A method for evaluating the spatial angular resolution of virtual auditory display devices

Abstract

This invention discloses a method for evaluating the spatial angular resolution of a virtual auditory display device. The evaluation method includes: a sound source type definition step, a sound source direction definition step, a sound source sound pressure definition step, a perceptual difference definition step, and a measurement step. The beneficial effect of this invention is that it reduces the spatial angular error factor of the measuring person, and more accurately reflects the spatial angular resolution of the virtual auditory display device.

Description

Technical Field

[0001] This invention relates to virtual auditory display, and more particularly, to a method for evaluating the spatial angular resolution of a virtual auditory display device. Background Technology

[0002] The human auditory system can locate sound sources and determine their spatial orientation by observing sound propagation. Virtual auditory display devices use HRTF (Head-Related Transfer Function) databases and 3D speech synthesis algorithms to reproduce sound signals with binaural characteristics, giving spatial information to virtual sound played through stereo headphones, thus enabling users to "locate sounds by sound." Currently, methods for evaluating the spatial angular resolution of virtual auditory display devices include: verbal reporting, computer-aided methods (using a computer screen to project two-dimensional graphics), and positioning device-assisted methods (using a tracker placed on a spherical model for judgment). The drawback is that these evaluation methods require the intervention of auditory personnel; however, different auditory personnel have varying spatial resolution capabilities, therefore, the quality of virtual auditory display devices cannot be objectively determined. Summary of the Invention

[0003] The purpose of this invention is to solve the problems of spatial angular resolution differences among auditory testers, inconsistent and cumbersome measurement procedures in existing evaluation technologies, and to propose a novel method for evaluating the spatial angular resolution of virtual auditory display devices.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: 1. A method for evaluating the spatial angular resolution of a virtual auditory display device, characterized in that it includes: a sound source type definition step, a sound source direction definition step, a sound source sound pressure definition step, a perceptual difference definition step, and a measurement step.

[0005] As a preferred method for evaluating the spatial angular resolution of virtual auditory display devices, white noise is used as the test sound source in the sound source type definition step.

[0006] As a preferred method for evaluating the spatial angular resolution of virtual auditory display devices, in the sound source direction definition step, the azimuth and pitch angles remain independent. The corresponding data for the azimuth and pitch angles are as follows: the corresponding angles for the azimuth are 0°, 25°, 45°, 65°, 90°, 115°, 135°, 155°, 180°, 200°, 225°, 245°, 270°, 290°, 315°, and 335°, and the corresponding data for the pitch angles are -65°, -45°, -25°, 0°, 25°, 45°, and 65°.

[0007] As a preferred method for evaluating the spatial angular resolution of virtual auditory display devices, in the sound source sound pressure definition step, the pressure field sound pressure of the test listener at the (0°, 0°) position is tested. An artificial head is placed at the position of the test listener to ensure that the same sound playback effect can be produced by using speakers and headphones. The amplitude of the excitation signal sound pressure at the position of the test listener is adjusted to 72dBA±1dB.

[0008] As a preferred method for evaluating the spatial angular resolution of virtual auditory display devices, the perceptual difference definition step refers to the angular difference between the perceived location of the real sound source and the perceived location of the virtual sound source at the same physical spatial position by the same auditor.

[0009] As a preferred method for evaluating the spatial angular resolution of virtual auditory display devices, the measurement steps include...

[0010] Step S1: Position the audiometer in the reference position: The audiometer sits in a swivel chair with the center of his head at a reference point where the azimuth and pitch angles are 0.

[0011] Step S2: The listening personnel grip the pistol tightly with both hands, arms outstretched, aiming the muzzle at a fixed point where the azimuth and elevation angles of the column are 0, while simultaneously looking directly at the reference point. They then press the confirm button to calibrate the head position tracker and the tracker on the pistol. In the case of a real sound source, only the pistol needs to be calibrated.

[0012] Step S3: Before each playback of the sound source excitation signal, the listening personnel should turn their body back to the direction of the reference point and simultaneously pull the confirm button on the pistol to inform the testing system that the listening personnel are ready; then play the excitation signal.

