阅读说明：本技术 一种基于移动设备的行人步态检测方法 (Pedestrian gait detection method based on mobile device ) 是由 徐强 韩业强 宋亦凡 于 2019-11-07 设计创作，主要内容包括：本发明公开了一种基于移动设备的行人步态检测方法,该方法包括以下步骤：a、在移动设备坐标系下收集移动设备在运动中的传感器数据；b、根据手机的传感器数据,计算得出移动设备的旋转矩阵,将移动设备坐标系下的三轴加速度计数据转换到地理坐标系下；c、提取出地理坐标系下加速度的垂直分量,获取信号强度；d、找出频率在[0.5,4]Hz频率范围内信号强度最大的前2位的频率,确认两者之间是否满足较大频率与较小频率的比值在[1.5,2.5]范围内；e、利用波峰检测方式即可确定具体的步伐检测时间。该方法根据行人行走的加速度信息频率特性,过滤掉行人与手机相对运动的信息,最终提取出有效数据进行步态检测,提高步态检测的准确度。(The invention discloses a pedestrian gait detection method based on mobile equipment, which comprises the following steps: a. collecting sensor data of the mobile equipment in motion under a mobile equipment coordinate system; b. calculating a rotation matrix of the mobile equipment according to the sensor data of the mobile phone, and converting the triaxial accelerometer data under the coordinate system of the mobile equipment into a geographic coordinate system; c. extracting a vertical component of the acceleration under the geographic coordinate system to obtain signal intensity; d. finding out the frequency of the first 2 bits with the maximum signal intensity in the frequency range of [0.5,4] Hz, and determining whether the ratio of the larger frequency to the smaller frequency between the two is in the range of [1.5,2.5 ]; e. the specific step detection time can be determined by using a peak detection mode. According to the method, the information of relative motion between the pedestrian and the mobile phone is filtered out according to the acceleration information frequency characteristic of walking of the pedestrian, effective data are finally extracted for gait detection, and the gait detection accuracy is improved.)

1. A pedestrian gait detection method based on mobile equipment is characterized by comprising the following steps: the method comprises the following steps:

a. collecting sensor data of the mobile equipment in motion under a coordinate system of the mobile equipment, wherein the sensor data comprises a three-axis accelerometer, a three-axis gyroscope and a three-axis magnetometer;

b. calculating a rotation matrix of the mobile equipment according to the sensor data of the mobile phone, and converting the triaxial accelerometer data under the coordinate system of the mobile equipment into a geographic coordinate system;

c. extracting a vertical component of the acceleration under the geographic coordinate system, namely a z-axis component of the geographic coordinate system, performing spectrum analysis on the vertical component by adopting fast Fourier transform, and acquiring signal intensity corresponding to each frequency with the frequency between [0 and sampling frequency/2 ];

d. finding out the frequency of the first 2 bits with the maximum signal intensity within the frequency range of [0.5,4] Hz, determining whether the ratio of the larger frequency to the smaller frequency between the two frequencies is within the range of [1.5,2.5], when the frequency is within the range of [1.5,2.5], the larger frequency is the moving frequency of the pedestrian, obtaining the signal under the corresponding frequency, and performing band-pass filtering on the vertical component of the accelerometer under the geographic coordinate system, and when the frequency ratio is not within the range of [1.5,2.5], the smaller frequency is the moving frequency of the pedestrian, obtaining the signal under the corresponding frequency, and performing band-pass filtering on the vertical component of the accelerometer under the geographic coordinate system;

e. and obtaining a time domain change curve under the corresponding frequency through inverse Fourier transform, performing peak detection on the filtered vertical component data of the accelerometer under a geographic coordinate system, and determining the specific step detection time by using a peak detection mode.

Technical Field

The invention relates to the technical field of positioning based on mobile equipment, in particular to a pedestrian gait detection method based on the mobile equipment.

Background

The current positioning technology of the mobile device needs to rely on a Pedestrian Dead Reckoning (PDR) system to a great extent, and such a scheme that a beacon node is not required to be pre-installed in a building, and the step length and the direction of a Pedestrian are calculated by using an intrinsic inertial sensor (such as an acceleration sensor, a gyroscope, a magnetometer and the like) of the mobile device, so as to estimate the track of the person who goes out in the building.

Pedestrian walking is a periodic motion process with alternating feet, and the periodicity of the periodic motion process is reflected on inertial sensor data of the mobile equipment, such as acceleration, a gyroscope and the like. A commonly used algorithm in gait detection is a wave crest/zero crossing detection algorithm based on accelerometer data, and has the advantages of simple algorithm implementation, small calculated amount and convenient real-time detection.

At present, the accuracy of hardware equipment of the inertial sensor of the mobile equipment is not high generally, the models of the sensors equipped with different equipment are different, and the collected acceleration signals contain noise due to the random change of the walking state of pedestrians, so that the accuracy of the traditional detection algorithm is not high. On the other hand, the pedestrian is in a random state in the process of using the mobile device, and may have unfixed relative motion with the device, especially in the case that the pedestrian holds the device to swing around, so that the motion information of the pedestrian is polluted by the relative change information, and the detection omission condition occurs in the gait detection.

Disclosure of Invention

The present invention is directed to a pedestrian gait detection method based on a mobile device, so as to solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: a pedestrian gait detection method based on a mobile device comprises the following steps:

a. collecting sensor data of the mobile equipment in motion under a coordinate system of the mobile equipment, wherein the sensor data comprises a three-axis accelerometer, a three-axis gyroscope and a three-axis magnetometer;

b. calculating a rotation matrix of the mobile equipment according to the sensor data of the mobile phone, and converting the triaxial accelerometer data under the coordinate system of the mobile equipment into a geographic coordinate system;

c. extracting a vertical component of the acceleration under the geographic coordinate system, namely a z-axis component of the geographic coordinate system, performing spectrum analysis on the vertical component by adopting fast Fourier transform, and acquiring signal intensity corresponding to each frequency with the frequency between [0 and sampling frequency/2 ];

d. finding out the frequency of the first 2 bits with the maximum signal intensity within the frequency range of [0.5,4] Hz, determining whether the ratio of the larger frequency to the smaller frequency between the two frequencies is within the range of [1.5,2.5], when the frequency is within the range of [1.5,2.5], the larger frequency is the moving frequency of the pedestrian, obtaining the signal under the corresponding frequency, and performing band-pass filtering on the vertical component of the accelerometer under the geographic coordinate system, and when the frequency ratio is not within the range of [1.5,2.5], the smaller frequency is the moving frequency of the pedestrian, obtaining the signal under the corresponding frequency, and performing band-pass filtering on the vertical component of the accelerometer under the geographic coordinate system;

e. and obtaining a time domain change curve under the corresponding frequency through inverse Fourier transform, performing peak detection on the filtered vertical component data of the accelerometer under a geographic coordinate system, and determining the specific step detection time by using a peak detection mode.

Compared with the prior art, the invention has the beneficial effects that: according to the pedestrian gait detection method based on the mobile device, the accelerometer data in the vertical direction is adopted, interference and shaking in the horizontal direction of the movement of the pedestrian can be avoided, the frequency spectrum characteristic of the accelerometer data after fast Fourier change is filtered, the noise of sensor hardware equipment is effectively filtered, and the gait detection can be effectively achieved by 95% of accuracy under the conditions that the mobile device is normally held by a hand, the body side swings, the inside of a bag, a pocket and the like.

Drawings

FIG. 1 is a schematic diagram of a moving coordinate system according to the present invention.

FIG. 2 is a schematic diagram of a geographic coordinate system according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: