Wearable device for measuring three-dimensional surface topological structure of back of human body

Abstract

A wearable device for measuring the three-dimensional surface topology of the back of a human body comprises a close-fitting flexible fabric for surrounding the trunk of a subject, a plurality of straight strips, a plurality of three-dimensional motion sensors and a processor. One end of each straight strip is connected to the close-fitting flexible fabric and attached to the back of a subject. The three-dimensional motion sensor is implemented by an inertial measurement unit. A plurality of three-dimensional motion sensors are disposed in corresponding sensor slots on the plurality of straight strips. And more than one three-dimensional motion sensor is arranged on each straight strip. The three-dimensional motion sensor forms a matrix covering a back area to be measured of a subject, comprises 9 vertical slots and 7 horizontal band sites, and collects 63 measurement points on the back in total. Three-dimensional space measurement is achieved by capturing and measuring the sagittal angle of the sensor groove, three-dimensional space position coordinates of the sensor groove are formed, and therefore a three-dimensional surface topological structure of the back is formed. And the processor calculates and records the measured data and is connected with the smart phone.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 498,801, filed April 27, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to the field of medical imaging. More specifically, it relates to the technical field of measuring the three-dimensional surface topology of the human back. Background Technology

[0004] Scoliosis is a three-dimensional structural spinal deformity, generally considered a serious musculoskeletal disorder affecting the trunk, impacting people of all ages, with a higher prevalence in adolescents (approximately 3%) (Negrini S, 2018). In children and adolescents aged 10-16, 4-5% have scoliosis, while approximately 3-4% of adults have it, demonstrating an increasing prevalence with age (90% > 50%). The progression of scoliosis mostly occurs during puberty and continues until skeletal maturity (Di Felice F, 2018). Although adults are less likely to develop scoliosis than adolescents, they can still develop it due to degenerative factors. Without timely treatment, severe curvature can lead to impaired lung function, severe back pain, changes in appearance, and psychological burden. Therefore, early diagnosis and close monitoring are crucial for the treatment of scoliosis, as there is a chance to successfully treat mild curvature non-surgically before the need for surgery in later stages (Weinstein SL, 2013).

[0005] The most common and gold standard approach to diagnosing musculoskeletal disorders related to the trunk is an outpatient visit and radiological examination. However, this method has several drawbacks, including radiation exposure, high cost, and the need for repeat visits for further radiological examinations, followed by expert review of the images. Furthermore, many hospitals worldwide cannot afford the necessary radiological imaging equipment, hindering the widespread adoption of this standard diagnostic method.

[0006] To address the shortcomings of radiological examinations, medical professionals have been exploring alternative tools, such as scoliometers and depth cameras, to examine the topology of the trunk surface and monitor trunk musculoskeletal health. While these tools address radiation exposure and cost concerns, outpatient visits and professional assistance are still necessary. Depth cameras have proven to be quite accurate, but scoliometers, often used in conjunction with radiological examinations, are less accurate than both depth cameras and traditional radiological examinations.

[0007] Therefore, the application provides a replacement method / device, which can accurately measure the three-dimensional surface topology of the back of a human body in an economic and radiation-free manner, so as to solve the above problems. The method can be directly used by ordinary people in their own living environment without the help of professional practitioners in a clinic. Utility model content

[0008] The application aims to provide a device, apparatus or method for solving the above technical problems.

[0009] According to a first aspect of the application, a wearable multi-sensor device for measuring the three-dimensional surface topology of the back of a subject is provided. The wearable multi-sensor device comprises a plurality of straight straps, a plurality of three-dimensional motion sensors and a tight and flexible fabric.

[0010] According to an embodiment of the application, the plurality of three-dimensional motion sensors are configured in corresponding sensor slots on the plurality of straight straps.

[0011] According to an embodiment of the application, the tight and flexible fabric can be a polyester, nylon or spandex fabric.

[0012] According to another embodiment of the application, the three-dimensional motion sensor is an inertial measurement unit.

