JP2024019949A - Sound environment simulator and sound environment simulation method - Google Patents

Abstract

[Problem] To reduce the processing load while ensuring the accuracy of sound environment simulation. A sound environment simulator simulates a sound environment in a target world. A reflection path is a path of reflected sound that is output from a sound source, reflected by a reflecting object, and reaches an observation point. The sound environment simulator extracts reflective objects that can form a reflection path for a combination of a sound source and an observation point as simulation candidates. The sound environment simulator calculates, for each simulation candidate, an evaluation value that increases as the length of the reflection path becomes shorter. The sound environment simulator selects at least one simulation candidate as a representative reflecting object based on the evaluation value. The sound environment simulator simulates sound propagation characteristics along a reflection path formed by a representative reflecting object without using any reflecting objects other than the representative reflecting object. [Selection diagram] Figure 4

Description

The present disclosure relates to simulation of sound environments.

Patent Document 1 discloses a technique for performing a geometric acoustic simulation in order to analyze the acoustic characteristics of a sound field of a building. The inner product of the normal vector of the surface involved in the reflection of the sound wave and each of the plurality of predetermined reference vectors is calculated. Surfaces involved in reflection are classified into a plurality of groups depending on the combination of signs of the inner products. When calculating the reflection direction of a sound wave, the inner product of the sound ray vector of the sound wave and each of the plurality of reference vectors is calculated. The reflection direction is calculated without considering surfaces classified into a predetermined group that should be excluded from the candidates determined according to the combination of signs of the inner product.

Japanese Patent Application Publication No. 2004-077352

In sound environment simulation, it is desirable to accurately reproduce the sounds heard at observation points. For this purpose, it is preferable to consider not only the direct sound from the sound source to the observation point, but also the reflected sound that is reflected by objects and reaches the observation point. However, in the real world, there are many objects around the sound source and observation point, and many reflected sounds often reach the observation point. If a simulation takes all reflected sounds into account, the processing load will be enormous. This is undesirable from the viewpoint of computer resources and costs.

One objective of the present disclosure is to provide a technique that can reduce the processing load while ensuring the accuracy of sound environment simulation.

The first aspect relates to a sound environment simulator that simulates the sound environment in the target world.
The sound environment simulator is
one or more processors;
and one or more storage devices storing world configuration information indicating at least the positions of the sound source and the reflecting object in the target world.
A reflection path is a path of reflected sound that is output from a sound source, is reflected by any reflecting object, and reaches an observation point.
The one or more processors are:
Based on the world configuration information, reflective objects that can form a reflection path for the combination of sound source and observation point are extracted as simulation candidates,
Based on the world configuration information, an evaluation value is calculated for each simulation candidate that increases as the length of the reflection path becomes shorter.
selecting at least one simulation candidate as a representative reflecting object based on the evaluation value;
Sound propagation characteristics along a reflection path formed by a representative reflecting object are simulated without using any reflecting object other than the representative reflecting object.

The second aspect relates to a sound environment simulation method in which a computer simulates the sound environment in the target world.
The world configuration information indicates at least the positions of the sound source and the reflecting object in the target world.
A reflection path is a path of reflected sound that is output from a sound source, is reflected by any reflecting object, and reaches an observation point.
The sound environment simulation method is
Extracting reflective objects that can form a reflective path for a combination of a sound source and an observation point as simulation candidates based on world configuration information;
Calculating an evaluation value that increases as the length of the reflection path becomes shorter for each simulation candidate based on the world configuration information;
selecting at least one of the simulation candidates as a representative reflecting object based on the evaluation value;
simulating sound propagation characteristics along a reflection path formed by the representative reflecting object without using any reflecting object other than the representative reflecting object.

According to the present disclosure, a representative reflective object is selected based on the evaluation value. Then, instead of all reflective objects, only the selected representative reflective object is used in the simulation. This makes it possible to reduce the processing load while ensuring simulation accuracy.

