JP2008107866A - Movement analysis method and analysis system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a movement analysis method and analysis system that can analyze a rotation such as a golf or tennis swing and determine whether there is a rotation axis deviation and there is a correct rotation. <P>SOLUTION: A movement to be analyzed is imaged and recorded as digital images (S1, S2). Changes in the digital images with time are extracted and expressed as functions (S4). The functions are Fourier-transformed into spectra (S5). Images are synthesized from the Fourier-transformed spectra (S6 to S9). The images are arranged in order from the lowest order spectrum to the highest order spectrum to create an animation (S10). The imaged movement is judged on the animation (S11). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique related to analysis of body movements, for example, to a technique for analyzing body movements in a type of exercise or competition in which the body rotates mainly like golf or tennis.

The type of exercise or competition that mainly performs the motion of rotating the body, such as golf and tennis, still has a large number of competition population, and many people go to the practice field because they want to improve.
Although there are differences among individuals, there is a difference between individuals in the practice area, so that the rotation axis on the body does not “shake” during rotation, and a smooth swing, that is, a swing of a clean arc-shaped locus can be performed. In many cases, two points are important.

Here, especially for beginners, it is impossible to understand whether or not the rotation axis is “blurred” and whether or not a swing of a beautiful arc-shaped locus is made by own body sense.
Therefore, the form is visually checked by reflecting itself in the mirror.

However, even for beginners, even if they see their form in the mirror, it may not be clear whether the rotation axis is “blurred” or whether a beautiful arc-shaped trajectory is swinging. Many.
Therefore, there is a need for an analysis method that enables even a beginner to visually understand whether or not the rotation axis is “blurred” and whether or not a swing of a beautiful arc-shaped locus is made.
On the other hand, at present, no effective analysis method is provided.

In the prior art, for example, a device that has a sensor unit for detecting a posture angle, a distance detection unit, and a calculation processing unit, and detects and analyzes body sway at rest and during exercise has been proposed (for example, Patent Document 1).
However, the related art analyzes a rotational motion such as a swing in golf or tennis, and determines whether or not the rotation axis is “blurred” or whether or not a swing of a fine arc-shaped locus is made. There is no mention of what to do.
JP 2006-55532 A

  The present invention has been proposed in view of the above-described problems of the prior art, and analyzes rotational motion such as a swing in golf or tennis to determine whether the rotational axis is “blurred” or a clean circle. It is an object of the present invention to provide an operation analysis method and an analysis system that can determine whether or not an arc trajectory swing is possible.

  The motion analysis method of the present invention includes a step (steps S1 and S2) of recording and storing (storing) a motion to be analyzed (for example, a rotational motion such as a swing in golf or tennis) as a digital image, and recording. A step of extracting a change of the digital image with respect to time and expressing it as a function (step S4), a step of obtaining a spectrum by Fourier transforming the function (step S5), and a spectrum (primary spectrum) obtained by the Fourier transform. ˜30th order spectrum) (steps S6 to S9: No loop in step S8) and the image obtained from the lower order spectrum is obtained from the higher order spectrum. A step of creating an animation by arranging the images in order (step S10), and shooting using the animation Step of determining the operations (Step S11: 3, 4) is characterized by having a (claim 1: 2).

  In the motion analysis method of the present invention, in the step of determining the captured motion (step S11: FIG. 3 and FIG. 4), the images obtained from the low-order spectrum are arranged in the order of the images obtained from the high-order spectrum. A step of determining whether or not the rotation axis can be confirmed in the created animation (step S22), a step of determining that the axis is not shaken during the operation when the rotation axis can be confirmed (step S23), It is preferable to include a step (step S24) for determining that the shaft is shaken during the operation when the rotation shaft cannot be confirmed (Claim 2: FIG. 3).

  Alternatively, in the motion analysis method of the present invention, the step of determining the captured motion (step S11: FIG. 3 and FIG. 4) is performed on the image obtained from the higher order spectrum from the image obtained from the lower order spectrum. A step (step S32) for determining whether or not portions (δ1, δ2) showing that the circular motion is performed in the animations arranged in order appear intermittently and periodically, and the circular motion is performed. A step (step S33) for determining that the uniform acceleration motion is performed when the portions (δ1, δ2) appearing intermittently and periodically appear, and the portions (δ1, δ2) representing the circular motion. ) Does not appear intermittently and periodically, it is preferable to include a step (step S34) for determining that the uniform acceleration motion is not performed (Claim 3: FIG. 4).

