Step Counting System and Method

Abstract

Disclosed is a step counting method comprising the steps of, firstly, acquiring an electric signal on an electrode that is in contact or coupled with a human skin, the signal is caused by the human body capacitance variation during foot-lifting and foot-landing; secondly, processing the electric signal by a signal processing circuit that is electrically connected with the electrode and outputting a signal stream that records the foot-lifting and foot-landing information to a central control unit; and thirdly, analyzing the received signal stream by the central control unit that is electrically connected with the signal processing circuit to calculate the step number. The proposed step counting method accomplished by monitoring the electric signal on the electrode caused by the human body capacitance variation can improve the step counting accuracy.

Claims

1. A step counting method, comprising: acquiring, by an electrode that is in contact or coupled with a human skin, an electric signal caused by a human capacitance variation during foot-lifting and foot-landing of a human body; and processing, by a signal processing circuit electrically connected with the electrode, the electric signal, and outputting a signal stream that records the foot-lifting and foot-landing information of the human body to a central control unit; and analyzing, by the central control unit electrically connected with the signal processing circuit, the received signal stream, counting the foot-lifting and foot-landing information of the human body recorded in the signal stream. wherein the signal processing circuit provides a bias voltage for the electrode, and the signal processing circuit has an input impedance larger than one kilo-ohm.

2. The step-counting method according to claim 1, wherein the signal processing circuit supplies charges for the electrode as a charge source.

3. The step-counting method according to claim 1, wherein the human body capacitance describes the electric field between the human body and the environment.

4. The step-counting method according to claim 1, wherein the step number information is acquired by the following steps: a) The signal processing circuit acquires the electrical signal caused by variations in the human body capacitance from the electrode in contact or coupled with the skin and forwards the processed signal to the central control unit for the first data. b) When the first data meets the preset condition, the central control unit acquires the second data and checks if the second data meets the preset condition. Then, the step number is obtained according to the first and second data.

5. The step-counting method according to claim 4, wherein the first data and the second data include but are not limited to one or more of the following data: a single raw data, a group of raw data, a single change rate data of the raw data, a group change rate data of raw data, a single rate of change rate data of the raw data, a group rate of change rate data of raw data.

6. The step-counting method according to claim 4, wherein the preset condition is a threshold value based on the raw data or the change rate of raw data or the rate of change rate of raw data for comparison.

7. A step counting system based on human body capacitance, comprising: An electrode, which is in contact or coupled with the human skin; and a signal processing circuit that is electrically connected with the electrode to process the electric signal on the electrode and outputs a signal stream that records foot-lifting and foot-landing information; and a central control unit that is electrically connected with the signal processing circuit, analyzes the signal stream received from the signal processing circuit and counts the foot-lifting or foot-landing number. wherein, during the foot-lifting or foot-landing action, the human body capacitance changes, a conduction current or displacement current signal occurs on the electrode, and after the current signal being processed by the signal processing circuit, a signal is received by the central control unit which records the step information. wherein the signal processing circuit provides a bias voltage for the electrode, and the signal processing circuit has an input impedance larger than one kiloohm.

8. The step-counting system according to claim 7, wherein the signal processing circuit, as a charge source, supplies charges for the electrode.

9. The step counting system according to claim 7, wherein the signal processing circuit includes, but is not limited to, one or more of the following functions: filtering, amplification, analog-to-digital conversion.

10. The step counting system according to claim 7, wherein the output signal from the signal processing circuit carries the step information, and the central control unit obtains the step number by detecting and counting the peaks in the received signal.

11. The step counting system according to claim 7, wherein all or part of components or units in the step counting system are integrated into a single silicon chip.

12. A computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are configured to make a computer execute the step-counting method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the technical solutions of the present disclosure and constitute a part of the description. They are used to explain the technical solutions of the present disclosure together with the embodiments of the present disclosure and do not constitute a limitation on the technical solutions of the present disclosure.

