Hybrid Spatialization for Telepresence Audio

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Solution Overview

Problem

Conventional methods for delivering spatialized audio in telepresence systems using crosstalk cancellation and vector-based amplitude panning face limitations, including sensitivity to tracker errors and inaccurate localization cues, especially with more than three loudspeakers and varying listener positions.

Innovation Solution

Implementing a hybrid scheme that uses crosstalk cancellation below a specified frequency threshold (e.g., 1000-2000 Hz) and modified vector-based amplitude panning above it, forming an over-determined system to determine amplitude weights for all loudspeakers, without assuming equidistant listener positions and avoiding arbitrary decomposition of loudspeaker areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If crosstalk cancellation is used for spatialization, then accurate localization cues are achieved, but sensitivity to tracker errors increases

Engineering Contradiction:

Improvelocalization accuracyVSAvoidsensitivity to tracker errors

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the operational parameters of the spatialization system by switching between two different methods (crosstalk cancellation and VBAP) based on frequency thresholds. This allows the system to optimize for localization accuracy at certain frequencies while avoiding error sensitivity at others, directly resolving the contradiction between measurement precision and reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the frequency spectrum into different bands, applying crosstalk cancellation to lower frequencies where localization cues are most critical, and VBAP to higher frequencies where tracker errors become more problematic. This segmentation allows each method to operate in its optimal frequency range, balancing accuracy and reliability

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If vector-based amplitude panning is used with more than three loudspeakers, then system versatility is improved, but localization accuracy deteriorates

Engineering Contradiction:

Improveloudspeaker configuration flexibilityVSAvoidlocalization accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent changes the spatialization method based on frequency parameters, using VBAP for higher frequencies with multi-loudspeaker configurations. This allows the system to maintain versatility with various loudspeaker arrangements while compensating for localization accuracy degradation through frequency-selective processing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite spatialization approach by combining crosstalk cancellation and VBAP methods in a hybrid frequency-domain system. This composite approach leverages the strengths of each method (accurate localization from CC at low frequencies, configuration flexibility from VBAP at high frequencies) to overcome their individual limitations

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If crosstalk cancellation is used, then localization accuracy is improved, but complexity of HRTF individualization increases

Engineering Contradiction:

Improvelocalization accuracyVSAvoidHRTF individualization complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the frequency spectrum to apply crosstalk cancellation only to lower frequencies where localization cues are most critical and HRTF individualization is most beneficial. This segmentation reduces the overall complexity of HRTF processing while maintaining localization accuracy in the most important frequency range

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the spatialization strategy based on frequency parameters, switching from crosstalk cancellation to VBAP above a certain frequency threshold. This parameter-based switching reduces the burden of HRTF individualization across the entire frequency spectrum while preserving accurate localization where it matters most

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12126984B2Three-dimensional audio source spatialization

Publication Date: 2024.10.22 GOOGLE LLC

AI summary

Techniques of delivering audio in a telepresence system include specifying a frequency threshold below which crosstalk cancellation (CC) is used and above which VBAP is used. In some implementations, such a frequency threshold is between 1000 Hz and 2000 Hz. Moreover, in some implementations, the improved techniques include modifying VBAP for more than three loudspeakers by forming an over-determined system to determine the amplitude weights for all loudspeakers at once.