Program, information processing device, and information processing method

Abstract

The present disclosure relates to a program, an information processing device, and an information processing method that make it possible to measure the position of an electronic device in a system with high accuracy, the system comprising: a plurality of devices equipped with speakers; and an electronic device equipped with a microphone. A plurality of audio output blocks that are present at known positions: output an audio signal consisting of spread code signals in a horizontal direction, in which spread codes are spread-modulated so that the audio receiving block can receive the audio signal as a direct wave; and outputting the audio signal to the ceiling such that the audio signal is reflected from the ceiling or the like and can thereafter be received as a reflected wave. An audio receiving block may receive audio signals from one audio output block and from at least two paths (i.e., direct and reflected waves). Accordingly, the audio receiving block may configure the equations corresponding to the two paths, and thus calculate the position of the audio receiving unit with high precision. The present invention can be applied to game controllers and HMDs.

Description

Technical Field

[0001] The present disclosure relates to a program, an information processing apparatus, and an information processing method, and more particularly, to a program, an information processing apparatus, and an information processing method capable of highly accurately measuring the position of a receiving-side device using direct waves and reflected waves of signals transmitted by a plurality of transmission-side devices. Background Art

[0002] There is a technique in which a transmitting device modulates data codes using a code sequence to generate a modulated signal and emits the modulated signal as sound, and a receiving device receives the emitted sound, correlates the modulated signal, which is the received audio signal, with the code sequence, and measures the distance to the transmitting device based on the correlation peak.

[0003] In addition, as this positioning technique, a technique for improving positioning accuracy by using direct waves and reflected waves of emitted sound for positioning has been proposed (see Non-Patent Document 1).

[0004] Prior Art Documents

[0005] Non-Patent Documents

[0006] Non-Patent Document 1: MIRAGE: 2D SOURCE LOCALIZATION USING MICROPHONE PAIR AUGMENTATION WITH ECHOES Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, in the technique described in Non-Patent Document 1, since direct waves and reflected waves of the same signal are used for positioning, there is a possibility that the direct wave and the reflected wave cannot be distinguished when the emitted sound is received, making it impossible to achieve accurate positioning.

[0009] In view of this situation, the present disclosure has been made, and specifically, an object of the present disclosure is to highly accurately measure the position of a receiving-side device using both direct waves and reflected waves of signals transmitted by a plurality of transmitting-side devices.

[0010] Solutions to the Problems

[0011] An information processing apparatus and program according to an aspect of the present disclosure are an information processing apparatus and program including: an audio receiving unit that receives an audio signal including a spread spectrum signal obtained by performing spread spectrum modulation using an extended code, the audio signal being output from each of a plurality of audio output blocks located at known positions; and a position calculation unit that calculates the position of the audio receiving unit based on distances to the plurality of audio output blocks, the distances being determined based on propagation times, the propagation times being the times taken for the audio signals of the plurality of audio output blocks to be transmitted to and received by the audio receiving unit, wherein the audio receiving unit receives the audio signal transmitted by a direct wave from the plurality of audio output blocks and the audio signal transmitted by a reflected wave reflected by a reflecting object after being output from the plurality of audio output blocks, and the position calculation unit calculates the position of the audio receiving unit based on the audio signals transmitted by each of the direct wave and the reflected wave.

[0012] An information processing method according to an aspect of the present disclosure is an information processing method of an information processing apparatus including: an audio receiving unit that receives an audio signal including a spread spectrum signal obtained by performing spread spectrum modulation using an extended code, the audio signal being output from each of a plurality of audio output blocks located at known positions; and a position calculation unit that calculates the position of the audio receiving unit based on distances to the plurality of audio output blocks, the distances being determined based on propagation times, the propagation times being the times taken for the audio signals of the plurality of audio output blocks to be transmitted to and received by the audio receiving unit, the information processing method including: causing the audio receiving unit to receive the audio signal transmitted by a direct wave from the plurality of audio output blocks and the audio signal transmitted by a reflected wave reflected by a reflecting object after being output from the plurality of audio output blocks, and causing the position calculation unit to calculate the position of the audio receiving unit based on the audio signals transmitted by each of the direct wave and the reflected wave.

[0013] According to an aspect of the present disclosure, an audio receiving unit receives an audio signal including a spread spectrum signal obtained by performing spread spectrum modulation using an extended code, the audio signal being output from each of a plurality of audio output blocks located at known positions, the position calculation unit calculates the position of the audio receiving unit based on distances to the plurality of audio output blocks, the distances being determined based on propagation times, the propagation times being the times taken for the audio signals of the plurality of audio output blocks to be transmitted to and received by the audio receiving unit, the audio signal receiving unit receives the audio signal transmitted by a direct wave from the plurality of audio output blocks and the audio signal transmitted by a reflected wave reflected by a reflecting object after being output from the plurality of audio output blocks, and the position calculation unit calculates the position of the audio receiving unit based on the ranging signals transmitted by each of the direct wave and the reflected wave. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a diagram for describing a configuration embodiment of the acoustic positioning system of the present disclosure.

[0015] Figure 2 is for describing Figure 1 a diagram of an appearance configuration embodiment of the audio output block in

[0016] Figure 3 is for describing by Figure 1 a diagram of the functions implemented by the audio output block in

[0017] Figure 4 is for describing by Figure 1 a diagram of the functions implemented by the electronic device in

[0018] Figure 5 is a diagram for describing communication using an extended code.

[0019] Figure 6 is a diagram for describing the autocorrelation and cross-correlation of an extended code.

[0020] Figure 7 is a diagram for describing the propagation time of an extended code using cross-correlation.

[0021] Figure 8 is a diagram for illustrating a configuration example of a propagation time calculation unit.

[0022] Figure 9 is a diagram for illustrating human hearing.

[0023] Figure 10 is a diagram for describing the frequency shift of an extended code.

[0024] Figure 11 is a diagram for describing the process for the frequency shift of an extended code.

[0025] Figure 12 is a diagram for describing how to obtain the position of an electronic device.

[0026] Figure 13 is a diagram for describing the coordinate system when using reflected waves.

[0027] Figure 14 is a diagram for describing the first constraint condition for selecting direct waves and reflected waves.

[0028] Figure 15 is a diagram for describing the second constraint condition for selecting direct waves and reflected waves.

[0029] Figure 16 is a diagram for describing the third constraint condition for selecting direct waves and reflected waves.

[0030] Figure 17 is a flowchart for describing the position measurement process performed by an electronic device.

[0031] Figure 18 is a flowchart for describing the position measurement process of an audio output block.

[0032] Figure 19 is a flowchart for describing the propagation time calculation process.

[0033] Figure 20 is a diagram for describing an example of the case where the direct wave is blocked as a first modification example.

[0034] Figure 21 is a diagram for describing the cross - correlation with the direct wave in the case where the direct wave is blocked.

[0035] Figure 22 is a flowchart for describing a first modification example of the position measurement process performed by an electronic device.

[0036] Figure 23 is a diagram for describing a second modification example.

[0037] Figure 24 is a diagram for describing Modification Example 3.

[0038] Figure 25 is a diagram for describing Modification Example 4.

[0039] Figure 26 is a diagram for describing Modification Example 5.

[0040] Figure 27 is a diagram for describing Modification Example 5.

[0041] Figure 28 is a diagram showing a configuration example of a general - purpose computer. Detailed Description of the Preferred Embodiment

[0042] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that in this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0043] Hereinafter, the modes for implementing the present technology will be described. The description will be given in the following order.

[0044] 1. Preferred Embodiment

[0045] 2. First Modification Example

[0046] 3. Second Modification Example

[0047] 4. Third Variant Example

[0048] 5. Fourth Variant Example

[0049] 6. Fifth Variant Example

[0050] 7. Embodiment Executed by Software

[0051] <<1. Preferred Embodiment>>

[0052] <Configuration Embodiment of Acoustic Positioning System>

[0053] Specifically, the present disclosure enables a plurality of devices each including a speaker and a device including a microphone to accurately measure the position of the device including the microphone by using the direct wave and reflected wave of the emitted sound with high precision.

[0054] Figure 1 A configuration embodiment of an acoustic positioning system to which the technology of the present disclosure is applied is shown.

[0055] Figure 1 The acoustic positioning system 11 in [reference] includes audio output blocks 31-1 to 31-4 and an electronic device 32. It should be noted that hereinafter, when it is not necessary to particularly distinguish the audio output blocks 31-1 to 31-4 from each other, they are simply referred to as the audio output block 31, and other configurations are also referred to in a similar manner.

[0056] Each of the audio output blocks 31-1 to 31-4 includes a speaker and emits sound by including an audio signal in a sound such as music content, a game, or known music. The audio signal is a ranging signal, and the ranging signal includes a modulation signal obtained by performing spread spectrum modulation on a data code for determining the position of the electronic device 32 by using an extended code.

[0057] The electronic device 32 is carried or worn by a user and is, for example, a smart phone or a head-mounted display (HMD) used as a game controller.

[0058] The electronic device 32 includes an audio input block 41. The audio input block 41 includes an audio input unit 51 such as a microphone and a position detection unit 52. The audio input unit 51 receives sound including an audio signal as a ranging signal emitted from each of the audio output blocks 31-1 to 31-4.

[0059] The audio input block 41 determines in advance the positions in space of each of the audio output blocks 31-1 to 31-4 as known position information through communication (ranging signal or other communication means) between the audio output block 31 and the electronic device 32. The audio input block 41 causes the audio input unit 51 to receive an audio signal as a ranging signal and outputs the audio signal to the position detection unit 52. The ranging signal includes a modulation signal contained in the sound emitted from the audio output block 31. The position detection unit 52 obtains the distances to each of the audio output blocks 31-1 to 31-4 based on the audio signal as the ranging signal including the modulation signal provided from the audio input block 41, and detects its own position relative to the audio output blocks 31-1 to 31-4 based on the obtained distances.

[0060] With this configuration, for example, in the case where the electronic device 32 is an HMD or a smartphone including a perspective display unit, the movement of the head of a user wearing the HMD or the smartphone (i.e., the electronic device 32) can be tracked.

[0061] Furthermore, since the position of the HMD or the smartphone as the electronic device 32 relative to the audio output blocks 31-1 to 31-4 is determined, the sound output from the audio output blocks 31-1 to 31-4 can be output with sound field localization corrected according to the determined position. This configuration allows the user wearing the HMD (electronic device 32) to experience immersive sound according to the movement of the head.

