y C 、Z C are the three-dimensional coordinates of the center of gravity of the upper body of the human body, P i is the relative mass of each body segment of the human body, X iC 、Y iC 、Z iC are the coordinates of the center of gravity of the segment.

[0019] Furthermore, the specific implementation method of step S4 is:

[0020] The gravity borne by the L1-L5 lumbar segments of the human body increases progressively, so the gravity is loaded progressively; the gravity borne by all segments of the upper body of the human body except the waist is applied to the upper surface of the L1 lumbar segment, and only 1 / 5 of the waist gravity is applied to the upper surfaces of the L2-L5 lumbar segments respectively; the calculation formula for the gravity borne by each segment is as follows:

[0021] m i =M 体重 *P i (5)

[0022] G i =m i g (6)

[0023] Among them, m i is the actual mass of each segment of the upper body of the human body, M 体重 is the weight of the standard human body, P i is the relative mass of each segment of the human body, G i is the weight of each segment; the acting point of the gravity borne by the upper body of the human body is set at the midpoint of the upper surface of each vertebral body;

[0024] Equivalently load the gravity borne by the upper body of the human body as component forces in the horizontal and vertical directions; the vertebral inclination angle is obtained from the center of gravity offset angle, and its calculation formula is as follows:

[0025]

[0026] Among them, X1, Y1 are the two-dimensional coordinates of the center of gravity of the upper body in each movement mode of the lumbar spine, and X0, Y0 are the two-dimensional coordinates of the center of gravity of the upper body in the normal standing state of the human body;

[0027] Furthermore, calculate the component forces of the gravity borne by the upper body of the human body in the horizontal and vertical directions:

[0028] F 竖直 =M 躯干g cosθ (9)

[0029] F 水平 = M 躯干 g sinθ (10)

[0030] where F 竖直 is the magnitude of the vertical component of the gravitational force relative to the surface of the L1 vertebra in each lumbar movement mode, F 水平 is the magnitude of the horizontal component of the gravitational force relative to the surface of the L1 vertebra in each movement mode, M 躯干 is the mass of the upper body of the human body, and g is the acceleration due to gravity;

[0031] The total gravitational moment of the lumbar spine in a movement mode is affected by the moment generated by the center of gravity offset. The center of gravity offset is the distance between the center of gravity in different spinal movement postures and the center of gravity position in the normal standing position. Four movement modes of forward flexion, backward extension, left and right lateral flexion of the human body are designed. The center of gravity offset position is in the coronal plane or sagittal plane. The sagittal plane is only applicable to the calculation of the center of gravity offset distance in the forward flexion and backward extension movement modes, and the coronal plane is only applicable to the calculation of the center of gravity offset distance in the left and right lateral flexion movement modes. The calculation of the center of gravity offset distance is as follows:

[0032]

[0033] where x 偏 and y 偏 are the transverse and longitudinal coordinates of the offset center of gravity in the coronal plane or sagittal plane respectively, and x0 and y0 are the transverse and longitudinal coordinates of the center of gravity in the coronal plane or sagittal plane in the normal standing state. For the calculation of the center of gravity offset distance in the forward flexion and backward extension movement modes, the transverse coordinate x 偏 and the longitudinal coordinate y 偏 of the offset center of gravity in the sagittal plane correspond to the three-dimensional coordinates X C and Y C of the center of gravity in the forward flexion and backward extension states of the human body respectively. For the calculation of the center of gravity offset distance in the left and right lateral flexion movement modes, the transverse coordinate x 偏 and the longitudinal coordinate y 偏 of the offset center of gravity in the coronal plane correspond to the three-dimensional coordinates Z C and Y C of the center of gravity in the left and right lateral flexion states of the human body respectively;

[0034] The total moment generated by the center of gravity offset is:

[0035] M d = m 躯干 *g*d*cosθ (12)

[0036] where M d is the moment generated by the center of gravity offset, m 躯干where \(m\) is the weight of the human torso, \(g\) is the acceleration due to gravity, and \(d\) is the distance of the center of gravity offset;

[0037] The gravitational moment is loaded on the posterior surface of each vertebral body. Based on the uniform distribution of the gravitational moment in each segment of the lumbar spine, 1 / 5 of the total gravitational moment of the lumbar spine in an activity mode is applied to each of the L1 - L5 segments of the lumbar spine.

