Device and method for measuring girth of multiple parts of human body

Abstract

The invention discloses a human body multi-part circumference measuring device and method.The device comprises a multi-part circumference measuring assembly, a calibration assembly and a host module, the measuring assembly is composed of a telescopic flexible belt, three-axis MEMS gyroscope sensors distributed at equal angles and ABS material fixing side plates; the calibration assembly realizes sensor horizontal zero calibration through a cast iron base and an acrylic pressure plate, and the host module comprises a power supply, a data analysis circuit and a computer with special software, and supports data wireless transmission and analysis display; the measurement method comprises two steps of device calibration and circumference measurement, sensor data are processed through Kalman filtering, quaternion complementary filtering and an improved ICP algorithm, the circumference is calculated in combination with an adaptive polygon approximation method, and a data synchronization and exception handling mechanism is provided. The method can realize dynamic real-time measurement of multiple parts such as waistline and chest circumference, is convenient, is not interfered by environment and clothes, is suitable for scenes such as health monitoring and exercise evaluation, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of health testing technology, and in particular relates to a device and method for measuring the circumference of multiple parts of the human body. Background Technology

[0002] Human body circumference measurement is a fundamental data support method for fields such as health monitoring, sports training assessment, and clothing pattern design. Existing technologies are mainly divided into two categories: contact measurement and non-contact measurement.

[0003] Contact measurement, represented by the manual tape measure method, relies on the operator's experience to wrap around and read the measurement. This method is not only labor-intensive but also has significant subjective errors (usually ≥1.5cm). It is also difficult to adapt to people with special body types such as obesity and limited limb movement. Although some improved contact devices use tape measures to tighten clothing to reduce interference, they still require manual assistance and cannot achieve real-time tracking in dynamic scenarios. For example, they cannot capture breathing fluctuations or instantaneous changes in torso circumference during running.

[0004] Non-contact measurement, including technologies such as infrared matrix scanning and laser 3D imaging, avoids interference from direct contact. However, it suffers from problems such as complex equipment structure, high manufacturing costs (a single device typically costs over 50,000 yuan), poor portability, and susceptibility to the effects of clothing wrinkles, thickness, and ambient lighting conditions, resulting in insufficient data accuracy and stability (errors can reach over 2cm under clothing interference). Furthermore, existing non-contact systems are mostly designed for static posture measurement, lacking dynamic adaptability and failing to meet the continuous monitoring needs of circumference changes during movement in sports science. They are also difficult to apply to scenarios such as home health monitoring.

[0005] In summary, existing technologies generally suffer from technical bottlenecks such as lack of dynamic measurement capabilities, poor synchronization of multiple body parts, high sensitivity to environmental interference, and cumbersome or costly operation. They cannot provide high-precision, low-latency, and convenient dynamic circumference data support for scenarios such as medical health assessment and sports science monitoring. There is an urgent need for a multi-body circumference measurement solution that combines accuracy, dynamic adaptability, and practicality. Summary of the Invention

[0006] To address the problems in the prior art, the present invention proposes the following technical solution: A multi-body circumference measurement device includes a multi-body circumference measurement assembly, a calibration assembly, and a host module. The multi-body circumference measurement assembly is used to acquire spatial position information of human body circumference. The calibration assembly is used to calibrate the initial posture of the sensing elements inside the measurement assembly. The host module is used to realize wireless transmission, calculation and analysis of measurement data, and result display. The multi-part circumference measurement assembly includes a belt, a gyroscope sensor, and a fixed side plate. The gyroscope sensor is fixed by a groove in the fixed side plate and a silicone pad, and then wrapped and encapsulated by the belt, which is distributed along the circumference of the belt. The calibration assembly includes a calibration base and a pressure plate. The upper surface of the calibration base has a groove that matches the multi-part circumference measurement assembly. The pressure plate is pressed against the measurement assembly to keep the gyroscope sensor horizontal. The host module includes a power supply module, a data analysis circuit, and a computer. The power supply module supplies power to each component, the data analysis circuit receives and processes sensor data, and the computer installs data processing software.