[0013] Step S4: The listening tester holds the gun firmly with both hands and pulls the confirm button in the direction of the perceived sound source, which serves as the direction of the listening tester's response.

[0014] Let the actual sound source perception angle of the same listening tester be . θ is the azimuth angle. The virtual sound source is perceived at an angle of pitch. The perceived difference in this measurement is as follows: Average azimuth and elevation positioning errors:

[0015] Compared with the prior art, the advantages of the present invention are: by using this method to reduce the spatial angle error factor of the measuring person, it can more realistically reflect the spatial angle resolution of the virtual auditory display device. Attached Figure Description

[0016] Figure 1 This is a reference diagram of a predefined coordinate system in one embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram illustrating the definition of perceptual difference proposed in this invention.

[0018] Figure 3 This is a schematic diagram of a real sound source playback system according to an embodiment of the present invention.

[0019] The following items are numbered in the diagram: 1. Grid fixing frame; 2. Visual shield; 3. Speaker orientation adjustment mechanism; 4. Speaker; 5. Lifting swivel chair; 6. Listening personnel; 7. Measurement orientation transmitter fixing device; 8. Orientation indicator device. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be noted that these descriptions are for the purpose of aiding understanding the invention and do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

[0021] See Figure 1 The diagram shows a reference coordinate system for the spatial angular resolution of a real sound source playback system and a virtual auditory display device. Coordinate system definition: The speaker orientation uses a counter-clockwise coordinate system, with an azimuth angle of 0° ≤ θ < 360°. On the horizontal plane, θ = 0° represents directly in front, and θ = 90°, 180°, and 270° represent directly left, directly behind, and directly right, respectively. The elevation angle is -90° ≤ φ ≤ 90°, with -90°, 0°, and +90° representing directly below, on the horizontal plane, and directly above, respectively.

[0022] See Figure 2 The figure shows the angular difference between the perceived location of a real sound source and the perceived location of a virtual sound source for the same tester at the same physical location. Perceptual difference = |BA|.

[0023] See Figure 3 The figure shows a device for evaluating the spatial angular resolution of a virtual auditory display device. The evaluation device comprises: a grid frame, a speaker, an orientation adjustment mechanism, a height-adjustable swivel chair, a visual shield, a positioning transmitter fixing device, and an orientation indicator device.

[0024] The grid mounting bracket has a hemispherical upper part and a cylindrical lower part. The center of the upper part of the bracket is located at the origin of a conventional spherical coordinate system. The speaker is fixed to the grid mounting bracket by the orientation adjustment mechanism.

[0025] The adjustable swivel chair is located inside the grid frame. It is positioned along the lower axis of the frame. The adjustable swivel chair is used to move the center of the head of the person sitting in the chair to the origin of a pre-defined spherical coordinate system.

[0026] The visual shield is located inside the grid frame. The visual shield surrounds the perimeter of the swivel chair. The visual shield is used to block the view of the person sitting in the swivel chair, preventing them from seeing the physical location of the speaker.

[0027] Methods for evaluating the spatial angular resolution of virtual auditory display devices include:

[0028] Young people with normal hearing and extensive experience in determining the location of virtual sound sources are selected as audiometry personnel. The personnel are seated in the adjustable swivel chair. The height of the chair is adjusted so that the center of the personnel's head is at the origin of the agreed coordinate system. The personnel hold the location indicator device, arms outstretched, with the muzzle pointed at the indicator mark on the speaker corresponding to the reference point of the visual shield. Simultaneously, the personnel's eyes are also focused on the indicator mark. The personnel then press the confirm button on the location indicator device to zero both the head position tracker of the virtual sound source generating device and the tracker on the handheld location indicator device. In real sound source testing, only the tracker on the handheld location indicator device needs to be zeroed.