[0062] <Embodiment of the Appearance Configuration of the Audio Output Block>

[0063] Next, with reference to Figure 2 the embodiment of the appearance configuration of the audio output block 31 and the principle of detecting the position of the electronic device 32 will be described.

[0064] As Figure 2 shown, the audio output block 31 includes audio output units 31a-1 and 31a-2. Each of the audio output units 31a-1 and 31a-2 includes a cylindrical housing and serves as a speaker, and emits sound including a spread spectrum signal.

[0065] In Figure 2 the audio output block 31, the audio output unit 31a-1 points to the ceiling, and the audio output unit 31a-2 points horizontally.

[0066] Furthermore, the audio output units 31a-1 and 31a-2 may include speakers with different frequency band characteristics. And for example, in Figure 2 the audio output unit 31a-1 may include an enabled speaker, and the audio output unit 31a-2 may include a woofer.

[0067] Note thatFigure 2 The arrangement examples of the audio output units 31a-1 and 31a-2 in [[ ]] are merely examples, and another arrangement may be adopted. In addition, the audio output units 31a-1 and 31a-2 may be speakers other than the enabled speakers and subwoofers, as long as their band characteristics are different from each other. However, it is desirable that the bandwidths are different from each other in order to identify each speaker.

[0068] The electronic device 32 receives the input of the sound emitted from each of the audio output units 31a-1 and 31a-2 of the audio output block 31, obtains the distances to each of the audio output units 31a-1 and 31a-2 based on the correlation between the extended signal of the received sound and the spreading code, and obtains its own position based on the obtained distances to each of the audio output units 31a-1 and 31a-2.

[0069] At this time, since Figure 2 the audio output units 31a-1 and 31a-2 in [[ ]] have different sound emission directions and positions, there are at least two paths for the sound to reach the electronic device 32.

[0070] Specifically, assuming use in a room, one of the sounds emitted from the audio output units 31a-1 and 31a-2 is received as a direct wave, and the other is received as a reflected wave reflected from a reflector (such as the ceiling of the room).

[0071] In [[ ]] Figure 2 in the audio output block 31 placed on the floor 62, the sound transmitted from the audio output unit 31a-1 is received by the electronic device 32 as a reflected wave reflected from the ceiling 61, as shown by the path RP. On the other hand, an embodiment is shown in which the sound transmitted from the audio output unit 31a-2 is received by the electronic device 32 as a direct wave indicated by the path DP.

[0072] The position of a reflector such as the ceiling can be determined in advance together with the position of the audio output block 31, so that the electronic device 32 can obtain its own position based on the distance to the audio output block 31 based on the direct wave and the distance to the audio output block 31 based on the reflected wave using the geometric constraints of the indoor space, and the geometric constraints of the indoor space are determined based on the respective positions of the reflector and the audio output block 31.

[0073] Compared with the configuration in which the audio output block 31 includes only one audio output unit 31a corresponding to a speaker, such a configuration can achieve a more robust measurement of the position of the electronic device 32.

[0074] <Functional configuration embodiment of the audio output block>

[0075] Next, reference will be made to Figure 3Describe the functions to be implemented by the audio output block 31.

[0076] The audio output block 31 includes a spread code generation unit 71, a known music source generation unit 72, an audio generation unit 73, audio output units 74-1 and 74-2, and a communication unit 75.

[0077] The spread code generation unit 71 generates a spread code and outputs the spread code to the audio generation unit 73.

[0078] The known music source generation unit 72 stores known music, generates a known music source based on the stored known music, and outputs the known music source to the audio generation unit 73.

[0079] The audio generation unit 73 applies spread spectrum modulation to the known music source using the spread code to generate a sound including a spread spectrum signal, and outputs the sound to the audio output units 74-1 and 74-2.

[0080] More specifically, the audio generation unit 73 includes a spreading unit 81, a frequency shift processing unit 82, and a sound field control unit 83.

[0081] The spreading unit 81 applies spread spectrum modulation using the spread code to the known music source to generate a spread spectrum signal.

[0082] The frequency shift processing unit 82 shifts the frequency of the spread code in the spread spectrum signal to a frequency corresponding to the respective frequency band characteristics of the audio output units 74-1 and 74-2.

[0083] Based on the information about the position of the electronic device 32 provided by the electronic device 32, the sound field control unit 83 reproduces the sound field according to its own position relationship.

[0084] The audio output units 74-1 and 74-2 are, for example, speakers, and have a configuration corresponding to the audio output units 31a-1 and 31a-2 described in Figure 2 The audio output units 74-1 and 74-2 are, for example, speakers, and output the known music source and the sound based on the spread spectrum signal provided by the audio generation unit 73.

[0085] The communication unit 75 is controlled by the audio generation unit 73, communicates with the electronic device 32 via Wi-Fi communication, Bluetooth (registered trademark) communication, etc., and receives a request for sound emission to measure the position provided by the electronic device 32. In addition, the communication unit 75 transmits its own position information and the position information about reflectors (such as the ceiling) to the electronic device 32 before emitting sound.

[0086] <Configuration Embodiment of the Electronic Device>

[0087] Next, with reference toFigure 4 Describe a configuration embodiment of the electronic device 32.

[0088] The electronic device 32 includes an audio input block 41, a control unit 42, and a communication unit 43.

[0089] The audio input block 41 receives the input of the sound emitted from each of the audio output blocks 31-1 to 31-4, obtains the distances to each of the audio output blocks 31-1 to 31-4 based on the correlation between the spread spectrum signal of the received sound and the spreading code, obtains its own position based on the obtained distances, and outputs its own position to the control unit 42.

[0090] In the case where the electronic device 32 is a smart phone used as a game controller, the control unit 42 controls, for example, the communication unit 43 based on the position of the electronic device 32 provided from the audio input block 41 to send a command for setting the sound field based on the position of the electronic device 32 to the audio output blocks 31-1 to 31-4.

[0091] In this case, the sound field control unit 83 of each of the audio output blocks 31-1 to 31-4 adjusts the sound output from the audio output unit 74 based on the command for setting the sound field sent by the electronic device 32 to achieve the best sound field for the user having the electronic device 32.

[0092] The audio input unit 51 is, for example, a microphone, collects the sound emitted from each of the audio output blocks 31-1 to 31-4, and outputs the sound to the position detection unit 52.

[0093] The position detection unit 52 detects its own position based on the sound emitted from each of the audio output blocks 31-1 to 31-4, and outputs its own position to the control unit 42.

[0094] More specifically, the position detection unit 52 includes a known music source removal unit 91, a space transfer characteristic calculation unit 92, a propagation time calculation unit 93, and a position calculation unit 94.

[0095] The space transfer characteristic calculation unit 92 calculates the space transfer characteristic based on the information about the sound supplied from the audio input unit 51, the characteristics of the microphone constituting the audio input unit 51, and the characteristics of the speaker of the audio output unit 74 constituting the audio output block 31, and outputs the space transfer characteristic to the known music source removal unit 91.

[0096] The known music source removal unit 91 stores the music source stored in advance in the known music source generation unit 72 of the audio output block 31 as a known music source.

[0097] Then, the known music source removal unit 91 removes the components of the known music source from the sound supplied from the audio input unit 51, taking into account the spatial transmission characteristics supplied from the spatial transmission characteristic calculation unit 92, and outputs the result to the propagation time calculation unit 93.

[0098] That is, the known music source removal unit 91 removes the components of the known music source from the sound collected by the audio input unit 51, and outputs only the spread spectrum signal components to the propagation time calculation unit 93.

[0099] The propagation time calculation unit 93 calculates the propagation time from when the sound is emitted from each of the audio output blocks 31-1 to 31-4 to when the sound is collected by the audio input unit 51 based on the spread spectrum signal components included in the collected sound, and outputs the propagation time to the position calculation unit 94.

[0100] Note that the method for calculating the propagation time will be described in detail later.

[0101] The position calculation unit 94 calculates the position of the electronic device 32 based on the propagation time of each of the audio output blocks 31-1 to 31-4 provided from the propagation time calculation unit 93, and outputs the position to the control unit 42.

[0102] To start the self-position measurement process, the control unit 42 communicates with the audio output block 31 to obtain the position information of each audio output block 31 and the position information of reflectors such as the ceiling, and outputs the position information to the position calculation unit 94.

[0103] <Communication Principle Using Spread Code>

[0104] Next, the principle of communication using spread code will be described with reference to Figure 5 In the transmission side in the left part of

[0105] In Figure 5 the spread unit 81 performs spread spectrum modulation by multiplying the input signal Di having a pulse width Td to be transmitted by the spread code Ex to generate a transmission signal De having a pulse width Tc, and transmits the transmission signal De to the reception side in the right part of Figure 5 At this time, when the frequency band Dif of the input signal Di is indicated by, for example, the frequency band -1 / Td to 1 / Td, the frequency band Exf of the transmission signal De is widened to the frequency band -1 / Tc to 1 / Tc (1 / Tc > 1 / Td) by multiplying by the spread code Ex, thereby spreading the energy across the frequency axis.

[0106] It should be noted that

[0107] Note that Figure 5An embodiment in which the transmitted signal De is interfered by the interference wave IF is shown.

[0108] On the receiving side, the transmitted signal De interfered by the interference wave IF is received as the received signal De'.

[0109] The cross-correlation calculation unit 131 (of the propagation time calculation unit 93 Figure 8 )) applies despreading to the received signal De' using the same spreading code Ex to recover the received signal Do.

[0110] At this time, the frequency band Exf' of the received signal De' includes the component IFEx of the interference wave, but in the frequency band Dof of the despread received signal Do, the energy is extended by restoring the component IFEx of the interference wave to the extended frequency band IFD, so that the influence of the interference wave IF on the received signal Do can be reduced.

[0111] That is, as described above, in communication using a spreading code, the influence of the interference wave IF generated on the transmission path of the transmitted signal De can be reduced, and the noise resistance can be improved.

[0112] In addition, in the spreading code, for example, the autocorrelation is in the form of a pulse, as shown in the waveform diagram at the upper part of Figure 6 and the cross-correlation is 0, as shown in the waveform at the lower part of Figure 6 . It should be noted that Figure 6 shows the change of the correlation value in the case of using the Gold sequence as the spreading code, where the horizontal axis represents the coding sequence and the vertical axis represents the correlation value.