[0007] As a preferred embodiment of the above technical solution, the belt is made of a stretchable flexible composite material with a ratio of elastic fiber to polyester fiber of 3:7, the length adjustment range is 50-150cm, and the surface is provided with anti-slip texture.

[0008] As a preferred embodiment of the above technical solution, the gyroscope sensor is a three-axis MEMS gyroscope with a sampling rate ≥200Hz, zero bias stability ≤0.1° / s, measurement range ±2000° / s, and is distributed at equal angles along the circumference of the belt with an interval ≤5°, and the number is 10-20.

[0009] As a preferred embodiment of the above technical solution, the calibration base is made of cast iron, with anti-slip pads at the bottom and a horizontal accuracy of the groove on the upper surface ≤0.05mm; the pressure plate is made of transparent acrylic, with an anti-slip rubber layer covering the lower surface, and weighs 1kg.

[0010] As a preferred embodiment of the above technical solution, the power module is a rechargeable lithium battery with a capacity of 5000mAh and an output voltage of 5V / 2A, which supports USB-C interface charging and has a single charge life of ≥8 hours; the core of the data analysis circuit is an STM32F407 main control chip, which integrates a CAN bus interface with a transmission rate of 1Mbps and a Bluetooth 5.0 wireless transmission module.

[0011] A method for measuring the circumference of multiple parts of the human body based on the above-mentioned device includes the following steps: Step 1: Device calibration. Place the calibration base horizontally, put the multi-part circumference measurement assembly into the base groove, press it together with the pressure plate, and send a zeroing command through the computer software to complete the zeroing of the gyroscope sensor. Step 2: Circumference measurement. The subject wears the calibrated measurement assembly around the target area, sets the measurement parameters through computer software and starts the test. The gyroscope sensor collects angular velocity data and transmits it to the data analysis circuit. After filtering, coordinate calculation, point cloud registration and circumference calculation, the computer displays the data and generates a report.

[0012] As a preferred embodiment of the above technical solution, the calibration in step one must be performed before each measurement, and recalibration must be performed when the ambient temperature changes by more than 5°C; the zeroing operation lasts for 2 seconds, and the software displays "calibration complete" after receiving the sensor feedback confirmation signal.

[0013] As a preferred embodiment of the above technical solution, the data analysis process in step two includes: suppressing sensor zero-bias drift using the Kalman filter algorithm, calculating three-dimensional coordinates using the quaternion complementary filter algorithm, performing point cloud registration using the improved ICP algorithm, and calculating the girth using the polygon approximation method with adaptive side number adjustment; when the sensor data exceeds the ±3σ range, interpolation is used for substitution, and the software issues an alarm when three consecutive sensor data are abnormal.

[0014] The beneficial effects of this invention are as follows: This invention, through the collaborative design of a multi-body circumference measurement assembly, a calibration assembly, and a main module, uses a gyroscope sensor array and a flexible sensing belt as its core architecture, coupled with a precise calibration mechanism and an efficient data processing flow, effectively overcoming many bottlenecks in existing technologies for human body circumference measurement. Compared to traditional contact measurement, it does not rely on operator experience. Through the distributed layout of the sensor array and automated data acquisition, it completely solves the problems of large subjective errors, high labor intensity, and lack of dynamic tracking capabilities, and can capture millisecond-level changes in the circumference of multiple body parts in real time during breathing fluctuations and movement. Compared to non-contact measurement technology, it adopts a contact sensing design, which is not affected by clothing wrinkles, thickness, or ambient lighting conditions. Moreover, the device has a compact structure, excellent portability, and significantly reduced manufacturing costs, making it more suitable for widespread application in diverse scenarios such as home health monitoring and sports training assessment. Meanwhile, through optimization techniques such as Kalman filtering and improved ICP algorithm, combined with data synchronization mechanism and anomaly handling scheme, the high accuracy and stability of measurement data are ensured. With intuitive software operation interface and report generation function, the measurement process is made more convenient and the data presentation is more professional. It provides high-precision, low-latency and easy-to-operate dynamic circumference data support for fields such as medical and health assessment and clothing pattern design, and has broad practical value and application prospects. Attached Figure Description