[0038] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for determining the lumbar spine load under different spinal activity modes. This method constructs an image - taking scene with a reference object. On this basis, a camera device is used to take spinal activity images of the sagittal plane and coronal plane of the human body. Thus, the reference object can be used to register the taken images, and then the three - dimensional coordinates of the center of gravity of each link of the human body and the coordinates of the center of gravity of the upper body of the human body are calculated according to the registered and corrected images. Taking the standard normal standing posture as the benchmark, the offset of the center of gravity of the upper body of the human body under different activity modes is calculated, and then the loads on each segment of the lumbar spine generated by the offset center of gravity in different postures are calculated, including its own gravity and moment. The present invention can conveniently and accurately calculate the three - dimensional coordinate position of the center of gravity of the upper body of the human body and the magnitudes of the gravity and gravitational moment received by each segment of the lumbar spine in the dynamic spinal activity mode, so as to be able to more accurately study the biomechanical characteristics of the lumbar spine when the human torso is moving. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is the flowchart of the method implementation of the embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of the relative positions of the reference object and two shooting positions in the embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of taking spinal activity images in the embodiment of the present invention;

[0042] Figure 4 is a schematic diagram of the load applied to the lumbar spine by the gravity of the upper body in different postures in the embodiment of the present invention;

[0043] Figure 5 is a schematic diagram of the load applied to the lumbar spine by the gravity of the upper body in the state of offset caused by spinal activity in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The present invention will be further described below in conjunction with the drawings and embodiments.

[0045] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0047] As Figure 1 shown, this embodiment provides a method for determining lumbar spine loads under different spinal movement patterns, including the following steps:

[0048] S1. Image acquisition: Use two standard-sized flat plates as reference objects and attach them adjacent to two adjacent vertical sides of a square column; Use a camera device to take spinal movement images of the human body's sagittal plane and coronal plane at two positions; The shooting plane of the camera device is kept parallel to the plane where the reference objects are located; During the shooting process, the object to be photographed is located in front of or beside the reference objects, keeping the foot position fixed and completing different spinal movements;

[0049] S2. Image registration: Take one endpoint of the intersecting edge of the two reference objects as the origin of the coordinate system and establish a three-dimensional rectangular coordinate system in space; Correct the size of the captured images to restore the shape and size of each body segment of the human body in three-dimensional space;

[0050] S3. Center of gravity position calculation: According to the corrected image data and the established coordinate system, obtain the coordinates of the proximal and distal joint points of each body segment of the human body, calculate the three-dimensional coordinates of the center of gravity of each body segment of the human body, and then calculate the three-dimensional coordinates of the center of gravity of the upper half of the human body; Based on the center of gravity coordinates under different spinal movement patterns, generate a center of gravity movement curve, and then calculate the center of gravity position at any movement angle;

[0051] S4. Lumbar spine load calculation: Gradually load the gravity of the upper half of the human body onto the L1-L5 lumbar spine segments of the human body, and calculate the horizontal and vertical component forces; Calculate the total gravity moment according to the center of gravity offset distance and distribute it proportionally to each lumbar spine segment.

[0052] The relevant technical content involved in this method will be further described in detail below.

[0053] 1. Spinal movement patterns

[0054] There are four modes of human spinal movement: forward flexion, backward extension, left and right lateral flexion. Volunteers are required to perform these four spinal movements. Each movement mode starts from the normal standing position. The normal standing posture is that the feet are shoulder-width apart, the hands hang naturally, and the head looks straight ahead. According to the requirements, perform each spinal movement mode separately. For example, when performing forward flexion, flex forward naturally with the arms in a relaxed state. Starting from the normal posture, take an image at each forward flexion angle. And so on, a total of 8 forward flexion angles are taken. When reaching the eighth angle, the forward flexion angle reaches the maximum. Here, it should be noted that it is not required that the angles between every two adjacent forward flexion postures are equal. This is because of the difficulty in measuring the forward flexion angle. That is, the researchers can divide the eight forward flexion postures between the normal posture and the maximum forward flexion posture of the volunteer, but try to make the difference between each flexion angle the smallest. Designing eight flexion or extension angles for each movement mode is to generate the center of gravity offset curve of this movement mode later, so as to calculate the center of gravity position at any flexion or extension angle.