[0013] According to another embodiment of the application, the wearable multi-sensor device further comprises a processor to calculate and record the data measured by the three-dimensional motion sensors, and can be wirelessly and / or wiredly connected to a smart phone.

[0014] According to a second aspect of the application, a method for real-time measuring the three-dimensional surface topology of the back of a subject is provided. The method comprises the following steps:

[0015] Wearing the wearable multi-sensor device as described above on the upper body of the subject, and attaching the plurality of straight straps to the back of the subject so that the plurality of three-dimensional motion sensors are synchronously attached to the back of the subject;

[0016] Measuring and obtaining the sagittal angle of the corresponding sensor slot where each three-dimensional motion sensor is located by each three-dimensional motion sensor;

[0017] Calculating the plurality of sagittal angles to form the three-dimensional spatial position coordinates of each sensor slot; and

[0018] Processing the three-dimensional spatial position coordinates to form the three-dimensional surface topology of the back of the subject.

[0019] According to one embodiment of the present application, processing the three-dimensional spatial position coordinates is generating three-dimensional point cloud data from the three-dimensional spatial position coordinates, and processing the three-dimensional point cloud data by a B-spline function to obtain the curvature of the back of the subject. BRIEF DESCRIPTION OF DRAWINGS

[0020] Embodiments of the present application will be described in greater detail below with reference to the accompanying drawings, in which:

[0021] Figures 1A-1B is a schematic diagram of a wearable multi-sensor device; wherein Figure 1A shows a wearable multi-sensor device with multiple inertial measurement units on multiple straight strips on a flexible fabric; Figure 1B shows the structure of the inertial measurement units on the straight strips;

[0022] Figure 2 shows the use of the Pythagorean theorem to calculate the three-dimensional spatial position coordinates of the matrix slots, where the hypotenuse is the length of a single slot on a straight strip;

[0023] Figures 3A-3B shows the point cloud data detected by the sensors; wherein Figure 3A shows the final spline obtained from the point cloud data of a single straight strip; Figure 3B shows a three-dimensional graph of the point cloud data from 5 straight strips obtained via exemplary data;

[0024] Figure 4 shows the constructed three-dimensional surface profile of the patient's back; and

[0025] Figure 5 A three-dimensional surface color profile image generated using the "Hausdorff distance" method is described, in which the location of the largest hump angle can be identified. DETAILED DESCRIPTION

[0026] In the following description, devices, apparatuses, and / or methods for measuring the three-dimensional surface topology of a human back are listed as preferred examples. It will be apparent to those skilled in the art that modifications including additions and / or substitutions can be made without departing from the scope and spirit of the present application, and that specific details can be omitted in order not to obscure the present application; however, the present disclosure is written in order to enable those skilled in the art to practice the content of the present application without undue experimentation.

[0027] Due to the high incidence and fast progression of scoliosis in the adolescent population, it is usually diagnosed through several screening programs, such as multi-step diagnosis in schools or primary health clinics. Patients who do not require immediate treatment are usually followed up with regular monitoring to observe the progression of the scoliosis curve. It is worth noting that the diagnosis and monitoring of scoliosis is a costly process, as clinicians need to spend a lot of manpower and clinical time to screen and monitor, and considering that most congenital scoliosis will not progress much, resulting in most monitoring being done out of caution; considering the cost of equipment for diagnosis and monitoring (such as radiological images) and the personnel expenses of related practitioners and other hospital staff, it would be very beneficial to both clinics and patients if the cost of scoliosis diagnosis and monitoring could be reduced.

