VIBRATION CONTROL APPARATUS, VIBRATION CONTROL PROGRAM, AND VIBRATION CONTROL METHOD

A vibration control apparatus configured to control a vibration generated by a vibration apparatus, using a signal, includes processer circuitry, and an energy controller configured to convert a waveform of the signal while maintaining energy of the signal.

FIELD

The technology described herein relates to a vibration control apparatus, a vibration control program, and a vibration control method.

BACKGROUND

In recent years, in the fields of smartphones, gaming machines, Virtual Reality (VR) apparatuses, robotic steering support, and the like, the enhancement of vibration feedback has been advanced. Specifically, a vibration device capable of presenting realistic tactile sensation by reproducing vibration in a wide frequency band has been developed.

Non-Patent Document 1: Hideto Takenouchi, Nan Cao, Hikaru Nagano, Masashi Konyo, Satoshi Tadokoro, the 2017 IEEE/SICE International Symposium on System Integration “Extracting Haptic Information from High-Frequency Vibratory signals Measured on a Remote Robot to Transmit Collisions with Environments”, pp.968-973, December, 2017

Non-Patent Document 3: Nan Cao, Hikaru Nagano, Masashi Konyo, Satoshi Tadokoro, the 27th IEEE International Symposium on Robot and Human Interactive Communication “Sound reduction of vibration feedback by perceptually similar modulation”, August, 2018

However, an attempt to present, for example, a high frequency vibration of 300 Hz or more, may cause device problems, sensory perception problems, and auditory noise problems. Since the amplitude of the vibrator is small in a high frequency band, it is not easy for a type of a device utilizing resonance to generate vibrations of both a high frequency band and a low frequency band. In addition, sufficient amplitude is required to make a human perceive vibration because human perception peaks at 200 to 300 Hz and weakens at the vibration frequency more than the peak. In addition, in the range of the frequency exceeding about 300 Hz, vibration comes to be audible as sound. For example, an attempt to generate a vibration in combination with a music or movie content is made, the vibration may be recognized as noise that disturbs the sound source of the music or movie content.

SUMMARY

In one aspect, a vibration control apparatus configured to control a vibration generated by a vibration apparatus, using a signal, the vibration controlling apparatus comprising: processer circuitry; and an energy controller configured to convert a waveform of the signal while maintaining energy of the signal.

In one aspect, a vibration of a high frequency band that are easily perceived by human can be generated.

DESCRIPTION OF EMBODIMENT(S)

Hereinafter, an embodiment will now be described with reference to the accompanying drawings. However, the following embodiment is merely illustrative and is not intended to exclude the application of various modifications and technologies not explicitly described in the embodiment. Namely, the present embodiment can be variously modified and implemented without departing from the scope thereof.

Further, each of the drawings does not intend to include only the element appearing therein and therein to the elements illustrated in the drawing. Hereinafter, in the drawings, same reference numbers designate the same or similar parts, unless otherwise specified.

FIG. 1is a block diagram schematically illustrating an example of the configuration of a vibration generating system100according to an embodiment.

The vibration generating system100includes a vibration control apparatus1, a Digital Analog Converter (DAC)2, a high-frequency vibration31, a low-frequency vibration32, an earphone (L)41, and an earphone (R)42.

The DAC2, which may be referred to as Universal Serial Bus(USB) audio, converts a digital signal input from the vibration control apparatus1into an analog signal. Then, the DAC2outputs the analog signal after the conversion to the high-frequency vibration31, the low-frequency vibration32, the earphone (L)41and the earphone (R)42. In the subsequent stage of the DAC2, a non-illustrated amplifier for driving the high-frequency vibration31, the low-frequency vibration32, the earphones (L)41, and the earphones (R)42may be provided.

The low-frequency vibration32shown inFIG. 1is an example of a first vibration apparatus and generates vibration due to signal components less than a predetermined frequency. The high-frequency vibration31shown inFIG. 1is an example of a second vibration apparatus and generates vibration due to a signal component of the predetermined frequency or higher. The low-frequency vibration32may be omitted in the vibration generating system100. In that case, vibration due to signal components below a predetermined frequency may be generated from the high-frequency vibration31, or vibration due to signal components below the predetermined frequency may not be generated in the vibration generating system100.

The predetermined frequency for separating a signal component of the vibration output from the low-frequency vibration32and a signal component of a signal output from the high-frequency vibration31may be a frequency in a range from 80 Hz to 400 Hz.

The earphone (L)41generates a sound to be input into the left ear of a person among a stereo sound source. The earphone (R)42generates a sound to be input into the right ear of a person among the stereo sound source. The earphone (L)41and the earphone (R)42may be omitted in the vibration generating system100. The earphone (L)41and the earphone (R)42may be of a common shape to generate a monaural sound source. Further alternatively, the vibration generating system100may include a speaker in place of the earphone (L)41and the earphone (R)42, or may output sound from a sound source of three or more channels.