[0055] 2. Image acquisition

[0056] Image acquisition is achieved according to the following steps:

[0057] (a) First, make two standard-sized flat plates as references. In this embodiment, cardboard is used. There is no special requirement for the size selection. It is recommended to choose 50 cm because it is relatively simple in the later registration calculation. Then, make or select a suitable square column by yourself. The side size of the square column must be larger than the cardboard. Stick the already made cardboard on two adjacent side surfaces of the column that are perpendicular to each other.

[0058] (b) The shooting device uses a single-lens reflex camera. Use the single-lens reflex camera to sequentially shoot the movements on the sagittal plane and the coronal plane of the human body at two shooting positions. The positions of the two shooting positions are as Figure 2 shown. Preferably, the distances L1 and L2 between the two shooting positions and the two references can be equal, but they can also be unequal according to the actual situation. The single-lens reflex camera is fixed on a horizontal tripod. The shooting plane of the single-lens reflex camera is kept parallel to the plane where the reference is located, that is, the angle between the main optical axis of the camera and the reference plane is kept at about 90°. During the image acquisition process, the height of the tripod and the distance from the reference are kept unchanged. It is recommended that the height of the camera can be 1.2 m, and the distance between the lens and the reference is about 4.1 m. Control the shooting range by adjusting the focal length and the shooting distance so that the shooting range covers the reference and the entire research object. The positions of the camera are kept the same when shooting the movements on the sagittal plane and the coronal plane of the human body. The process of shooting the spinal movement images is as Figure 3 shown.

[0059] (c) The subject should be able to perform four kinds of spinal activities flexibly. The height of the subject is the average height of adult men or women. The subject wears a tight vest and shorts to fully expose the bony landmark joints of each body segment. During the image acquisition process, the sagittal plane or coronal plane of the human body remains in the same plane as the plane where the reference object is located. There is no mutual occlusion between the human body and the reference object during the spinal activity shooting of the subject. During the image acquisition process, the position of the subject's feet does not deflect or move. It is recommended to draw footprints at the position of the research object to observe whether the position of the feet changes during the spinal activity of the research object. When shooting the movements on the sagittal plane and coronal plane of the human body, the position of the human body relative to the reference object remains consistent.

[0060] 3. Image registration

[0061] Based on the two groups of images of lumbar spine activities on the sagittal plane and coronal plane of the human body collected, a three-dimensional rectangular coordinate system of the space where the research object is located can be established. The origin position of the three-dimensional rectangular coordinate system is a fixed point relative to the human body. The origin position is set at the intersection side length endpoint of the reference object so that it is consistent with the origin position marked when processing the pictures of lumbar spine activities on the sagittal plane and coronal plane of the human body. Assume that the forward flexion, backward extension, and left and right lateral flexion activities of the human lumbar spine are all planar activities on the sagittal plane and coronal plane of the human body, that is, when the human lumbar spine performs forward flexion and backward extension activities, the coordinate positions of the center of gravity of the upper body of the human body all change in the sagittal plane of the human body, and when the human lumbar spine performs left and right lateral flexion activities, the coordinate positions of the center of gravity of the upper body of the human body all change in the coronal plane of the human body. Due to the influence of various factors in actual shooting, and the collected images are two-dimensional, while the space where the human body is located is three-dimensional, there may be a certain error between the human body size in the image and the actual size. When performing image processing, the scale is used as the reference standard for measurement. The scale is made by measuring the side length of the reference object in the actual situation and the side length of the reference object in the collected image, and is used as the scale between the sizes of each body segment link in the captured image and the actual sizes of each body segment link of the human body, so as to correct and calibrate the data in the captured image, and thus more accurately and realistically restore the shape and size of each body segment link of the human body in three-dimensional space.