[0113] That is, by using the highly random spreading codes set for each of the audio output blocks 31-1 to 31-4, the audio input block 41 can appropriately distinguish and determine the spectral signals included in the sounds for each of the audio output blocks 31-1 to 31-4.

[0114] In addition, in the case where highly random spreading codes are also set for the audio output units 74-1 and 74-2, the audio input block 41 can distinguish and determine the spectral signals for each of the audio output blocks 31-1 to 31-4 and further for each of the audio output units 74-1 and 74-2.

[0115] The spreading code can be not only the Gold sequence, but also the M sequence, pseudo-random noise (PN), etc.

[0116] <Method for calculating the propagation time by the propagation time calculation unit>

[0117] The timing at which the peak of the observed cross-correlation is observed in the audio input block 41 is the timing at which the sound emitted from the audio output block 31 is collected in the audio input block 41, and thus varies depending on the distance between the audio input block 41 and the audio output block 31.

[0118] That is, for example, as Figure 7 shown in the left part of, when the distance between the audio input block 41 and the audio output block 31 is the first distance, the peak is detected at time T1, as Figure 7 shown in the right part of, when the distance between the audio input block 41 and the audio output block 31 is the second distance, which is longer than the first distance, the peak is observed at time T2 (>T1).

[0119] Note that in Figure 7 the horizontal axis represents the elapsed time since the sound is output from the sound output block 31, and the vertical axis represents the intensity of the cross-correlation.

[0120] That is, the distance between the audio input block 41 and the audio output block 31 can be obtained by multiplying the time from when the sound is emitted from the audio output block 31 to when the peak is observed in the cross-correlation (i.e., the propagation time from when the sound is emitted from the audio output block 31 to when the sound is collected in the audio input block 41) by the speed of sound.

[0121] <Configuration Embodiment of Propagation Time Calculation Unit>

[0122] Next, a configuration embodiment of the propagation time calculation unit 93 will be described with reference to Figure 8 the following.

[0123] The propagation time calculation unit 93 includes an inverse shift processing unit 130, a cross-correlation calculation unit 131, and a peak detection unit 132.

[0124] The inverse shift processing unit 130 restores the spread-spectrum modulated spreading code signal to the original frequency band in the audio signal collected by the audio input unit 51 through downsampling, and outputs the restored signal to the cross-correlation calculation unit 131, where the spread-spectrum modulation has been frequency-shifted through upsampling in the frequency shift processing unit 82 of the audio output block 31.

[0125] It should be noted that the frequency band shift performed by the frequency shift processing unit 82 and the frequency band restoration performed by the inverse shift processing unit 130 will be described in detail later with reference to Figure 10 the following.

[0126] The cross-correlation calculation unit 131 calculates the cross-correlation between the spreading code and the received signal obtained by removing the known music source from the audio signal collected by the audio input unit 51 of the audio input block 41, and outputs the cross-correlation to the peak detection unit 132.

[0127] The peak detection unit 132 detects the peak time in the cross-correlation calculated by the cross-correlation calculation unit 131, and outputs the peak time as the propagation time.

[0128] Here, since it is well known that the calculation of the cross-correlation performed in the cross-correlation calculation unit 131 has a particularly large computational complexity, this calculation is implemented by an equivalent calculation with a smaller computational complexity.

[0129] Specifically, as represented by the following equations (1) and (2), the cross-correlation calculation unit 131 performs Fourier transform on each of the transmission signal output as sound by the audio output unit 74 of the audio output block 31 and the received signal obtained by removing the known music source from the audio signal received by the audio input unit 51 of the audio input block 41.

[0130] [Mathematical formula 1]

[0131]

[0132] [Mathematical formula 2]

[0133]

[0134] Here, g represents the received signal obtained by removing the known music source from the audio signal received by the audio input unit 51 of the audio input block 41, and G represents the result of the Fourier transform performed on the received signal g obtained by removing the known music source from the audio signal received by the audio input unit 51 of the audio input block 41.

[0135] In addition, h represents the transmission signal to be output by the audio output unit 74 of the audio output block 31, and H represents the result of the Fourier transform performed on the transmission signal to be output by the audio output unit 74 of the audio output block 31.

[0136] In addition, V represents the speed of sound, V represents the speed of the audio input unit 51 of the electronic device 32, t represents time, and f represents frequency.

[0137] Next, the cross-correlation calculation unit 131 obtains the cross-spectrum by multiplying the results G and H of the Fourier transform represented by the following equation (3) with each other.

[0138] [Mathematical formula 3]

[0139] P(f) = G(f)H(f)…(3)

[0140] Here, P represents the cross-spectrum obtained by multiplying the results G and H of the Fourier transform with each other.

[0141] Then, as shown in the following equation (4), the cross-correlation calculation unit 131 performs an inverse Fourier transform on the cross-spectrum P to obtain the cross-correlation between the transmission signal h output by the audio output unit 74 of the audio output block 31 and the reception signal g obtained by removing the known music source from the audio signal received by the audio input unit 51 of the audio input block 41.

[0142] [Mathematical formula 4]

[0143]

[0144] Here, p represents the cross-correlation between the transmission signal h output by the audio output unit 74 of the audio output block 31 and the reception signal g obtained by removing the known music source from the audio signal received by the audio input unit 51 of the audio input block 41.

[0145] Then, the distance between the audio input block 41 and the audio output block 31 is calculated by obtaining the propagation time T based on the peak value of the cross-correlation p using the following mathematical formula (5).

[0146] [Mathematical formula 5]

[0147] D = T × V…(5)

[0148] Here, D represents the distance between the audio input unit 51 of the audio input block 41 and the audio output unit 74 of the audio output block 31, T represents the propagation time, and V represents the speed of sound. Additionally, the speed of sound V is, for example, 331.5 + 0.6 × Q (m / s) (Q is the temperature in °C).

[0149] It should be noted that the cross-correlation calculation unit 131 can further obtain the speed v of the electronic device 32 (the audio input unit 51) by obtaining the cross-correlation p.

[0150] More specifically, the cross-correlation calculation unit 131 obtains the cross-correlation p while changing the speed v within a predetermined range (for example, -1.00 m / s to 1.00 m / s) with a predetermined step size (for example, 0.01 m / s step size), and obtains the speed v indicating the maximum peak of the cross-correlation p as the speed v of the electronic device 32 (the audio input unit 51).

[0151] The absolute speed of the electronic device 32 (the audio input block 41) can also be obtained based on the speed v obtained for each of the audio output blocks 31-1 to 31-4.

[0152] <Frequency shift>

[0153] The frequency band of the spread code signal is the Nyquist frequency Fs that is half of the sampling frequency. For example, when the Nyquist frequency Fs is 8 kHz, the frequency band is set to 0 kHz to 8 kHz that is lower than the Nyquist frequency Fs.

[0154] Incidentally, as Figure 9 shown, it is known that the human auditory sense has high sensitivity to sounds in the frequency band around 3 kHz regardless of the loudness level, decreases from about 10 kHz, and humans can hardly hear when exceeding 20 kHz.

[0155] Figure 9 Shows the change in the sound pressure level of each frequency at each loudness level of 0, 20, 40, 60, 80, and 100 nm, where the horizontal axis represents the frequency and the vertical axis represents the sound pressure level. Note that the thick alternating long and short dashed lines represent the sound pressure level of the microphone and indicate that the sound pressure level is constant regardless of the loudness level.

[0156] Therefore, when the frequency band of the spread spectrum signal is 0 kHz to 8 kHz, there is a possibility that the sound of the spread code signal is perceived as noise by the human auditory sense when the sound of the spread code signal is emitted together with the sound of a known music source.

[0157] For example, in the case of assuming that music is reproduced at -50 dB, Figure 10 the range below the sensitivity curve L in [] is set as the range Z1 that humans cannot hear (the range that is difficult to determine by the human auditory sense), and the range above the sensitivity curve L is set as the range Z2 that humans can hear (the range that is easy to determine by the human auditory sense).

[0158] In Figure 10 the horizontal axis represents the frequency band and the vertical axis represents the sound pressure level.

[0159] Therefore, for example, when the range where the sound of the reproduced known music source and the sound of the spread code signal can be separated from each other is within -30 dB, the sound of the spread code signal output in the range of 16 kHz to 24 kHz represented by the range Z3 within the range Z1 can be made inaudible (difficult to determine by the human auditory sense) to humans.

[0160] So, as illustrated in the upper left part of Figure 11 the frequency shift processing unit 82 upsamples the spread code signal Fs containing the spread code by m times to generate spread code signals Fs, 2Fs,... mFs, as Figure 11 illustrated in the middle left part.

[0161] Then, as shown in the lower left part of Figure 11 the frequency shift processing unit 82 uses as a reference Figure 10The extended code signal uFs in the frequency band of 16 kHz to 24 kHz, which is inaudible to humans as described, is applied with a frequency band limit to perform frequency shift on the extended code signal Fs including the extended code signal, and the audio output unit 74 emits sound together with a known music source.

[0162] As Figure 11 shown in the lower right part of , the inverse shift processing unit 130 extracts the extended code signal uF by limiting the frequency band of the sound obtained by removing the known music source from the sound collected by the audio input unit 51 by the known music source removal unit 91 to the range of 16 kHz to 24 kHz, as Figure 11 shown in the lower right part of .

[0163] Then, as Figure 10 shown in the upper right part of , the inverse shift processing unit 130 performs 1 / m times downsampling to generate the extended code signal Fs including the extended code, thereby restoring the frequency band to the original frequency band.

[0164] By performing frequency shift in this way, even when emitting the sound including the extended code signal in the state of emitting the sound of the known music source, it is possible to make the sound including the extended code signal less audible (less determinable by human hearing).

[0165] Note that in the above, an example of making the sound including the extended code signal less audible (difficult to be determined by human hearing) by frequency shift has been described. However, since high-frequency sounds have high directivity and are vulnerable to multipath effects due to reflections from walls, etc. and sound blocking by obstacles, it can also be assigned to Figure 2 the audio output unit 74-1(31a-1) in to propagate the extended code signal through the reflected wave of the path RP.

[0166] In addition, in a similar way, a frequency band below 3 kHz can also be specified as a peak and a frequency band that is difficult to be determined by human hearing can be assigned to Figure 2 the audio output unit 31a-2 in to propagate the extended code signal through the direct wave of the path DP.