The vibration control apparatus1includes a Central Processing Unit (CPU)11, a memory12, and a storing apparatus13.

The vibration control apparatus1according to an example of the present embodiment may convert acoustic information such as music, movies, sounds, and the like into a tactile signal. In the frequency range exceeding about 300 to 400 Hz, vibration becomes audible as a sound, resulting in noise. Therefore, a vibration sensible apparatus for such as music and moving images in the related art removes a high-frequency band by applying a low-pass filter at about several hundred Hz. In contrast, the vibration control apparatus1of one example of the present embodiment converts a waveform of a high-frequency band into a waveform of a different frequency of a low-frequency band, and outputs the waveform of the low-frequency band obtained by the conversion.

Further, the vibration control apparatus1of one example of the present embodiment may modulate the high-frequency vibration generated when the robot contacts an object to a frequency band that can be perceived by human. Transmitting the vibration generated when the robot contacts an object to a remote operator makes the operator possible to grasp the strength of the collision with the object and the situation of the friction. When contacting an object, a robot like a construction robot which grasps a metal casing sometimes generates a vibration of a band which a human does not perceive. With the foregoing situation in view, the vibration control apparatus1of one example of the present embodiment modulates the frequency band of an output signal.

Furthermore, the vibration control apparatus1according to an example of the present embodiment may be applied to a chair, a suit, a headset, or the like including a vibration apparatus.

The memory12is a storing apparatus including a Read Only Memory (ROM) and a Random Access Memory (RAM).

The storing apparatus13is a apparatus that readably and writably stores data, and may be exemplified by a Hard Disk Drive (HDD), a Solid State Drive (SSD), and a Storage Class Memory (SCM). The storing apparatus13stores the generated teacher data, a learning model, and the like.

The CPU11is a processing apparatus that performs various controls and arithmetic operations, and achieves various functions by executing the Operating System (OS) and a program stored in the memory12. Specifically, the CPU11may function as a frequency removing controlling unit111, a time-division controlling unit112, an energy controlling unit113, and a signal outputting unit114as shown inFIG. 1.

The CPU11is an example of a computer, and illustratively controls the operation of the entire vibrating control apparatus1. The apparatus that controls the operation of the entire vibration control apparatus1is not limited to the CPU11, and may be, for example, any one of an MPU and a DSP, an ASIC, a PLD, an FPGA, and a dedicated processor. The apparatus that controls the operation of the entire vibration control apparatus1may be a combination of two or more of a CPU, an MPU and a DSP, an ASIC, a PLD, an FPGA, and a dedicated processor. Note that an MPU is an abbreviation of a Micro Processing Unit, a DSP is an abbreviation of a Digital Signal Processor, and an ASIC is an abbreviation of Application Specific Integrated Circuit. A PLD is an abbreviation of a Programmable Logic Device, and an FPGA is an abbreviation of a Field Programmable Gate Array.

The frequency removing controlling unit111removes a first signal component having a frequency equal to or lower than the predetermined frequency.

The time-division controlling unit112divides a second signal component except for the first signal component removed by the frequency removing controlling unit111at intervals of a predetermined time.

The energy controlling unit113converts the waveform of the second signal component while maintaining the energy of the second signal component at every predetermined time divided by the time-division controlling unit112.

The signal outputting unit114outputs, in addition to the second signal component after the conversion of the waveform by the energy controlling unit113, the first signal component removed by the frequency removing controlling unit111.

FIG. 2is a graph showing waveform of a signal before and after conversion by the vibration control apparatus1shown inFIG. 1.

The frequency band can be modified by replacing the waveform of the frequency band to another waveform having equivalent energy, considering human perception characteristics to a high-frequency vibration and focusing on vibration energy correlated with the human perception characteristics, rather than the waveform itself, for a high-frequency band. In the example shown inFIG. 2, a waveform of the reference number A1is converted into a waveform of the reference number A2.

An arbitrary successive vibration signal can be converted into an arbitrary waveform while maintaining equivalent tactile sensation felt by human or allowing a high-frequency band, which is not easily felt by human, to be felt, by time-dividing the signal at appropriate intervals considering the human perception characteristic and converting the divided signal in a unit of each divided segment into vibration energy.

Proper selection of the frequency of the vibration after the conversion makes it possible to efficiently drive a vibrator according to the response range of the vibrator, to reduce the auditory noise, and to convert the frequency to an arbitrary sound source.

It is said that the human perception to a vibration is up to about 1 kHz. Therefore, vibrations above 1 kHz are often ignored. On the other hand, it is known that, if a vibration of 1 kHz or more is an amplitude modulated wave whose amplitude fluctuates in a band to the extent felt by human, the envelope component of the vibration can be perceived.

