KR20120049072A - Real-time step counter detection apparatus and method - Google Patents

Abstract

PURPOSE: A real-time step counting apparatus using a three shaft acceleration sensor and a method using the same are provided to control a threshold for detecting steps and a time interval in which energy supplies according to an energy change caused by various steps and to accurately count the number of a step at walking of various speeds by detecting omitted steps. CONSTITUTION: A real-time step counting apparatus using a three shaft acceleration sensor is as follows. Whether a first energy input to a three shaft acceleration sensor is smaller than the maximum threshold or not is confirmed after inputting the energy larger than the threshold to the three shaft acceleration sensor(S1). If the first energy is smaller than the maximum threshold, a movement responding to the first energy is detected as a step and the number of the step is increased. The maximum threshold is updated by using the first energy when the first energy is larger than the maximum threshold Whether a current step index which is a time interval between a time point in which the larger energy is input and a point in which the first energy is input is or not is confirmed(S3). An omission of the step is decided when the current step index is larger than a previous step index so that the number of the step is increased.

Description

Real-time step counting device using 3-axis acceleration sensor and its method {REAL-TIME STEP COUNTER DETECTION APPARATUS AND METHOD}

The present invention relates to a real-time step number detection apparatus and method using a three-axis acceleration sensor, and more particularly to a technique for detecting the number of steps accurately at various step speeds.

Efforts have been made to detect human behavior during walking and detect the number of steps while using the acceleration sensor and apply it to various fields. One of the most frequent things in a person's daily life is physical movement, which is walking and frequent movements, and involves very complex mechanisms for various parts of the body. For the application of walking motion measurement, a mechanical step counter that displays the physical number of weights using the law of inertia has been typically used, but recently, a small acceleration sensor using MEMS (Micro Electro Mechanical System) technology is used. Applications have been attempted to do this by using.

This application calculates the number of steps by acquiring data from the acceleration sensor and then removing noise and setting a fixed threshold based on energy. However, this method has a problem that it is difficult to calculate the exact number of steps in each situation of converting in real time such as walking slowly or running. In order to solve this problem, a technique for allowing a user to set a threshold for detecting the number of steps in advance according to each situation has been proposed. However, this proposed technique may make the user uncomfortable because the threshold for detecting the number of steps must be continuously set whenever the walking situation changes.

An apparatus and method for detecting a real-time step using a three-dimensional acceleration sensor for automatically detecting the number of steps automatically in various steps such as slow walking or running fast are proposed.

In the real-time step count detection method using the three-axis acceleration sensor according to an aspect of the present invention, is the first energy input from the three-axis acceleration sensor is less than the maximum threshold after the energy is greater than the maximum threshold from the three-axis acceleration sensor Confirming; Determining that the operation corresponding to the first energy is a step if the first energy is less than the maximum threshold, and increasing the number of steps; if the first energy is greater, updating the maximum step energy using the first energy; Checking whether a current step index, which is a time interval between when the large energy is input and the input time of the first energy, is greater than a previous step index; Determining that the step is missing from the current step index if the current step index is larger than the previous step index, increasing the number of steps, and checking whether the second energy input from the 3-axis acceleration sensor is smaller than the minimum threshold; If the second energy is less than the minimum threshold, then checking whether the third energy input from the 3-axis acceleration sensor is greater than the minimum threshold; And if the third energy is less than the minimum threshold, update the minimum step energy using the third energy, and if the third energy is greater, use the maximum step energy and the minimum step energies before the maximum step energy and the minimum step energy are updated, and Updating the minimum threshold and the current step index.

If the current step index is larger than the previous step index, the step is determined to be missing from the current step index, and the number of steps is increased. If the step size is smaller, the step of checking whether the second energy input from the 3-axis acceleration sensor is smaller than the minimum threshold is determined. If the current step index is twice as large as the previous step index, it may be determined that the step is missing from the current step index and may increase the number of steps.

The previous step index may be obtained as an average of a set number of step indexes before the current step index.

And updating the maximum threshold value and the minimum threshold value using the following equations.

[ Equation ]

At this time, Min T is the minimum threshold, Max T is the maximum threshold, MP _n is the minimum energy of the first step before the minimum step energy is updated, MP _{n -1} is MP _n The minimum energy of the previous step and A and B are different constants.