  The motion analysis system of the present invention records (stores) a shooting unit (14) for shooting a motion to be analyzed (for example, a rotational motion such as a swing in golf or tennis) and a digital image of the shot motion. Storage unit (22: database), a function extraction unit (26) for extracting a change with respect to time of the recorded digital image and calculating a function indicating the change, and a function calculated by the function extraction unit (26) A Fourier transform unit (28) for Fourier-transforming the spectrum and an image for creating an animation by synthesizing images (FIGS. 7 to 10) from the spectrum (primary spectrum to 30th-order spectrum) obtained by the Fourier transform And a production unit (Claim 4: FIG. 1).

As a result of various studies, the inventor has photographed a motion to be analyzed (for example, a rotational motion such as a swing in golf or tennis), recorded (stored) it as a digital image, and a change of the recorded digital image with respect to time. To obtain a function, Fourier-transform the function to obtain a spectrum, and synthesize an image (FIGS. 7 to 10) from a spectrum (first-order spectrum to thirty-order spectrum) obtained by the Fourier transform. If created (Claims 1 and 4), when a so-called “shaking of the axis” is performed, the rotation axis can be clearly seen in the created animation (reference numerals in FIGS. 8 to 10). It was found that a rotating body indicated by “γ” can be observed).
In addition, when a so-called “clean circular motion” or “equal acceleration motion” is performed, a portion indicating that circular motion is being performed in the created animation (or a portion indicating that it is an equal acceleration motion) : Δ1, δ2) appear intermittently and periodically.

  Therefore, according to the motion analysis method and / or motion analysis system of the present invention having the above-described configuration, the above-described animation, that is, “the motion to be analyzed (for example, a rotational motion such as a swing in golf or tennis). ), A function is obtained by extracting a change with respect to time, a spectrum is obtained by Fourier transforming the function, and an image (FIG. 7 to FIG. 7) is obtained from a spectrum (first order spectrum to 30th order spectrum) obtained by Fourier transform. 10) Analyzing the “animation created by combining”, whether it is “shaking the axis” and whether it is rotating at a constant speed (the miracle of a beautiful circle is drawn) Whether or not) can be determined.

Specifically, by determining whether or not the rotation axis can be visually recognized (whether or not the rotating body indicated by the symbol “γ” in FIG. 8 to FIG. 10 can be observed), It can be determined whether or not it is in a “blurred” state.
Alternatively, it is an equal acceleration motion by determining whether or not a portion indicating that it is an equal acceleration motion (or a portion indicating that a circular motion is performed: δ1, δ2) appears intermittently and periodically. It can be determined whether or not.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
Here, in the illustrated embodiment, a digital image is taken at 30 frames per second, and an animation is created from an image composed of the primary spectrum to an image composed of the 30th spectrum using the 30-frame digital image. Yes.

In FIG. 1, which is a functional block diagram showing the configuration of the entire system, the entire analysis system according to the illustrated embodiment is denoted by reference numeral 10. The analysis system 10 includes a photographing unit 14, a system main body 20, and a display unit 40 (display or the like).
The system body 20 includes a storage unit 22 such as a database, a sorting unit 24, a function extraction unit 26, a Fourier transform unit 28, and an animation creation unit 30.

The photographing unit 14 photographs the motion (for example, golf swing) of the exerciser P, who is the subject, and records it in the storage unit 22 as a digital image.
As described above, in the illustrated embodiment, shooting is performed at a speed of 30 frames per second. In the illustrated embodiment, an animation is created using 30 frames of digital images, so that the storage unit 22 stores 30 frames of digital images (frames No. 0 to No. 29: see FIG. 5). The

  The sorting unit 24 has a function of sorting recorded digital images in units of pixels (pixels) (see FIG. 6). For the sorting function itself, a conventionally known technique can be applied as it is.

  The function extraction unit 26 extracts a change with respect to time of the image (for example, how the green color of the pixel has changed over time) in each pixel sorted by the sorting unit 24, and the time is extracted. -Find the function F (t) of the image change. For the function for obtaining the time-image change function F (t), a conventionally known technique may be applied as it is.

  The Fourier transform unit 28 performs a Fourier transform on the time-image change function F (t) obtained by the function extraction unit 26. Conventionally known techniques can be applied as they are to the function itself for performing the Fourier transform.