On the other hand, a vibration energy model (see, for example, the Cited Document 4) is known as human perception characteristics to a high-frequency vibration of about 100 Hz or more. Therefore, it has been found that the vibration is not distinguished even if the carrier frequency of the amplitude modulated wave is replaced while maintaining the high-frequency vibration energy (see, for example, Cited Document 2 and Cited Document 3). However, even if the vibration energy is maintained, the envelope component of the vibration can be perceived as a difference in tactile information in some cases as described above, and the perceivable range has not been investigated. In Cited document 2, although a method of converting a signal by time division based on vibration energy has been devised, a method of maintaining a low-frequency component has not been considered.

FIG. 3is a graph showing the discriminability of a vibration by human.FIG. 4is a diagram illustrating a sample waveform of the vibration used in the three-alternative forced choice discrimination experiment conducted to determine the discriminability shown in the graph ofFIG. 3.

The graph shown inFIG. 3is obtained by investigating the human perception discriminability while maintaining vibration energy on the premise of a vibration energy model that has previously known (for example, see Cited Reference 4). The reference number B1and the reference number B2inFIG. 4represent the same waveform, the reference number B3inFIG. 4represents a different waveform. The subject is caused to compare the constant amplitude fluctuation indicated by the reference numbers B1and B2inFIG. 4with the amplitude modulated stimulus indicated by the reference number B3, and to answer which is the amplitude modulated wave. InFIG. 3, the correct answer rate obtained in the three-alternative forced choice discrimination experiment is represented by Sensitivity (d′: d-prime), which is a discriminability index based on the signal-detection theory, and d′ of 1 or less means that the correct answer rate is less than about 60%.

According to the graph shown inFIG. 3, the upper limit value of the discriminable frequency for the envelope component is about 80 to 125 Hz. It is also shown that there is no need to maintain the envelope components above this frequency upper limit and that stimuli are not discriminated if the carrier frequency of amplitude modulated wave is replaced while maintaining the vibration energy.

As mentioned above, when the energy fluctuates in the low frequency range even if the vibration energy is maintained, the fluctuation may be perceived as a difference in tactile information, but its perceivable range has not been investigated. Then, based on the finding that the upper limit of perceivable low-frequency fluctuation is approximately 80 to 125 Hz, the vibration energy is converted while maintaining the low-frequency component by two countermeasures (see countermeasures [1] and [2] to be described below).

FIG. 5is a graph illustrating a waveform of the signal before and after the conversion for each segment by the vibration control apparatus1shown inFIG. 1.

Since the human perception to a high frequency is based on vibration energy rather than the waveform itself, the high frequency is perceived as the same sensation when the vibration energy is maintained. However, if the vibration energy fluctuates in the range of about 80-125 Hz or less, it is necessary to reproduce the fluctuation of vibration energy.

Therefore, in one example of the present embodiment, as a means for maintaining the fluctuation of the vibration energy of a predetermined frequency (e.g., about 80 to 125 Hz) or less, the vibration is time-divided in the section of for example, about 80 to 200 Hz, the vibration energy is obtained for each segment, and the vibration is converted into a vibration having a different carrier frequency.

In the example shown inFIG. 5, the original vibration signal represented by the reference number C1is converted into a converted signal represented by the reference number C2such that the converted signal has the same energy as the energy of the original vibration signal in the same time segment.

The width of the time division (in other words, the division width) may be set to such an extent that the energy fluctuation of 80 to 125 Hz or less can be expressed (in other words, to such an extent that the peaks of the fluctuation match) (countermeasure [1]). The frequency of the division width may be 80 to 125 Hz or more, but an excessive short division width worsens the estimation accuracy of the vibration energy of the longer cycle than the division width. Therefore, by the following countermeasure [2], the waveform of which energy is unable to be estimated is output without any modification.

In addition, a component having a frequency equal to or lower than the predetermined frequency may be extracted and the extracted component may be presented as a stimulus vibration without any modification (countermeasure [2]). Although the predetermined frequency may be 80 to 125 Hz or more, a component of a predetermined frequency component or more may be represented by the energy controlling unit113of the second signal component. This makes the frequency selection possible to have arbitrary. However, if the predetermined frequency is set to excessively high, a problem of noise may occur or a wide-band vibration apparatus may be required.

According to the above-described countermeasure [1] and countermeasure [2], a predetermined frequency may be about 80 to 400 Hz. 400 Hz is an upper limit in terms of a noise problem and the performance of the vibration apparatus.

The setting of the predetermined frequency also involves the selection of the carrier frequency used when the vibration is converted. Since the peak vibration frequency at which human perception is enhanced is around 200 to 250 Hz, it is practical to use a carrier frequency of about 150 to 400 Hz as a carrier frequency that is not noisy while increasing sensitivity. The carrier frequency may be a constant multiple of the division width. Further, multiple different frequencies may be used as the carrier frequency and may include a high frequency range of 400 Hz or more.

Further, a predetermined frequency for separating the low frequency and high frequency does not have to coincide with the frequency of the division width for calculating the energy.

According to the cited document 4, the compensation energy, which is the vibration energy compensated in order to enhance the human perceivability, can be expressed by the following Expression.

