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1. Field of the Invention
The disclosure relates to a method, system and computer readable media for human movement recognition, and particularly to a method, system and computer readable media for human movement recognition using an inertial measurement unit (IMU).
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Currently, the most well-known positioning system is the global positioning system (GPS), which uses satellite technology, and is widely installed in automobile and mobile apparatus applications. However, since GPS technology requires transmission and reception of satellite signals, it is only suitable for outdoor usage. When used indoors, GPS may suffer from poor signal reception. Therefore, a major goal of academics and industry is to develop a practical positioning system that can be used indoors.
Current research papers show that positioning systems using a pattern comparison algorithm can provide acceptable positioning results with a margin of error of only a few meters caused by the instability of the wireless signal, which causes shifting of the positioning results. When the positioning system is applied in a multi-floor building, a vertical shifting between floors corresponds to an unacceptable error. To avoid such error, one approach is to obtain the user's current floor information in advance, and update the information only when a specific human movement occurs. In this way, the positioning results are fixed to a certain floor such that the vertical shifting between floors is eliminated, and the accuracy of the positioning system is enhanced.
Current mobile apparatuses installed with IMU are becoming increasingly popular. If such IMU can be used for the purpose of human movement recognition, any other costs for the purpose of human movement recognition can be saved. Accordingly, there is a need to design a method and system for human movement recognition which uses IMU such that the method and system for human movement recognition can be easily integrated into the modern mobile apparatuses.
One exemplary embodiment of this disclosure discloses a method for human movement recognition, comprising the steps of: retrieving successive measuring data for human movement recognition from an inertial measurement unit; dividing the successive measuring data to generate at least a human movement pattern waveform if the successive measuring data conforms to a specific human movement pattern; quantifying the at least a human movement pattern waveform to generate at least a human movement sequence; and determining a human movement corresponding to the inertial measurement unit by comparing the at least a human movement sequence and a plurality of reference human movement sequences.
Another embodiment of this disclosure discloses a system for human movement recognition. The system for human movement recognition comprises an IMU, a pattern retrieving unit and a pattern recognition unit. The IMU is configured to provide successive measuring data of a human movement. The pattern retrieving unit is configured to divide the successive measuring data to generate at least a human movement pattern waveform and quantify the at least a human movement pattern waveform to generate at least a human movement sequence. The pattern recognition unit is configured to compare the at least a human movement sequence and a plurality of reference human movement sequences to determine the human movement.
Another embodiment of this disclosure discloses computer readable media having program instructions for human movement recognition, the computer readable media comprising programming instructions for retrieving successive measuring data for human movement recognition from an inertial measurement unit; programming instructions for dividing the successive measuring data to generate at least a human movement pattern waveform if the successive measuring data conforms to a specific human movement pattern; programming instructions for quantifying the at least a human movement pattern waveform to generate at least a human movement sequence; and programming instructions for determining a human movement corresponding to the inertial measurement unit by comparing the at least a human movement sequence and a plurality of reference human movement sequences.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
This disclosure provides exemplary embodiments of a method and system for human movement recognition. In the exemplary embodiments of this disclosure, an IMU is used for the recognition of human movement based on a wireless detection network. However, the method and system for human movement recognition of the exemplary embodiments of this disclosure are not limited to applications of wireless detection network. The method and system for human movement recognition of the exemplary embodiments of this disclosure can recognize users moving between floors, including but not limited to riding in an elevator and walking up or down stairs.
In this exemplary embodiment, the IMU 102 is an accelerometer, an electronic compass, an angular accelerometer, or the combination thereof. The successive measuring data is comprised of values of tri-axial acceleration, tri-axial Euler angle, tri-axial angular acceleration, or the combination thereof. The system 100 can determine whether the user 150 is riding in an elevator or walking up or down stairs.
The following illustrates applying the method for human movement recognition shown in
In step 203, the pattern retrieving unit 104 determines whether the successive measuring data conforms to a specific human movement pattern. Ordinarily, if the user 150 is riding in an upward-moving elevator, the waveform of a tri-axial acceleration value of the successive measuring data exhibits a convex-horizontal-concave manner. On the other hand, if the user 150 is riding in a downward-moving elevator, the waveform of a tri-axial acceleration value of the successive measuring data exhibits a concave-horizontal-convex manner.
On the other hand, if the user 150 is walking up or down stairs, an angle value of the successive measuring data will periodically exceed a threshold, as shown in
In step 204, the pattern retrieving unit 104 divides the successive measuring data to generate at least a human movement pattern waveform. If the pattern retrieving unit 104 determines that the successive measuring data conforms to an elevator-riding behavior pattern, the pattern retrieving unit 10 divides the successive measuring data to at least a human movement pattern waveform by taking a waveform in a convex-horizontal-concave manner or in a concave-horizontal-convex manner as a basic unit, as shown in
In step 205, at least a human movement sequence is generated by quantifying the at least a human movement pattern waveform. In an exemplary embodiment of this disclosure, the pattern retrieving unit 104 uses a full pattern sampling algorithm, which samples a human movement pattern waveform to generate a human movement sequence. As shown in
In another exemplary embodiment of this disclosure, the pattern retrieving unit 104 uses a boundary discrete pattern sampling algorithm, which takes the maximum and minimum values of a human movement pattern waveform as the maximum and minimum values of a corresponding human movement sequence, and then the human movement pattern waveform is divided into a plurality of value regions. Next, the human movement pattern waveform is quantified according to the value regions, and the human movement sequence records the corresponding values when the human movement pattern waveform moves from one value region to another value region.