1 is a conceptual diagram for providing an overview of a sound environment simulator according to an embodiment. FIG. 2 is a conceptual diagram for explaining direct sound and reflected sound. FIG. 3 is a schematic diagram for explaining an overview of reflected sound simulation according to the embodiment. FIG. 3 is a conceptual diagram for explaining an overview of reflected sound simulation according to the embodiment. FIG. 3 is a conceptual diagram for explaining a first example of evaluation values according to the embodiment. FIG. 7 is a conceptual diagram for explaining a second example of evaluation values according to the embodiment. FIG. 3 is a conceptual diagram for explaining an example of objects to be excluded from the sound environment simulation according to the embodiment. 1 is a block diagram illustrating a configuration example of a sound environment simulator according to an embodiment. FIG. 3 is a flowchart summarizing sound environment simulation processing according to the embodiment.

Embodiments of the present disclosure will be described with reference to the accompanying drawings.

1. Sound Environment Simulation FIG. 1 is a conceptual diagram for explaining an overview of a sound environment simulator 100 according to an embodiment. The sound environment simulator 100 simulates the sound environment in the target world 1. Examples of the target world 1 include a city, a building, the site of a facility, and the like.

Various sound sources 10 exist in the target world 1. The sound source 10 may be a moving object or a stationary object. Examples of the moving sound source 10 include a vehicle, a robot, a flying object, and the like. The vehicle may be a self-driving vehicle or a vehicle driven by a driver. Examples of robots include logistics robots, cleaning robots, work robots, and the like. Robots may emit voice messages to communicate with humans. Examples of flying objects include drones and the like. Examples of the stationary sound source 10 include a street vision, a speaker, an alarm, and the like. Note that the sound source 10 is not particularly limited.

The sound environment simulator 100 simulates, for example, how sound is heard at the observation point 20 within the target world 1. For example, the observation point 20 is the position of a person (listener). As another example, the observation point 20 is the position of a robot that performs sound recognition. Note that the observation point 20 is not particularly limited.

As shown in FIG. 2, the sound reaching the observation point 20 from the sound source 10 is classified into "direct sound Sd (direct wave)" and "reflected sound Sr (reflected wave)." Direct sound Sd is sound that directly reaches observation point 20 from sound source 10 without being reflected. The direct path Pd is the path of the direct sound Sd.

On the other hand, the reflected sound Sr is a sound that is output from the sound source 10, is reflected by any reflecting object 30, and reaches the observation point 20. The reflective objects 30 are various objects that exist within the target world 1. Examples of the reflective object 30 include a wall, a board, a ceiling, a floor, the ground, a structure, a moving object (eg, a vehicle, a robot), and the like. Note that the reflective object 30 is not particularly limited. The reflected path Pr is the path of the reflected sound Sr. That is, the reflection path Pr is a combination of the path from the sound source 10 to the reflection object 30 and the path from the reflection object 30 to the observation point 20. The reflection path Pr can be calculated geometrically based on the positional relationship between the sound source 10, the observation point 20, and the reflection object 30.

In sound environment simulation, it is desirable to accurately reproduce the sounds heard at the observation point 20. To this end, the sound environment simulator 100 performs a sound environment simulation taking into consideration not only the direct sound Sd but also the reflected sound Sr. That is, the sound environment simulation includes a simulation of the sound propagation characteristics of the reflected sound Sr along the reflection path Pr.

The number of sound sources 10 considered in the sound environment simulation may be two or more. When the sound source 10 has directivity, the direction in which sound is output from the sound source 10 is considered in the sound environment simulation.

In order to reduce the processing load, only "early reflection" that is reflected only once may be considered instead of considering multiple reflections of two or more times. Sufficient simulation accuracy can be obtained even if only the early reflected sound is considered.

As a result of the sound environment simulation, the intensity of the sound at the observation point 20 and the direction of arrival of the sound can be determined. Furthermore, the delay from the direct sound Sd to the reflected sound Sr at the observation point 20 can be seen. Such delays reflect spatial expansion. Therefore, based on the delay characteristics, it is possible to understand, for example, how a person at the observation point 20 perceives the space. Furthermore, it is also possible to know the filter effect depending on the material of the reflecting object 30 (material-dependent filter), that is, how the waveform of the reflected sound Sr changes.