The term A is the amplitude of the separated basis signals gk. The term Tfis the amplitude threshold and is the smallest amplitude that a human can feel in a signal having a frequency f. The term bfis an exponential value and is a nonlinear characteristic in a signal having a frequency f.

FIG. 6is a graph illustrating an amplitude threshold Tfused to calculate compensation energy.

As shown inFIG. 6, the amplitude threshold is different with frequencies, and even a relatively small amplitude can be perceived by a human in the range of about 102to 103Hz, but only a relatively large amplitude can be perceived by a human outside the above range.

FIG. 7is a graph representing of the exponential value bfused to calculate the compensation energy.

The exponential value bfofFIG. 7is an example of using a value obtained by linearly interpolating an exponential value bfof 400 Hz or less, which has been conventionally reported.

FIG. 8is a diagram illustrating use of a window function in the vibration control apparatus1shown inFIG. 1.

As shown in reference number D1, a high-range signal H(t) is input. As shown in the reference number D2, the high-range signal H(t) is divided into frames as signals hi, hi+1, h1+2, . . . for each frame i, i+1, i+2,..., respectively. As shown by the reference number D3, the signal h of each divided frame is separated into multiple basis signals g1, g2, g3. . . . As shown by the reference number D4, scalar values Ei, E1+1, E1+2, obtained by combining the compensation energy of all the basis signals g1, g2, g3are output on the basis of the frequencies f1, f2, f3, . . . that the basis signals g1, g2, g3, . . . have. As shown in the reference number D5, the scalar values Ei, Ei+1, Ei+2, . . . of the vibration energy calculated in respective frames i are converted into vibration waveform having an equivalent vibration energy but having respective different carrier frequencies, and a windowing process using the window function is performed on the amplitudes ai(t), ai+1(t) ai+2(t), . . . of the waveforms. As shown in reference number D6, the frame combination is performed for the first to N-th frames, and the amplitude A(t) of the vibration waveform is output. As shown in the reference number D7, a second vibration waveform S2(t) having a carrier frequency that makes the amplitude to be A(t) is outputted.

FIG. 9is a graph illustrating an example of a combining of a low frequency and a high frequency in the vibration control apparatus1shown inFIG. 1.

The second vibration waveform S2(t) generated from the high-range signal H(t) using the window function ofFIG. 8and indicated by the referenced number E1is combined with a first vibration waveform S1(t) corresponding to the outputted low-range signal L(t) without any modification and indicated by the reference number E2. Thereby, the combined waveform S1(t)+S2(t) represented by the reference number E3is output.

FIG. 10is a graph showing a specific example of the waveform of the signal before and after the conversion by the vibration control apparatus1shown inFIG. 1.

InFIG. 10, the waveform before the conversion (see reference number F1) and the waveform after conversion (see reference number F2) of the sound of the violin are represented in the form of the amplitudes per time.

The sound of high-frequency vibration like violin generates a large amount of auditory noise in the conventional tactile vibration, and when the low-pass filter is applied, the vibration which the human can recognize disappears. For the above, the compensation energy is calculated so that the waveform becomes a waveform of a single wavelength having a carrier frequency of low frequency for each time.

FIG. 11is a block diagram illustrating an example of the functional configuration of the ISM unit101in the vibration control apparatus shown inFIG. 1.

The ISM unit101functions as the time-division controlling unit112, an energy controlling unit113, the energy-to-vibration converting unit114a,and a vibration generating unit114b.In the present embodiment, the ISM unit101controls a vibration including the high-frequency component due to the high-frequency vibration31by using a signal. It is assumed that the high-frequency component of the signal X(t) is about 100 Hz or more, considering the human perception characteristic to vibration energy, but the high-frequency component may be converted into a low-frequency component less than 100 Hz. This makes it possible to emphasize the low-frequency component. The method of controlling a vibration on the basis of the time division of energy of the present disclosure is collectively referred to as ISM.

The time-division controlling unit112time-divides a vibration signal X(t) into N frames, and inputs the signal hiof the i-th time-divided frame into the energy controlling unit113. The number N of frames may be determined by a predetermined cycle and an overlap rate of the windowing process.

The energy controlling unit113calculates the compensation energy eifor the signal hiof the i-th frame, and inputs the calculated compensation energy into the energy-to-vibration converting unit114a.

The energy-to-vibration converting unit114agenerates a signal A(t) obtained by combining the respective compensation energy e1to eNof the first to N-th frames, and inputs the signal A(t) into the second vibration generating unit114b.

The vibration generating unit114boutputs, based on the synthesized signal A(t), a signal waveform S(t).

<B> Example of Operation:

A first embodiment of the generating process of the vibration waveform in the vibration control apparatus1shown inFIG. 1will now be described in accordance with a block diagram (Steps S1to S7) shown inFIG. 12.

A signal removing unit111aand a low-pass filter111bshown inFIG. 12correspond to the frequency removing controlling unit111shown inFIG. 1. The energy-to-vibration converting unit114a,the second vibration generating unit114b, and the first vibration generating unit114cshown inFIG. 12correspond to the signal outputting unit114shown inFIG. 1.

