Information processing device and method

Abstract

To provide a technique concerning sound field simulation.SOLUTION: Provided is an information processing device including a control unit. The control unit, in a virtual three-dimensional space, for a first component 11 that arrives at an observation point 20 from a sound source 10 by a shortest distance, adjusts a sound pressure level and an arrival timing at the observation point based on a representative frequency band of the sound source 10 and a material of an obstacle 30 through which the first component passes, and for a second component 12 other than the first component, adjusts a sound pressure level and an arrival timing at the observation point based on the representative frequency band of the sound source 10, combines the adjusted first component 11 and second component 12 in a ratio depending on an attribute of the sound source 10 and an attribute of the obstacle 30 to generate a synthetic sound, and simulates the generated synthetic sound as a sound that propagates in the virtual three-dimensional space from the sound source 10 to arrive at the observation point 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an information processing device and method. [Background technology]

[0002] Conventionally, a technology related to sound generation in a virtual space is known. For example, Patent Document 1 discloses a sound generation device having a sound processing means in which signal processing means capable of processing sound data are hierarchically connected, and an output destination determination means for determining an output destination of the sound source means based on the positional relationship between a sound source and a virtual sound receiving point. Patent Document 1 also discloses a technology for processing sound data using a first adjustment means for adjusting the volume of the sound data based on a parameter for determining the change in the sound that reaches the sound receiving point linearly by passing through an object from the sound source, and a second adjustment means for adjusting the volume of the sound data based on a parameter for determining the change in the sound that reaches the sound receiving point from the sound source by diffracting the object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-31303 A Summary of the Invention [Problem to be solved by the invention]

[0004] In sound field simulations that reproduce sound fields, especially large outdoor sound fields, in virtual three-dimensional spaces, the amount of calculation required is enormous because sound data from the sound source is calculated based on the direct sound and diffracted sound, etc. However, in the past, the amount of calculation was not sufficiently reduced, and there was room for improvement in technology related to sound field simulations.

[0005] In view of the above circumstances, an object of the present disclosure is to improve technology relating to sound field simulation. [Means for solving the problem]

[0006] An information processing device according to an embodiment of the present disclosure includes: An information processing device including a control unit, The control unit is adjusting a sound pressure level and an arrival time at an observation point of a first component that arrives at a shortest distance from a sound source to the observation point in a virtual three-dimensional space based on a representative frequency band of the sound source and a material of an obstacle through which the first component passes; For a second component other than the first component, a sound pressure level and an arrival timing at the observation point are adjusted based on a representative frequency band of the sound source; generating a synthetic sound by combining the adjusted first component and the adjusted second component in a ratio according to the attribute of the sound source and the attribute of the obstacle; The generated synthetic sound is simulated as sound propagating from the sound source through the virtual three-dimensional space to reach the observation point.

[0007] According to one embodiment of the present disclosure, the method comprises: A method executed by an information processing device, comprising: adjusting a sound pressure level and an arrival timing of a first component that arrives at an observation point in a shortest distance from a sound source in a virtual three-dimensional space based on a representative frequency band of the sound source and a material of an obstacle through which the first component passes; For a second component other than the first component, adjusting a sound pressure level and an arrival timing at the observation point based on a representative frequency band of the sound source; and generating a synthetic sound by combining the adjusted first component and the adjusted second component in a ratio according to an attribute of the sound source and an attribute of the obstacle; The generated synthetic sound is simulated as sound propagating from the sound source through the virtual three-dimensional space to reach the observation point. Effect of the Invention

[0008] According to one embodiment of the present disclosure, techniques relating to sound field simulation are improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a conceptual diagram of a simulation in a virtual three-dimensional space. [Diagram 2] 1 is a block diagram showing a schematic configuration of an information processing device; [Diagram 3] 4 is a flowchart showing an operation of the information processing device. [Figure 4] FIG. 1 is a diagram showing a specific example of a virtual three-dimensional space. [Diagram 5] FIG. 13 is a diagram showing another specific example of a virtual three-dimensional space. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described.

[0011] <Overview of the embodiment> With reference to FIG. 1, an overview of a simulation by an information processing device according to an embodiment of the present disclosure will be described. FIG. 1 is a conceptual diagram of a simulation in a virtual three-dimensional space VS. In the virtual three-dimensional space VS created in the information processing device, there are a sound source 10, an observation point 20, and an obstacle 30 between them. The virtual three-dimensional space VS is configured to correspond to a real sound field. A sound from the sound source 10 reaches the observation point 20 by a first component (Direct Path component, sometimes called "direct sound") 11 that passes from the sound source 10 through the obstacle 30 and reaches the observation point 20 in the shortest distance, and a second component (Reflection Path component, sometimes called "reflected sound") 12 that is a component other than the first component. The second component is a diffracted sound that reaches the observation point 20 by detouring the obstacle 30. Note that the second component may include a reflected sound that is reflected from the sound source 10 by surrounding structures and reaches the observation point 20.