로, 최소 임계치 및 최대 임계치 갱신조건이고, PD_n은 상기 최대 걸음 에너지가 갱신되기 전 첫 번째 걸음의 최대 에너지, PD_{n -1}은 PD_n 이전 걸음의 최대 에너지이다. And

Is the minimum threshold and maximum threshold update condition, PD _n is the maximum energy of the first step before the maximum step energy is updated, PD _{n -1} is PD _n It is the maximum energy of the previous step.

The current step index may be updated using the following equation.

[ Equation ]

Where Si represents the current step index, PD _n is the maximum energy of the first step before the maximum step energy is updated, MP _n is the minimum energy of the first step, K, J and H before the minimum step energy is updated. Is a constant and K has a value greater than J.

After the energy greater than the maximum threshold is input from the three-axis acceleration sensor, the maximum threshold value is set as the first and second hours in which the first energy less than the maximum threshold is not input and the time when no step is detected is set. The method may further include changing an intermediate value between a maximum threshold value and a minimum threshold value at the step detection or the maximum threshold value to an initial maximum threshold value before the step is detected.

The three-axis acceleration sensor may convert the three-axis acceleration value generated according to the user's walking into energy using a SVM (Signal Vector Magnitude) algorithm.

According to another aspect of the present invention, an apparatus for detecting real-time steps using a three-axis acceleration sensor includes: a three-axis acceleration sensor for converting a three-axis acceleration value generated according to a user's walking into energy using an SVM algorithm; If the first energy input from the three-axis acceleration sensor is less than the maximum threshold after the energy is greater than the maximum threshold is input from the three-axis acceleration sensor to determine the operation corresponding to the first energy to increase the number of steps Step count detection unit; A missing step number detecting unit configured to increase the number of steps by determining that the step is missing from the current step index when the current step index, which is a time interval between the time when the large energy is input and the input point of the first energy, is larger than a previous step index; If the first energy is greater than the maximum threshold, the maximum step energy is updated using the first energy, and if the current step index is less than the previous step index, the first energy is input and then is greater than the minimum threshold from the 3-axis acceleration sensor. An update unit configured to update the minimum step energy by using the third energy when a small second energy is input and a third energy smaller than the minimum threshold is input from the triaxial acceleration sensor after the second energy is input; And a threshold updating unit updating the maximum threshold value and the minimum threshold value using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. And a step index updater configured to update a current step index by using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated.

According to the real-time step number detection apparatus using the three-axis acceleration sensor and the method according to an embodiment of the present invention, the threshold and energy for detecting the step according to the energy change according to the various steps are adjusted and missing By detecting the steps, the number of steps can be accurately detected at various step speeds.

1 is a view showing the configuration of a real-time step detection device using a three-axis acceleration sensor according to an embodiment of the present invention.
2 is a diagram showing that the three-axis acceleration value is converted into energy.
3 is a flowchart of a real-time step count detection method using a three-axis acceleration sensor according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

1 is a view showing the configuration of a real-time step detection device using a three-axis acceleration sensor according to an embodiment of the present invention.

As shown, the real-time step number detection device 1 using the three-axis acceleration sensor according to an embodiment of the present invention, the three-axis acceleration sensor 2, the step number detection unit 3, the missing step number detection unit 4 And a step energy updater 5, a threshold value updater 6, and a step index updater 7. The apparatus for detecting real time steps 1 using the three-axis acceleration sensor 1 may have a hardware shape to be attached to the body of a pedestrian.

The 3-axis acceleration sensor 2 converts the 3-axis acceleration value generated according to the user's walking into energy using a SVM (Signal Vector Magnitude) algorithm. An example of this is shown in FIG. 2. As shown, the 3-axis acceleration sensor 2 converts the 3-axis acceleration value as shown in FIG. 2 (a) into the energy shown in FIG. 2 (b) using the SVM algorithm. The reason for converting the three-axis acceleration value into energy is that when the pedestrian attaches the detection device 1 to the body or walks in the pocket, the rotation state of the detection device 1 cannot be determined and the detection device (while walking) 1) is likely to rotate, so the effect of the rotation is eliminated.