The signal removing unit111agenerates a high-range signal H(t) by removing components of the predetermined frequency or less from the obtained signal X(t) before the conversion, and inputs the high-range signal H(t) into the time-division controlling unit112(Step S1).

The time-division controlling unit112time-divides the high-range signal H(t) into N frames, and inputs the signal hiof the i-th time-divided frame into the energy controlling unit113(Step S2). The number N of frames may be determined by a predetermined cycle and an overlap rate of the windowing process.

The energy controlling unit113calculates the compensation energy eifor the signal hiof the i-th frame, and inputs the calculated compensation energy into the energy-to-vibration converting unit114a(Step S3).

The energy vibration converting unit114agenerates a signal A(t) obtained by combining the respective compensation energy e1to eNof the first to N-th frames, and inputs the signal A(t) into the second vibration generating unit114b(Step S4).

The second vibration generating unit114boutputs the second vibration waveform S2(t) based on the combined signal A(t) (Step S5).

On the other hand, the low-pass filter111binputs a low-range signal L(t), which is obtained by filtering components of the predetermined frequency or less from the obtained signal X(t) before the conversion, into the first vibration generating unit114c(Step S6).

The first vibration generating unit114coutputs a first vibration waveform S1(t) based on the low-range signal L(t) (Step S7).

Next, the energy controlling process shown in Step S3ofFIG. 12will now be detailed in accordance with a block diagram (Steps S11to S14) shown inFIG. 13.

As shown inFIG. 13, the energy controlling unit113functions as a basis signal separation controlling unit113a,a frequency calculating unit113b,an energy compensation parameter calculating unit113c,and a compensation energy calculating unit113d.

The basis signal separation controlling unit113aseparates multiple basis signals g from the signal hiof the time-divided i-th frame, which is the input signal, and inputs the basis signal k-th base signal gkinto the frequency calculating unit113b(Step S11). For example, signals may be separated by, for example, the short-time Fourier analysis, the wavelet analysis, the Empirical Mode Decomposition (EMD) method.

The frequency calculating unit113bcalculates the frequency fkof the k-th basis signal gkby, for example, discrete Fourier analysis or Hilbert Spectrum analysis, and inputs the calculated frequency fkinto the energy compensation parameter calculating unit113c(Step S12).

The compensation energy calculating unit113dcalculates the compensation energy Ipcfor each basis signal gkbased on the exponent value bkand the amplitude threshold value Tkin accordance with Expression 1, and outputs a scalar value eiobtained by summing the compensation energies of all the basis signals gk(Step S14).

Next, description will now be made in relation to an separating process of a low-frequency component in the energy controlling process shown inFIG. 11as a second embodiment of the generating process of the vibration waveform in the vibration control apparatus1shown inFIG. 1in accordance with a block diagram (Step S101to S105) shown inFIG. 14.

As shown inFIG. 14, the energy controlling unit113functions as a basis signal separation controlling unit113a,a frequency calculating unit113b,an energy compensation parameter calculating unit113c,and a compensation energy calculating unit113d,and may also have a function of separating a low-frequency component to a low-frequency component combining unit113g.

The basis signal separation controlling unit113aseparates multiple basis signals g from the signal hiof the time-divided i-th frame, which is the input signal, and inputs the separated k-th basis signals gkinto the frequency calculating unit113b(Step S101). For example, signals may be separated by, for example, the short-time Fourier analysis, the wavelet analysis, the EMD method.

The frequency calculating unit113bcalculates the frequency fkof the k-th basis signal gkby, for example, discrete Fourier analysis or Hilbert Spectrum analysis, and inputs the calculated frequency fkinto the energy compensation parameter calculating unit113c(Step S102).

The compensation energy calculating unit113dcalculates the compensation energy Ipcfor each basis signal gkbased on the exponent value bkand the amplitude threshold value Tkin accordance with Expression 1, and outputs a scalar value eiobtained by summing the compensation energies of all the basis signals gk(Step S104).

The low-frequency component combining unit113ggenerates a low-frequency component L(t) by combining basis signals gkeach having a frequency fksmaller than the predetermined frequency (Step S105).

A sound source including signals of multiple frequency bands is sometimes desired to be presented as a vibration by emphasizing vibration energy of a particular frequency band. Description will now be made in relation to energy controlling units1131and1132serving as modifications applied when a waveform is converted by adjusting the energy of a basis signal present in a predetermined frequency band with reference toFIGS. 15A to 20.

FIG. 15A,FIG. 15BandFIG. 15Care graphs illustrating an example of generating a vibration according to ISM without emphasizing the waveform. InFIG. 15A,FIG. 15BandFIG. 15C, a band corresponding to the waveform of the cymbals (drum) of a high-frequency component from the music of the piano trio and the band corresponding to the waveform of the piano and the bass are shown. InFIG. 15A,FIG. 15BandFIG. 15C, the horizontal axis indicates time [s], the vertical axis indicates frequency [Hz], a dense spectrum has large power, and a thin spectrum has small power.