[0012] The real sound source 10 emits sound waves with a specific tone including various frequency components, but in the simulation according to this embodiment, the sound source 10 emits only the frequency components of the representative frequency band at a specific sound pressure level. As described later, among the sounds emitted by the real sound source 10, the frequency at which the peak of the sound pressure level appears and the frequency range nearby the frequency band are specified as the representative frequency band of the sound source 10. Note that instead of the representative frequency band, the frequency of the peak of the sound pressure level may be set as the representative frequency, and the sound source 10 may emit a sound of the representative frequency. Since the acoustic characteristics of the sound, such as the attenuation rate, differ depending on the frequency, a simulation based on the acoustic characteristics of the representative frequency band (or the representative frequency) can sufficiently reproduce the transmission of the real sound with a small amount of calculation. In addition, since the transmission of the sound is affected by the sound pressure level, each sound (sound source) has the sound pressure level as one of the attributes of the sound.

[0013] The observation point 20 is a point where sound propagating from the sound source 10 is observed. In the simulation according to this embodiment, a composite sound of a first component (direct sound) 11 and a second component (reflected sound) 12 that arrive at the observation point 20 at their respective arrival times from the sound source 10 is simulated as a sound heard by a person at that point.

[0014] The obstacle 30 is placed on the path that takes the shortest distance from the sound source 10 to the observation point 20. There are many different types of obstacles in reality, but in the simulation according to this embodiment, the obstacles 30 are classified into a number of obstacle groups. In addition, in the simulation, the material of the obstacle is set for each obstacle group, and the attenuation characteristics and propagation speed of sound passing through are set for each material. This setting makes it possible to reproduce the transmission of sound in reality with a small amount of calculation. Furthermore, each obstacle 30 has its size as one of its attributes.

[0015] First, an overview of this embodiment will be described, and details will be described later. In the simulation, the representative frequency band of the sound of the sound source 10 and the material of the obstacle 30 are specified. For a first component (direct sound) that passes from the sound source 10 through the obstacle 30 and arrives at the observation point 20 in the shortest distance, the information processing device (control unit) adjusts the sound pressure level at the observation point 20 and the arrival timing at the observation point 20 based on the representative frequency band of the sound source 10 and the material of the obstacle 30. Also, for a second component (reflected sound) other than the first component, the sound pressure level at the observation point 20 and the arrival timing at the observation point 20 based on the representative frequency band of the sound source 10. Next, the information processing device (control unit) generates a synthetic sound by combining the first component and the second component whose volume has been adjusted in a ratio according to the attribute of the sound source 10 (for example, sound pressure level) and the attribute of the obstacle 30 (for example, size of the obstacle 30). The generated synthetic sound simulates the sound that arrives at the observation point 20, i.e., the sound observed at the observation point 20.

[0016] Thus, according to this embodiment, the sound emitted by the sound source 10 is limited to a representative frequency band, and a simulation of the sound field is executed. In addition, the sound from the sound source 10 is divided into a first component (direct sound) 11 that passes through the obstacle 30 and a second component (reverberation sound) other than the first component, and is adjusted based on the representative frequency of the sound source 10 and the characteristics of the material of the obstacle 30. Furthermore, a synthetic sound is generated by combining the first component and the second component at a ratio according to the attributes of the sound source 10 and the attributes of the obstacle 30. Therefore, for example, when reproducing an actual outdoor sound field in a virtual three-dimensional space, the amount of calculation for the sound emitted by the sound source 10 hidden by the obstacle 30 can be reduced. Therefore, the technology related to the sound field simulation is improved in that it is easier to suppress an increase in the amount of calculation while ensuring the reproducibility of the sound field.

[0017] Next, the information processing device 50 that performs the simulation will be described in detail.

[0018] <Configuration of information processing device> The information processing device 50 is, for example, a computer such as a server device, etc. As shown in FIG.

[0019] The communication unit 51 includes one or more communication interfaces for connecting to a network or the like. The communication interface corresponds to, for example, a mobile communication standard such as 4G (4th Generation) or 5G (5th Generation), a wired LAN (Local Area Network) standard, or a wireless LAN standard, but is not limited thereto, and may correspond to any communication standard. In this embodiment, the information processing device 50 can communicate with other devices via the communication unit 51. Note that the information processing device 50 may exchange setting conditions and simulation results of the virtual three-dimensional space according to this embodiment via the communication unit 51.

[0020] The input unit 52 includes at least one input interface. The input interface is, for example, a physical key, a capacitive key, a pointing device, or a touch screen integrally provided with a display. The input unit 52 accepts an operation for inputting data used for the operation of the information processing device 50. The input unit 52 may be connected to the information processing device 50 as an external input device instead of being provided in the information processing device 50. As the connection interface, for example, an interface compatible with standards such as USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface) (registered trademark), or Bluetooth (registered trademark) can be used.