[0031] FIG. 1 schematically shows the human body capacitance model, the electric relation between a human body and the environment;

[0032] FIG. 2 schematically shows the electric field variation between the human body and ground when foot-lifting or foot-landing occurs;

[0033] FIG. 3 is the basic working steps of a step counting system provided by an embodiment of the present disclosure;

[0034] FIG. 4 is a schematic structural diagram of a step counting system provided by an embodiment of the present disclosure;

[0035] FIG. 5 is a schematic diagram of a connection mode provided by an embodiment of the present disclosure;

[0036] FIG. 6 is a circuit diagram of a signal processing circuit provided by an embodiment of the present disclosure;

[0037] FIG. 7 is a circuit diagram of a signal processing circuit provided by another embodiment of the present disclosure;

[0038] FIG. 8 is a signal diagram of a step counting method provided by an embodiment of the present disclosure;

[0039] FIG. 9 is another signal diagram of a step counting method provided by an embodiment of the present disclosure;

[0040] FIG. 10 is a schematic diagram of a system architecture platform for executing a step counting method provided by an embodiment of the present disclosure;

[0041] FIG. 11 is a basic flowchart of a step counting algorithm provided by an embodiment of the present disclosure;

[0042] FIG. 12 is a flowchart of a part of the step counting algorithm provided by an embodiment of the present disclosure;

[0043] FIG. 13 is a flowchart of a part of the step counting algorithm provided by an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0044] To achieve the objectives, technical solutions, and advantages of the present disclosure clearer, the present disclosure will be further described hereinafter with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure, but are not intended to limit the present disclosure.

[0045] In the description of the present disclosure, the meaning of several refers to be one or more, and the meaning of multiple refers to be more than two. The meanings of greater than, less than, more than, etc., are understood as not including this number, while the meanings of above, below, within, etc., are understood as including this number. If there is a description to the first and second, it is only for the purpose of distinguishing technical features, and shall not be understood as indicating or implying relative importance, implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0046] In the description of the present disclosure, unless otherwise explicitly defined, words such as setting, installing and connecting should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present disclosure, in combination with the specific contents of the technical solutions.

[0047] At present, almost all wearable and portable smart devices with step counting functionality count the steps through the inertial measurement sensor, and the accuracy of the step counting is limited. Due to the complexity of human movement, the step counting based on the inertial measurement sensor often misses to count or mistakenly counts. The identification and calculation of the steps thereof also take up a lot of hardware resources.

[0048] To address the above-described problems, the embodiments of the present disclosure provide a novel step counting method, a novel step counting system, an easy-to-implement corresponding step counting algorithm, and a computer-readable storage medium. The method comprises the following steps: signal acquiring as the first step, inferring that an electric signal on an electrode that is in contact or coupled with the body is generated caused by the human body capacitance variation when lifting and landing the foot. Signal processing as the second step, inferring that an electric signal processing circuit processes the electric signal, as described in the first step, and outputs a signal stream that contains the foot-lifting and foot-landing knowledge. Finally, signal analyzing as the third step, inferring that a central control unit that is electrically connected with the output of the electric signal processing circuit analyzes the received signal stream and counts the step numbers.

[0049] The embodiments of the present disclosure are further described below with reference to the accompanying drawings.

[0050] As shown in FIG. 1: FIG. 1 schematically shows the model of human body capacitance, the electric field between the human body and the surrounding environment. Since the human body is a good conductor, it can store charges. The environment around the human body can be regarded as the ground. So an electric field is formed between the human body and the surrounding environment. The present disclosure describes this electric field in terms of human body capacitance. Human body capacitance is a physical property of the human body itself, and its construction does not depend on external items like garment.

[0051] FIG. 2 schematically shows the electrostatic field between the foot and the ground during foot-lifting and foot-landing. As the distance between the foot and the ground changes, the electric field between them also changes. The present disclosure utilizes the phenomenon of human body capacitance variation caused by foot-lifting and foot-landing to perform accurate step counting.

[0052] FIG. 3 is the basic working steps of a step counting system provided by an embodiment of the present disclosure:

[0053] Step 1: A detection circuit directly or indirectly detects the human body capacitance variation when walking. The detection circuit can also directly or indirectly catch the variation of other physical properties caused by human body capacitance variation, such as charges on an electrode that is in contact or coupled with the human body.

[0054] Step 2: A central control unit performs numerical analysis on the signal output of the detection circuit to obtain step number information.