FIG. 15Ashows, as a distribution of a sound source spectrum, a waveform of the cymbals serving as a high-frequency component shown by a broken line and a waveform of the piano and the bass of a low-frequency component shown by a chain line.

FIG. 15Bshows a spectral distribution (centering at 200 Hz) when the waveform is converted by the ISM.FIG. 15Bextracts all the cymbals, the piano, and the bass as intensities due to the effect of ISM.

FIG. 15Cshows an example in which the waveform is converted into a signal by using the representative frequency of the basis signal, without converting to a signal having a frequency of 200 Hz based on the intensity. This visualizes which frequency band was emphasized.

FIG. 16A,FIG. 16BandFIG. 16Care graphs illustrating a first example in which a high-frequency component is emphasized in and separated from the sound source.FIG. 16A,FIG. 16BandFIG. 16Cshow an example in which cymbals (drum) of a high-frequency component is emphasized and separated from music of a piano trio. InFIG. 16A,FIG. 16BandFIG. 16C, the horizontal axis indicates time [s], the vertical axis indicates frequency [Hz], a dense spectrum has large power, and a thin spectrum has small power.

FIG. 16Ashows, as a distribution of a sound source spectrum, a waveform of the cymbals serving as a high-frequency component shown by a broken line and a waveform of the piano and the bass of a low-frequency component shown by a chain line.

FIG. 16Bshows a spectral distribution (centering at 200 Hz) when the waveform is converted by the ISM. InFIG. 16B, only the intensity of 3000 Hz or more is emphasized by +20 dB (100 times).

FIG. 16Cshows an example in which the waveform is converted into a signal by using the representative frequency of the basis signal, without converting to a signal having a frequency of 200 Hz based on the intensity. This visualizes which frequency band was emphasized. InFIG. 16C, the power of the spectrum of the cymbals is increased.

FIG. 17A,FIG. 17BandFIG. 17Care graphs illustrating a second example in which a high-frequency component is emphasized in and separated from the sound source.FIG. 17A,FIG. 17BandFIG. 17Cshow an example in which cymbals (drum) of a high-frequency component is emphasized in and separated from music of a piano trio. InFIG. 17A,FIG. 17BandFIG. 17C, the horizontal axis indicates time [s], the vertical axis indicates frequency [Hz], a dense spectrum has large power, and a thin spectrum has small power.

FIG. 17Ashows, as a distribution of a sound source spectrum, a waveform of the cymbals serving as a high-frequency component shown by a broken line and a waveform of the piano and the bass of a low-frequency component shown by a chain line.

FIG. 17Bshows a spectral distribution (centering at 200 Hz) when the waveform is converted by the ISM. InFIG. 17B, the intensity of 3000 Hz or more is emphasized by +20 dB (100 times), while the intensity of 1000 Hz or less is emphasized by −10 dB ( 1/10 times).

FIG. 17Cshows an example in which the waveform is converted into a signal by using the representative frequency of the basis signal, without converting to a signal having a frequency of 200 Hz based on the intensity. This visualizes which frequency band was emphasized. InFIG. 17C, the power of the spectrum of the cymbals is increased.

FIG. 18A,FIG. 18BandFIG. 18Care graphs illustrating an example in which a low-frequency component emphasized in and separated from a sound source.FIG. 18A,FIG. 18BandFIG. 18Cshow an example in which the piano and the bass of the low-frequency component is emphasized and separated from the music of a piano trio. InFIG. 18A,FIG. 18BandFIG. 18C, the horizontal axis indicates time [s], the vertical axis indicates frequency [Hz], a dense spectrum has large power, and a thin spectrum has small power.

FIG. 18Ashows, as a distribution of a sound source spectrum, a waveform of the cymbals serving as a high-frequency component shown by a broken line and a waveform of the piano and the bass of a low-frequency component shown by a chain line.

FIG. 18Bshows a spectral distribution (centering at 200 Hz) when the waveform is converted by the ISM. InFIG. 18B, the intensity of 1000 Hz or less is emphasized by +10 dB (10 times).

FIG. 18Cshows an example in which the waveform is converted into a signal by using the representative frequency of the basis signal, without converting to a signal having a frequency of 200 Hz based on the intensity. This visualizes which frequency band was emphasized. InFIG. 18C, the power of the spectrum of the piano and the base is increased.

A first modification of the energy controlling process illustrated inFIG. 11will be described in accordance with a block diagram (Steps S41to S45) illustrated inFIG. 19.

As shown inFIG. 19, the energy controlling unit1131functions as a gain calculating unit113ein addition to the basis signal separation controlling unit113a,the frequency calculating unit113b,the energy compensation parameter calculating unit113c,and the compensation energy calculating unit113dshown inFIG. 13.