[0021] The output unit 53 may include one or more output devices that output information to notify the user. The output devices may be, for example, but are not limited to, a speaker that outputs information as sound, or a display that outputs information as an image or video. The output unit 53 may include an interface for connecting an external output device.

[0022] The storage unit 54 includes one or more memories. Each memory included in the storage unit 54 may function as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 54 stores any information used in the operation of the information processing device 50. For example, the storage unit 54 may store a system program, an application program, a database, and the like. In this embodiment, an acoustic database in which various data used in the simulation is accumulated is stored in the storage unit 54. The information stored in the storage unit 54 may be updatable with information acquired via the communication unit 51, for example.

[0023] The control unit 55 includes one or more processors, one or more programmable circuits, one or more dedicated circuits, or a combination thereof. The processor is, for example, but is not limited to, a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for a specific process. The programmable circuit is, for example, but is not limited to, an FPGA (Field-Programmable Gate Array). The dedicated circuit may be, for example, an ASIC (Application Specific Integrated Circuit). The control unit 55 controls the operation of the entire information processing device 50.

[0024] The functions of the information processing device 50 are realized by executing a program according to this embodiment on a processor serving as the control unit 55. That is, the functions of the information processing device 50 are realized by software. The program causes a computer to execute the operations of the information processing device 50, thereby causing the computer to function as the information processing device 50. That is, the computer functions as the information processing device 50 in accordance with the program.

[0025] The program can be stored in a non-transitory computer-readable medium. The non-transitory computer-readable medium is, for example, a flash memory, a magnetic recording device, an optical disk, a magneto-optical recording medium, or a ROM. Furthermore, the program can be distributed by, for example, selling, transferring, or lending a portable medium, such as a Secure Digital (SD) card, a digital versatile disc (DVD), or a compact disc read only memory (CD-ROM), on which the program is stored.

[0026] The acoustic database stored in the storage unit 54 of the information processing device 50 will be described. In the acoustic database, various data are accumulated regarding the acoustic characteristics for each frequency band (or frequency), the materials of the obstacles 30 classified into a plurality of obstacle groups, the sound transmission characteristics of each material, and the like.

[0027] The acoustic characteristics for each frequency band (or frequency) stored in the acoustic database are, for example, attenuation characteristics and diffraction characteristics in space for each frequency band. The sound pressure gradually weakens while the sound propagates through the air. The attenuation of the sound depends on the temperature, humidity, and frequency of the air, and in this embodiment, the change in the attenuation characteristics due to the frequency is reflected in the simulation. Generally, high-frequency sounds have short wavelengths and are easily attenuated, while low-frequency sounds have long wavelengths and are not easily attenuated. Therefore, the attenuation characteristics (distance attenuation) in space for each frequency band (or frequency) are obtained and stored in the acoustic database. Also, generally, in the high-frequency range with short wavelengths, sound waves have high straightness and the diffracted volume is small. On the other hand, in the low-frequency range with long wavelengths, sound waves are likely to bend around obstacles, and the diffracted volume is large. Therefore, the proportion of diffracted sound for each frequency band (or frequency) is obtained and stored in the acoustic database. Also, since the sound pressure level also affects various acoustic characteristics, the relationship between the sound pressure level and the acoustic characteristics is also stored in the database. In this embodiment, the sound pressure level is treated as one of the attributes of the sound.

[0028] In the acoustic database, the obstacles 30 are classified into a plurality of obstacle groups. The classification of the obstacles 30 can be set arbitrarily, but in this embodiment, from the viewpoint of reducing the amount of calculation, it is preferable to set the classification roughly rather than finely. For example, the obstacles 30 are classified into groups such as "automobiles", "two-wheeled vehicles (motorcycles)", "artificial objects (buildings, etc.)", and "natural objects (trees, etc.)". The obstacles 30 (or obstacle groups) are characterized by their materials. The materials constituting each obstacle group are set, and for example, for the "automobile" group, the materials may be set together with their area ratios, such as "metal 80% + glass 20%". Note that, from the viewpoint of reducing the amount of calculation, it is preferable to set the materials as representative materials for each obstacle group (materials that occupy the majority of the area, or materials that constitute the part through which the sound traveling from the sound source 10 to the observation point 20 mainly passes). In addition, the attenuation characteristics (attenuation rate or transmittance) when the sound passes and the propagation speed of the sound are set for each material. Since the sound attenuation characteristics and propagation speed of each material differ depending on the frequency of the sound, it is desirable to set the sound attenuation characteristics and propagation speed for each frequency range (or frequency). Furthermore, even if it is the same automobile, a vehicle whose body is mostly made of glass (e.g., e-Palette (registered trademark), etc.) may be classified into a unique group different from automobiles because it has different sound attenuation characteristics from normal automobiles. From the viewpoint of sound reproducibility, it is preferable that the classification category of the obstacle 30 is as fine as possible, but the more finely it is divided, the more calculations tend to increase. Therefore, the classification category of the obstacle 30 can be appropriately determined by considering the balance between sound reproducibility and calculation amount.