The step number detecting unit 3 corresponds to the first energy when the first energy input from the triaxial acceleration sensor 2 is smaller than the maximum threshold after the energy greater than the maximum threshold is input from the triaxial acceleration sensor 2. The number of steps is increased by judging the operation as a step. Furthermore, the step detection unit 3 is the first and second set the time that the step is not detected because the first energy less than the maximum threshold is not input after the energy greater than the maximum threshold is input from the three-axis acceleration sensor 2 As time passes, the maximum threshold value may be changed to an intermediate value between the maximum threshold value and the minimum threshold value during the step detection before the step is detected, or the maximum threshold value may be changed to the initial maximum threshold value. The set first time may be '1' second, and the set second time may be '2' second.

The missed step detection unit 4 determines that the step is missed in the current step index when the current step index, which is a time interval between the time when the large energy is input and the input time of the first energy, is larger than the previous step index. To increase. In this case, if the current step index is twice as large as the previous step index, the missing step detection unit 4 may determine that the step is missing from the current step index and increase the number of steps. The previous step index may be obtained as an average of a set number of step indexes before the current step index. As described above, the reason why the step count detection unit 4 is provided is that when the threshold range is set and the step is detected, the narrower the threshold range, the higher the step detection probability, but there is an error that can recognize the noise component as the step. Therefore, by applying the HA (Heuristic Algorithm) to the missing step number detection unit 4, it is possible to detect missing steps between step indexes, and even when the step pattern changes abruptly, it is possible to adapt to the threshold range in real time.

The stepped energy updating unit 5 updates the maximum stepped energy by using the first energy when the first energy is greater than the maximum threshold value, and after the first energy is input when the current step index is smaller than the previous step index. When a second energy smaller than the minimum threshold is input from the 3-axis acceleration sensor, and a third energy smaller than the minimum threshold is input from the 3-axis acceleration sensor after the second energy is input, the minimum step energy is obtained using the third energy. Update

The threshold update unit 6 updates the maximum threshold value and the minimum threshold value using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. In this case, the threshold update unit 6 may update the maximum threshold value and the minimum threshold value by using Equation 1 below.

At this time, Min T is the minimum threshold, Max T is the maximum threshold, MP _n is the minimum energy of the first step before the minimum step energy is updated, MP _{n -1} is MP _n The minimum energy of the previous step and A and B are different constants.

로, 최소 임계치 및 최대 임계치 갱신조건이고, PD_n은 상기 최대 걸음 에너지가 갱신되기 전 첫 번째 걸음의 최대 에너지, PD_{n -1}은 PD_n 이전 걸음의 최대 에너지이다. 이와 같이 PD_n 및 PD_{n -1} 중 작은 값을 사용하여 임계치를 갱신하는 이유는, 3축 가속도 센서(2)를 포함한 검출장치(1)를 팔과 같은 신체의 한쪽 방향에 부착하였을 경우 비대칭적인 신호가 출력되고 이로 인해서 최대 걸음 에너지가 일정하지 않게 된다. 이런 경우 PD_n 만을 사용하여 임계치를 갱신하면 큰 걸음 에너지 다음에 작은 걸음 에너지가 들어올 때 임계치 범위가 너무 넓어지는 문제가 발생하기 때문이다.And

Is the minimum threshold and maximum threshold update condition, PD _n is the maximum energy of the first step before the maximum step energy is updated, PD _{n -1} is PD _n It is the maximum energy of the previous step. PD _n like this The reason why the threshold value is updated by using a smaller value among PD _{n −1} is that when the detection device 1 including the 3-axis acceleration sensor 2 is attached to one side of the body such as an arm, an asymmetrical signal is output. This causes the maximum step energy to be inconsistent. PD _{n in} this case This is because updating the threshold by using only causes a problem that the threshold range becomes too wide when a large step energy is input followed by a small step energy.

The step index updating unit 7 updates the current step index by using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. At this time, the step index updater 7 may update the current step index using Equation 2 below.

Where Si represents the current step index, PD _n is the maximum energy of the first step before the maximum step energy is updated, MP _n is the minimum energy of the first step, K, J and H before the minimum step energy is updated. Is a constant and K has a value greater than J.