The basis signal separation controlling unit113aseparates multiple basis signals g from the signal hiof the time-divided i-th frame, which is the input signal, and inputs the separated k-th basis signal gkinto the frequency calculating unit113b(Step S41). For example, signals may be separated by, for example, the short-time Fourier analysis, the wavelet analysis, the EMD method.

The frequency calculating unit113bcalculates the frequency fkof the k-th basis signal gkby, for example, discrete Fourier analysis or Hilbert Spectrum analysis, and inputs the calculated frequency fkinto the energy compensation parameter calculating unit113c(Step S42).

The gain calculating unit113eoutputs gain values Gkpredetermined for respective frequency bands in accordance with the calculated frequency fkof the basis signals gk(Step S44). If the energy is to be emphasized, the gain is set to Gk>1, and if the energy is to be suppressed, the gain is set to 0≤Gk<1. The adjustment of the energy by emphasizing or suppressing may be performed on a single frequency band or on multiple frequency bands. Further alternatively, the adjustment of the energy may be performed on the entire frequency band input into the energy controlling unit1131.

The compensation energy calculating unit113dcalculates compensation energy Ipcadjusted with a gain using the following Expression 2 for the amplitude A of the separated basis signal gk, and outputs a scalar value eiobtained by summing compensation energy of all the basis signals gk(Step S45).

A second modification of the energy controlling process illustrated inFIG. 11will be described in accordance with a block diagram (Steps S51to S55) illustrated inFIG. 20.

As shown inFIG. 20, the energy controlling unit1132functions as a gain calculating unit113eand a signal source recognizing unit113fin addition to the basis signal separation controlling unit113a,the frequency calculating unit113b,the energy compensation parameter calculating unit113c,and the compensation energy calculating unit113dshown inFIG. 13.

The basis signal separation controlling unit113abasis signals multiple basis signals g from the signal hiof the time-divided i-th frame, which is the input signal, and inputs the basis signald k-th basis signal gkinto the frequency calculating unit113b(Step S51). For example, signals may be basis signald by, for example, the short-time Fourier analysis, the wavelet analysis, the EMD method.

The frequency calculating unit113bcalculates the frequency fkof the k-th basis signal gkby, for example, discrete Fourier analysis or Hilbert Spectrum analysis, and inputs the calculated frequency fkinto the energy compensation parameter calculating unit113c(Step S52).

The signal source recognizing unit113festimates a recognition candidate from, for example, the inputted signals hiand the history of hion the basis of the set signal characteristics, and recognizes a signal source that the basis signal gkbelongs to, and outputs the results of the recognition in the form of ID (identifier) or the like (Step S54). The signal source recognizing unit113fmay prepare a recognizer in advance by machine learning or the like. For example, the characteristics of many instruments are learned by deep learning, and the candidates (e.g., piano, bass, drum) for which instruments are included in the present input signal hi(or, if the input signal hiis too short, the history of each of multiple input signals hi) may be estimated, and the instrument that the basis signal gkpertains to may be identified.

The gain calculating unit113eoutputs gain values Gkfor respective predetermined frequency bands in accordance with the IDs specified by the signal source recognizing unit113f(Step S55). If the energy is to be emphasized, the gain is set to Gk>1, and if the energy is to be suppressed, the gain is set to 0≤Gk<1. The adjustment of the energy by emphasizing or suppressing may be performed on a single frequency band or on multiple frequency bands. Further alternatively, the adjustment of the energy may be performed on the entire frequency band input into the energy controlling unit1132.

The compensation energy calculating unit113dcalculates compensation energy Ipcadjusted with a gain using Expression 2 for the amplitude A of the basis signald basis signal gk, and outputs a scalar value eiobtained by summing compensation energy of all the basis signals gk(Step S56).

Next, an energy combining process shown in Step S4ofFIG. 11will be detailed with reference to a block diagram (Steps S21to S23) shown inFIG. 21.

An energy-to-vibration converting unit114afunctions as an energy equivalent converting unit1141a,a windowing processing unit1142a,and a frame combining unit1143a.

As shown inFIG. 21, the energy equivalent converting unit1141aconverts the scalar values eiof the vibration energy calculated in respective frames i into vibration waveforms having the same vibration energy but different carrier frequencies, and outputs the amplitudes ai(t) of the waveforms to the windowing processing unit1142a(Step S21).

The windowing processing unit1142aperforms a windowing processing using the window function ofFIG. 8on the amplitudes ai(t) of the respective input frames i, and inputs the processing result to the frame combining unit1143a(Step S22).

The frame combining unit1143aperforms frame combining on the input from the windowing processing unit1142afor the first to N-th frames, and outputs the amplitude A(t) of the vibration waveform (step S23).

Next, the details of a generating process of the compensated vibration waveform shown in Step S5ofFIG. 11will be described in accordance with a block diagram (Steps S31and S32) shown inFIG. 22.

As shown inFIG. 22, the second vibration generating unit114bfunctions as an amplitude-to-vibration converting unit1141band a waveform outputting unit1142b.The second vibration generating unit114bhas an input signal A(t) and outputs a sine wave having a carrier frequency. The phase of the generated waveform may be controlled such that the vibration is smoothly connected.