[0167] <Method for obtaining the position of an electronic device (Time of Arrival TOA positioning)>

[0168] Next, how to obtain the position of the audio input unit 51-i of the electronic device 32 based on the distance Dik between the audio input unit 51-i of the electronic device 32 and the audio output block 31-k will be described. There are various methods for obtaining the position of the audio input unit 51-i of the electronic device 32, and Time of Arrival (TOA) positioning and Time Difference of Arrival (TDOA) positioning are well known.

[0169] Time of arrival (TOA) positioning is a method for obtaining the position of a receiving device based on the distance relationships between multiple transmitting devices with known positions and the receiving device.

[0170] On the other hand, time difference of arrival (TDOA) positioning is a method for obtaining the position of a receiving device based on the distance difference relationships between multiple transmitting devices with known positions and the receiving device.

[0171] First, time of arrival (TOA) positioning will be described. Here, it is assumed that the position of the audio output block 31 (the audio output unit 74 thereof) serving as the transmitting device is known.

[0172] For example, as Figure 12 shown, assume that the position of the audio output block 31-1 (the audio output unit 74-1 thereof) is (X1, Y1, Z1), the position of the audio output block 31-2 (the audio output unit 74-2 thereof) is (X2, Y2, Z2), the position of the audio output block 31-3 (the audio output unit 74-3 thereof) is (X3, Y3, Z3), and the position of the audio output block 31-4 (the audio output unit 74-4 thereof) is (X4, Y4, Z4).

[0173] Furthermore, assume that the position of the audio input unit 51-1 (of the audio input block 41-1 of the electronic device 32-1) is (x1, y1, z1), and the position of the audio input unit 51-2 (of the audio input block 41-2 of the electronic device 32-2) is (x2, y2, z2).

[0174] These are generalized such that the position of the audio output block 31-k (the audio output unit 74-k thereof) is (Xk, Yk, Zk), and the position of the audio input unit 51-i (of the audio input block 41-i of the electronic device 32-i) is (xi, yi, zi).

[0175] In this case, the distance Dik between the audio output block 31-k (the audio output unit 74-k thereof) and the audio input unit 51-i (of the audio input block 41-i of the electronic device 32-i) is represented by the following mathematical formula (6).

[0176] [Mathematical formula 6]

[0177]

[0178] Here, Ds represents the distance offset corresponding to the system delay between the audio output block 31 and the audio input block 41.

[0179] Therefore, in the case of obtaining the respective distances Di1 to Di4 between the audio input unit 51-i (of the audio input block 41-i of the electronic device 32-i) and the audio output units 74 of the audio output blocks 31-1 to 31-4, the position (xi, yi, zi) of the audio input unit 51-i (of the audio input block 41-i of the electronic device 32-i) can be obtained by solving the system of simultaneous equations represented by the following equation (7).

[0180] Note that here, only the audio output unit 74-2 will be described, where the audio output unit 74-2 emits the sound that will be collected as a direct wave by the electronic device 32 corresponding to the audio output units 74-1 and 74-2 of the audio output units 31a-1 and 31a-2, but basically similar equations are also generated for the reflected wave. In addition, the case of using the reflected wave will be described in detail later with reference to Figure 13 the situation of using the reflected wave will be described in detail later.

[0181] [Mathematical formula 7]

[0182]

[0183] Note that in the above, when the distance offset Ds corresponding to the time offset caused by the operation delay is known, the number of unknowns is three, and three simultaneous equations are sufficient; therefore, if the positions of the three audio output units 74 are known, a solution can be obtained.

[0184] <Coordinate system in the case of using the reflected wave>

[0185] In the case of using the reflected wave, it is necessary to set the coordinate system of the audio output block 31 to ensure a mirror position relationship with respect to the reflector of the reflected sound.

[0186] For example, as Figure 13 shown, consider the case where the reflector is the ceiling and the sound emitted from the audio output block 31 reaches the electronic device 32 after being reflected by the ceiling.

[0187] Here, the position coordinates of the audio output units 31a-1 and 31a-2 of the audio output block 31 are Ps1(X, Y, Z) and Ps2(X, Y, Z) respectively, the position coordinates of the electronic device are M(x, y, z), and the height of the ceiling 61 is Z'.

[0188] Note that it is assumed that the audio output unit 31a-1 serving as the speaker that emits the sound as the reflected wave and the audio output unit 31a-2 serving as the speaker that emits the sound as the direct wave are sufficiently close to each other compared to the distance to the electronic device 32 and are represented by the same position coordinates Ps1(X, Y, Z) and Ps2(X, Y, Z).

[0189] In this case, the distance of the path DP of the direct wave between the audio output unit 31a-1 and the electronic device 32 is the distance between the position Ps1(X, Y, Z) of the audio output unit 31a-1 and the position M(x, y, z) of the electronic device 32, and is represented by √((X - x) 2 +(Y - y) 2 +(Z - z) 2 ) + Ds.

[0190] On the other hand, the distance of the path RP through which the reflected wave propagates is calculated using the position Pvs(X, Y, Z + 2(Z’ - Z)), which has a mirror relationship with the position Ps1(X, Y, Z) of the audio output unit 31a-1 across the ceiling 61 in the Z direction of the position regarded as that of the audio output block 31.

[0191] Therefore, the distance of the propagation path RP of the reflected wave is the distance between the position Pvs(X, Y, Z + 2(Z’ - Z)), which has a mirror relationship with the position Ps1(X, Y, Z) of the audio output unit 31a-1 across the ceiling 61, and the position M(x, y, z) of the electronic device 32, and is represented by √((X - x) 2 +(Y - y) 2 +(Z - (Z + 2(Z’ - z)) 2 ) + Ds. That is, an equation generated using this coordinate system is generated for each audio output block 31, and a system of simultaneous equations corresponding to the mathematical formula (7) is generated.

[0192] Note that although Figure 13 an embodiment in which the reflecting object is the ceiling is shown, even when different objects are the reflecting objects, the coordinate system needs to be set in a similar manner.

[0193] <Method for obtaining the position of an electronic device (Time Difference of Arrival (TDOA) positioning)>

[0194] As described above, in the case of the method for obtaining the position of an electronic device based on Time of Arrival (TOA) positioning, in order to measure the above propagation time, the transmission time and the reception time need to be strictly managed, making the complete synchronization of the clocks used in the audio input unit 51 and the audio output block 31 (of the audio input block 41 of the electronic device 32) a mandatory requirement.

[0195] However, in practice, it is difficult to achieve the complete synchronization of the clocks of the audio input unit 51 and the audio output block 31 (of the audio input block 41 of the electronic device 32).

[0196] Therefore, in time difference of arrival (TDOA) positioning, the use of the distance difference between the electronic device 32 and the audio output blocks 31-1 to 31-i compensates for the error caused by the asynchronous clocks used to measure the distance and eliminates the need for clock synchronization. Note that the clocks used in the electronic device 32 and the audio output blocks 31 do not need to be synchronized, but the timing of the sounds emitted from the audio output blocks 31-1 to 31-4 needs to be synchronized.

[0197] More specifically, it can be obtained by solving a set of simultaneous equations represented by the following mathematical formula (8).

[0198] [Mathematical formula 8]

[0199]

[0200] Note that in mathematical formula (8), t1, t2, t3, t4,... represent the arrival times of the sounds emitted from the audio output blocks 31-1 to 31-4. Additionally, the above formula (8) only represents the formula for the direct wave, but the formula for the reflected wave is also generated in the same way.

[0201] <Constraints for distinguishing direct waves and reflected waves>

[0202] In the present invention, as described above, unless the spreading code signals obtained from the direct wave and the spreading code signals obtained from the reflected wave are clearly and separately processed, the set of simultaneous equations shown in mathematical formula (8) cannot be generated, making it difficult to perform appropriate position measurement.

[0203] The spreading code signals obtained from the direct wave and the spreading code signals obtained from the reflected wave are obtained from the peaks obtained from the direct wave and the peaks obtained from the reflected wave, respectively; however, in various cases, peaks caused by reflection other than the first peak to be obtained initially can also be detected, so it is necessary to first appropriately select the pairs of peaks to be detected.

[0204] Therefore, according to the first to third constraint conditions based on the geometric constraints of the space where the audio output block 31 is placed, the first peaks to be detected of the direct wave and the reflected wave from the same audio output block 31 are detected respectively.

[0205] <First constraint condition>

[0206] The first constraint condition is as follows: when the installation position of the audio output block 31 is known, the range of the timing for detecting the peak of the reflected wave is determined based on the timing of the peak of the detected direct wave.

[0207] For example, as shown in the upper part of Figure 14 , when the peak of the direct wave is detected, as shown in the lower part of Figure 14 , the peak of the reflected wave is detected with a certain time delay.

[0208] Since the position of the audio output block 31 can be determined in advance and the distance can be obtained based only on the direct wave, it is possible to estimate the peak of the reflected wave detected with respect to the peak of the direct wave within a predetermined range β indicated by the dashed line in, for example, Figure 14 Therefore, when the peak of the direct wave that satisfies the condition indicated by the dashed line in Figure 14 is used as a reference, the peak of the reflected wave is selected within the determined predetermined range β.

[0209] <Second Constraint Condition>

[0210] The second constraint condition is a condition for detecting the peak of the direct wave earlier than the peak of the reflected wave.

[0211] That is, due to the geometric constraint, the path of the reflected wave becomes longer than the path of the direct wave. Therefore, as shown by the peak of the direct wave in the upper part of Figure 14 and the peak of the reflected wave in the lower part of Figure 14 , the peak of the reflected wave appears after the peak of the direct wave.

[0212] Therefore, for example, when the peak of the direct wave in the upper part of Figure 15 and the peak of the reflected wave shown in the lower part of Figure 15 are detected, since the peak of the direct wave appears after the peak of the reflected wave in the lower part of Figure 15 , the direct wave surrounded by the circular mark in the upper part of Figure 15 is not selected as the direct wave.

[0213] <Third Constraint Condition>

[0214] The third constraint condition is as follows: when the peak of the direct wave and the peak of the reflected wave appear at almost the same timing, there is a possibility that the peak of the reflected wave and the peak of the direct wave have already been detected.