[0029] As described above, in the acoustic database, first, a correspondence table of a plurality of obstacle groups and the types of obstacles 30 classified into each obstacle group is stored with respect to the obstacles 30. Then, for each obstacle group, a representative material constituting the obstacle 30 is set. In addition, for each material constituting the obstacle 30, the attenuation characteristics and sound propagation speed when sound passes through are set for each frequency range (or frequency), and stored in the acoustic database.

[0030] In this embodiment, the size of the obstacle 30 is treated as one of the attributes of each obstacle 30. The amount of the first component (direct sound) and the second component (reflected sound) that reach the observation point 20 or the ratio at the observation point 20 varies depending on the size of the obstacle 30. Therefore, the relationship between the size of the obstacle 30 and the ratio of the first component and the second component that reach the observation point 20 from the sound source 10 is also stored in the acoustic database.

[0031] The acoustic characteristics and diffraction characteristics for each frequency band, as well as the sound propagation characteristics of the obstacle 30, may be theoretically obtained, but may also be experimentally obtained. For example, in a real space, the sound source 10 and the obstacle 30 are placed at predetermined positions, and an acoustic measurement device is placed at the position of the observation point 20, to configure an environment for measuring the acoustic characteristics. In this measurement environment, when a sound in a specific frequency range is output from the sound source 10 at a set sound pressure level, the sound at the observation point 20 at this time is measured by the acoustic measurement device. By changing the frequency and sound pressure level of the sound output from the sound source 10 in various ways, the sound at the observation point under each condition is measured. Then, data regarding the change in the frequency and sound pressure level of the sound is obtained by comparing the output sound of the sound source 10 with the measured sound at the observation point 20. Similarly, by changing the type and size of the obstacle group for the obstacle 30 in various ways, the sound at the observation point 20 under each condition is measured, and data regarding the obstacle 30 is obtained from the measurement results. In particular, by using a material for the obstacle 30 that does not transmit sound, i.e., a material through which the first component that reaches the observation point in the shortest distance from the sound source is zero, sound containing only the second component can be acquired. By conducting an experiment using an obstacle 30 made of such a material, it is possible to separate the first and second components at the observation point. Furthermore, by combining and comparing an experiment in which the sound waves from the sound source 10 are changed and an experiment in which the type of obstacle group is changed, it is possible to experimentally determine various coefficients related to acoustic characteristics.

[0032] In this way, various coefficients are created and stored in the acoustic database for the acoustic characteristics and diffraction characteristics for each frequency band, and the sound propagation characteristics of the obstacle 30. When performing the operation of Fig. 3 described below, the control unit 55 can obtain coefficients used in simulating the sound field by searching the acoustic database using the representative frequency band of the sound source 10, the sound pressure level, the obstacle group, etc. as queries.

[0033] <Operation flow of information processing device> The operation of the information processing device 50 according to this embodiment will be described with reference to Fig. 3. The operation in Fig. 3 corresponds to the method according to this embodiment. The method according to this embodiment is a simulation of how a sound from a sound source 10 sounds (is observed) at an observation point 20, and in particular, a simulation of a case where the sound source 10 is blocked by an obstacle 30 (obstruction state or occlusion state).

[0034] Step S11: The control unit 55 of the information processing device 50 identifies a representative frequency band of an output sound from the sound source 10 in the virtual three-dimensional space VS corresponding to the sound field, and also identifies an obstacle 30 through which the first component of the sound (sound wave) passes.

[0035] Specifically, first, the control unit 55 creates a virtual three-dimensional space VS corresponding to the sound field. Any method can be adopted for creating the virtual three-dimensional space VS. For example, the control unit 55 acquires setting conditions for the sound field (virtual three-dimensional space VS) and information on each target object required for the simulation via the communication unit 51 or the input unit 52. In this embodiment, position information of the sound source 10 in the sound field (i.e., information indicating the position from which the sound is emitted), position information of the observation point 20, and position information of the obstacle 30 are acquired. Note that, for the sound source 10, sound source data of the sound emitted by the sound source 10 (e.g., data indicating the sound pressure level for each frequency) is acquired, and for the obstacle 30, information such as the type, structure, and size of a specific object may also be acquired. Note that, in this embodiment, there is one sound source 10 and one obstacle 30, but other sound sources or other objects (placed objects in the sound field) may exist in the virtual three-dimensional space VS. For example, the control unit 55 may create a virtual three-dimensional space VS as shown in FIG. 4. In FIG. 4, an automatic transport robot that generates sound is placed as a sound source 10, and a person is placed at the position of an observation point 20.