The animation creation unit 30 synthesizes the primary spectrum obtained as a result of the Fourier transform for all the pixels, and creates an image composed of the primary spectrum as shown in FIG. Hereinafter, an image composed of the secondary spectrum (FIG. 8) to an image composed of the 30th order spectrum (FIG. 10) is created. And first, the image consisting of the primary spectrum (Fig. 7)
An animation displayed in the order of an image consisting of a primary spectrum (FIG. 7) to an image consisting of a 30th order spectrum (FIG. 10) is arranged in the order of an image consisting of a low order spectrum → an image consisting of a high order spectrum. .

The display unit 40 displays the animation displayed in the order of the image composed of the primary spectrum to the image composed of the 30th order spectrum created by the animation creation unit 30.
Here, the display unit 40 can also display a digital image captured by the imaging unit 14 (see FIG. 5), a digital image sorted by the sorting unit 24 (FIG. 6), and the like.

Next, an analysis method according to the illustrated embodiment will be described with reference to FIG.
First, in step S <b> 1 of FIG. 2, the shooting unit 14 captures an action of the athlete P (for example, a golf swing). The photographed operation is recorded as a digital image in the storage unit 22 (step S2).
As described above, in the illustrated embodiment, the captured motion is recorded in 30 frames (frame No. 0 to frame No. 29) (see FIG. 5). Frame No. 0 to frame No. 29 are arranged in time series.

  In step S3, the data of the digital images (30 frames: frame No. 0 to No. 29) stored in the storage unit 22 are sequentially called by the sorting unit 24, and each of the 30 frames of digital images is displayed in FIG. As shown in FIG.

When sorting is completed for all 30 frames (when step S3 is completed), in the function extraction unit 26, the frame No. 0-No. For the same pixel at 29, a change with respect to time is extracted to obtain a function F (t) of the change (step S4).
Here, frame No. 0-No. 29 are arranged in the order of passage of time. 0-No. A change in the same pixel at 29 indicates that the pixel changes over time. That is, in step S4, an image (for example, green) is displayed for each pixel. 0 → No. It is determined as a function of time-image change F (t) how it changes as it advances in the order of 29.

In the illustrated embodiment, the change of the green signal in the pixel is used as the change of the pixel. This is because, in a normal digital camera using a CCD, the color filter for each pixel has the largest number of green color filters, and as a result, the resolution of green is the highest.
Here, in step S4, the function extraction unit 26 can extract a change in the color reflected light intensity vector with respect to time, and obtain a function indicating the change.

If the function F (t) of the green signal change with respect to the time of the same pixel is obtained, the function is Fourier transformed (step S5).
By performing the Fourier transform, the change of the green signal with respect to time is converted into the change of the spectrum with respect to the frequency.

  “N” indicating the order of the spectrum is set to 1 (step S6), and the animation creation unit 30 synthesizes and stores an image having the primary spectrum as shown in FIG. 7 from the primary spectrum in all pixels. Recording is performed in the unit 22 (step S7).

Then, it is determined whether or not “n = 30”, in other words, whether or not the image synthesized in step S7 is an image composed of a 30th-order spectrum (step S8).
If it is not “n = 30” (NO in step S8), the value of “n” is incremented by 1 (step S9), and step S7 is repeated.
That is, in step S7, starting from the synthesis of the image composed of the primary spectrum, the image is synthesized in the order of the spectrum from the image composed of the lower order spectrum to the image composed of the higher order spectrum. All of the images consisting of the image to the 30th order spectrum are synthesized and recorded in the storage unit 22 (NO in step S8).

  Here, an example of an image consisting of the secondary spectrum is shown in FIG. 8, an example of an image consisting of the 15th order spectrum is shown in FIG. 9, and an example of an image consisting of the 30th order spectrum is shown in FIG. Has been.

In step S7, if all the images (FIG. 7) composed of the primary spectrum (FIG. 10) (FIG. 10) composed of the primary spectrum are synthesized by the animation creating unit 30 (YES in step S8), An animation that changes from an image composed of the next spectrum (FIG. 7) to an image composed of the 30th order spectrum (FIG. 10) is created (step S10).
Steps S <b> 6 to S <b> 10 are processes in the animation creation unit 30.