[0062] 4. Center of gravity position calculation

[0063] According to the collected image data and the origin position, combined with the national standards of the relative mass of each link and the relative position of the center of mass of each link of Chinese adults, the bony joint points at the proximal and distal ends of each link in the human body image are marked. By measuring the distances from each joint point to the origin of the coordinate system, the two-dimensional coordinates of the proximal and distal end joint points of each link of the human body are obtained. Among them, to simplify the calculation, for the problem of the left arm or right arm occlusion that appears in the forward flexion and backward extension activity mode of the human lumbar spine photographed in the sagittal plane direction of the human body, the coordinate data of the left arm or right arm are referenced by the right arm or left arm during the joint point marking.

[0064] Since the flexion, extension, and left and right lateral flexion movements of the human lumbar spine are all planar movements in the sagittal and coronal planes of the human body, the three-dimensional coordinates of the joint points of each segment of the human body in the standard posture and the positions of the coronal and sagittal planes of the human body in the space rectangular coordinate system can be obtained from the two-dimensional coordinates of the joint points in the two standard posture images collected above. Furthermore, the three-dimensional coordinates of the joint points of each body segment in each motion state of the human body in the captured images can be obtained.

[0065] According to the coordinates of the proximal and distal joint points of each segment of the human body, calculate the three-dimensional coordinates of the center of gravity of each body segment of the human body. The calculation formula is as follows:

[0066] X iC = X 近 -(X 近 - X 远 )L CS , Y iC = Y 近 -(Y 近 - Y 远 )L CS , Z iC = Z 近 -(Z 近 - Z 远 )L CS (1)

[0068] Among them, X iC , Y iC , Z iC are the coordinates of the center of gravity of the segment, X 近 , Y 近 , Z 近 are the coordinates of the proximal joint point of the segment, X 远 , Y 远 , Z 远 are the coordinates of the distal joint point of the segment, and L CS is the position of the center of mass of the segment relative to the proximal joint point of the segment.

[0069] In the standing position, the gravity borne by the position where the lumbar spine is located comes from the sum of the gravity received by several segments of the upper body of the human body. The three-dimensional coordinates of the center of gravity of the upper body of the human body can be calculated using the following formula. Specifically:

[0070]

[0071] Among them, X C , Y C , Z C are the three-dimensional coordinates of the center of gravity of the upper body of the human body, P i is the relative mass of each body segment of the human body, and X iC , Y iC, Z iC is the center of gravity coordinate of the link.

[0072] In the above steps, it is required that each spinal movement mode needs eight degrees of mobility. The center of gravity movement curve of this movement mode can be drawn using the calculated center of gravity point coordinates, so as to calculate the center of gravity position at any movement angle without the need for experimental measurement.

[0073] 5. Lumbar load calculation

[0074] The gravity received by the L1-L5 lumbar segments of the human body increases progressively. The gravity loading is applied progressively. The gravity received by all links of the upper body except the waist is applied to the upper surface of the L1 lumbar segment. The links of the upper body mentioned here include: head and neck, chest, left and right collarbones, left and right upper arms, left and right forearms, left and right hands, and waist. Only 1 / 5 of the waist gravity is applied to the upper surfaces of the L2-L5 lumbar segments respectively.

[0075] The calculation formula for the gravity received by each link is as follows:

[0076] m i = M 体重 * P i (5)

[0077] G i = m i g (6)

[0078] Among them, m i is the actual mass of each link of the upper body of the human body, M 体重 is the weight of the standard human body, P i is the relative mass of each link of the human body, G i is the weight of each link; the acting point of the gravity received by the upper body of the human body is set at the midpoint of the upper surface of each vertebral body segment.

[0079] Figure 4 is a schematic diagram of the load applied to the lumbar spine by the gravity of the upper body in different postures. In the figure, on the left is the L1-L5 lumbar segments in the normal posture, and A1 is the center of gravity of the upper body in the normal posture; on the right is the L1-L5 lumbar segments in the offset state caused by spinal movement, and A2 is the center of gravity of the upper body in the offset state caused by spinal movement.