[0215] For example, as shown in the upper part of Figure 16 , when the peak of the direct wave is detected, as shown in the lower part of Figure 16 , when the peak of the reflected wave is detected at almost the same timing, the possibility that the peak of the reflected wave and the peak of the direct wave have already been detected is high. Therefore, it is necessary to ensure that such a peak of the reflected wave is not selected.

[0216] That is, as described above, according to the first to third constraint conditions, the first timing pair of the peak of the direct wave and the peak of the reflected wave is selected from the multiple peaks of the direct wave and the multiple peaks of the reflected wave, the peak of the direct wave appears before the peak of the reflected wave, and the two peaks are separated by a range β approximately.

[0217] This makes it possible to robustly select the appropriate peaks of the direct wave and the reflected wave.

[0218] <Position measurement process>

[0219] Next, the position measurement process of the audio output block 31 and the electronic device 32 will be described with reference to the flowchart in Figures 17 to 19 .

[0220] Note that Figure 17 is the flowchart for describing the process of the electronic device 32, Figure 18 is the flowchart for describing the process of the audio output block 31. Figure 19 is for explaining Figure 17 the propagation time calculation process in step S18 of

[0221] In step S11 ( Figure 17 ), the control unit 42 of the electronic device 32 determines whether an instruction to start the position measurement process has been issued through a user operation of an operation unit (not shown) or the like, and repeats a similar process until the instruction is received.

[0222] Then, in step S11, when an instruction to start the position measurement process is indicated, the process proceeds to step S12.

[0223] In step S12, the control unit 42 controls the communication unit 43 to request the audio output block 31 to start the position measurement process.

[0224] In step S31 ( Figure 18 ), the audio generation unit 73 of the audio output block 31 controls the communication unit 75 to determine whether the electronic device 32 has requested to start the position measurement process, and repeats a similar process until the request is received.

[0225] Then, in step S31, when the electronic device 32 requests to start the position measurement process, the process proceeds to step S32.

[0226] In step S32, the audio generation unit 73 controls the communication unit 75 to send the self - part information together with the information indicating the start of the position measurement process to the electronic device 32. Through this process, the position information about each of the audio output blocks 31 - 1 to 31 - 4 is transmitted from the audio output blocks 31 - 1 to 31 - 4 to the electronic device 32.

[0227] In step S13 ( Figure 17 ), the control unit 42 of the electronic device 32 controls the communication unit 43 to acquire the information indicating the start of the position measurement process and the position information provided by the audio output block 31, and provides the acquired information to the position calculation unit 94.

[0228] In step S14, the control unit 42 controls the communication unit 43 to request the audio output block 31 to emit a sound.

[0229] In step S33( Figure 18 ), the audio generation unit 73 of the audio output block 31 controls the communication unit 75 to determine whether a sound emission has been requested, and repeats a similar process until a sound emission is requested.

[0230] Then, in step S33, when a sound emission has been requested, the process proceeds to step S34.

[0231] In step S34, the audio generation unit 73 controls the extended code generation unit 71 to generate and obtain an extended code.

[0232] In step S35, the audio generation unit 73 controls the known music source generation unit 72 to generate and obtain the stored known music source.

[0233] In step S36, the audio generation unit 73 controls the extension unit 81 to perform spread spectrum modulation on a predetermined data code by multiplying the predetermined data code by the extended code to generate an extended code signal.

[0234] In step S37, as described in the left part of the reference Figure 11 , the audio generation unit 73 controls the frequency shift processing unit 82 to perform a frequency shift on the extended code signal according to the respective frequency characteristics of the audio output units 74-1 and 74-2.

[0235] In step S38, the audio generation unit 73 outputs the known music source and the frequency-shifted extended code signal to the audio output units 74-1 and 74-2, each of which includes a speaker, to emit (output) the signal as sound.

[0236] By performing the above processing in each of the audio output blocks 31-1 to 31-4, it is possible to emit sound and allow the user having the electronic device 32 to listen to the sound as the known music source.

[0237] In addition, since the extended code signal can be shifted to a frequency band that is inaudible to the person including the user and output as sound, the electronic device 32 can measure the distance to the audio output block 31 based on the emitted sound including the extended code signal shifted to the inaudible frequency band without the user hearing unpleasant sounds.

[0238] In step S15( Figure 17 ), the audio input unit 51 including a microphone collects sound and outputs the collected sound to the known music source removal unit 91 and the space transmission characteristic calculation unit 92 of the position detection unit 52.

[0239] In step S16, the spatial transfer characteristic calculation unit 92 calculates the spatial transfer characteristic based on the sound supplied from the audio input unit 51, the characteristics of the audio input unit 51, and the characteristics of the audio output units 74-1 and 74-2 of the audio output block 31, and outputs the spatial transfer characteristic to the known music source removal unit 91 which is known.

[0240] In step S17, the known music source removal unit 91 generates an anti-phase signal of the known music source in consideration of the spatial transfer characteristic supplied from the spatial transfer characteristic calculation unit 92, removes the component of the known music source from the sound supplied from the audio input unit 51, and then outputs the result to the propagation time calculation unit 93.

[0241] In step S18, the propagation time calculation unit 93 performs a propagation time calculation process to calculate the propagation time of the sound output from the audio output block 31 to the audio input unit 51.

[0242] <Propagation time calculation process>

[0243] Here, the propagation time calculation process performed by the propagation time calculation unit 93 will be described with reference to Figure 19 the flowchart in.

[0244] In step S51, as described in the right part of reference Figure 11 , the inverse shift processing unit 130 inversely shifts the frequency band of the spread code signal obtained by removing the known music source from the sound input to the audio input unit 51 provided by the known music source removal unit 91.

[0245] In step S52, the cross-correlation calculation unit 131 calculates the cross-correlation between the spread code signal obtained by inversely shifting the frequency band of the sound input to the audio input unit 51 and removing the known music source and the spread code signal of the sound output from the audio output block 31 by using the calculations of the above equations (1) to (4).

[0246] In step S53, the peak detection unit 132 detects the peak in the calculated cross-correlation.

[0247] In step S54, the peak detection unit 132 outputs the time detected as the peak in the cross-correlation as the propagation time to the position calculation unit 95.

[0248] It should be noted that by calculating the cross-correlation with the spread code signal of the sound output from each of the multiple audio output blocks 31, the propagation time corresponding to each of the multiple audio output blocks 31 is obtained.

[0249] Here, the description returns to Figure 17 the flowchart in.

[0250] In step S19, the position calculation unit 95 selects direct waves and reflected waves for each of the plurality of audio output blocks 31 based on the propagation times corresponding to each of the plurality of audio output blocks 31, according to the first to third constraint conditions described in reference Figures 14 to 16 Thereby, for each audio output block 31, direct waves and reflected waves are selected.

[0251] In step S20, the position calculation unit 95 calculates, for each of the plurality of audio output blocks 31, the distance based on the direct wave and the distance based on the reflected wave.

[0252] In step S21, the position calculation unit 95 generates, for each of the plurality of audio output blocks 31, a set of simultaneous equations including the above equation (7) or equation (8), and solves the set of simultaneous equations to calculate its own position, and outputs the result to the control unit 42, where its own position in the above equation (7) or equation (8) is unknown according to the distance based on the direct wave and the distance based on the reflected wave.

[0253] In step S22, the control unit 42 performs processing based on the position of the electronic device 32 as the obtained own position, and ends the processing.

[0254] For example, the control unit 42 controls the communication unit 43 to send commands for controlling the level and timing of the sound output from each of the audio output units 74 of the audio output blocks 31-1 to 31-4 to the audio output blocks 31-1 to 31-4, so that a sound field based on the obtained position of the electronic device 32 can be realized.

[0255] Therefore, in the audio output blocks 31-1 to 31-4, the sound field control unit 83 controls the level and timing of the sound output from the audio output unit 74 based on the commands sent from the electronic device 32, so as to realize a sound field corresponding to the position of the user having the electronic device 32.

[0256] Through the above series of processes, the position of the electronic device 32 is measured by constructing a set of simultaneous equations based on the distance information obtained from the direct wave and the reflected wave of the sound emitted from the audio output block 31, thereby allowing the accuracy of the measured position of the electronic device 32 to be improved.

[0257] It should be noted that, in the above, an embodiment has been described in which an audio signal based on sound (sound wave) is used as a transmission medium for a modulation signal used as a ranging signal; however, a different transmission medium, such as radio wave or light, can be used. For example, in an intelligent factory or the like, a user position tracking system or the like can be realized, which determines the position of a smart phone owned by a user by transmitting and receiving a ranging signal including a modulation signal using a radio wave such as ultra-wideband (UWB) as a transmission medium.

[0258] As described above, in the case of transmitting and receiving a ranging signal including a modulated signal using radio waves such as UWB as a transmission medium, the audio output block 31 that transmits (outputs) a ranging signal including an audio signal that emits sound can be replaced by, for example, a radio wave output block 31 that transmits (outputs) a ranging signal including a radio wave signal, and can be configured to be installed at a known position in a smart factory. Further, in this case, the audio input block 41 that collects and receives (inputs) a ranging signal including an audio signal can be replaced by, for example, a radio wave input block 41 that receives (inputs) a ranging signal including a radio wave signal, etc., and can be configured to be incorporated into a smart phone owned by a user.

[0259] Further, in the case of using a transmission medium such as light in addition to sound waves and radio waves, the audio output block 31 and the audio input block 41 can be replaced by, for example, a light output block 31 and a light input block 41 that transmit and receive light signals using light as a transmission medium, and the light signals are used as ranging signals including modulated signals.

[0260] Further, the audio output block 31 and the audio input block 41 can be replaced by a ranging signal output block 31 that outputs (transmits) a ranging signal and a ranging signal input block 41 that receives (inputs) a ranging signal, respectively, regardless of the type of the transmission medium of the ranging signal.

[0261] Further, regarding the modulated signal, examples of transmitting and receiving a signal modulated by a spreading code have been described; however, other signals can be used, specifically, transmission signals such as frequency modulated continuous wave (FMCW) or BLE beacons can be used.

[0262] <<2. First Modified Example>>

[0263] In the above, an embodiment has been described in which the direct wave and the reflected wave of the sound emitted from the audio output block 31 can be collected by the electronic device 32, and the height of the ceiling is also known.

[0264] However, it can be imagined that only the direct wave or the reflected wave of the sound emitted from the audio output block 31 can be collected, or the height of the ceiling is unknown.