[0036] Next, the control unit 55 specifies the representative frequency band of the sound source 10 based on the acquired sound source data for the sound source 10 to be simulated. Any method can be adopted for specifying the representative frequency band. For example, the control unit 55 refers to the sound pressure level for each frequency indicated in the sound source data. Then, the control unit 55 may specify a predetermined range of frequencies centered on a frequency at which a peak of the sound pressure level appears as the representative frequency band of the sound source 10. In FIG. 4, a graph with sound pressure on the vertical axis and frequency on the horizontal axis is shown as the sound source data of the sound source 10 (automatic transport robot). The control unit 55 refers to the sound pressure level for each frequency indicated in the sound source data, and specifies the frequency at which a peak of the sound pressure level appears as the representative frequency. Then, the control unit 55 may set a frequency range (hatched range) of a predetermined width including the representative frequency as the representative frequency band of the sound source 10. Alternatively, the control unit 55 may obtain the frequencies at which the sound pressure level is lower than the peak by a predetermined percentage (dB) on the low-frequency side and the high-frequency side of the representative frequency, and specify the frequency range where the sound pressure level is lower than the peak by the predetermined percentage as the representative frequency band. In this way, the control unit 55 specifies the representative frequency band of the sound source 10 according to the sound pressure level indicated by the acquired sound source data.

[0037] Furthermore, the control unit 55 acquires information on the type, structure, size, and other properties of the obstacle 30 disposed between the sound source 10 and the observation point 20, and identifies the obstacle 30. After identifying the obstacle 30, the control unit 55 classifies the identified obstacle 30 into one of the obstacle groups based on a correspondence table between the obstacle groups stored in the acoustic database and the obstacles 30 classified into each group. Next, the control unit 55 reads out data on the material of the classified obstacle group from the acoustic database. The data on the material of the obstacle 30 is used as a coefficient parameter when simulating a sound propagating from the sound source 10 through the virtual three-dimensional space and reaching the observation point 20 in the shortest distance.

[0038] Step S12: The control unit 55 adjusts the sound pressure level at the observation point 20 and the arrival timing at the observation point 20 of the first component that arrives at the observation point 20 from the sound source 10 in the shortest distance, based on the representative frequency band of the sound source 10 and the material of the obstacle 30 through which the first component passes. Since the method of this embodiment is a simulation of the case where the sound source 10 is blocked by the obstacle 30, the first component (direct sound) that arrives at the observation point 20 in the shortest distance from the sound source 10 passes through the obstacle 30.

[0039] Specifically, the control unit 55 reads out information on the sound attenuation characteristics and propagation speed of the material of the obstacle 30 from the acoustic database based on the representative frequency band of the sound source 10 and the material of the obstacle 30 identified in step S11. Note that the attenuation characteristics of sound in an object generally change depending on the frequency. In the example of FIG. 4, the obstacle 31 is classified into a group of vehicles whose bodies are mostly made of glass. The direct sound 11 traveling from the sound source 10 to the observation point 20 in the shortest distance passes through two pieces of glass (glass on both sides of the body). Therefore, the material of the obstacle 31 is set to two pieces of glass. The simulation of the first component (direct sound) 11 uses the attenuation characteristics and propagation speed of glass when sound in the representative frequency band of the sound source 10 passes through the obstacle 31. If the attenuation rate (transmittance rate) of sound passing through one pane of glass is 0.5, then the sound passing through the two panes of glass of obstacle 31 will be attenuated to 0.5 x 0.5 = 0.25. In addition, the time it takes for sound to propagate through the glass part of obstacle 31 can be calculated from the propagation speed of the glass.

[0040] Further, the control unit 55 calculates the linear distance between the sound source 10 and the observation point 20 from each of the three-dimensional coordinates in the virtual three-dimensional space VS. Then, based on the speed of sound in the space (here, in the air), the time required for the sound to propagate through the space to the observation point 20 (between the sound source 10 and the obstacle 31, the internal space of the obstacle 31, and between the obstacle 31 and the observation point 20) is calculated. Also, based on the attenuation characteristics in the space of the representative frequency band of the sound source 10, the attenuation of the sound pressure level when propagating through the space to the observation point 20 is calculated. Note that, here, in order to reduce the calculation load, the attenuation amount is calculated based on the representative frequency band of the sound source 10, but the control unit 55 may more accurately calculate the distance attenuation of the sound in the air based on predetermined conditions including the environmental conditions of the sound field (temperature distribution, humidity, wind direction, etc.).

[0041] Then, the propagation time of the direct sound 11 from the sound source 10 to the observation point 20 is calculated by adding the propagation time in space (through the air) and the propagation time through the obstacle 31. Also, the attenuation of the sound pressure level of the direct sound 11 from the sound source 10 to the observation point 20 is calculated by adding the attenuation in space and the attenuation through the obstacle 31 (two pieces of glass). Since the propagation time and sound pressure level change compared to when the obstacle 31 does not exist, the process of obtaining them corresponds to adjusting the sound pressure level at the observation point 20 and the arrival timing at the observation point 20.