[0055] As shown in FIG. 4: FIG. 4 is a schematic structural diagram of a step counting system provided by an embodiment of the present disclosure. In this embodiment, a step counting system 400 comprises an electrode 410, a signal processing circuit 420, and a central control unit 430. The electrode 410 is electrically connected to the signal processing circuit 420, and the signal processing circuit 420 is electrically connected to the central control unit 430. The electrode 410 is used for acquiring an electric signal caused by the variation of the human body capacitance. When the electrode 410 is in direct contact with the human body, the electrical signal on the electrode 410 caused by the human body capacitance variation is the conduction current signal; when the electrode 410 is coupled with the human body, the electrical signal on the electrode 410 caused by the human body capacitance variation is the displacement current. The signal processing circuit 420 provides a bias voltage for the electrode 410 and has an input impedance higher than one kiloohm. This bias voltage also acts as a charge source for the electrode. Because the human body capacitance is only about one hundred picofarads, the human body capacitance variation caused by human walking is extremely weak. To sense the weak human body capacitance variation, the step counting system converts the sensing of the slight human body capacitance variation into the sensing of the weak charge flow at the electrode caused by the human body capacitance variation. The signal processing circuit 420 performs signal processing to the electrical signals on the electrode 410 and transmits the processed signals to the central control unit 430. The central control unit 430 analyzes the signal through a corresponding step counting algorithm to obtain step count information.

[0056] According to some embodiments, the electrode is in direct contact or coupled with the human body. When the human body lifts or lands a foot, the human body capacitance changes, and the change causes the flow of charges on the body, which also manifests as the flow of charges at the electrode.

[0057] According to some embodiments, the signal processing circuit provides a bias voltage to the electrode and has an input impedance higher than one kiloohm. Therefore, the flow of charges on the electrode can be reflected as the observable and readable voltage change on the electrode. The signal processing circuit performs signal processing to the voltage signal.

[0058] According to some embodiments, the signal processing circuit includes, but is not limited to, one or more of the following circuit units: filtering unit, amplification unit, and analog-to-digital conversion unit.

[0059] Advantageously, by placing a capacitor between the electrode and the signal processing circuit, the amplitude and response time of the voltage signal variation can be adjusted; thus, the accuracy of the step number detection can be further improved.

[0060] As shown in FIG. 5, FIG. 5 is a schematic diagram of a connection mode provided by an embodiment of the present disclosure.

[0061] In this embodiment, as shown in case of A in FIG. 5, the electrode 501 placed in the smart wearable device 500 is in direct contact with the skin 503, and the electrical signal on the electrode caused by the human body capacitance variation is the conduction current signal; As shown in case of B in FIG. 5, the electrode 501 is coupled with the skin 503, that is, a medium 502 is sandwiched between the electrode 501 and the skin 503, in this case, the electrical signal on the electrode caused by the human body capacitance variation is the displacement current signal.

[0062] According to some embodiments, the medium 502 mentioned above is a low-conductivity medium, including but not limited to air, fabric, or rubber wristbands.

[0063] According to some embodiments, the material, size, and placement position of the electrode 501 are not limited.

[0064] Advantageously, the electrode 501 is a piece of conductor inside or on the surface of the smart wearable device 500.

[0065] As shown in FIG. 6: FIG. 6 is a circuit diagram of a signal processing circuit provided by an embodiment of the present disclosure. In this embodiment, the electrode is connected to a resistor network composed of R1, R2, and R3. This network provides a stable bias voltage for the electrode and an input impedance higher than one kiloohm for the signal processing circuit. Providing a stable bias voltage can give the electrode the potential to have the flowable charges and a observable and readable voltage. R4, C1, R5, and C2 form a second-order low-pass filter network. The output of the circuit is connected to a high-precision analog-to-digital conversion module to ensure that the output voltage variation caused by the charge flow at the electrode is detectable.

[0066] As shown in FIG. 7, FIG. 7 is a circuit diagram of a signal processing circuit provided by another embodiment of the present disclosure. In this embodiment, a general analog-to-digital conversion module replaces the high-precision analog-to-digital conversion module, as shown in FIG. 6, but the operational amplifiers are added. The amplification circuit is composed of operational amplifier OP1 and operational amplifier OP2. Resistors R2, R3, and R4 form a resistor network to provide a stable bias voltage for the electrode and an input impedance higher than one kilo-ohm for the signal processing circuit. Providing a stable bias voltage can give the electrode the potential to have the flowable charges and a observable and readable voltage. R1, C1, R7, and C2 are low-pass filter networks. The circuit design can reduce the cost, power consumption, and volume of the signal processing circuit. The circuit uses the operational amplifier to amplify the weak voltage variation caused by the charge flow at the electrode. A general analog-to-digital conversion module can detect the voltage variation at the output caused by the charge flow at the electrode.