Such a sound environment simulation is useful for designing the target world 1. For example, if target world 1 is a city such as a smart city, there is a need to design a city that is more comfortable for people. For example, there may be situations in which it is desired to convey audio information to people, such as announcements at stations or on the streets, or conversations between robots and humans. In such a scene, the audio information may not be transmitted properly to the person due to the surrounding environment. If we can identify problems in audio transmission in advance through sound environment simulation, we can take measures to resolve them and provide feedback to the design. For example, it is possible to change the materials and arrangement of the constituent elements (eg, walls) in the city so that problems with audio transmission are resolved. As another example, if it is found that a sound of a particular frequency is easily absorbed, it is possible to consider refraining from outputting the sound of that particular frequency from the sound source 10.

In addition, sound is one of the important factors that influence human behavior. Therefore, the sound environment simulation is also useful for simulating human behavior in the target world 1. The simulation results of human behavior in the target world 1 can also be fed back to the design of the target world 1.

Also known is a technology that collects information in the real world and reproduces the state of the real world in a virtual world in real time. Such technology is also called digital twin. This digital twin can also be used to predict the future state of target world 1. At this time, by predicting human behavior based on the results of the sound environment simulation, it becomes possible to predict the future state of the target world 1 with higher accuracy.

2. Reducing the processing load of sound environment simulation 2-1. Overview As described above, in sound environment simulation, it is desirable to accurately reproduce the sounds heard at the observation point 20. For this purpose, it is preferable to consider not only the direct sound Sd from the sound source 10 to the observation point 20 but also the reflected sound Sr. However, in the real world, there are many reflecting objects 30 around the sound source 10 and the observation point 20, and many reflected sounds Sr often reach the observation point 20. If a simulation is performed taking all reflected sounds Sr into consideration, the processing load will be enormous. This is undesirable from the viewpoint of computer resources and costs.

Therefore, according to the present embodiment, the number of reflected sounds Sr considered in the sound environment simulation is limited to a small number. Note that, as described above, the reflected sound Sr is a sound that is output from the sound source 10, is reflected by any reflecting object 30, and reaches the observation point 20, and the reflected sound Pr is the path of the reflected sound Sr. Therefore, the reflecting object 30, the reflected path Pr, and the reflected sound Sr have a one-to-one correspondence and can be said to be equivalent. Limiting the number of reflected sounds Sr to be considered in the sound environment simulation to a small number means limiting the number of reflection paths Pr and reflecting objects 30 to be considered in the sound environment simulation to a small number.

Hereinafter, an overview of the simulation of reflected sound Sr according to the present embodiment will be explained with reference to FIGS. 3 and 4.

Since many reflective objects 30 exist around the sound source 10 and the observation point 20, many reflection paths Pr can be formed for one combination of the sound source 10 and the observation point 20. Hereinafter, the reflecting object 30 that can form a reflection path Pr for the combination of the sound source 10 and the observation point 20 will be referred to as a "simulation candidate." The sound environment simulator 100 temporarily extracts simulation candidates.

Subsequently, the sound environment simulator 100 calculates an "evaluation value Q" for each of the extracted simulation candidates. The evaluation value Q represents the degree of contribution to the sound intensity (sound pressure) at the observation point 20. Therefore, the evaluation value Q depends at least on the length of the reflection path Pr from the sound source 10 to the observation point 20. Specifically, the shorter the length of the reflection path Pr formed by a certain reflection object 30, the higher the evaluation value Q of that reflection object 30. Conversely, the longer the reflection path Pr formed by a certain reflection object 30 becomes, the shorter the evaluation value Q of that reflection object 30 becomes. Note that various examples of the evaluation value Q will be described later.