  If an animation that changes from an image composed of the primary spectrum to an image composed of the 30th order spectrum in sequence is created, the animation is displayed on the display 40, and the motion photographed in step S1 is analyzed (step S1). S11).

The analysis in step S11 is shown in FIGS.
In FIG. 3, first, an animation of the frequency and spectrum is observed (step S21), and it is determined whether or not the rotation axis can be confirmed in the animation (step S22).
Specifically, it is determined whether or not the rotator γ in FIGS. 8 to 10 can be observed.
According to the inventor's research, in the movement of the athlete P (for example, golf swing), if the rotation axis is not shaken (generally, it is judged as an excellent form swing), the movement of the athlete P In the meaning corresponding to the body, even in an image composed of a higher-order spectrum, an area indicated by reference numeral γ in FIGS. 8 to 10 and an area showing a rotating body are observed. On the other hand, when the rotation axis is blurred (generally, it is determined that the form is inferior), the region indicated by the symbol γ in FIGS. 8 to 10 is not observed.

  If the rotation axis can be confirmed (in other words, if a region indicated by the symbol γ is observed in FIGS. 8 to 10) (YES in step S22), it is determined that the axis is not shaken (step S23). If the rotation axis cannot be confirmed (in other words, when the region indicated by the symbol γ in FIGS. 8 to 10 is not observed) (NO in step S22), it is determined that the axis is shaken.

  In FIG. 4, the motion photographed in step S <b> 1 in FIG. 2 is analyzed as “whether or not a uniform circular motion is being performed?”.

In FIG. 9 showing an example of an image having a 15th-order spectrum, a portion δ1 related to the movement of the golf ball appears. The portion corresponding to δ1 does not appear in FIG. 8 showing an example of an image having a secondary spectrum, but appears in FIG. 10 showing an example of an image having a 30th order spectrum (δ2).
As shown in δ1 and δ2, in the animation of the image composed of the primary spectrum (FIG. 7) to the image composed of the 30th order spectrum (FIG. 10), the portion that appears intermittently and periodically becomes intermittent as the order increases. If it appears at, it indicates that a uniform acceleration motion (a so-called “clean” circular motion) is being performed.

FIG. 4 determines whether or not a uniform acceleration motion (clean circular motion) is being performed based on whether or not a portion such as δ1 or δ2 (a spectrum indicating circular motion) appears intermittently and periodically.
In FIG. 4, first, an animation of the frequency and the spectrum is observed (step S31), and it is determined whether or not the spectrum showing the circular motion can be regularly observed in the animation (step S32).

If the spectrum indicating the circular motion can be observed regularly (YES in step S32), it is determined that the form is performing a uniform acceleration motion (step S33).
If the spectrum indicating the circular motion cannot be regularly observed (NO in step S32), it is determined that the form does not perform the uniform acceleration motion.

Forms in physical movement vary from person to person, and there are cases where “shaking the axis” does not immediately mean “poor form”. Similarly, there is a case where it can be said that the motion is uniform acceleration (clean circular motion) and is not bad because it is not uniform acceleration motion (clean circular motion).
Therefore, in FIG. 3 and FIG. 4, the result of the analysis is whether the form is “unsharp” (FIG. 3) or “is performing a constant acceleration motion (clean circular motion)”. Whether or not there is (FIG. 4).

  In that sense, the determination of whether or not “the rotation axis can be confirmed” in FIG. 3 (or whether or not an area as indicated by the symbol γ in FIGS. 8 to 10 is observed) (step S22) and subsequent steps. The determination (steps S23 and S24) and the determination of whether or not “a spectrum showing a circular motion can be observed periodically” in FIG. 4 (step S32) and the subsequent determination (steps S33 and S34) are performed on the software. It can be processed, but is preferably done by an experienced instructor.

  Although not clearly shown, both the analysis shown in FIG. 3 and the analysis shown in FIG. 4 can be performed. In that case, the analysis shown in FIG. 3 and the analysis shown in FIG. 4 may be performed simultaneously in parallel. Alternatively, after one of the analyzes is performed, the other analysis may be performed.

In the illustrated embodiment described above, the photographing unit 14 is used to photograph a motion to be analyzed, for example, a rotational motion such as a swing in golf or tennis as a 30-frame digital image.
The system main body 20 obtains a function by extracting a change with respect to time from the captured 30-frame digital image, obtains a spectrum by performing Fourier transform on the function, and obtains a spectrum (primary spectrum to 30 obtained by Fourier transform). An animation is created by synthesizing images (FIGS. 7 to 10) from the next spectrum.
Then, by analyzing the animation, it is possible to determine whether the rotation is “shaking the axis” and whether a constant-speed rotation is being performed (whether a beautiful miracle is drawn). It can be judged.