[0015] Figure 1 The diagram shown is a structural schematic of the calibration assembly in a multi-body circumference measurement device; Figure 2 The diagram shown is a structural schematic of the circumference measurement assembly in a multi-body circumference measurement device; Figure 3 The diagram shows a schematic of the main module structure in a multi-body circumference measurement device.

[0016] Explanation of reference numerals in the attached figures: 1. Belt; 2. Gyroscope sensor; 3. Fixed side plate; 4. Calibration base; 5. Pressure plate; 6. Power module; 7. Data analysis circuit; 8. Computer. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0018] Human body multi-part circumference measurement device This device includes a multi-part circumference measurement assembly, a calibration assembly, and a main unit module. These components work together to acquire, calibrate, transmit, analyze, and display circumference data. The specific structure is as follows: Multi-part circumference measurement assembly The core is used to directly obtain spatial location information of human body circumference, including: Belt 1: Made of stretchable and flexible composite material (elastic fiber to polyester fiber ratio 3:7), with a length adjustment range of 50-150cm. The surface has anti-slip texture to ensure close contact with human skin without affecting limb movement. Gyroscope sensor 2: A three-axis MEMS (Micro-Electro-Mechanical Systems) gyroscope is selected, with a sampling rate ≥200Hz, zero bias stability ≤0.1° / s, measurement range ±2000° / s, and equidistant angular distribution along the belt circumference (interval ≤5°). The number is adapted to the belt length and is 10-20. Fixed side plate 3: Made of lightweight hard plastic (ABS material), each side plate corresponds to a gyroscope sensor and has a groove that matches the shape of the sensor (tolerance ±0.1mm). After the sensor is embedded in the groove, it is fixed by a silicone pad and then wrapped and sealed by a belt to ensure that the sensor and the belt are fixed in relative position and that the surface of the belt is flat and fits the human body.

[0019] Calibration Assembly Used to calibrate the initial attitude of the gyroscope sensors within the multi-part girth measurement assembly, ensuring a consistent measurement benchmark, including: Calibration base 4: Made of cast iron, with anti-slip pads on the bottom and grooves on the upper surface that match the shape of the multi-part circumference measurement assembly for placing the measurement assembly; Pressure plate 5: Made of transparent acrylic material, with a non-slip rubber layer on the lower surface. After being placed above the measuring assembly, it achieves uniform pressing through its own weight and external downward pressure, ensuring that all gyroscope sensors are in a horizontal position with the calibration base. This allows for zeroing of the position of the gyroscope sensor 2 in the multi-part circumference measuring device. At the same time, the software in computer 8 sends commands to control the gyroscope sensor to zero. Once the calibration is complete, the calibration of the multi-part circumference measuring device is finished.

[0020] Host module Used for wireless transmission, calculation and analysis of measurement data, and display of results, including: Power module 6: Uses a rechargeable lithium battery (capacity 5000mAh, output voltage 5V / 2A), supports USB-C interface charging, and has a single charge life of ≥8 hours, powering the data analysis circuit and gyroscope sensor; Data Analysis Circuit 7: The core adopts the STM32F407 main control chip, which integrates a CAN (Controller Area Network) bus interface (transmission rate 1Mbps) and a Bluetooth 5.0 wireless transmission module. The CAN bus is used to receive the raw data from each gyroscope sensor, and the Bluetooth module is used to transmit the processed data to the computer. Computer 8: Install dedicated data processing software (supports Windows 10 and above), with functions such as user registration, test control, real-time data display, report generation, and historical data storage (supports Excel format export).