[0028] In order to avoid the burden of radiological monitoring on patients, hospitals and practitioners, many medical devices have been developed to study the two-dimensional topology of the human back surface, such as scoliometers, "spine mice" and structured light technology, and there are related documents and other methods (such as three-dimensional surface topology) that apply topological measurement devices (such as depth cameras) to the diagnosis and monitoring of scoliosis. Although the use of external monitoring devices solves the problem of radiation exposure and the burden of radiological images; however, patients still need to go to the clinic, and because these devices are expensive, they need to be operated by trained technicians. In addition, because these devices mainly focus on measuring a small part of the back in two dimensions, the accuracy is lower compared to radiological monitoring. In contrast, the use of depth camera technology to detect three-dimensional surface topology provides more accurate results, as it focuses on three dimensions rather than two; however, similarly, patients still need to go to the clinic, as the cost of depth cameras is too high to allocate one to each patient for remote monitoring, and without an expert, it is still quite complex for the general public. So far, there is no device that can successfully achieve radiation-free monitoring of musculoskeletal disorders of the torso, and allow users to diagnose and monitor scoliosis remotely without the involvement of a professional practitioner, while also achieving the advantage of being inexpensive.

[0029] According to a first aspect of the present application, a wearable multi-sensor device for measuring the three-dimensional surface topology of the human back is provided, comprising a plurality of straight strips, a plurality of three-dimensional motion sensors and a tight and flexible fabric.

[0030] According to an embodiment of the present application, the plurality of three-dimensional motion sensors are arranged on the plurality of straight strips.

[0031] According to an example of the present application, the fabric can be selected from, but not limited to, polyester, nylon or spandex fabric.

[0032] According to one embodiment of the present application, the three-dimensional motion sensor is an inertial measurement unit.

[0033] According to one embodiment of the present application, the wearable multi-sensor device further comprises a processor to calculate and record the data measured by the three-dimensional motion sensor, and can be connected to a smartphone wirelessly and / or by wire. The smartphone application can display real-time information, and can also upload to the cloud network for further processing and interpretation.

[0034] Diagnosing and monitoring trunk musculoskeletal diseases by detecting three-dimensional surface topography is a recognized and reliable alternative to radiological detection. The wearable multi-sensor device proposed in the present application provides a solution that can accurately measure the three-dimensional surface topography of the back of the human body without radiation, making it a safe alternative to radiation imaging. In addition, compared with other similar high-precision tools, the device of the present application is cheaper and can be afforded by ordinary people, and since it is suitable for anyone, it can achieve the effect of remotely monitoring the musculoskeletal diseases of the trunk without the assistance of professional practitioners to measure, thereby reducing the frequency of users seeking medical treatment and medical professional diagnosis.

[0035] Compared with existing medical devices and services, the existing device is handheld and needs to be operated by relevant practitioners to measure two-dimensional surface topography, but the wearable multi-sensor device provided by the present application is a wearable device and can measure three-dimensional surface topography without the need for relevant practitioners to operate. Therefore, whether in the overall design of the device / device or in data collection, it can be seen that there are significant differences between the present application and the prior art.

[0036] In addition, compared with medical devices mainly for monitoring purposes, the device of the present application can capture a larger area of the trunk surface, and thus provide more potential information and higher accuracy.

[0037] When preparing the wearable multi-sensor device, there are some key components. First, a comfortable fabric is needed that must be able to accurately capture the surface features of the trunk without being too tight to restrict the user's movements.

[0038] In addition, multiple sensors are required to measure the three-dimensional structure in space. Therefore, the adoption of an inertial measurement unit is a suggested way for measuring the three-dimensional structure in space, but is not limited to the use of an inertial measurement unit only, but different types of sensors can be adopted according to the data required. According to the type of musculoskeletal disease, a professional practitioner can confirm the position of the sensor on the device and the number of sensors according to the resolution required to be achieved, and then install the sensors on the device accordingly, which can be installed on the device by methods such as suturing.

[0039] Reference Figures 1A-1B The wearable multi-sensor device includes a tight flexible fabric that can be wrapped around the torso, and a straight strap with multiple sensors connected to the fabric. The wearable multi-sensor device does not have any radiation in its associated hardware, so it is less harmful to the human body compared to radiation imaging.