Specifically, it is determined whether or not the rotation axis can be visually recognized based on whether or not a region (region showing a rotating body) indicated by a symbol γ in FIGS. 8 to 10 can be observed. Thereby, it can be determined whether or not the rotational movement is in a so-called “shaking shaft” state.
Alternatively, it is determined whether or not the portion is an isoacceleration motion by determining whether or not a portion indicating the isoacceleration motion (for example, a portion such as δ1 in FIG. 9 or δ2 in FIG. 10) appears intermittently and periodically. It can be determined whether or not.

  Here, since the photographing unit 14 can use an inexpensive device such as a home digital video, photographing a rotational motion (a golf swing in the illustrated example) to be analyzed is a specific one. There is no need to perform it at a place, and it is not necessary to attach “markers” as conventionally used to various parts of the body.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, in the illustrated embodiment, the operation to be determined is a 30-frame digital image, but the number of frames can be freely increased or decreased.
The animation is created by animation of an image composed of a primary spectrum to an image composed of a 30th-order spectrum, but it is possible to use only an image composed of a lower-order spectrum (for example, operation It is also possible to use images with a higher order spectrum (when the operation speed is high).
Further, in the illustrated embodiment, a golf swing is illustrated, but the analysis as described in the illustrated embodiment is performed for tennis swing, baseball pitching, and other rotational movements about the body. I can do it.

Functional block diagram showing the configuration of the entire analysis system according to the embodiment The flowchart which shows the analysis method which concerns on embodiment The flowchart which shows an example of the analysis of the operation | movement which rotates a body. The flowchart which shows the example of analysis different from FIG. Explanatory drawing which shows 1 process of an analysis. Explanatory drawing which shows the process different from FIG. The figure which shows an example of the figure which consists of a primary spectrum. The figure which shows an example of the figure which consists of a secondary spectrum. The figure which shows an example of the figure which consists of a 15th-order spectrum. The figure which shows an example of the figure which consists of a 30th order spectrum.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Analysis system 14 ... Imaging unit 20 ... System main body 22 ... Storage unit 24 ... Sorting unit 26 ... Function extraction unit 28 ... Fourier transform unit 30 ... Animation creation Unit 40 ... Display unit P ... Subject γ ... Area indicating rotating body δ1, δ2 ... Parts related to the movement of the golf ball

Claims (4)

  A step of photographing an operation to be analyzed and recording it as a digital image, a step of extracting a change with respect to time of the recorded digital image and expressing it as a function, a step of obtaining a spectrum by Fourier transforming the function, The process of synthesizing an image from the spectrum obtained by Fourier transform, the process of creating an animation by arranging the image obtained from the lower order spectrum to the image obtained from the higher order spectrum, and shooting using the animation And a step of determining the performed operation.   The step of determining the captured motion is a step of determining whether or not the rotation axis can be confirmed in the animation created by arranging the images obtained from the low-order spectrum to the images obtained from the high-order spectrum. And a step of determining that the shaft is not shaken when the rotation axis is confirmed and a step of determining that the shaft is shaken when the rotation axis is not confirmed. The operation analysis method according to claim 1.   In the process of determining the captured motion, the part showing the circular motion in the animation created by arranging the image obtained from the lower order spectrum to the image obtained from the higher order spectrum is intermittent. And a step of determining whether or not it appears periodically, a step of determining that a uniform acceleration motion is being performed when a portion showing that the circular motion appears intermittently and periodically, and a circular motion 2. The motion analysis method according to claim 1, further comprising a step of determining that the uniform acceleration motion is not performed when a portion indicating that the motion is performed does not appear intermittently and periodically.   An imaging unit that captures the motion to be analyzed, a storage unit that records a digital image of the captured motion, and a function extraction that calculates a change in time of the recorded digital image and calculates a function indicating the change A unit, a Fourier transform unit that obtains a spectrum by Fourier transforming the function calculated by the function extraction unit, and an animation creation unit that creates an animation by synthesizing an image from the spectrum obtained by the Fourier transform The motion analysis system.

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