The sound environment simulator 100 selects at least one simulation candidate as the "representative reflective object 30-X" based on the evaluation value Q. More specifically, the sound environment simulator 100 selects a simulation candidate with a relatively high evaluation value Q as the representative reflecting object 30-X. The number of selected representative reflecting objects 30-X may be one. In other words, the sound environment simulator 100 may select only one simulation candidate with a relatively high evaluation value Q as the representative reflecting object 30-X. Typically, the sound environment simulator 100 selects one simulation candidate with the highest evaluation value Q as at least the representative reflecting object 30-X. The sound environment simulator 100 may select only one simulation candidate with the highest evaluation value Q as the representative reflecting object 30-X.

The “representative reflected sound Sr-X” is the reflected sound Sr reflected by the representative reflecting object 30-X. “Representative reflection path Pr-X” is a reflection path Pr formed by the representative reflection object 30-X. The representative reflection object 30-X, the representative reflection path Pr-X, and the representative reflected sound Sr-X have a one-to-one correspondence and can be said to be equivalent. Selecting the representative reflecting object 30-X means selecting the representative reflected sound Sr-X or the representative reflected path Pr-X.

The sound environment simulator 100 simulates the sound propagation characteristics of the representative reflected sound Sr-X along the representative reflection path Pr-X. At this time, the sound environment simulator 100 uses only the selected representative reflecting object 30-X (representative reflected sound Sr-X, representative reflected path Pr-X) and does not use anything else. In other words, objects other than the representative reflecting object 30-X (representative reflected sound Sr-X, representative reflected path Pr-X) are excluded from the simulation target. The sound environment simulator 100 uses only the representative reflecting object 30-X without using any reflecting objects 30 other than the representative reflecting object 30-X, and the sound propagation of the representative reflected sound Sr-X along the representative reflecting path Pr-X. Simulate the characteristics.

The inventor of the present application has confirmed through experiments that the way the actual sound is heard can be reproduced fairly accurately even by sound environment simulation using only the representative reflecting object 30-X. That is, the inventor of the present application has confirmed that the accuracy of the sound environment simulation can be ensured even if only the representative reflecting object 30-X is used.

In this way, according to the present embodiment, the representative reflective object 30-X is selected based on the evaluation value Q. Then, instead of all the reflecting objects 30, only the selected representative reflecting object 30-X is used for the sound environment simulation. This makes it possible to reduce the processing load while ensuring the accuracy of the sound environment simulation. As a result, computer resources and costs are also reduced. When the number of representative reflecting objects 30-X is one, the effect is even higher.

2-2. Examples of Evaluation Values Various examples of evaluation values Q will be explained below. Here, for simplicity, multiple reflections of two or more times are not considered, and only early reflections that are reflected only once are considered.

2-2-1. First Example FIG. 5 is a conceptual diagram for explaining a first example of the evaluation value Q. The evaluation value Q depends on the length Lp of the reflection path Pr from the sound source 10 to the observation point 20. That is, as expressed by the following formula (1), the evaluation value Q is expressed as a function of the length Lp of the reflection path Pr.

Formula (1): Q=f(Lp)

More specifically, the shorter the length Lp of the reflection path Pr, the higher the evaluation value Q becomes. In the example shown in FIG. 5, the length Lp-1 of the first reflection path Pr-1 formed by the first reflection object 30-1 is equal to the length Lp-1 of the second reflection path Pr-1 formed by the second reflection object 30-2. -2 is shorter than the length Lp-2. Therefore, the evaluation value Q of the first reflective object 30-1 is higher than the evaluation value Q of the second reflective object 30-2.

2-2-2. Second Example FIG. 6 is a conceptual diagram for explaining a second example of the evaluation value Q. In the example shown in FIG. 6, the length Lp-1 of the first reflection path Pr-1 formed by the first reflection object 30-1 and the second reflection path Pr formed by the second reflection object 30-2 are -2 lengths Lp-2 are equal. However, the distance Da-1 from the sound source 10 along the first reflection path Pr-1 to the first reflection object 30-1 is the distance Da-1 from the sound source 10 along the second reflection path Pr-2 to the second reflection object 30-2. It is shorter than the distance Da-2. In this case, the evaluation value Q of the first reflective object 30-1 may be set higher than the evaluation value Q of the second reflective object 30-2. This is because the first reflecting object 30-1, which is closer to the sound source 10, can reflect more sound waves toward the observation point 20.