[0080] Figure 5 is a schematic diagram of the load applied to the lumbar spine by the gravity of the upper body in the offset state caused by spinal movement. Figure 5It shows the loading mode of gravity on the spine after the center of gravity of the upper body shifts. Since the lumbar spine has a certain angle of inclination relative to the upright state of the human body in various activity modes, the gravity acting on the upper body of the human body is not always perpendicular to the upper surface of the L1 vertebral body. Therefore, the gravity acting on the upper body of the human body is equivalently loaded as component forces in the horizontal and vertical directions. The angle of vertebral inclination can be obtained from the angle of center of gravity shift, and its calculation formula is as follows:

[0081]

[0082] where X1 and Y1 are the two-dimensional coordinates of the center of gravity of the upper body in each lumbar activity mode, and X0 and Y0 are the two-dimensional coordinates of the center of gravity of the upper body in the normal standing state of the human body.

[0083] Furthermore, calculate the component forces of the gravity acting on the upper body of the human body in the horizontal and vertical directions:

[0084] F 竖直 = M 躯干 g cosθ (9)

[0085] F 水平 = M 躯干 g sinθ (10)

[0086] where F 竖直 is the magnitude of the vertical component force of gravity relative to the surface of the L1 vertebral body in each lumbar activity mode, F 水平 is the magnitude of the horizontal component force of gravity relative to the surface of the L1 vertebral body in each activity mode, M 躯干 is the mass of the upper body of the human body, and g is the acceleration due to gravity.

[0087] The magnitude of the total gravitational moment in a certain lumbar activity mode is affected by the moment generated by the center of gravity shift. The center of gravity shift is the distance between the center of gravity in different spinal activity postures and the center of gravity position in the normal standing position.

[0088] This method designs four activity modes of human forward flexion, backward extension, left and right lateral flexion. The center of gravity shift position is on the coronal plane or the sagittal plane. The sagittal plane is only applicable to the calculation of the center of gravity shift distance in the forward flexion and backward extension activity modes, and the coronal plane is only applicable to the calculation of the center of gravity shift distance in the left and right lateral flexion activity modes. The center of gravity shift distance is calculated as follows:

[0089]

[0090] where x 偏 and y 偏 are the transverse and longitudinal coordinates of the shifted center of gravity on the coronal plane or the sagittal plane, respectively, and x0 and y0 are the transverse and longitudinal coordinates of the center of gravity on the coronal plane or the sagittal plane in the normal standing state. For the calculation of the center of gravity shift distance in the forward flexion and backward extension activity modes, the transverse coordinate x of the shifted center of gravity on the sagittal plane偏 and the vertical coordinate y 偏 respectively correspond to the three-dimensional coordinates X of the center of gravity of the human body in the forward flexion and backward extension states C and Y C ; For the calculation of the offset distance of the center of gravity in the left and right lateral flexion movement modes, the horizontal coordinate x of the offset center of gravity in the coronal plane 偏 and the vertical coordinate y 偏 respectively correspond to the three-dimensional coordinates Z of the center of gravity of the human body in the left and right lateral flexion states C and Y C .

[0091] The total torque generated by the center of gravity offset is:

[0092] M d = m 躯干 * g * d * cosθ (12)

[0093] Wherein, M d is the torque generated by the center of gravity offset, m 躯干 is the weight of the human torso, g is the acceleration due to gravity, d is the center of gravity offset distance, calculated by formula (11), and the calculation of cosθ is as shown in formula (8).

[0094] The gravitational torque is loaded on the posterior surface of each vertebral body. According to the uniform distribution of the gravitational torque in each segment of the lumbar spine, 1 / 5 of the total gravitational torque in a certain movement mode of the lumbar spine is applied to each of the L1-L5 segments of the lumbar spine respectively.

[0095] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can be in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0096] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, so that the instructions executed by the processors of the computer or other programmable data processing devices generate means for realizing the specified functions in the Figure 1 one or more flows Figure 1 or more flows and / or blocks

[0097] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that implements in the process Figure 1 one process or a plurality of processes and / or blocks Figure 1 the functions specified in one block or a plurality of blocks.