[0040] In some embodiments, the wearable multi-sensor device further includes a processor that can record data and connect to a smartphone through an application. The smartphone application can display information in real time and automatically upload to the cloud network for further data processing and interpretation.

[0041] The embodiments aim to verify the accuracy of the multi-sensor device in measuring the back surface of a three-dimensionally printed plastic scoliosis torso model, and should be considered as a proof of concept and feasibility study of the present application, to facilitate further development of wearable multi-sensor devices for measuring musculoskeletal diseases.

[0042] According to a second aspect of the present application, a method for real-time measurement of the three-dimensional surface topology of the back of a subject is provided.

[0043] In one embodiment, the method comprises the following steps:

[0044] The wearable multi-sensor device is equipped on the upper body of the subject, and the multiple straight straps are attached to the back of the subject, so that the multiple three-dimensional motion sensors are synchronously attached to the back of the subject;

[0045] The multiple sagittal angles of the sensor groove corresponding to each three-dimensional motion sensor are captured and measured;

[0046] The multiple sagittal angles are calculated to form the three-dimensional spatial position coordinates of each corresponding sensor groove; and

[0047] The three-dimensional spatial position coordinates are processed to form the three-dimensional surface topology of the back of the subject.

[0048] In one embodiment, wherein the processing the three-dimensional spatial position coordinates is generating three-dimensional point cloud data from the three-dimensional spatial position coordinates, and processing the three-dimensional point cloud data by a B-spline function to obtain the curvature of the back of the subject.

[0049] Embodiments

[0050] Embodiment 1, Precision evaluation of wearable multi-sensor device

[0051] The customized plastic torso prosthesis was from the Limb and Orthotic Service of Princess Margaret Hospital for Children, Hong Kong Shatin Tai Po Chung Ring. The prosthesis was three-dimensionally sculpted according to the digital profile obtained from scanning a scoliosis patient using a Spectra three-dimensional scanner and integrated computer-aided design and manufacturing (CAD / CAM) system (Vorum, Canada). The patient gave informed consent before the scanning procedure, and the patient's main curve was approximately 26.5 degrees at T5 to T11 in a forward bending position. The simplified prototype of the wearable multi-sensor device with a single straight strap three-dimensionally printed with sensor slots for inertial measurement unit (IMU) sensors to measure the three-dimensional space was used for measurement. A wire readout system was used for data acquisition on Arduino (version 1.8.19).

[0052] Before measurement, the prosthesis was placed on a stable platform, and the start and end points were marked on the back of the prosthesis, with the horizontal line intersecting the lower start point. The matrix used included 9 vertical slots and 7 horizontal band sites to cover the main back area to be measured. On each straight strap, the straight strap was manually adhered to the back with adhesive to achieve sufficient contact, with the vertical direction of the straight strap perpendicular to the starting line and the axial angle of the straight strap fixed at zero degrees.

[0053] During the measurement process, the inertial measurement unit chip was manually placed and fixed in each sensor slot of the straight strap, so that the sagittal angle of the slot could be obtained by computer. After 10 consecutive data points were collected, the average value of each slot was taken as the sagittal tilt angle. Finally, the sagittal tilt angle data of each matrix slot were calculated to generate the three-dimensional surface topology of the patient.

[0054] After all the sagittal tilt angle data of each matrix slot were collected, a scoliometer measurement was performed by an experienced examiner to record the torso rotation angle of the main protrusion of the back (also known as the back hump) to verify the surface measurement results of the wearable device prototype.

[0055] To generate the three-dimensional surface topology of the back, the sagittal inclination angle data collected from each matrix slot can be used to independently calculate the three-dimensional spatial position coordinates of the slot, which can subsequently generate three-dimensional point cloud data to reorganize the three-dimensional surface topology. The sagittal inclination angle data is converted to three-dimensional spatial position coordinates by the Pythagorean theorem in Euclidean geometry (also known as the Pythagorean theorem, Equation 1). Figure 2 Figures 3A-3B As shown, after calculating the three-dimensional spatial position coordinates, the point cloud data of the straight strip is processed by B-spline to obtain the natural smooth curvature of the prosthesis back. Finally, referring to Figure 4 , the three-dimensional surface of the patient is constructed on the open-source MeshLab system (ISTI-CNR, version 2022.02) through the point cloud data.