The generalization is as follows. The distance from the sound source 10 to the reflecting object 30 (reflection point) along the reflection path Pr is hereinafter referred to as a "first distance Da." The evaluation value Q becomes higher as the first distance Da becomes shorter. The evaluation value Q is expressed, for example, by the following formula (2).

Formula (2): Q=f(Lp)+g(Da)

In equation (2), the weight of the first term (f(Lp)) may be set larger than the weight of the second term (g(Da)).

The second example further improves simulation accuracy.

2-2-3. Third Example The materials of the reflective objects 30 existing in the target world 1 are not uniform but vary. The reflectance ρ of the reflective object 30 depends on the material of the reflective object 30. In the third example, the evaluation value Q depends on the reflectance ρ of the reflective object 30. Specifically, the higher the reflectance ρ of the reflective object 30, the higher the evaluation value Q becomes. In this case, the evaluation value Q is expressed by the following formula (3) or formula (4).

Formula (3): Q=f(Lp)+h(ρ)
Formula (4): Q=f(Lp)×h(ρ)

The third example further improves simulation accuracy.

2-2-4. Fourth Example A combination of the second and third examples described above is also possible. This further improves simulation accuracy.

2-3. Other Examples of Exclusion Targets As described above, some reflective objects 30 are excluded from the sound environment simulation based on the evaluation value Q. Based on yet another aspect, some reflective objects 30 may be excluded from the sound environment simulation.

FIG. 7 is a conceptual diagram for explaining an example of exclusion targets from the sound environment simulation. The fixed range RNG is a finite range that includes the sound source 10. For example, the fixed range RNG is a range up to a fixed distance (eg, 5 m) from the sound source 10. The contribution of the reflective object 30 that exists outside the certain range of RNG is considered to be small. Therefore, the reflective object 30 that exists outside the certain range RNG may be unconditionally excluded from the sound environment simulation.

More specifically, the sound environment simulator 100 uses the fixed range RNG as the search range when extracting the reflective object 30 that can form the reflective path Pr as a simulation candidate. That is, the sound environment simulator 100 extracts reflective objects 30 that can form a reflection path Pr as simulation candidates from among the reflective objects 30 existing within a certain range RNG. In other words, the sound environment simulator 100 excludes in advance the reflective objects 30 that exist outside the certain range of RNG from simulation candidates. This makes it possible to further reduce the processing load while ensuring the accuracy of the sound environment simulation.

As another example, the contribution of the reflective object 30 whose size is less than a predetermined value is considered to be small. Therefore, reflective objects 30 whose size is less than a predetermined value may be unconditionally excluded from the sound environment simulation. More specifically, the sound environment simulator 100 extracts, as simulation candidates, reflective objects 30 that can form a reflection path Pr from among the reflective objects 30 whose size is equal to or larger than a predetermined value. In other words, the sound environment simulator 100 excludes in advance reflective objects 30 whose size is less than a predetermined value from simulation candidates. This makes it possible to further reduce the processing load while ensuring the accuracy of the sound environment simulation.

2-4. Effects As explained above, according to the present embodiment, the representative reflective object 30-X is selected based on the evaluation value Q. Then, instead of all the reflecting objects 30, only the selected representative reflecting object 30-X is used for the sound environment simulation. This makes it possible to reduce the processing load while ensuring the accuracy of the sound environment simulation. As a result, computer resources and costs are also reduced. When the number of representative reflecting objects 30-X is one, the effect is even higher.

3. Specific example of sound environment simulator 3-1. Configuration Example FIG. 8 is a block diagram showing a configuration example of the sound environment simulator 100 according to the present embodiment. The sound environment simulator 100 includes one or more processors 110 (hereinafter simply referred to as "processors 110"), one or more storage devices 120 (hereinafter simply referred to as "storage devices 120"), and an input/output device 130. Contains.