[0265] More specifically, for example, as Figure 20 shown, consider a state in which the audio output blocks 31-1 and 31-2 and the electronic device 32 exist, and an obstacle 101 exists at an intermediate position between the two.

[0266] In this case, as Figure 20 shown, the direct waves that propagate through the paths DP1 and DP2 of the sound emitted from the audio output blocks 31-1 and 31-2 are blocked by the obstacle 101 and do not reach the electronic device 32.

[0267] On the other hand, among the sounds emitted from the audio output blocks 31-1 and 31-2, the reflected waves that propagate through the paths RP1 and RP2 and are reflected from the ceiling reach the electronic device 32.

[0268] Therefore, the timing at which the peak of the observed cross-correlation is observed in the audio input block 41 of the electronic device 32 is detected as the waveform Figure 21 shown.

[0269] Note that in Figure 21 , the first and second from the top indicate the cross-correlation of the direct waves propagating through the paths DP1 and DP2, and the third and fourth from the top indicate the cross-correlation of the reflected waves propagating through the paths RP1 and RP2.

[0270] Comparing Figure 21 the upper two waveforms with the lower two waveforms in, there is no marked peak as indicated by the upper two waveforms in the direct waves passing through the paths DP1 and DP2, but a marked peak marked with a circle appears in the lower two waveforms in the reflected waves passing through the paths RP1 and RP2 as in Figure 21 .

[0271] Note that peaks also appear in the direct waves passing through the two paths DP1 and DP2 in Figure 21 , but it is obvious that the peaks are not the peaks of the direct waves because the peaks appear later than the peaks of the reflected waves passing through the paths RP1 and RP2, or the peaks are not significant and do not have high levels at both ends of the wave.

[0272] Therefore, in this case, as Figure 21 shown, it can be determined from the cross-correlation waveform that only the reflected wave is detected.

[0273] In this case, the position calculation unit 94 determines from the cross-correlation waveform that there is no direct wave and only the reflected wave is detected, forms a set of simultaneous equations using only the information related to the distances obtained based on the reflected wave, and measures the position of the electronic device 32 by solving the set of simultaneous equations.

[0274] Note that here, an example where the direct wave is blocked by the obstacle 101 and only the reflected wave is detected has been described; however, in the case where the reflected wave is blocked by the obstacle 101 and only the peak of the direct wave is detected, a set of simultaneous equations is formed only with the direct wave, and the set of simultaneous equations is solved to calculate the position of the electronic device 32.

[0275] In addition, when the height of the ceiling is unknown, the number of equations is increased to form simultaneous equations so that the height of the ceiling can also be regarded as unknown and is calculated together with the position of the electronic device 32. Therefore, it is desirable to install a sufficient number of audio output blocks 31 so that simultaneous equations including unknowns such as the height of the ceiling can be constructed.

[0276] <Variation of Position Measurement Processing>

[0277] Next, referring to Figure 12 the flowchart, a variation of the position measurement processing of the electronic device 32 is described in the case where the above-mentioned reflected wave and direct wave are blocked, the case where the height of the ceiling is known, and the case where the height of the ceiling is unknown.

[0278] Note that the processing of the audio output block 31 is similar to the processing described in the flowchart of Figure 17 and thus its description is omitted.

[0279] In addition, Figure 12 Steps S51 to S59 and S63 of Figure 17 are the same as Steps S11 to S19 and S22 of

[0280] That is, in Steps S51 to 59 of the flowchart of Figure 12 , the sound emitted from the audio output block 31 is collected, the propagation time from the audio output block 31 is calculated, and the direct wave and the reflected wave are determined, and then the processing proceeds to Step S60.

[0281] In Step S60, as described in referring to Figure 20 and 21 , the position calculation unit 95 determines whether only the reflected wave is detected based on the cross-correlation of the direct wave and the reflected wave.

[0282] If it is determined in Step S60 that only the reflected wave is detected, the process proceeds to Step S61.

[0283] In Step S61, the position calculation unit 95 calculates the distance based only on the reflected wave of each of the plurality of audio output blocks 31.

[0284] In Step S62, the position calculation unit 95 generates simultaneous equations including the above-mentioned equation (7) or equation (8) (wherein only the distance based on the reflected wave, its own position, and the height of the ceiling are unknown) for each of the plurality of audio output blocks 31, solves the simultaneous equations to calculate its own position and the height of the ceiling, and outputs the result to the control unit 42. Note that here, it is assumed that the height of the ceiling is unknown, but in the case where the height of the ceiling is known, the height of the ceiling is substituted and used for the calculation.

[0285] On the other hand, when it is determined in step S60 that not only the reflected wave but also the direct wave is detected, the process proceeds to step S64.

[0286] In step S64, the position calculation unit 95 calculates the distance based on the direct wave and the distance based on the reflected wave for each of the plurality of audio output blocks 31.

[0287] In step S65, the position calculation unit 95 determines whether the height of the ceiling is known.

[0288] When it is determined in step S65 that the height of the ceiling is known, the process proceeds to step S66.

[0289] In step S66, the position calculation unit 95 generates a system of simultaneous equations including the above equation (7) or equation (8) for each of the plurality of audio output blocks 31, solves the system of simultaneous equations to calculate its own position, and outputs the result to the control unit 42. In the above equation (7) or equation (8), only the own position is unknown based on the distance based on the direct wave and the distance based on the reflected wave.

[0290] On the other hand, when it is determined in step S65 that the height of the ceiling is unknown, the process proceeds to step S67.

[0291] In step S67, the position calculation unit 95 generates a system of simultaneous equations including the above equation (7) or equation (8) (where the own position and the height of the ceiling are unknown) from the distance based on the direct wave and the distance based on the reflected wave for each of the plurality of audio output blocks 31, solves the system of simultaneous equations to calculate its own position and the height of the ceiling, and outputs the result to the control unit 42.

[0292] Through the above processing, even when the sound includes only the reflected wave (or direct wave) due to an obstacle preventing the direct wave (or reflected wave) from being collected, the distance can be obtained and a system of simultaneous equations can be formed based on only the successfully collected reflected wave (direct wave), and the position of the electronic device 32 can be obtained based on cross-correlation.

[0293] In addition, the height of the top plate can be obtained using substantially the same processing regardless of whether the height is known or unknown.

[0294] In either case, since the position of the electronic device 32 can be calculated using basically two paths: the direct wave and the reflected wave, the position can be obtained with high precision. In addition, even if the direct wave or the reflected wave cannot be detected for some reason, the position of the electronic device 32 can be calculated using only the detected direct wave or reflected wave.

[0295] <<3. Second Modification Example>>

[0296] In the foregoing, embodiments have been described in which the audio output blocks 31-1 to 31-4 are installed indoors and the position of the electronic device 32 is measured while being carried.

[0297] The size of the indoor space can vary, and examples of the indoor space can include a gymnasium, a hall, etc.

[0298] At this time, in the case of a conventional positioning system, for example, in order to implement a positioning system using detection devices including an infrared sensor, a camera, etc., it is necessary to install detection devices 141-11 and 141-12, etc. on the ceiling 142 to cover a wide range as shown in the left part of Figure 23 the figure.

[0299] In this case, it is necessary to install the detection devices 141-11 and 141-12 on the ceiling 142, and in places such as a gymnasium and a hall, such installation may be time-consuming.

[0300] However, in the acoustic positioning system of the present disclosure, for example, as shown in the right part of Figure 23 the figure, a wide range can be covered only by placing the audio output blocks 31-11 and 31-12 on the floor surface 151 of a gymnasium or a hall.

[0301] As described above, the acoustic positioning system can be easily set up, and the position of the electronic device 32 can be measured with high precision by measuring the position using direct waves and reflected waves.

[0302] <<4. Third Variant Example>>

[0303] In the foregoing, embodiments have been described in which the audio output block 31 is installed by being placed on the floor; however, for example, as shown in Figure 24 the figure, the audio output block can be provided on the ceiling or the like.

[0304] Figure 24 An embodiment of the acoustic positioning system is shown in which the audio output blocks 31-21 and 31-22 are provided on the ceiling of a gymnasium or a hall.

[0305] In this case, the position of the electronic device 32 can be obtained based on the sound emitted from each of the audio output blocks 31-21 and 31-22, the sound including direct waves collected through paths DP21 and DP22 and reflected waves collected through paths RP21 and RP22.

[0306] At this time, the reflected waves through paths RP21 and RP22 are reflected from the bottom surface 161 and collected by the electronic device 32.

[0307] Even in a case having a structure as shown in Figure 24In the acoustic positioning system configured as shown, the position of the electronic device 32 can also be measured with high accuracy by using distance results obtained from direct waves passing through paths DP21 and DP22 and reflected waves passing through paths RP21 and RP22 to form simultaneous equations.

[0308] <<5. Fourth Modification Example>>

[0309] In the above, an embodiment has been described in which the audio output block 31 is provided on a ceiling or the like and reflected waves reflected from the floor surface are used; however, the reflecting object is not limited to the ceiling or the floor surface, and any object that reflects sound, such as a wall, can be used.

[0310] Figure 25 An embodiment of the acoustic positioning system is shown, in which audio output blocks 31-31 are installed on the floor surface of a gymnasium or a hall, and the emitted sound is reflected from the wall surface 171 and used as a reflected wave.

[0311] In this case, the sound emitted from the audio output blocks 31-31 is collected by the electronic device 32 as sound including a direct wave passing through path DP31 and a reflected wave passing through path RP31, and the position can be obtained.

[0312] At this time, the sound including the reflected wave passing through path RP31 is reflected from the wall surface 171 and collected by the electronic device 32.

[0313] Even in the acoustic positioning system configured as shown in Figure 25 the position of the electronic device 32 can also be measured with high accuracy by using distance results obtained from the direct wave passing through path DP31 and the reflected wave passing through path RP31 to form simultaneous equations.

[0314] In addition, based on the simultaneous equations of the respective distances based on the combination of the reflected waves reflected from the ceiling, the ground, and the wall, the position can be measured with higher accuracy.

[0315] <<6. Fifth Modification Example>>

[0316] In the above, it has been described that the acoustic positioning system includes: an audio output block 31 that emits sound; however, a configuration that combines the functions of the audio output block 31 and the functions of the electronic device 32 that measures the position can also be adopted.