In yet another exemplary embodiment of this disclosure, the pattern retrieving unit 104 uses a time discrete pattern sampling algorithm, which takes the maximum and minimum values of a human movement pattern waveform as the maximum and minimum values of a corresponding human movement sequence, and then the human movement pattern waveform is divided into a plurality of value regions. Next, the human movement pattern waveform is quantified according to the value regions, and the human movement sequence records the corresponding values when the human movement pattern waveform moves from one value region to another value region, or when the human movement pattern waveform remains in a value region over a predetermined period of time.
In step 206, the pattern recognition unit 106 compares the at least a human movement sequence and a plurality of reference human movement sequences to determine a human movement of the user 150 corresponding to the IMU 102. In an exemplary embodiment of this disclosure, the reference human movement sequence is determined according to stored elevator-riding behavior patterns and stair-walking behavior patterns of a training step at the initialization setup.
In an exemplary embodiment of this disclosure, the pattern recognition unit 106 uses a pattern-matching algorithm for the comparison of the at least a human movement sequence and the plurality of reference human movement sequences. The pattern-matching algorithm sums up the differences of a human movement sequence and a reference human movement sequence, and determines the human movement of the user 150 accordingly. The pattern-matching algorithm is represented by the function
Err(T, C)=Σi=0k|T[i]−C[i]|
wherein Err(T, C) is the total difference of the human movement sequence and a reference human movement sequence, C[i] is the human movement sequence, T[i] is the reference human movement sequence, and k is the length of the human movement sequence and the reference human movement sequence.
In an exemplary embodiment of this disclosure, if the length of the human movement sequence is different from the length of the reference human movement sequence, or if there is an offset between the human movement sequence and the reference human movement sequence, the human movement sequence can be shifted to be aligned with the reference human movement sequence, and an interpolation computation can be executed to fill the human movement sequence such that the lengths of the human movement sequence and the reference human movement sequence are the same. Next, the pattern recognition unit 106 compares a plurality of Err(T, C) according to different reference human movement sequences, and determines the human movement of the user 150 corresponding to the reference human movement sequence with the smallest Err(T, C).
In an exemplary embodiment of this disclosure, the pattern recognition unit 106 uses a longest-common-substring algorithm for the comparison of the at least a human movement sequence and the plurality of reference human movement sequences. The longest-common-substring algorithm determines the similarity between a human movement sequence and a reference human movement sequence according to the ratio of the length of the longest common substring of the human movement sequence and the reference human movement sequence to the length of the human movement sequence and the reference human movement sequence. The longest-common-substring algorithm is represented by the function
wherein C′ is the human movement sequence, T′ is the reference human movement sequence, S is the similarity between the human movement sequence and the reference human movement sequence, and LCS is the computation of the longest-common-substring algorithm. For instance, if a human movement sequence is [5, 4, 3, 2, 1, 2, 3, 2, 1, 1, 1, 2, 3, 4, 5], and a reference human movement sequence is [5, 4, 3, 2, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 4], then the longest-common-substring of these two sequences is [5, 4, 3, 2, 1, 2, 3, 2, 1, 1, 1, 2, 3, 4], and the similarity S between the human movement sequence and the reference human movement sequence is 2*14/(15+15)=0.93. Next, the pattern recognition unit 106 compares a plurality of the similarities S between the human movement sequence and a plurality of reference human movement sequences and determines the human movement of the user 150 corresponding to the reference human movement sequence with the greatest similarity S.
In an exemplary embodiment of this disclosure, the pattern recognition unit 106 uses a longest-common-subsequence algorithm for the comparison of the at least a human movement sequence and the plurality of reference human movement sequences. The longest-common-subsequence algorithm determines the similarity between a human movement sequence and a reference human movement sequence according to the ratio of the length of the longest common sequence of the human movement sequence and the reference human movement sequence to the length of the human movement sequence and the reference human movement sequence. The longest-common-subsequence algorithm is represented by the function
wherein C′ is the human movement sequence, T′ is the reference human movement sequence, S is the similarity between the human movement sequence and the reference human movement sequence, and LCS is the computation of the longest-common-subsequence algorithm. For instance, if a human movement sequence is [5, 4, 3, 2, 1, 2, 3, 2, 1, 1, 1, 2, 3, 4, 5], and a reference human movement sequence is [5, 4, 3, 2, 1, 1, 2, 3, 2, 1, 1, 1, 2, 3, 4], then the longest-common-sequence of these two sequences is [2, 3, 2, 1, 1, 1, 2, 3, 4], and the similarity S between the human movement sequence and the reference human movement sequence is 2*9/(15+15)=0.6. Next, the pattern recognition unit 106 compares a plurality of the similarities S between the human movement sequence and a plurality of reference human movement sequences and determines the human movement of the user 150 corresponding to the reference human movement sequence with the greatest similarity S.
Another embodiment of this disclosure discloses computer readable media having program instructions for human movement recognition, the computer readable media comprising programming instructions for retrieving successive measuring data for human movement recognition from an inertial measurement unit; programming instructions for dividing the successive measuring data to generate at least a human movement pattern waveform if the successive measuring data conforms to a specific human movement pattern; programming instructions for quantifying the at least a human movement pattern waveform to generate at least a human movement sequence; and programming instructions for determining a human movement corresponding to the inertial measurement unit by comparing the at least a human movement sequence and a plurality of reference human movement sequences. The related details are as the above embodiments.
In conclusion, the method and system for human movement recognition of this disclosure uses an IMU to detect the human movement. Through the steps of retrieving, dividing and comparing, a user's human movement can be determined. Accordingly, the method and system for human movement recognition of this disclosure can be integrated into various modern mobile apparatus installed with IMUs.
The above-described exemplary embodiments are intended to be illustrative only. Those skilled in the art may devise numerous alternative embodiments without departing from the scope of the following claims.
Number | Date | Country | Kind |
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099138777 | Nov 2010 | TW | national |