[0098] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, such that a series of operation steps are executed on the computer or other programmable apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in Figure 1 one process or a plurality of processes and / or blocks Figure 1 one block or a plurality of blocks.

[0099] As mentioned above, it is only the preferred embodiment of the present invention, and is not a limitation of the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for determining lumbar spine loads under different spinal movement patterns, characterized in that Including the following steps: S1. Image acquisition: Use two standard-sized flat plates as references, adjacent to and attached to two adjacent vertical sides of a square column; Use a camera device to take spinal movement images of the human sagittal plane and coronal plane at two camera positions; The shooting plane of the camera device is kept parallel to the plane where the reference is located; During the shooting process, the object to be photographed is located in front of or beside the reference, keeping the foot position fixed and completing different spinal movements; S2. Image registration: Use one end point of the intersecting side of the two references as the origin of the coordinate system to establish a three-dimensional rectangular coordinate system in space; Perform size correction on the captured images to restore the shape and size of each body segment of the human body in three-dimensional space; S3. Center of gravity position calculation: According to the corrected image data and the established coordinate system, obtain the coordinates of the proximal and distal joint points of each link of the human body, calculate the three-dimensional coordinates of the center of gravity of each body segment of the human body, and then calculate the three-dimensional coordinates of the center of gravity of the upper body of the human body; Based on the center of gravity coordinates under different spinal movement modes, generate a center of gravity movement curve, and then calculate the center of gravity position at any movement angle; S4. Lumbar spine load calculation: Gradually load the gravity of the upper body of the human body onto the L1-L5 segments of the lumbar spine of the human body, and calculate the horizontal and vertical component forces; Calculate the total gravity moment according to the center of gravity offset distance and distribute it proportionally to each segment of the lumbar spine.

2. A method for determining lumbar spine load under different spinal movement patterns according to claim 1, characterized in that, In step S1, the flat plate is a square cardboard with a set side length, and the side size of the square column is larger than the reference; By adjusting the focal length of the camera device, ensure that the shooting range of the camera device covers the object to be photographed and the reference.

3. A method for determining lumbar spine load under different spinal movement patterns according to claim 1, characterized in that In step S2, establish a scale according to the proportional relationship between the size of the reference in the captured image and the standard size of the actual reference, which is used as the scale between the size of each body segment of the human body in the captured image and the actual size of each body segment of the human body, and perform size correction on the data in the captured image to accurately and truly restore the shape and size of each body segment of the human body in three-dimensional space.

4. A method for determining lumbar spine load under different spinal movement patterns according to claim 1, characterized in that, In step S3, according to the corrected image data and the origin position in the established coordinate system, combined with the relative mass of the human body link and the relative position parameters of the link centroid, mark the proximal and distal bony joint points of each link of the human body in the image, and obtain the coordinates of the proximal and distal joint points of each link of the human body by measuring the distance from each joint point to the origin of the coordinate system.

5. A method for determining lumbar spine load under different spinal movement patterns according to claim 1, characterized in that, In step S3, calculate the three-dimensional coordinates of the center of gravity of each body segment of the human body according to the coordinates of the proximal and distal joint points of each link of the human body. The calculation formula is as follows: X iC = X 近 -(X 近 - X 远 )L CS , Y iC = Y 近 -(Y 近 - Y 远 )L CS , Z iC = Z 近 -(Z 近 - Z 远 )L CS (1) Among them, X iC , Y iC , Z iC are the coordinates of the center of gravity of the link, X 近 , Y 近 , Z 近 are the coordinates of the proximal joint point of the link, X 远 , Y 远 , Z 远 are the coordinates of the distal joint point of the link, L CS is the position of the center of mass of the link relative to the proximal joint point of the link; Then, calculate the three-dimensional coordinates of the center of gravity of the upper body of the human body. The calculation formula is as follows: Among them, X C , Y C , Z C are the three-dimensional coordinates of the center of gravity of the upper body of the human body, P i is the relative mass of each body segment of the human body, and X iC , Y iC , Z iC are the coordinates of the center of gravity of the segment.