[0021] Methods for measuring the circumference of multiple parts of the human body This method, based on the aforementioned device, includes two core steps: calibration and measurement. The specific process is as follows: Step 1: Calibration of the multi-site circumference measuring device S101: Place the calibration base 4 stably on a horizontal surface and confirm that the upper surface of the base is level using a level (horizontal error ≤ 0.1°). S102: Take out the multi-part circumference measurement assembly, lay it flat in the groove of the calibration base, and ensure that the belt is fully extended and the fixed side plate is in contact with the groove of the base; S103: Press the pressure plate 5 smoothly onto the measuring assembly, ensuring that the pressure plate is in contact with all fixed side plates and that there is no obvious warping; S104: Run the data processing software through computer 8, log in and select "calibration mode". The software sends a zeroing command to the data analysis circuit 7. The data analysis circuit synchronizes the command to all gyroscope sensors through the CAN bus. S105: After receiving the command, the sensor performs a zeroing operation (lasting 2 seconds). After the zeroing is completed, it sends a confirmation signal to the data analysis circuit. The software displays "Calibration complete", and the calibration process ends. At this time, the initial attitude of all sensors is unified to the horizontal reference.

[0022] (Note: Calibration must be performed before each measurement, or recalibrated when the ambient temperature changes by more than 5°C, to ensure measurement accuracy.) Step 2: Multi-site circumference measurement device testing S201: The subject should maintain a natural standing posture and wear the calibrated multi-site circumference measurement assembly around the target area (waist, chest, hips, etc.). Adjust the belt length to make the belt fit tightly against the skin (it is advisable to be able to insert a finger, and the tightness should be moderate). Ensure that the fixed side plate is not twisted and that the sensor array completely covers the circumference of the measurement area. S202: The operator completes user registration through computer software (entering information such as name, gender, age, and measurement site), selects "measurement mode", and sets measurement parameters (measurement duration is adjustable from 1 to 60 minutes, and data sampling interval is 10ms). S203: Click "Start Test". The software sends a measurement start command to the data analysis circuit. The gyroscope sensor starts to collect the spatial angular velocity data of the human body circumference and transmits it to the data analysis circuit in real time via the CAN bus. S204: The data analysis circuit preprocesses the raw data: First, it suppresses sensor zero-bias drift by using the Kalman filter algorithm (process noise covariance Q=1e-5, observation noise covariance R=1e-1), and then calculates the real-time spatial attitude of each sensor by using the quaternion complementary filtering algorithm (accelerometer weight 0.01, gyroscope weight 0.99) to obtain the three-dimensional coordinates (x, y, z) of each sensor. S205: The ICP (Iterative Closest Point) algorithm is used to register the point cloud of the 3D coordinates of all sensors (iterations ≤ 20, convergence error ≤ 0.01mm). The discrete sensor nodes are fitted into a continuous girth profile curve, and then the perimeter is calculated using a 32-sided polygon approximation method. The specific formula is as follows: in, The distance between sensor nodes, (x) i y i , z i ), (x j y j , z j ( ) represents the three-dimensional coordinates of two adjacent sensors; total girth: Where n is the number of sensors. The distance between the last sensor and the first sensor; S206: The data analysis circuit transmits the calculated real-time circumference data to the computer via Bluetooth 5.0, and the software displays the circumference change curve and current value in real time (accuracy ±0.1cm). S207: After the measurement reaches the set time or "Stop Test" is clicked, the software automatically generates a test report, which includes the measurement location, measurement duration, real-time circumference data sequence, average value, maximum value, minimum value and circumference change trend chart. It supports direct export of Excel format files, and the measurement process ends.

[0023] It should be added that: 1. Sensor array data synchronization mechanism Each gyroscope sensor communicates synchronously with the data analysis circuit via a CAN bus, employing a timestamp synchronization strategy: the data analysis circuit sends a synchronization clock signal every 10ms, and each sensor starts data acquisition synchronously after receiving the clock signal, ensuring that the sampling time deviation of all sensors is ≤1ms, thus avoiding girth calculation errors caused by asynchronous data from multiple sensors.