Processor 110 performs various information processing. For example, processor 110 includes a CPU (Central Processing Unit). The storage device 120 stores various information necessary for processing by the processor 110. Examples of the storage device 120 include volatile memory, nonvolatile memory, HDD (Hard Disk Drive), SSD (Solid State Drive), and the like.

Simulation program PROG is a computer program executed by processor 110. The functions of the sound environment simulator 100 are realized through cooperation between the processor 110 that executes the simulation program PROG and the storage device 120. The simulation program PROG is stored in the storage device 120. The simulation program PROG may be recorded on a computer-readable recording medium. The simulation program PROG may be provided via a network.

The input/output device 130 is an interface for receiving information from a user and providing information to the user. Input/output device 130 includes an input device and an output device. Examples of the input device include a keyboard, mouse, touch panel, and the like. Examples of the output device include a display, a touch panel, a speaker, and the like. Furthermore, the input/output device 130 may include a communication device that communicates with various devices existing in the actual target world 1.

3-2. World Configuration Information The world configuration information 200 indicates at least the positions of the constituent elements of the target world 1. Components of the target world 1 include at least a sound source 10 and a reflective object 30. Components of the target world 1 may include objects (eg, humans, robots) that can serve as the observation point 20. The components of the target world 1 may be moving objects or stationary objects. Examples of moving objects include vehicles, robots, flying objects, and the like. Examples of stationary objects include walls, boards, ceilings, floors, the ground, structures, and the like.

The world configuration information 200 may include information corresponding to the reflectance ρ of the constituent elements of the target world 1. In particular, the world configuration information 200 may include information corresponding to the reflectance ρ of the reflective object 30. The information corresponding to the reflectance ρ may be the reflectance ρ itself, or may be the material.

The world configuration information 200 may indicate the sizes of the components of the target world 1. In particular, the world configuration information 200 may indicate the size of the reflective object 30.

When the sound source 10 has directivity, the world configuration information 200 may indicate the direction (range) in which sound is output from the sound source 10.

The world configuration information 200 may include a semantic model regarding the target world 1. The semantic model is a 3D model based on ideas such as BIM (Building Information Modeling) and CIM (Construction Information Modeling). The semantic model includes attribute information of the constituent elements (particularly stationary objects) of the target world 1. Examples of the attribute information of the component include the type, position, size, material, color, etc. of the component.

Processor 110 acquires world configuration information 200 via input/output device 130. For example, the world configuration information 200 is created by a user and input via the input/output device 130. As another example, the processor 110 may communicate with a moving object existing in the real target world 1 and obtain the actual position of the moving object in real time. World configuration information 200 is stored in storage device 120.

3-3. Processing Example FIG. 9 is a flowchart summarizing the sound environment simulation processing according to the present embodiment.

In step S100, processor 110 reads world configuration information 200 from storage device 120.

In step S110, the processor 110 extracts, as a simulation candidate, a reflecting object 30 that can form a reflection path Pr for the combination of the sound source 10 and the observation point 20, based on the world configuration information 200. Observation point 20 may be specified by the user. The number of sound sources 10 may be two or more. When the sound source 10 has directivity, the direction in which sound is output from the sound source 10 is taken into consideration. As explained in Section 2-3 above, some reflective objects 30 may be excluded from simulation candidates in advance.

In step S120, the processor 110 calculates an evaluation value Q for each simulation candidate based on the world configuration information 200. The evaluation value Q is as explained in Section 2-2 above.

In step S130, the processor 110 selects at least one simulation candidate as the representative reflective object 30-X based on the evaluation value Q. The processor 110 may select only one simulation candidate with a relatively high evaluation value Q as the representative reflecting object 30-X. The processor 110 may select one simulation candidate with the highest evaluation value Q as at least the representative reflecting object 30-X. The processor 110 may select only one simulation candidate with the highest evaluation value Q as the representative reflecting object 30-X.