[0042] In this way, the control unit 55 adjusts the sound pressure level at the observation point 20 and the timing of arrival at the observation point for the first component that arrives from the sound source 10 to the observation point 20 in the shortest distance, based on the representative frequency band of the sound source 10 and the material of the obstacle 30 through which the first component passes.

[0043] Step S13: The control unit 55 adjusts the sound pressure level at the observation point 20 and the arrival timing at the observation point 20 of the second component (reflected sound) other than the first component (direct sound) from the sound source 10 based on the representative frequency band of the sound source 10. Since the method of this embodiment is a simulation of the case where the sound source 10 is blocked by an obstacle 30, the second component (reflected sound) is a sound that propagates around the obstacle 30.

[0044] Specifically, the control unit 55 reads data such as the propagation speed, attenuation characteristics, and degree of diffraction of the sound of the representative frequency band from the acoustic database based on the information of the representative frequency band of the sound source 10 specified in step S11. In addition, the control unit 55 obtains a representative propagation path that bypasses the obstacle 30 based on structural data on the obstacle 30. For example, in the example of FIG. 4, the paths that propagate through space from the sound source 10 to the observation point 20 include a path that bypasses the front of the vehicle 31 to reach the observation point 20, a path that bypasses the rear of the vehicle 31 to reach the observation point 20, and a path that bypasses the upper part of the vehicle 31 to reach the observation point 20. Among these, the path with the shortest path distance is set as the representative propagation path. The calculation of the distance of each path may be an approximation calculation that connects the sound source 10 and the end of the vehicle 31, and the end of the vehicle 31 and the observation point 20 with a straight line, respectively. In this case, the volume of diffracted sound can also be calculated based on the angle between a line connecting the sound source 10 and the end of the vehicle 31 and a line connecting the end of the vehicle 31 and the observation point 20.

[0045] Based on the speed of sound in space (here, in air), the time required for the sound to propagate along the representative propagation path from the sound source 10 to the observation point 20 is calculated. Also, based on the attenuation characteristics when the representative frequency band of the sound source 10 propagates along the representative propagation path and the degree of diffraction of the representative frequency band, the sound pressure level at the observation point 20 is calculated. Since the propagation time and sound pressure level change compared to when the obstacle 31 does not exist, the process of obtaining them corresponds to adjusting the sound pressure level at the observation point 20 and the arrival timing at the observation point 20. By adjusting the sound pressure level and the arrival timing based on the representative propagation path, the amount of calculation can be reduced. The second component may be obtained as a diffracted sound that reaches the observation point 20 via multiple paths, reflecting the diffraction phenomenon as accurately as possible. Therefore, the method of obtaining the second component can be appropriately determined in consideration of the balance between the reproducibility of the sound and the amount of calculation.

[0046] In this way, the control unit 55 adjusts the sound pressure level at the observation point 20 and the arrival timing at the observation point 20 of the second component (reverberation sound) other than the first component that arrives at the observation point 20 from the sound source 10 based on the representative frequency band of the sound source 10.

[0047] Step S14: The control unit 55 generates a synthetic sound by combining the first component adjusted in step S12 and the second component adjusted in step S13 in a ratio according to the attributes of the sound source 10 and the attributes of the obstacle 30, and simulates the generated synthetic sound as a sound propagating from the sound source 10 through the virtual three-dimensional space VS to reach the observation point 20.

[0048] Here, the attribute of the sound source 10 is the sound pressure level of the sound source 10, and the attribute of the obstacle 30 is the size of the obstacle 30. For example, the higher the sound pressure level of the sound source 10, the higher the ratio of the second component (reverberation sound) is set. Conversely, the lower the sound pressure level of the sound source 10, the higher the ratio of the first component (direct sound) is set, since the reverberation sound is drowned out by environmental noise and becomes smaller.

[0049] Moreover, the smaller the size of the obstacle 30, the higher the ratio of the sound that reaches the observation point 20 from the sound source 10 to the entire generated sound. Also, the ratio of the second component (reflected sound) that can reach the observation point 20 by going around the obstacle 30 is set to be higher than the first component (direct sound). Conversely, the larger the size of the obstacle 30, the more sound that hits the obstacle 30 and cannot reach the observation point 20, so the ratio of the sound that reaches the observation point 20 from the sound source 10 to the entire generated sound is lower. Also, the ratio of the second component (reflected sound) that can reach the observation point 20 by going around the obstacle 30 is set to be lower than the first component (direct sound). Note that each ratio may be calculated in advance or may be experimentally obtained.