[0317] Figure 26The acoustic positioning system therein includes audio output blocks 201-1 and 201-2, each including a combination of the functions of the audio output block 31 and the electronic device 32 as the measurement position. The audio output blocks 201-1 and 201-2 include audio output units 74-1-1 and 74-2-1, and 74-1-2 and 74-2-2 that emit sounds, and audio input units 51-1 and 51-2, which respectively have the functions of the above-mentioned audio output block 31 and electronic device 32.

[0318] As Figure 26 shown, this configuration allows the audio output blocks 201-1 and 201-2 to transmit and receive spread code signals.

[0319] Therefore, an acoustic positioning system as shown in the Figure 27 upper part can be realized. Note that Figure 27 the acoustic positioning system in the upper part of includes audio output blocks 201-1 to 201-n and 201-x, and each audio output block includes a combination of the functions of the audio output block 31 and the electronic device 32 as the measurement position.

[0320] Each of the audio output blocks 201-1 to 201-n and 201-x includes audio output units 74-1 and 74-2 that emit sounds and an audio input unit 51, and has the functions of the above-mentioned audio output block 31 and electronic device 32.

[0321] Here, as shown in the Figure 27 upper part of, the case where the acoustic positioning system includes audio output blocks 201-1 to 201-n with known positions and an audio output block 201-x with an unknown position is considered.

[0322] In Figure 27 the case of the upper part of, the audio output blocks 201-1 to 201-n with known positions act as the above-mentioned audio output block 31, and the audio output block 201-x with an unknown position acts as the electronic device 32.

[0323] Therefore, when the audio output block 201-x is newly installed, its own installation position can be measured.

[0324] After installing the audio output block 201-x and measuring the position, as shown in the Figure 27 lower part of, when a new audio output block 201-y is installed alone, not only are the positions of the audio output blocks 201-1 to 201-n known, but also the position of the audio output block 201-x is known.

[0325] Therefore, in addition to the audio output blocks 201-1 to 201-n, the audio output block 201-x serves as the audio output block 31, such that the newly installed audio output block 201-y functions similarly to the electronic device 32, enabling the measurement of the newly installed position.

[0326] As described above, after installing the audio output blocks 201 with known reference positions in a sufficient number to form simultaneous equations, the position of the newly installed audio output block 201 can be measured sequentially using the position measurement process.

[0327] This eliminates the need to measure the position separately when installing a new audio output block 201.

[0328] <<7. Embodiment Executed by Software>>

[0329] Incidentally, the above series of processes can be executed by hardware, but can also be executed by software. In the case where the series of processes are executed by software, the program forming the software is installed from a recording medium into, for example, a computer built into dedicated hardware or a general-purpose computer capable of executing various functions by installing various programs.

[0330] Figure 28 An example of the configuration of a general-purpose computer is shown. This computer includes a central processing unit (CPU) 1001. The input / output interface 1005 is connected to the CPU 1001 via a bus 1004. A read-only memory (ROM) 1002 and a random access memory (RAM) 1003 are connected to the bus 1004.

[0331] The input / output interface 1005 is connected to an input unit 1006, an output unit 1007, a storage unit 1008, and a communication unit 1009. The input unit 1006 includes input devices (such as a keyboard or mouse for a user to input operation commands). The output unit 1007 outputs images of a processing operation screen and processing results to a display device. The storage unit 1008 includes a hard disk drive or the like for storing programs and various types of data. The communication unit 1009 includes a local area network (LAN) adapter or the like and performs communication processing via a network represented by the Internet. In addition, a drive 1010 for reading data from and writing data to a removable storage medium 1011 such as a magnetic disk (including a floppy disk), an optical disk (including a compact disc read-only memory (CD-ROM) and a digital versatile disc (DVD)), a magneto-optical disk (including a mini disc (MD)), or a semiconductor memory is connected.

[0332] The CPU 1001 performs various types of processing according to a program stored in the ROM 1002 or a program read from a removable storage medium 1011 (such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory) that is installed in the storage unit 1008 and loaded from the storage unit 1008 into the RAM 1003. The RAM 1003 also appropriately stores data required for the CPU 1001 to perform various types of processing and the like.

[0333] In the computer configured as described above, for example, the CPU 1001 loads a program stored in the storage unit 1008 into the RAM 1003 via the input / output interface 1005 and the bus 1004 and executes the program, thereby performing the above-described series of processes.

[0334] For example, a program executed by a computer (CPU 1001) can be provided by being recorded on a removable storage medium 1011 such as an encapsulated medium. In addition, the program can be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

[0335] In the computer, the program can be installed in the storage unit 1008 via the input / output interface 1005 by attaching the removable storage medium 1011 to the drive 1010. In addition, the program can be received by the communication unit 1009 via a wired or wireless transmission medium for installation on the storage unit 1008. In addition, the program can be installed in the ROM 1002 or the storage unit 1008 in advance.

[0336] It should be noted that a program executed by a computer can be a program that performs processing in time series according to the order described in this specification, or can be a program that performs processing in parallel or at a necessary timing such as when a call is made.

[0337] Note that [[ID=--]]Figure 28 the CPU 1001 in Figure 28 Figure 1 implements the functions of the audio output block 31 and the audio input block 41 in

[0338] In addition, in this specification, a system means a group of multiple components (devices, modules (components), etc.), and it does not matter whether all the components are in the same housing. Therefore, multiple devices housed in separate housings and connected to each other via a network and a single device including multiple modules housed in a single housing are both systems.

[0339] It should be noted that the embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present disclosure.

[0340] For example, the present disclosure may have a cloud computing configuration, in which a function is shared by multiple devices via a network and processing is collaboratively performed.

[0341] In addition, each step described in the above flowchart may be executed by one device or may be executed by multiple devices in a shared manner.

[0342] In addition, in the case where a step includes multiple processes, the multiple processes included in one step may be executed by one device or may be executed by multiple devices in a shared manner.

[0343] It should be noted that the present disclosure may also have the following configurations.

[0344] <1>A program that causes a computer to function as:

[0345] An audio receiving unit configured to receive an audio signal that includes a spread code signal obtained by performing spread spectrum modulation on a spreading code, the audio signal being output from each of a plurality of audio output blocks located at known positions;

[0346] A position calculation unit configured to calculate the position of the audio receiving unit based on the distances to the plurality of audio output blocks, the distances being determined based on the propagation time, which is the time taken for the audio signals of the plurality of audio output blocks to be transmitted to and received by the audio receiving unit, where

[0347] the audio receiving unit receives the audio signal transmitted through a direct wave from the plurality of audio output blocks and the audio signal transmitted through a reflected wave reflected by a reflector after being output from the plurality of audio output blocks, and

[0348] the position calculation unit calculates the position of the audio receiving unit based on the audio signals transmitted by each of the direct wave and the reflected wave.

[0349] <2>The program according to <1>, wherein

[0350] it further includes a propagation time calculation unit that calculates the propagation time taken for each of the audio signals of the plurality of audio output blocks to be transmitted to the audio receiving unit, and

[0351] the position calculation unit calculates the position of the audio receiving unit based on the distances to the plurality of audio output blocks and the known positions of the plurality of audio output blocks, the distances being determined based on the propagation time of each of the direct wave and the reflected wave of the audio signals of the plurality of audio output blocks.

[0352] <3>The program according to <2>, wherein

[0353] the propagation time calculation unit includes:

[0354] A cross - correlation calculation unit that calculates the cross - correlation between the spread - code signal in the audio signal received by the audio receiving unit and the spread - code signal in the audio signals output from multiple audio output blocks; and

[0355] A peak detection unit that detects the time when a peak appears in the cross - correlation as the propagation time, and

[0356] A position calculation unit selects the peak of the direct wave and the peak of the reflected wave from the peaks in the cross - correlation, and calculates the position of the audio receiving unit based on the distances to the multiple audio output blocks and the known positions of the multiple audio output blocks. The distances are determined based on the propagation times of the audio signals corresponding to each of the selected peak of the direct wave and the selected peak of the reflected wave.

[0357] <4>The program according to <3>, wherein

[0358] The position calculation unit selects the peak of the direct wave and the peak of the reflected wave from the peaks in the cross - correlation according to the geometric constraint conditions determined based on the known positions of the multiple audio output blocks, and calculates the position of the audio receiving unit based on the distances to the multiple audio output blocks and the known positions of the multiple audio output blocks. The distances are determined based on the propagation times corresponding to each of the selected peak of the direct wave and the selected peak of the reflected wave.

[0359] <5>The program according to <4>, wherein

[0360] The position calculation unit selects the peak of the direct wave and the peak of the reflected wave from the peaks in the cross - correlation. The time difference between the peak of the direct wave and the peak of the reflected wave is within a predetermined range according to the geometric constraint conditions determined based on the known positions of the multiple audio output blocks, and the peak of the direct wave appears earlier than the peak of the reflected wave. Then, based on the distances to the multiple audio output blocks and the known positions of the multiple audio output blocks, the position of the audio receiving unit is calculated. The distances are determined based on the propagation times corresponding to each of the selected peak of the direct wave and the selected peak of the reflected wave.

[0361] <6>The program according to <2>, wherein

[0362] When the position of the reflector is unknown, the position calculation unit calculates the position of the audio receiving unit and the position of the reflector based on the distances to the multiple audio output blocks and the known positions of the multiple audio output blocks. The distances are determined based on the propagation times of each of the direct wave and the reflected wave of the audio signals of the multiple audio output blocks.

[0363] <7>The program according to <6>, wherein

[0364] In a case where the reflecting object is a ceiling and the height of the ceiling is unknown, the position calculation unit calculates the position of the audio receiving unit and the height of the ceiling based on the distances to a plurality of audio output blocks and the known positions of the plurality of audio output blocks, where the distances are determined based on the propagation times of each of the direct waves and the reflected waves of the audio signals of the plurality of audio output blocks.

[0365] <8>The program according to <3>, wherein,

[0366] In a case where the position calculation unit cannot select, from the peaks in the cross-correlation, the peak corresponding to the peak of the direct wave according to the geometric constraint conditions determined based on the known positions of the plurality of audio output blocks, the position calculation unit only selects the peak of the reflected wave, and calculates the position of the audio receiving unit based on the distances to the plurality of audio output blocks and the known positions of the plurality of audio output blocks, where the distances are determined based on the propagation time corresponding to the selected peak of the reflected wave.

[0367] <9>The program according to <1>, wherein,

[0368] Each of the plurality of audio output blocks outputs an audio signal including a spreading code signal as a direct wave and an audio signal including a spreading code signal as a reflected wave.