[0024] 2. Data anomaly handling mechanism When the raw data of a certain gyroscope sensor exceeds the normal range (±3σ, where σ is the standard deviation of the sensor's historical calibration data), the data analysis circuit automatically determines it as abnormal data and replaces it with interpolated data from two adjacent sensors to ensure the continuity of the girth profile curve. If three consecutive sensor readings are abnormal, the software will issue an alarm (audio + pop-up) to remind the operator to check the status of the measuring device.

[0025] 3. Dynamic Dimension Reconstruction and Optimization An improved ICP algorithm is adopted, which adds a contour smoothing preprocessing step to the traditional algorithm to remove local abnormal bulge data caused by human skin folds, and improves the iterative convergence speed by 30%. The polygon approximation method adopts an adaptive side number adjustment strategy: when the girth change rate is ≥0.5cm / s (such as during violent movement), the number of sides is automatically increased to 64 to improve the accuracy of capturing instantaneous changes; when the girth is stable (change rate <0.1cm / s), the number of sides is kept at 32 to balance accuracy and computational efficiency.

[0026] Example 1: Dynamic measurement of waist circumference during health check-ups 1. Equipment preparation: Take out the multi-part circumference measurement device, calibration assembly and main module, fully power the power module, connect the data analysis circuit and the computer, and start the data processing software; 2. Calibration operation: Complete the device calibration according to step one. After the software displays "Calibration complete", remove the measuring device. 3. Subject wearing: The subject stands, and the operator puts the measuring device around the subject's waist (at the level of the navel), adjusts the belt length to fit snugly against the skin, and confirms that the fixed side plate is not twisted; 4. Measurement parameter settings: Enter the subject information in the software, select "waist circumference measurement", set the measurement duration to 3 minutes (respiratory cycle monitoring) and the sampling interval to 10ms; 5. Data collection and analysis: Click "Start Test" and the software will display the waist circumference change curve in real time. After the data collection is completed, a report will be automatically generated, including the average waist circumference, the maximum / minimum waist circumference during the respiratory cycle and the range of change. 6. Subsequent operations: Click "Stop Test", remove the measuring device, close the software, and the measurement is complete.

[0027] Example 2: Dynamic monitoring of chest circumference during exercise training 1. Device calibration: Same as steps 1-2 in Example 1; 2. Wearing and Adjustment: The subject wears a tight-fitting sportswear garment, and the measuring device is worn around the chest (at the level of the nipples). The length of the strap is adjusted to fit the surface of the sportswear garment to ensure that the device does not slip during exercise. 3. Parameter settings: Enter the subject information, select "Chest circumference measurement", set the measurement duration to 30 minutes (running training monitoring), and the sampling interval to 10ms; 4. Dynamic measurement: When the subject begins running training, the software transmits and displays dynamic changes in chest circumference in real time. When the exercise intensity increases, the software automatically adjusts the polygon approximation to 64 sides to capture instantaneous changes in circumference. 5. Data Export: After training, stop the measurement and export an Excel report. The report contains the average chest circumference and trend graphs for different exercise stages (warm-up, acceleration, constant speed, deceleration), providing data support for exercise intensity assessment.

[0028] This invention, through the collaborative design of a gyroscope sensor array and a flexible sensing belt, combined with three-dimensional coordinate reconstruction and optimization algorithms, effectively solves the core defects of existing technologies in dynamic circumference measurement, providing a brand-new solution for high-precision and convenient measurement of circumference of multiple parts of the human body, and has broad application prospects.

