3D Audio Processing via HRTF Filtering in VR

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Solution Overview

Problem

Current VR technologies fail to provide a realistic 3D audio experience due to the use of 2D audio data, which limits user immersion and engagement.

Innovation Solution

The method involves filtering audio data using a head-related transfer function (HRTF) filter to create a 3D audio effect by adjusting monaural sound data based on the distances between sound sources and a target object in a VR scenario, synthesizing the data into 7.1-channel audio, and incorporating reverberation effects to enhance spatial awareness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If 2D audio data is used in VR headphones, then the device complexity is reduced and ease of manufacture is improved, but the realism of sounds and user experience deteriorate

Engineering Contradiction:
Improveease of manufactureVSAvoidrealism of sounds
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent transforms 2D audio data into 3D spatial audio by introducing vertical dimension processing. It separates audio into left, right, and center channels, then applies HRTF filtering to create elevation information, converting planar audio representation into three-dimensional spatial audio that mimics real-world sound propagation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces HRTF (Head-Related Transfer Function) filtering as an intermediary process between the audio source and output speakers. This intermediary applies frequency-dependent filtering based on simulated head, ear, and torso geometry to transform dry audio signals into spatially-positioned sound fields that preserve realism while working with standard 2D audio data

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If HRTF filtering and 3D audio processing are implemented, then the realism and immersion of audio experience are improved, but the device complexity and processing requirements increase

Engineering Contradiction:
Improverealism of soundsVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the audio processing into distinct functional modules: audio data reception, channel separation (left, right, center), HRTF filtering stage, reverberation processing, and final synthesis. This segmentation allows each component to be optimized independently and simplifies the overall system architecture despite the complexity of 3D audio processing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary channel separation and HRTF filter preparation before final audio synthesis. By pre-processing the audio data into spatial components and pre-calculating HRTF filters based on virtual speaker positions, the system reduces real-time processing complexity while maintaining high realism in the final output

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly enhances user experience by providing a more immersive and vivid 3D audio environment, allowing for precise audio adjustments and spatial awareness within VR scenarios.

Implementation Method 1

filtering audio data using a head-related transfer function (HRTF) filter to create a 3D audio effect by adjusting monaural sound data based on the distances between sound sources and a target object

Methodology Applied
Scientific EffectHead-Related Transfer Function (HRTF):

Implementation Method 2

synthesizing the data into 7.1-channel audio

Methodology Applied
Scientific EffectAudio synthesis:

Implementation Method 3

incorporating reverberation effects to enhance spatial awareness

Methodology Applied
Scientific EffectReverberation: Reverberation

Data Source

PatentEP3629145B1Method for processing 3D audio effect and related products
Publication Date: 2022.12.14 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3629145B1 patent drawingFigure 1
  • EP3629145B1 patent drawingFigure 2~3
  • EP3629145B1 patent drawingFigure 4

AI summary

A method for processing a 3D audio effect and related products are provided. The method includes the following. In a VR scenario, eight first positions of eight monaural sound sources and eight pieces of monaural data corresponding to the eight monaural sound sources are obtained (201, 401, 501), where the eight monaural sound sources correspond to a target object, and each eight monaural sound source locates at a position with unique 3D coordinates. A second position of a target object in the VR scenario is obtained(202, 402, 502), where the second position has 3D coordinates, and the eight first positions and the second position are based on the same coordinate origin. A distance between each of the eight first positions and the second position is determined to obtain eight distances(203, 403, 503). The eight pieces of monaural data are adjusted according to the eight distances (204, 504). The eight pieces of monaural data adjusted are synthesized to sound data (205, 505).