[0050] The control unit 55 combines the first component adjusted in step S12 and the second component adjusted in step S13 based on their ratio to generate a synthetic sound. This synthetic sound is the sound measured at the observation point 20. As described above, the information processing device 50 (control unit 55) can simulate a sound that propagates from the sound source 10 through the virtual three-dimensional space VS and reaches the observation point 20.

[0051] For convenience of explanation, it is described as if step S13 is executed after step S12, but steps S12 and S13 may be executed in the reverse order or simultaneously. After step S14, the process ends.

[0052] Next, the operation of the information processing device 50 will be described with reference to Fig. 5, which is another specific example of the virtual three-dimensional space. Note that the description of parts that overlap with Fig. 4 will be simplified.

[0053] Step S11: The control unit 55 of the information processing device 50 constructs a virtual three-dimensional space VS corresponding to the sound field. In Fig. 5, an automatic transfer robot is placed as the sound source 10, a two-wheeled vehicle 32 is placed as an obstacle, and a person is placed at the position of the observation point 20.

[0054] Next, the control unit 55 specifies a representative frequency band of sound waves to be output from the sound source 10 in the virtual three-dimensional space VS. In this embodiment, the sound source data of the sound source 10 (automatic transfer robot) has a peak in sound pressure level on the relatively low frequency side, as shown in FIG. 5. The control unit 55 can specify the frequency at which the sound pressure peaks as the representative frequency, and set a frequency range of a predetermined width including the representative frequency (hatched range on the low frequency side) as the representative frequency band of the sound source 10. Note that the boundary of the frequency band may be set as a frequency that is a predetermined decibel (dB) lower than the maximum sound pressure level, for example.

[0055] Obstacle 32 is classified into the group of "two-wheeled vehicle (motorcycle)", for example. Metal parts constituting most of the body of a two-wheeled vehicle are present in the path of direct sound 11 traveling in the shortest distance from sound source 10 to observation point 20. Therefore, the material of obstacle 32 is set to be metal.

[0056] Step S12: The control unit 55 adjusts the sound pressure level of the first component (direct sound) at the observation point 20 and the arrival timing at the observation point 20 based on the representative frequency band of the sound source 10 and the material of the obstacle 32. In this embodiment, the attenuation characteristics and propagation speed of metal for the representative frequency band of the sound source 10 are used in the simulation. Since metal practically does not allow most sound to pass through, the sound pressure level of the first component (direct sound) 11 at the observation point 20 may be set to approximately 0.

[0057] Step S13: The control unit 55 adjusts the sound pressure level of the second component (reverberation sound) at the observation point 20 and the arrival timing at the observation point 20 based on the representative frequency band of the sound source 10. Specifically, the control unit 55 acquires data such as the propagation speed, attenuation characteristics, and degree of diffraction of the sound of the representative frequency band in space from the acoustic database. The control unit 55 also obtains a representative propagation path that bypasses the obstacle 32 based on structural data on the obstacle 32. In the example of FIG. 5, the shortest path among the paths from the sound source 10 to the observation point 20 by bypassing the motorcycle 32 is set as the representative propagation path. Then, based on the speed of sound in space (here, in the air), the time it takes to propagate the representative propagation path from the sound source 10 to the observation point 20 is calculated. Also, based on the attenuation characteristics and degree of diffraction in space of the representative frequency band of the sound source 10, the attenuation of the sound pressure level when propagating the representative propagation path to the observation point 20 is calculated. In this way, for the second component (reverberation), the sound pressure level at the observation point 20 and the arrival timing at the observation point 20 are adjusted.

[0058] Step S14: The control unit 55 generates a synthetic sound by combining the first component adjusted in step S12 and the second component adjusted in step S13 in a ratio according to the attribute (sound pressure level) of the sound source 10 and the attribute (size) of the obstacle 30. In the example of FIG. 5, since the size of the obstacle 30 is relatively small, the ratio of the entire sound reaching the observation point 20 from the sound source 10 to the generated sound is high, and the ratio of the second component (reverberation sound) is set high relative to the first component (direct sound). In the embodiment of FIG. 5, since the first component (direct sound) is almost 0, the sound measured at the observation point 20 is substantially only the second component (reverberation sound). In this way, the sound propagating from the sound source 10 through the virtual three-dimensional space VS to reach the observation point 20 is simulated.

[0059] In this way, the control unit 55 uses the representative frequency band of the sound source 10 to simulate the sound propagating from the sound source 10 in the virtual three-dimensional space VS to reach one observation point 20. The control unit 55 also performs simulation by grouping obstacles and categorizing the materials of the obstacles. This allows the sound field simulation to be performed by limiting the frequency band of the sound source and simplifying the materials of the obstacles. As a result, a sound field simulation that takes into account the balance between reducing the amount of calculation and reproducibility of the sound field is realized.