6. A method for determining lumbar spine load under different spinal movement patterns according to claim 1, characterized in that The specific implementation method of step S4 is: The gravity borne by the L1-L5 segments of the lumbar spine of the human body increases gradually, so the gravity is loaded section by section; Apply the gravity borne by all segments of the upper body of the human body except the waist to the upper surface of the L1 segment of the lumbar spine, and only apply 1 / 5 of the waist gravity to the upper surfaces of the L2-L5 segments of the lumbar spine respectively; The calculation formula for the gravity borne by each segment is as follows: m i = M 体重 * P i (5) G i = m i g(6) Among them, m i is the actual mass of each link of the upper body of the human body, M 体重 is the body weight of the standard human body, P i is the relative mass of each link of the human body, G i is the weight of each link; the action point of the gravity acting on the upper body of the human body is set at the midpoint of the upper surface of each vertebral body; Equivalently load the gravity borne by the upper body of the human body as component forces in the horizontal and vertical directions; The vertebral inclination angle is obtained from the center of gravity offset angle. The calculation formula is as follows: Among them, X1 and Y1 are the two-dimensional coordinates of the center of gravity of the upper body in each lumbar spine movement mode, and X0 and Y0 are the two-dimensional coordinates of the center of gravity of the upper body in the normal standing state of the human body; Furthermore, calculate the component forces of the gravity acting on the upper body of the human body in the horizontal and vertical directions: F 竖直 = M 躯干 g cosθ (9) F 水平 = M 躯干 g sinθ (10) Among them, F 竖直 is the magnitude of the vertical component of gravity relative to the surface of the L1 vertebra in each lumbar spine movement mode, and F 水平 is the magnitude of the horizontal component of gravity relative to the surface of the L1 vertebra in each movement mode, M 躯干 is the mass of the upper body of the human body, and g is the acceleration due to gravity; The total gravitational moment of the lumbar spine in a movement mode is affected by the moment generated by the center of gravity offset. The center of gravity offset is the distance between the center of gravity in different spinal movement postures and the center of gravity position in the normal standing position; four movement modes of forward flexion, backward extension, left and right lateral flexion of the human body are designed, and the center of gravity offset position is on the coronal plane or the sagittal plane; the sagittal plane is only applicable to the calculation of the center of gravity offset distance in the forward flexion and backward extension movement modes, and the coronal plane is only applicable to the calculation of the center of gravity offset distance in the left and right lateral flexion movement modes; the calculation of the center of gravity offset distance is as follows: Among them, x 偏 and y 偏 are respectively the transverse and longitudinal coordinates of the offset center of gravity in the coronal plane or sagittal plane, and x0 and y0 are respectively the transverse and longitudinal coordinates of the center of gravity in the coronal plane or sagittal plane in the normal standing state; for the calculation of the center of gravity offset distance in the flexion and extension movement modes, the transverse coordinate x 偏 and longitudinal coordinate y 偏 of the offset center of gravity in the sagittal plane respectively correspond to the three-dimensional coordinates X C and Y C of the center of gravity in the flexion and extension states of the human body; for the calculation of the center of gravity offset distance in the left and right lateral flexion movement modes, the transverse coordinate x 偏 and longitudinal coordinate y 偏 of the offset center of gravity in the coronal plane respectively correspond to the three-dimensional coordinates Z C and Y C of the center of gravity in the left and right lateral flexion states of the human body; The total moment generated by the center of gravity offset is: M d = m 躯干 * g * d * cosθ (12) Among them, M d is the moment generated by the center of gravity offset, m 躯干 is the weight of the human torso, g is the acceleration due to gravity, and d is the center of gravity offset distance; The gravitational moment is loaded on the posterior surface of each vertebral body. According to the uniform distribution of the gravitational moment in each segment of the lumbar spine, the L1-L5 segments of the lumbar spine are respectively applied with 1 / 5 of the total gravitational moment of the lumbar spine in a movement mode.

Images