Arbitrary Microphone Array for 3D Audio Reproduction
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Solution Overview
Problem
Current binaural sound reproduction methods for creating virtual and augmented reality audio environments are limited by the need for precise microphone placement or idealized microphone arrays, which restrict the flexibility and accuracy of recording and reproducing three-dimensional audio fields.
Innovation Solution
The method involves using an electronic device with multiple microphones arranged in an arbitrary but known configuration, obtaining spatial acoustic transfer information, and applying it to audio data to achieve plane-wave decomposition, which is then combined with head-related transfer information to reconstitute a three-dimensional audio field, allowing for flexible recording and playback of realistic 3D audio environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microphones are placed at ear canals of human or mannequin, then binaural audio accuracy is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent uses spherical harmonic decomposition to create a mathematical model that copies the acoustic properties of idealized microphone arrays (such as first-order spherical arrays) onto arbitrary device geometries. This allows consumer electronics with non-ideal microphone placements to achieve binaural audio quality previously only attainable with precisely positioned microphones on mannequins or human ear canals.
Solution Approach 2:
The patent transforms the acoustic field representation from physical microphone positions to spherical harmonic coefficients. By changing the parameter space from spatial coordinates to spherical harmonic domains, the system can accurately represent sound fields regardless of the original microphone arrangement, enabling arbitrary device geometries to achieve idealized array performance.
2Measurement precision
If spherical, hemispherical or cylindrical microphone arrays are used, then idealized geometry accuracy is improved, but adaptability to different device form-factors decreases
Solution Approach 1:
The patent creates a universal processing framework using spherical harmonic decomposition that can handle any microphone array geometry. The same mathematical operations and transfer function applications work regardless of whether the microphones are arranged in spherical, hemispherical, cylindrical, or completely arbitrary patterns, making the system universally applicable to diverse device form-factors while maintaining spatial audio accuracy.
Solution Approach 2:
The patent elevates the problem from three-dimensional physical space to a higher-dimensional spherical harmonic space. By representing acoustic fields in terms of spherical harmonic coefficients rather than physical microphone positions, the system gains the ability to handle arbitrary geometries, as the mathematical framework operates in an abstracted dimension that transcends specific physical arrangements.
3Productivity
If plane-wave decomposition is applied to arbitrary microphone arrays, then processing efficiency is improved, but measurement precision requirements increase
Solution Approach 1:
The patent pre-calculates and stores spatial acoustic transfer functions for the specific device geometry before actual audio processing. These pre-computed transfer functions, which capture the acoustic characteristics of the arbitrary microphone arrangement, enable efficient real-time processing without requiring complex runtime calculations, thus improving productivity while maintaining accuracy through the use of precise pre-characterized device-specific data.
Data Source
AI summary
Systems, methods, and computer readable media to improve the operation of an electronic device having multiple microphones organized in an arbitrary, but known, arrangement in the device are described (i.e., having a specific form-factor). In general, techniques are disclosed for using a priori knowledge of an electronic device's spatial acoustic transfer functions to recreate or reconstitute a prior recorded three-dimensional (3D) audio field or environment. More particularly, techniques disclosed herein enable the efficient recording of a 3D audio field. That audio field may later be reconstituted using an acoustic characterization based on the device's form-factor. In addition, sensor data may be used to rotate the audio field so as to enable generating an output audio field that takes into account the listener's head position.