The amplitude-to-vibration converting unit1141bconverts the input amplitude A(t) into a vibration (Step S31).

The waveform outputting unit1142boutputs the sine wave S2(t) having the carrier frequency so that the amplitude becomes A(t) (Step S32).

According to the vibration control apparatus1, the signal control program, and a vibration control method according to the example of the embodiment can bring the following effects and advantages, for example.

The time-division controlling unit112divides a signal for controlling a vibration by the vibration apparatus at intervals of a predetermined time. The energy controlling unit1131and1132each convert the waveform of the second signal component at every predetermined time divided by the time-division controlling unit112. The energy controlling unit1131and1132each convert the waveform of a signal having a specific frequency band by adjusting the energy of the signal, and convert the waveform of a signal having a frequency band except for the specific frequency band while maintaining the energy of the signal. Further, the energy control units1131and1132may each convert the waveform of a signal, which is extracted on the basis of a particular feature value, by adjusting the energy the signal, and convert the waveform of a signal, which is not extracted on the basis of the particular feature value, into a waveform having a frequency band different from the frequency of the signal while maintaining energy of the signal. This can generate a vibration of the high-frequency band that is easy to perceive by human, and also a vibration corresponding to an arbitrary signal source can be emphasized or suppressed and then output. Accordingly, the energy can be adjusted according to the sensitivity and preference to a vibration of the individual person. In addition, the generation of auditory noise generated by the vibration of a high frequency band can be suppressed.

The energy controlling unit1131and1132each adjust energy of a signal of the specific frequency band by multiplying the energy and a gain value determined according to the specific frequency band. This makes it possible to emphasize and suppress a vibration corresponding to an arbitrary signal source with ease.

The gain value may be determined based on another feature of the signal, such as ID, as well as the frequency. This facilitates the emphasis or suppression of a vibration corresponding to a particular signal source.

The time-division controlling unit112divides the component of the signal at the intervals having a lower limit of 80 Hz. This makes it possible to efficiently extract a signal component of a high-frequency band which is a conversion target.

The signal outputting unit114outputs, for a signal included in a vibration and having a frequency equal to or less than a predetermined frequency, a first signal component that does not undergo the waveform conversion by the energy controlling unit1131or1132and a second signal component that undergoes the waveform conversion by the energy controlling unit1131or1132. Accordingly, the signal component of the low frequency band that is not the conversion target can be output to the vibration apparatus without being modified.

The predetermined frequency separating the first signal component and the second signal component ranges from 80 Hz to 400 Hz. Thereby, it is possible to appropriately convert the waveform of the high-frequency component.

For the first signal component output by the signal outputting unit114, the vibration thereof is generated by the low-frequency vibration32among the multiple vibration apparatuses. For the second signal component output by the signal outputting unit114, the vibration thereof is generated by the high-frequency vibration31among the multiple vibration apparatuses. This makes it possible to cause a person to realistically feel a vibration of the high frequency band and a vibration of the low frequency band. The low-frequency vibration32may be omitted in the vibration generating system100. In that case, a vibration due to signal components below a predetermined frequency may be generated from the high-frequency vibration31, or a vibration due to signal components below the predetermined frequency do not have to be generated in the vibration generating system100.

The disclosed technologies are not limited to the respective embodiments described above, and may be variously modified without departing from the scope of the embodiments. The respective configurations and processes of the respective embodiments can be selected, omitted, and combined according to the requirements.

The vibration generating system100illustrated inFIG. 1includes the high-frequency vibration31and the low-frequency vibration32, but is not limited this. The number of vibrations provided in the vibration generating system100may be varied.

FIG. 23is a block diagram illustrating an example of the configuration of a DAC2for the vibration generating system100ofFIG. 1which uses multiple vibration apparatuses310and320.

The high-frequency gain adjuster21aoutputs a second vibration waveform S2(t) inputted from the vibration control apparatus1to the high-range vibration apparatus310via a high-range vibration apparatus driving circuit22a.

The low-range gain adjuster21boutputs the first vibration waveform S1(t) inputted from the vibration control apparatus1to the low-range vibration apparatus320via the low-range vibration apparatus driving circuit22b.

FIG. 24is a block diagram showing a configuration example of a DAC when using a single vibration apparatus in the vibration generating system100shown inFIG. 1.

In the example shown inFIG. 24, the DAC2shown inFIG. 1functions as a high-range gain adjuster21a,a low-range gain adjuster21b,and a vibration apparatus driving circuit22. In addition, the high-frequency vibration31and the low-frequency vibration32shown inFIG. 1function as a vibration apparatus30.

The high-range gain adjuster21aand the low-range gain adjuster21brespectively output a second vibration waveform S2(t) and a first vibration waveform S1(t), which are input from the vibration control apparatus1, to the common vibration apparatus30via the common vibration apparatus driving circuit22.