In step S140, the processor 110 determines the sound propagation characteristics of the reflected sound Sr along the representative reflection path Pr-X formed by the representative reflecting object 30-X without using any reflecting object 30 other than the representative reflecting object 30-X. Perform a simulation. Note that the processor 110 also simulates the sound propagation characteristics of the direct sound Sd of the direct path Pd.

In step S150, processor 110 outputs the result of the sound environment simulation via input/output device 130.

Through the sound environment simulation, the intensity of the sound at the observation point 20 and the direction of arrival of the sound can be determined. Furthermore, the delay from the direct sound Sd to the reflected sound Sr at the observation point 20 can be seen. Such delays reflect spatial expansion. Therefore, based on the delay characteristics, it is possible to understand, for example, how a person at the observation point 20 perceives the space. Furthermore, it is also possible to know the filter effect depending on the material of the reflecting object 30 (material-dependent filter), that is, how the waveform of the reflected sound Sr changes. The results of the sound environment simulation are reflected in the design and simulation of target world 1.

1 Target world 10 Sound source 20 Observation point 30 Reflecting object 30-X Representative reflecting object 100 Sound environment simulator 110 Processor 120 Storage device 130 Input/output device 200 World configuration information Pr Reflection path Pr-X Representative reflection path Sr Reflected sound Sr-X Representative Reflected sound PROG simulation program

Claims (9)

A sound environment simulator that simulates a sound environment in a target world,
one or more processors;
one or more storage devices storing world configuration information indicating at least the positions of the sound source and the reflecting object in the target world;
The reflection path is a path of reflected sound that is output from the sound source, is reflected by any reflecting object, and reaches the observation point,
The one or more processors are:
Based on the world configuration information, extracting the reflecting object that can form the reflecting path for the combination of the sound source and the observation point as a simulation candidate;
Based on the world configuration information, for each of the simulation candidates, calculate an evaluation value that increases as the length of the reflection path becomes shorter;
selecting at least one simulation candidate as a representative reflective object based on the evaluation value;
A sound environment simulator that simulates sound propagation characteristics along the reflection path formed by the representative reflection object without using the reflection object other than the representative reflection object. The sound environment simulator according to claim 1,
The one or more processors select only one simulation candidate as the representative reflecting object based on the evaluation value. The sound environment simulator according to claim 1,
The one or more processors select one simulation candidate with the highest evaluation value as at least the representative reflecting object. The sound environment simulator. The sound environment simulator according to claim 3,
The one or more processors select only the one simulation candidate with the highest evaluation value as the representative reflecting object. The sound environment simulator. The sound environment simulator according to any one of claims 1 to 4,
a first distance is a distance from the sound source to the reflecting object along the reflection path;
The evaluation value becomes higher as the first distance becomes shorter. Sound environment simulator. The sound environment simulator according to any one of claims 1 to 4,
The world configuration information further indicates information corresponding to the reflectance of the reflective object,
The evaluation value increases as the reflectance of the reflecting object increases. The sound environment simulator according to any one of claims 1 to 4,
A sound environment simulator, wherein the one or more processors exclude the reflecting object that exists outside a certain range including the sound source from the simulation candidates. The sound environment simulator according to any one of claims 1 to 4,
The world configuration information further indicates the size of the reflective object,
The one or more processors exclude the reflective object whose size is less than a predetermined value from the simulation candidates. A sound environment simulation method for simulating a sound environment in a target world using a computer,
The world configuration information at least indicates the positions of the sound source and the reflecting object in the target world,
The reflection path is a path of reflected sound that is output from the sound source, is reflected by any reflecting object, and reaches the observation point,
The sound environment simulation method includes:
Extracting the reflecting object that can form the reflecting path for the combination of the sound source and the observation point as a simulation candidate based on the world configuration information;
Calculating, for each of the simulation candidates, an evaluation value that increases as the length of the reflection path becomes shorter, based on the world configuration information;
selecting at least one of the simulation candidates as a representative reflective object based on the evaluation value;
A sound environment simulation method comprising: simulating sound propagation characteristics along the reflection path formed by the representative reflection object without using the reflection object other than the representative reflection object.

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