[0067] FIG. 8 and FIG. 9 show the detected signals of foot-lifting and foot-landing when the circuit shown in FIG. 6 is used as the signal processing circuit and the step counting system shown in FIG. 4 is worn on the wrist with the electrode in contact with the skin. When lifting or landing the foot, the human body capacitance varies due to the distance change between the human body and the ground. The human body capacitance variation is expressed as the process of charge flow at the electrode, that is, a charging and discharging process. And the variation is expressed as voltage variation at the output of the signal processing circuit. The voltage signal has peaks in different directions. When walking at a slow speed, the peak voltage signals 801a, 801b, 801c are obtained by the central control unit when the foot lifts, and the peak voltage signals 802a, 802b, 802c are obtained by the central control unit when the foot lands. When the human body walks faster and the electrode contacts the skin, the collected voltage signal is shown in FIG. 9. The peak signal 902 is the peak voltage signal obtained by the central control unit when the foot lifts, and 901 is the peak voltage signal obtained by the central control unit when the foot lands. Since the time interval between the foot-lifting and foot-landing is relatively short, the voltage at the output of the signal processing circuit has not completely dropped back to the bias voltage level, and the next peak signal occurs. The frequency of peaks represents the frequency of foot-lifting and foot-landing.

[0068] According to some embodiments, the direction of the peak signal is the opposite of the above description of FIG. 8 and FIG. 9. When a foot-lifting happens, the peak signal occurs as 802a, 802b, 802c in FIGS. 8 and 901 in FIG. 9, and when a foot-landing happens, the peak signal occurs as 801a, 801b, 801c in FIGS. 8 and 902 in FIG. 9. The direction of the peak signal is depending on factors like the connection mode of the electrode.

[0069] As shown in FIG. 10, FIG. 10 is a schematic diagram of a system architecture platform for executing a step counting method provided by an embodiment of the present disclosure.

[0070] The system architecture platform 1000 of the embodiment of the present disclosure comprises one or more processors 1010 and a memory 1020, and one processor 1010 and one memory 1020 are taken as examples in FIG. 10.

[0071] The processor 1010 and the memory 1020 may be connected by a bus or other ways, and connecting by bus is taken as an example in FIG. 10.

[0072] As a non-transient computer-readable storage medium, the memory 1020 may be used to store non-transient software programs and non-transient computer-executable programs. In addition, the memory 1020 may comprise a high-speed random access memory, and may also comprise a non-transitory memory, such as at least one disk memory device, a flash memory device, or other non-transitory solid storage devices. In some embodiments, the memory 1020 optionally comprises a memory 1020 remotely disposed with respect to the processor 1010, which may be connected to the system architecture platform 1000 through a network. Examples of the networks above comprise, but are not limited to, the Internet, intranet, local area networks, mobile communication networks, and combinations thereof.

[0073] Those skilled in the art can understand that the apparatus structure shown in FIG. 10 does not constitute a limitation to the system architecture platform 1000, and may comprise more or less components than the illustrated components, or combine some components, or have different component arrangements.

[0074] As shown in FIG. 11, FIG. 11 is a basic flowchart of a step counting algorithm provided by an embodiment of the present disclosure. The step counting algorithm of the embodiment of the present disclosure comprises, but is not limited to, step S1100, step S1110, and step S1120.

[0075] At step S1100, The control center unit gets the first data from the raw data, which is the output of the signal processing unit.

[0076] At step S1110, If the first data meets the preset condition, get the second data with the same procedure. Otherwise, get a new first data.

[0077] At step S1120, Perceive the step information from the first and the second data by comparisons with preset thresholds.

[0078] In this embodiment, as the distance between the human body and the ground changes when the human body performs a foot-lifting or foot-landing action, resulting in the human body capacitance variation, an electric signal caused by the human body capacitance variation on the electrode that is in contact or coupled with the human body occurs. Then the signal processing is carried out on the electric signal and the central control unit gets the first data from the raw data of the processed electric signal; when the first data meets the preset condition, the second data is acquired with the same procedure. It is also necessary to confirm whether the second data meets the preset condition. Afterwards, the step number information is obtained according to the comparison of the first data and the second data with predefined thresholds. Judging whether the acquired data meets the preset condition can filter out some signals of human body capacitance changes caused by non-foot-lifting or non-foot-landing action of the human body.