3 is a flowchart of a real-time step count detection method using a three-axis acceleration sensor according to an embodiment of the present invention. At this time, the real-time step number detection method using the three-axis acceleration sensor may be performed in the detection device shown in FIG. The three-axis acceleration sensor may convert the three-axis acceleration value generated according to the user's walking into energy using a SVM (Signal Vector Magnitude) algorithm.

As shown, the real-time step number detection device checks whether the first energy input from the three-axis acceleration sensor is smaller than the maximum threshold after inputting the energy greater than the maximum threshold from the three-axis acceleration sensor (S1).

If the first energy is less than the maximum threshold value, the real-time step count detection device determines that the operation corresponding to the first energy is a step, and increases the number of steps, and if the first energy is greater, updates the maximum step energy by using the first energy ( S2). In this case, the real-time step count detection device has passed the first and second hours in which the time at which the step is not detected because the first energy smaller than the maximum threshold is not input after the energy greater than the maximum threshold is input from the three-axis acceleration sensor. As a result, the maximum threshold value may be changed to an intermediate value between the maximum threshold value and the minimum threshold value during the step detection before the step is detected, or the maximum threshold value may be changed to the initial maximum threshold value.

The apparatus for detecting a real-time step count checks whether the current step index, which is a time interval between the time when the large energy is input and the input time of the first energy, is greater than the previous step index (S3). In this case, the previous step index may be obtained as an average of a set number of step indexes before the current step index.

If the current step index is greater than the previous step index, the real-time step detection device determines that the step is missing from the current step index, and increases the number of steps. If the step number is smaller, the second energy input from the 3-axis acceleration sensor is smaller than the minimum threshold. Check if small (S4). In this case, if the current step index is twice as large as the previous step index, the apparatus may determine that the step is missing from the current step index and increase the number of steps.

If the second energy is less than the minimum threshold, the real-time step detection apparatus checks whether the third energy input from the 3-axis acceleration sensor is greater than the minimum threshold (S5).

The real-time step number detecting device updates the minimum step energy by using the third energy when the third energy is smaller than the minimum threshold, and when the third energy is larger, the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. The maximum threshold value and the minimum threshold value and the current step index are updated by using the S6. In this case, the real-time step count detection apparatus may update the maximum threshold value and the minimum threshold value by using Equation 1 above. The apparatus for detecting real-time steps may update the current step index using Equation 2 above.

So far, the present invention has been described with reference to the embodiments. Those skilled in the art will understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. Therefore, the scope of the present invention should not be limited to the above-described examples, but should be construed to include various embodiments within the scope and equivalents of the claims.

Claims (13)

Confirming whether the first energy input from the three-axis acceleration sensor is smaller than the maximum threshold after inputting an energy larger than the maximum threshold from the three-axis acceleration sensor;
Determining that the operation corresponding to the first energy is a step if the first energy is less than the maximum threshold, and increasing the number of steps; if the first energy is greater, updating the maximum step energy using the first energy;
Checking whether a current step index, which is a time interval between when the large energy is input and the input time of the first energy, is greater than a previous step index;
Determining that the step is missing from the current step index if the current step index is larger than the previous step index, increasing the number of steps, and checking whether the second energy input from the 3-axis acceleration sensor is smaller than the minimum threshold;
If the second energy is less than the minimum threshold, then checking whether the third energy input from the 3-axis acceleration sensor is greater than the minimum threshold; And
If the third energy is less than the minimum threshold, the minimum step energy is updated using the third energy, and if the third energy is greater, the maximum threshold and the minimum step energy are used using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. A method for detecting real-time steps using a three-axis acceleration sensor, comprising: updating a threshold and a current step index. The method of claim 1,
If the current step index is larger than the previous step index, the step is determined to be missing from the current step index, and the number of steps is increased. ,
And determining that the step is missing from the current step index when the current step index is twice as large as the previous step index, thereby increasing the number of steps. The method of claim 2,
The previous step index is
A method for detecting real-time steps using a three-axis acceleration sensor, which is obtained as an average of a set number of step indexes before the current step index. The method of claim 1,
If the third energy is less than the minimum threshold, the minimum step energy is updated using the third energy, and if the third energy is greater, the maximum threshold and the minimum step energy are used using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. Updating the threshold and the current step index,
And updating the maximum threshold value and the minimum threshold value using the following equations.
[ Equation ]