[0056] Equation 1: Adjacent side = Hypotenuse x sin(a); Opposite side = Hypotenuse x cos(a).

[0057] To detect the accuracy of the wearable multi-sensor device, additional clinical data of the back three-dimensional surface measured by the scoliometer is collected. Simply put, the scoliometer is placed on the generated three-dimensional prosthesis surface, and the data collection process of the scoliometer is simulated by artificial to collect data.

[0058] In addition, similar to the most common depth camera method for generating a three-dimensional surface of the back, the position of the maximum hump angle is identified by using the "Hausdorff distance" to generate a color contour map of the three-dimensional surface, which is intuitive for practitioners and patients, making it easier to track changes in the back topology. Therefore, the "Hausdorff distance" can be used to easily compare the three-dimensional surfaces obtained by different measurement methods.

[0059] The results show that the scoliometer detects a major protrusion of 10.0 degrees on the left side of the chest of the prosthesis back surface; using the wearable multi-sensor device prototype of the present application, a total of 63 measurement points on the prosthesis back are collected, and three-dimensional surface reconstruction and hump angle calculation are performed, and the calculation results show that the left side of the chest has a major protrusion of 10.7 degrees, which is similar to the measurement results of the scoliometer. As shown, Figure 5 The area of the back protrusion indicated by the color scale can be used to calculate the three-dimensional surface of the prosthesis back.

[0060] It is worth noting that professional practitioners can determine the position of the sensors on the wearable device according to the type of musculoskeletal disease, and the number of sensors required to achieve the desired resolution. Then, the sensors can be connected to the straight strip accordingly, and in some embodiments, the sensors can be sewn on the straight strip.

[0061] ​The above description is used for explaining and describing the present application, and is not intended to limit the present application to the precise forms disclosed. Many modifications and variations are apparent to those skilled in the art.

[0062] The above embodiments are selected and described in order to best explain the principles of the present application and its practical application, so that other skilled in the art can understand various embodiments of the present application and various modifications suitable for specific purposes.

Claims

1. A wearable device for measuring the three-dimensional surface topology of the back of a human body, characterized by, Comprising of: a tight and flexible fabric for wrapping around a subject's torso; a plurality of straight straps each having one end connected to the tight and flexible fabric and extending upwardly from the tight and flexible fabric, wherein the plurality of straight straps are for fitting on the subject's back; a plurality of three-dimensional motion sensors implemented in inertial measurement units configured in corresponding sensor slots on the plurality of straight straps, wherein each of the plurality of straight straps is provided with more than one of the three-dimensional motion sensors and the plurality of three-dimensional motion sensors are for synchronously fitting on the subject's back with the plurality of straight straps such that the plurality of three-dimensional motion sensors on the plurality of straight straps form a matrix to cover a desired back region of the subject's back, wherein the matrix comprises 9 vertical slot positions and 7 horizontal strap positions to collect a total of 63 measurement points on the back, wherein the three-dimensional motion sensors implemented in the inertial measurement units are for capturing a sagittal angle of the corresponding sensor slot thereof to be measured to enable three-dimensional spatial measurement, the sagittal angle being used to form a three-dimensional spatial position coordinate of each corresponding sensor slot to form a three-dimensional surface topology of the subject's back; and a processor for calculating and recording data measured by the three-dimensional motion sensors and wirelessly or wiredly connected to a smartphone, and a smartphone application of the smartphone is for displaying information in real time and automatically uploading the data to a cloud network.

2. The wearable device for measuring a three-dimensional surface topology of a human back according to claim 1, wherein the tight and flexible fabric is selected from polyester, nylon or spandex fabric. ​

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