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. A device for measuring the circumference of multiple parts of the human body, characterized in that, The device includes a multi-body circumference measurement assembly, a calibration assembly, and a host module. The multi-body circumference measurement assembly is used to acquire spatial position information of human body circumference. The calibration assembly is used to calibrate the initial posture of the sensing elements inside the measurement assembly. The host module is used to realize wireless transmission, calculation and analysis of measurement data, and result display. The multi-part circumference measurement assembly includes a belt (1), a gyroscope sensor (2) and a fixed side plate (3). The gyroscope sensor (2) is fixed by the groove of the fixed side plate (3) and a silicone pad, and then wrapped and encapsulated by the belt (1) and distributed along the circumference of the belt (1). The calibration assembly includes a calibration base (4) and a pressure plate (5). The upper surface of the calibration base (4) is provided with a groove that matches the multi-part circumference measurement assembly. The pressure plate (5) is pressed against the measurement assembly to keep the gyroscope sensor (2) horizontal. The host module includes a power supply module (6), a data analysis circuit (7), and a computer (8). The power supply module (6) supplies power to each component, the data analysis circuit (7) receives and processes sensor data, and the computer (8) installs data processing software.

2. The human body multi-part circumference measuring device according to claim 1, characterized in that, The belt (1) is made of a stretchable flexible composite material with a ratio of elastic fiber to polyester fiber of 3:

7. The length adjustment range is 50-150cm, and the surface is provided with anti-slip texture.

3. The human body multi-part circumference measuring device according to claim 1, characterized in that, The gyroscope sensor (2) is a three-axis MEMS gyroscope with a sampling rate ≥200Hz, zero bias stability ≤0.1° / s, measurement range ±2000° / s, and is distributed at equal angles along the circumference of the belt (1) with an interval ≤5°, and the number is 10-20.

4. The human body multi-part circumference measuring device according to claim 1, characterized in that, The calibration base (4) is made of cast iron, with anti-slip pads at the bottom and a horizontal accuracy of ≤0.05mm for the groove on the upper surface; the pressure plate (5) is made of transparent acrylic, with an anti-slip rubber layer covering the lower surface, and weighs 1kg.

5. The human body multi-part circumference measuring device according to claim 1, characterized in that, The power module (6) is a rechargeable lithium battery with a capacity of 5000mAh and an output voltage of 5V / 2A. It supports USB-C interface charging and has a battery life of ≥8 hours on a single charge. The core of the data analysis circuit (7) is an STM32F407 main control chip, which integrates a CAN bus interface with a transmission rate of 1Mbps and a Bluetooth 5.0 wireless transmission module.

6. A method for measuring the circumference of multiple parts of the human body based on the device described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Device calibration. Place the calibration base (4) horizontally, put the multi-part circumference measurement assembly into the base groove, press it together with the pressure plate (5), and send the zeroing command through the computer (8) software to complete the zeroing of the gyroscope sensor (2). Step 2: Circumference measurement. The subject wears the calibrated measurement assembly around the target area, sets the measurement parameters through the computer (8) software and starts the test. The gyroscope sensor (2) collects angular velocity data and transmits it to the data analysis circuit (7). After filtering, coordinate calculation, point cloud registration and circumference calculation, the computer (8) displays the data and generates a report.

7. The method for measuring the circumference of multiple parts of the human body according to claim 6, characterized in that, The calibration in step one must be performed before each measurement, and recalibration must be performed when the ambient temperature changes by more than 5°C; the zeroing operation lasts for 2 seconds, and the software displays "calibration complete" after receiving the sensor feedback confirmation signal.

8. The method for measuring the circumference of multiple parts of the human body according to claim 6, characterized in that, The data analysis process in step two includes: suppressing sensor zero-bias drift using the Kalman filter algorithm, solving the three-dimensional coordinates using the quaternion complementary filtering algorithm, performing point cloud registration using the improved ICP algorithm, and calculating the girth using the polygon approximation method with adaptive side number adjustment; when the sensor data exceeds the ±3σ range, interpolation is used for substitution, and the software issues an alarm when three consecutive sensor data are abnormal.

Images