At this time, Min T is the minimum threshold, Max T is the maximum threshold, MP _n is the minimum energy of the first step before the minimum step energy is updated, MP _{n -1} is MP _n The minimum energy of the previous step and A and B are different constants.
And

Is the minimum threshold and maximum threshold update condition, PD _n is the maximum energy of the first step before the maximum step energy is updated, PD _{n -1} is PD _n It is the maximum energy of the previous step. The method of claim 1,
If the third energy is less than the minimum threshold, the minimum step energy is updated using the third energy, and if the third energy is greater, the maximum threshold and the minimum step energy are used using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. Updating the threshold and the current step index,
And updating the current step index by using the following equation.
[ Equation ]

Where Si represents the current step index, PD _n is the maximum energy of the first step before the maximum step energy is updated, MP _n is the minimum energy of the first step, K, J and H before the minimum step energy is updated. Is a constant and K has a value greater than J. The method of claim 1,
After the energy greater than the maximum threshold is input from the three-axis acceleration sensor, the maximum threshold value is set as the first and second hours in which the first energy less than the maximum threshold is not input and the time when no step is detected is set. And changing the maximum threshold value to an initial maximum threshold value or changing the maximum threshold value to an initial maximum threshold value before the step is detected. The method according to any one of claims 1 to 6,
The three-axis acceleration sensor is a real-time step detection method using a three-axis acceleration sensor converts the three-axis acceleration value generated in accordance with the user's walking using the SVM (Signal Vector Magnitude) algorithm. A three-axis acceleration sensor for converting the three-axis acceleration value generated according to the user's walking into energy using the SVM algorithm;
If the first energy input from the three-axis acceleration sensor is less than the maximum threshold after the energy is greater than the maximum threshold is input from the three-axis acceleration sensor to determine the operation corresponding to the first energy to increase the number of steps Step count detection unit;
A missing step number detecting unit configured to increase the number of steps by determining that the step is missing from the current step index when the current step index, which is a time interval between the time when the large energy is input and the input point of the first energy, is larger than a previous step index;
If the first energy is greater than the maximum threshold, the maximum step energy is updated using the first energy, and if the current step index is less than the previous step index, the first energy is input and then is greater than the minimum threshold from the 3-axis acceleration sensor. An update unit configured to update the minimum step energy by using the third energy when a small second energy is input and a third energy smaller than the minimum threshold is input from the triaxial acceleration sensor after the second energy is input;
A threshold updating unit for updating a maximum threshold value and a minimum threshold value using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated; And
And a step index updater configured to update the current step index by using the maximum step energy and the minimum step energy before the maximum step energy and the minimum step energy are updated. The method of claim 8,
The missing step count detection unit,
And determining that the step is missing from the current step index when the current step index is twice as large as the previous step index, thereby increasing the number of steps. The method of claim 9,
The previous step index is
And a three-axis acceleration sensor obtained as an average of a set number of step indices before the current step index. The method of claim 8,
The threshold update unit,
And updating the maximum threshold value and the minimum threshold value by using the following equation.
[ Equation ]

At this time, Min T is the minimum threshold, Max T is the maximum threshold, MP _n is the minimum energy of the first step before the minimum step energy is updated, MP _{n -1} is MP _n The minimum energy of the previous step and A and B are different constants.
And

Is the minimum threshold and maximum threshold update condition, PD _n is the maximum energy of the first step before the maximum step energy is updated, PD _{n -1} is PD _n It is the maximum energy of the previous step. The method of claim 8,
The step index update unit,
And updating the current step index by using the following equation.
[ Equation ]

Where Si represents the current step index, PD _n is the maximum energy of the first step before the maximum step energy is updated, MP _n is the minimum energy of the first step, K, J and H before the minimum step energy is updated. Is a constant and K has a value greater than J. The method of claim 8,
The step detection unit,
After the energy greater than the maximum threshold is input from the three-axis acceleration sensor, the maximum threshold value is set as the first and second hours in which the first energy less than the maximum threshold is not input and the time when no step is detected is set. And changing the maximum threshold value to an initial maximum threshold value or changing the maximum threshold value to an initial maximum threshold value before the step is detected.

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