[0369] <10>The program according to <9>, wherein,

[0370] Each of the plurality of audio output blocks outputs, toward the horizontal direction, an audio signal including a spreading code signal as a direct wave, and outputs, toward the ceiling as a reflecting object, an audio signal including a spreading code signal as a reflected wave.

[0371] <11>The program according to <10>, wherein,

[0372] Each of the plurality of audio output blocks uses a woofer to output, toward the horizontal direction, an audio signal including a spreading code signal as a direct wave, and uses an enabled speaker to output, toward the ceiling as a reflecting object, an audio signal including a spreading code signal.

[0373] <12>The program according to <1>, wherein,

[0374] The reflecting object includes a ceiling, a floor, and a wall.

[0375] <13>The program according to <1>, wherein,

[0376] The audio receiving unit is provided on a smart phone or a head-mounted display (HMD).

[0377] <14>An information processing apparatus, comprising:

[0378] An audio receiving unit that receives an audio signal including a spread code signal obtained by performing spread spectrum modulation on a spread code, the audio signal being output from each of a plurality of audio output blocks located at known positions; and

[0379] A position calculation unit that calculates the position of the audio receiving unit based on the distances to the plurality of audio output blocks, the distances being determined based on the propagation time, which is the time taken for the audio signals of the plurality of audio output blocks to be transmitted to and received by the audio receiving unit, where

[0380] the audio receiving unit receives the audio signal transmitted by the direct wave from the plurality of audio output blocks and the audio signal transmitted by the reflected wave reflected by a reflector after being output from the plurality of audio output blocks, and

[0381] the position calculation unit calculates the position of the audio receiving unit based on the audio transmitted by each of the direct wave and the reflected wave.

[0382] <15>An information processing method of an information processing apparatus, the information processing apparatus including:

[0383] An audio receiving unit that receives an audio signal including a spread code signal obtained by performing spread spectrum modulation on a spread code, the audio signal being output from each of a plurality of audio output blocks located at known positions; and

[0384] A position calculation unit that calculates the position of the audio receiving unit based on the distances to the plurality of audio output blocks, the distances being determined based on the propagation time, which is the time taken for the audio signals of the plurality of audio output blocks to be transmitted to and received by the audio receiving unit,

[0385] The information processing method includes:

[0386] causing the audio receiving unit to receive the audio signal transmitted by the direct wave from the plurality of audio output blocks and the audio signal transmitted by the reflected wave reflected by a reflector after being output from the plurality of audio output blocks, and

[0387] causing the position calculation unit to calculate the position of the audio receiving unit based on the audio signals transmitted by each of the direct wave and the reflected wave.

[0388] Symbol Explanation

[0389] 11 Acoustic positioning system

[0390] 31, 31-1 to 31-4 Audio output blocks

[0391] 32 Electronic device

[0392] 41 Audio input block

[0393] 42 Control Unit

[0394] 43 Communication Unit

[0395] 51, 51-1 to 51-4 Audio Input Units

[0396] 71 Extended Code Generation Unit

[0397] 72 Known Music Source Generation Unit

[0398] 73 Audio Generation Unit

[0399] 74 Audio Output Unit

[0400] 81 Extension Unit

[0401] 82 Frequency Shift Processing Unit

[0402] 83 Sound Field Control Unit

[0403] 91 Known Music Source Removal Unit

[0404] 92 Spatial Transmission Characteristics Calculation Unit

[0405] 93 Propagation Time Calculation Unit

[0406] 94 Position Calculation Unit.

Claims

1. A program that causes a computer to function as: A ranging signal receiving unit configured to receive a ranging signal including an extended code signal obtained by performing spread spectrum modulation using an extended code, the ranging signal being output from each of a plurality of ranging signal output blocks located at known positions; and A position calculation unit configured to calculate the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks, the distances being determined based on the propagation time, which is the time taken for the ranging signals of the plurality of ranging signal output blocks to be transmitted to and received by the ranging signal receiving unit, where The ranging signal receiving unit receives the ranging signal transmitted by direct wave from the plurality of ranging signal output blocks and the ranging signal transmitted by reflected wave reflected by a reflector after being output from the plurality of ranging signal output blocks, and The position calculation unit calculates the position of the ranging signal receiving unit based on the ranging signals transmitted by each of the direct wave and the reflected wave.

2. The program according to claim 1, wherein It further includes a propagation time calculation unit that calculates the propagation time taken for each of the ranging signals of the plurality of ranging signal output blocks to be transmitted to the ranging signal receiving unit, and The position calculation unit calculates the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks and the known positions of the plurality of ranging signal output blocks, the distances being determined based on the propagation time of each of the direct wave and the reflected wave of the ranging signals of the plurality of ranging signal output blocks.

3. The program according to claim 2, wherein The propagation time calculation unit includes: A cross-correlation calculation unit that calculates the cross-correlation between the extended code signal in the ranging signal received by the ranging signal receiving unit and the extended code signal in the ranging signal output from the plurality of ranging signal output blocks; and A peak detection unit that detects the time when a peak appears in the cross-correlation as the propagation time, and The position calculation unit selects the peak of the direct wave and the peak of the reflected wave from the peaks in the cross-correlation, and calculates the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks and the known positions of the plurality of ranging signal output blocks, the distances being determined based on the propagation time of the ranging signal corresponding to each of the selected peak of the direct wave and the selected peak of the reflected wave.

4. The program according to claim 3, wherein The position calculation unit selects the peak of the direct wave and the peak of the reflected wave from the peaks in the cross-correlation according to the geometric constraint conditions determined based on the known positions of the plurality of ranging signal output blocks, and calculates the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks and the known positions of the plurality of ranging signal output blocks, where the distances are determined based on the propagation times corresponding to each of the selected peak of the direct wave and the selected peak of the reflected wave.

5. The program according to claim 4, wherein the position calculation unit selects the peak of the direct wave and the peak of the reflected wave from the peaks in the cross-correlation, the time difference between the peak of the direct wave and the peak of the reflected wave is within a predetermined range according to the geometric constraint conditions determined based on the known positions of the plurality of ranging signal output blocks, the peak of the direct wave appears earlier than the peak of the reflected wave, and calculates the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks and the known positions of the plurality of ranging signal output blocks, where the distances are determined based on the propagation times corresponding to each of the selected peak of the direct wave and the selected peak of the reflected wave.

6. The program according to claim 2, wherein when the position of the reflector is unknown, the position calculation unit calculates the position of the ranging signal receiving unit and the position of the reflector based on the distances to the plurality of ranging signal output blocks and the known positions of the plurality of ranging signal output blocks, where the distances are determined based on the propagation times of each of the direct wave and the reflected wave of the ranging signals of the plurality of ranging signal output blocks.

7. The program according to claim 6, wherein when the reflector is the ceiling and the height of the ceiling is unknown, the position calculation unit calculates the position of the ranging signal receiving unit and the height of the ceiling as the reflector based on the distances to the plurality of ranging signal output blocks and the known positions of the plurality of ranging signal output blocks, where the distances are determined based on the propagation times of each of the direct wave and the reflected wave of the ranging signals of the plurality of ranging signal output blocks.

8. The program according to claim 3, wherein when the position calculation unit cannot select the peak corresponding to the peak of the direct wave from the peaks in the cross-correlation according to the geometric constraint conditions determined based on the known positions of the plurality of ranging signal output blocks, the position calculation unit only selects the peak of the reflected wave, and calculates the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks and the known positions of the plurality of ranging signal output blocks, where the distances are determined based on the propagation time corresponding to the selected peak of the reflected wave.

9. The program according to claim 1, wherein Each of the plurality of ranging signal output blocks outputs a ranging signal including the spread code signal as the direct wave and a ranging signal including the spread code signal as the reflected wave.

10. The program according to claim 9, wherein, Each of the plurality of ranging signal output blocks outputs the ranging signal including the spread code signal as the direct wave toward the horizontal direction, and outputs the ranging signal including the spread code signal as the reflected wave toward the ceiling as the reflector.

11. The program according to claim 10, wherein, Each of the plurality of ranging signal output blocks uses a woofer to output the ranging signal including the spread code signal as the direct wave toward the horizontal direction, and uses an enabled speaker to output the ranging signal including the spread code signal toward the ceiling as the reflector.

12. The program according to claim 1, wherein, The reflector includes a ceiling, a floor, and a wall.

13. The program according to claim 1, wherein, The ranging signal receiving unit is provided on a smart phone or a head-mounted display (HMD).

14. The program according to claim 1, wherein, The ranging signal includes an audio signal, a radio wave signal, and an optical signal.

15. An information processing apparatus, comprising: A ranging signal receiving unit that receives a ranging signal including a spread code signal obtained by performing spread spectrum modulation using a spread code, the ranging signal being output from each of a plurality of ranging signal output blocks located at known positions; And A position calculation unit that calculates the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks, the distances being determined based on the propagation time, which is the time taken for the ranging signal of the plurality of ranging signal output blocks to be transmitted to and received by the ranging signal receiving unit, wherein, The ranging signal receiving unit receives the ranging signal transmitted through the direct wave from the plurality of ranging signal output blocks and the ranging signal transmitted through the reflected wave reflected by a reflector after being output from the plurality of ranging signal output blocks, and The position calculation unit calculates the position of the ranging signal receiving unit based on the ranging signal transmitted by each of the direct wave and the reflected wave.

16. An information processing method of an information processing apparatus, the information processing apparatus including: A ranging signal receiving unit that receives a ranging signal including a spread code signal obtained by performing spread spectrum modulation using a spread code, the ranging signal being output from each of a plurality of ranging signal output blocks located at known positions; And A position calculation unit that calculates the position of the ranging signal receiving unit based on the distances to the plurality of ranging signal output blocks, the distances being determined based on the propagation time, which is the time taken for the ranging signal of the plurality of ranging signal output blocks to be transmitted to and received by the ranging signal receiving unit, The information processing method includes: Cause the ranging signal receiving unit to receive the ranging signal transmitted by the direct wave from the plurality of ranging signal output blocks and the ranging signal transmitted by the reflected wave reflected by the reflector after being output from the plurality of ranging signal output blocks, and Cause the position calculation unit to calculate the position of the ranging signal receiving unit based on the ranging signals transmitted by each of the direct wave and the reflected wave.

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