[0029] Real-world sound source loudspeaker measurement steps: The measurement begins with system initialization. The computer controls the loudspeaker to emit sound according to the programmed loudspeaker angle, playing a prompt tone 'Please zero.' The tester holds the azimuth indicator with arms outstretched, pointing the muzzle of the indicator at a fixed point on the black shielding cloth of the visual shielding mechanism where the azimuth and elevation angles are 0. Simultaneously, both eyes are focused on this reference point. The tester then presses the confirmation button to complete the zeroing operation. Next, the system automatically plays the measurement sound (in this example, 2 seconds of white noise). After the sound finishes playing, the tester needs to determine the sound source location. Holding the azimuth indicator with arms outstretched, the tester points the muzzle at the perceived sound source location on the black shielding cloth of the visual shielding mechanism and presses the confirmation button to complete the azimuth determination operation. At this time, the computer collects the current sensor position information and calculates it together with the zeroing position azimuth information to determine the elevation and azimuth angles of the perceived sound source in the current system coordinate system, thus completing the azimuth determination.

[0030] Virtual sound source speaker measurement steps: To measure the virtual sound source, you need to wear headphones to listen to the virtual sound source. Other steps are the same as for measuring a real sound source.

[0031] After measurement, perceptual difference data is calculated for the same spatial position of the same person taking measurements. The average of all spatial positions measured is then used to determine the perceptual difference of the virtual auditory display device for that person. The statistical analysis of perceptual differences across all personnel can serve as evaluation data for the device's quality.

[0032] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for evaluating the spatial angular resolution of a virtual auditory display device, characterized in that, include: The steps for defining the sound source type, the sound source direction, the sound source sound pressure, the perceived difference, and the measurement steps.

2. The method for evaluating the spatial angle resolution of a virtual auditory display device according to claim 1, characterized in that, In the sound source type definition step, white noise is used as the test sound source.

3. The method for evaluating the spatial angle resolution of a virtual auditory display device according to claim 1, characterized in that, In the sound source direction definition step, the azimuth and elevation angles remain independent. The corresponding data for the azimuth and elevation angles are as follows: The corresponding angles for the azimuth are 0°, 25°, 45°, 65°, 90°, 115°, 135°, 155°, 180°, 200°, 225°, 245°, 270°, 290°, 315°, and 335°. The corresponding data for the elevation angles are -65°, -45°, -25°, 0°, 25°, 45°, and 65°.

4. The method for evaluating the spatial angle resolution of a virtual auditory display device according to claim 1, characterized in that, In the sound source sound pressure definition step, the pressure field sound pressure of the test listener at the (0°, 0°) position is tested. An artificial head is placed at the position of the test listener to ensure that the same sound playback effect can be produced by using loudspeakers and headphones. The amplitude of the excitation signal sound pressure at the position of the test listener is adjusted to 72dBA±1dB.

5. The method for evaluating the spatial angle resolution of a virtual auditory display device according to claim 1, characterized in that, In the step of defining the perceived difference, the angle difference between the perceived location of the real sound source and the virtual sound source at the same physical location is defined by the same listening tester.

6. The method for evaluating the spatial angle resolution of a virtual auditory display device according to claim 1, characterized in that, During the measurement process, Step S1: Position the audiometer in the reference position: The audiometer sits in a swivel chair with the center of his head at a reference point where the azimuth and pitch angles are 0. Step S2: The listening personnel grip the pistol tightly with both hands, arms outstretched, aiming the muzzle at a fixed point where the azimuth and elevation angles of the column are 0, while simultaneously looking directly at the reference point. They then press the confirm button to calibrate the head position tracker and the tracker on the pistol. In the case of a real sound source, only the pistol needs to be calibrated. Step S3: Before each playback of the sound source excitation signal, the listening personnel should turn their body back to the direction of the reference point and simultaneously pull the confirm button on the pistol to inform the testing system that the listening personnel are ready; then play the excitation signal. Step S4: The listening tester holds the gun firmly with both hands and pulls the confirm button in the direction of the perceived sound source, which serves as the direction of the listening tester's response. Let the actual sound source perception angle of the same listening tester be . θ is the azimuth angle. The virtual sound source is perceived at an angle of pitch. The perceived difference in this measurement is as follows: Average azimuth and elevation positioning errors:

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