[0060] In this embodiment, the simulation is performed when the sound source 10 is blocked by the obstacle 30. However, the information processing device and method of the present disclosure may be used to evaluate the high level of discriminability of the sound of the sound source 10 when it is blocked by the obstacle 30. Here, discriminability refers to the ease of understanding the fact of reproduction of an artificial sound and its intention when a certain sound (mainly an artificial sound) is reproduced in a sound field. For example, in this embodiment, various sounds (sample sounds) generated at various sound pressure levels are simulated at the observation point 20 in a state where the sound source 10 is blocked by the obstacle 30. The user (experiment participant) evaluates whether the presence of the sound source 10 can be recognized for the simulated sound reaching the observation point 20, or whether the sound heard can be identified as that of the sound source 10. Any method can be adopted for evaluating the discriminability of the sound. For example, the sound source 10 may output various sounds (sample sounds) in a state where sounds (noise) other than the sound source 10 exist in the sound field. The user scores the discriminability of each sample sound at the observation point. The score aggregation result may be stored in the storage unit 54 of the information processing device 50 as an evaluation result of the discriminability of each sample sound. Based on the aggregation result stored in the storage unit 54, the control unit 55 may extract, for example, the sample sound with the highest total score as the most discriminable sample.

[0061] In this way, it is possible to simulate what kind of sound the robot should make in an actual sound field so that a person can identify it, depending on the material, size, position, etc. of the obstacle 30 present, and to determine an appropriate sound for the robot to emit.

[0062] As described above, the information processing device 50 according to this embodiment adjusts the sound pressure level and the arrival timing at the observation point of the first component that arrives from the sound source 10 to the observation point 20 in the shortest distance in the virtual three-dimensional space VS based on the representative frequency band of the sound source 10 and the material of the obstacle 30 through which the first component passes, and adjusts the sound pressure level and the arrival timing at the observation point of the second component other than the first component based on the representative frequency band of the sound source 10. Then, the information processing device 50 generates a synthetic sound by combining the adjusted first component and second component at a ratio according to the attributes of the sound source 10 and the attributes of the obstacle 30, and simulates the generated synthetic sound as a sound that propagates from the sound source 10 in the virtual three-dimensional space and arrives at the observation point 20.

[0063] According to this configuration, the sound field is simulated by limiting the sound emitted by the sound source 10 to a representative frequency band. Therefore, when reproducing an outdoor sound field in a virtual three-dimensional space, for example, the amount of calculations for the sound emitted by the sound source 10 hidden behind an obstacle 30 is reduced. Therefore, it is possible to obtain a simulation result close to reality for the acoustics of the sound field, and to reduce the amount of calculations.

[0064] Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art may make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included in the scope of the present disclosure. For example, the functions included in each component or step can be rearranged so as not to be logically inconsistent, and multiple components or steps can be combined or divided into one. [Explanation of symbols]

[0065] 10. Sound Source 11 1st component (direct sound) 12 2nd component (reverberant sound) 20 Observation points 30~32 Obstacles 50 Information processing device 51 Communications Department 52 Input section 53 Output section 54 Memory section 55 Control section

Claims

1. An information processing device including a control unit, The control unit is adjusting a sound pressure level and an arrival time at an observation point of a first component that arrives from a sound source to an observation point in a shortest distance in a virtual three-dimensional space based on a representative frequency band of the sound source and a material of an obstacle through which the first component passes; For a second component other than the first component, a sound pressure level and an arrival timing at the observation point are adjusted based on a representative frequency band of the sound source; generating a synthetic sound by combining the adjusted first component and the adjusted second component in a ratio according to the attribute of the sound source and the attribute of the obstacle; An information processing device that simulates the generated synthetic sound as a sound propagating from the sound source through the virtual three-dimensional space and reaching the observation point.

2. 2. The information processing device according to claim 1, An information processing device, wherein the attribute of the sound source is a sound pressure level of the sound source, and the attribute of the obstacle is a size of the obstacle.

3. 3. The information processing device according to claim 2, The information processing device, wherein the sound pressure level of the second component and the arrival timing at the observation point are adjusted based on a representative propagation path of the second component.

4. 4. The information processing device according to claim 1, The control unit outputs various sample sounds from the sound source to simulate sounds arriving at the observation point, The information processing device further includes a storage unit configured to store an evaluation result of the level of discriminability at the observation point of each sample sound.

5. A method executed by an information processing device, comprising: adjusting a sound pressure level and an arrival timing of a first component that arrives at an observation point from a sound source in a virtual three-dimensional space in the shortest distance based on a representative frequency band of the sound source and a material of an obstacle through which the first component passes; For a second component other than the first component, a sound pressure level and an arrival timing at the observation point are adjusted based on a representative frequency band of the sound source; and generating a synthetic sound by combining the adjusted first component and the adjusted second component in a ratio according to an attribute of the sound source and an attribute of the obstacle; simulating the generated synthetic sound as sound propagating from the sound source through the virtual three-dimensional space to reach the observation point.

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