[0079] According to some embodiments, the first data and the second data include but are not limited to one or more of the following data: a single raw data acquired at the central control unit, a group of raw data acquired at the central control unit, a single change rate data of the raw data acquired at the central control unit, a group change rate data of raw data acquired at the central control unit, a single rate of change rate data of the raw data acquired at the central control unit, a group rate of change rate data of raw data acquired at the central control unit.

[0080] According to some embodiments, the preset conditions include but are not limited to one or more of the following comparison: bigger than a threshold, smaller than a threshold, bigger than or equal to a threshold, smaller than or equal to a threshold.

[0081] FIG. 12 is a flowchart of a part of the step counting algorithm provided by an embodiment of the present disclosure; This part of step counting algorithm of the embodiment of the present disclosure comprises, but is not limited to, step S1200, step S1210, step S1220, step 1230, and step 1240.

[0082] At step S1200, check whether a first data meets a preset condition.

[0083] At step S1210, when the result shows that the first data is bigger than the first preset threshold or smaller than a second preset threshold.

[0084] At step S1220, keep the first data and acquire a second data.

[0085] At step S1230, when the result shows that the second data is smaller than the third preset threshold or bigger than the fourth preset threshold.

[0086] At step S1240, it is concluded that a foot-lifting action or a foot-landing action occurs.

[0087] According to some embodiments, the related thresholds value can be equal.

[0088] According to some embodiments, the first data and the second data include but are not limited to one or more of the following data: a single raw data acquired at the central control unit, a group of raw data acquired at the central control unit, a single change rate data of the raw data acquired at the central control unit, a group change rate data of raw data acquired at the central control unit, a single rate of change rate data of the raw data acquired at the central control unit, a group rate of change rate data of raw data acquired at the central control unit.

[0089] FIG. 13 is a flowchart of a part of the step counting algorithm provided by an embodiment of the present disclosure; This part of step counting algorithm of the embodiment of the present disclosure comprises, but is not limited to, step S1300, step S1310, and step S1320.

[0090] At step S1300, check whether a first data meets a preset condition.

[0091] At step S1310, when the result shows that the first data is smaller than or equal to the first preset threshold and bigger than or equal to a second preset threshold.

[0092] At step S1320, discard the first data and acquire a new first data.

[0093] According to some embodiments, the first data and the second data include but are not limited to one or more of the following data: a single raw data acquired at the central control unit, a group of raw data acquired at the central control unit, a single change rate data of the raw data acquired at the central control unit, a group change rate data of raw data acquired at the central control unit, a single rate of change rate data of the raw data acquired at the central control unit, a group rate of change rate data of raw data acquired at the central control unit.

[0094] In addition, an embodiment of the present disclosure further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer-executable instruction, and the computer-executable instruction is executed by one processor or controller, for example, by one processor in the controller embodiment above, which can cause the processor to execute the step counting algorithm in the foregoing embodiments, for example, to execute the above-described algorithm steps S1100 to S1120 in FIG. 11, algorithm steps S1200 and S1240 in FIG. 12, algorithm steps S1300 to S1320 in FIG. 13.

[0095] Those of ordinary skills in the art will appreciate that all or some of the steps and systems in the methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some physical components or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As well known to those of ordinary skills in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or art for storing information (such as computer-readable instruction, data structure, programming module or other data). The computer storage medium includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disc (DVD) or other optical disc memory, magnetic cassette, magnetic tape, magnetic disk memory or other magnetic memory device, or may be any other medium that can be used to store the desired information and can be accessed by a computer. Moreover, it is well known to those of ordinary skills in the art that the communication medium typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transmission mechanism, and may include any information delivery medium.

[0096] The foregoing describes the preferred embodiments of the present disclosure in detail, but the embodiments of the present disclosure are not limited to the foregoing embodiments. Those skilled in the art can make various equal deformations or replacements without departing from the spirit of the embodiments of the present disclosure, and these equal deformations or replacements shall all fall within the scope limited by the claims of the embodiments of the present disclosure.