Head-Tracked Audio Latency Compensation via Angle Error Adjustment
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Solution Overview
Problem
Head-tracked audio systems in virtual reality and augmented reality environments suffer from spatial update latency, causing audio to appear unstable as the user's head moves, due to processing and communication delays between audio generation and output, leading to perceptual issues like sound dragging and intracranial perception of moving sounds.
Innovation Solution
A system that measures head movement since the last position update and applies interaural level differences (ILD) and interaural time differences (ITD) to the binaural audio signal to compensate for latency, using a position sensor to determine the current and past head angles, and adjusting the audio signal accordingly to maintain accurate sound localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If audio processing and communication delays are reduced to minimize latency, then audio stability improves, but processing time and computational resources are constrained
Solution Approach 1:
The system performs preliminary head position tracking and audio parameter calculation in advance of actual audio playback. By pre-computing the spatial parameters (ITD/ILD) based on predicted head position and pre-positioning audio data in buffers, the system minimizes real-time processing delays while maintaining accurate spatial audio correspondence with head movements.
Solution Approach 2:
The system dynamically adjusts audio spatial parameters based on real-time head position changes. By continuously updating ITD (interaural time difference) and ILD (interaural level difference) values as the user moves their head, the system maintains accurate sound localization without requiring excessive processing time, adapting the audio output to match current head orientation.
2Measurement precision
If head tracking precision is increased to improve audio localization, then spatial accuracy improves, but system complexity and computational load increase
Solution Approach 1:
The system extracts only the essential spatial parameters (head angle, ITD, ILD) needed for audio localization from the complete head tracking data stream. By focusing on and processing only these critical parameters rather than all available sensor data, the system achieves accurate spatial audio with reduced computational complexity and processing overhead.
Solution Approach 2:
The system transforms raw head position data into optimized audio spatial parameters (ITD and ILD values) that directly control audio output. By changing the parameter representation from general head position to specific audio-relevant spatial parameters, the system achieves precise audio localization with efficient processing suitable for real-time implementation.
3Use of energy by moving object
If audio processing is performed remotely to reduce on-device computational requirements, then device power consumption decreases, but communication latency increases
Solution Approach 1:
The audio processing system is segmented into distinct functional components distributed across different devices. The HWD performs local head tracking and sends position data to a remote device for audio processing, which then returns processed audio to the HWD. This segmentation allows computationally intensive tasks to be performed remotely while maintaining relatively low latency through optimized data exchange protocols and buffering strategies.
Data Source
AI summary
A system can include a position sensor configured to output position data of a HWD. The system can include one or more processors configured to identify a first head angle of the HWD using the position sensor, generate an audio signal using the first head angle, identify a second head angle of the HWD using the position sensor, determine an angle error based at least on the first head angle and the second head angle, and apply at least one of a time difference or a level difference to the audio signal based at least on the angle error to adjust the audio signal. The system can include an audio output device configured to output the adjusted audio signal. By adjusting the audio signal using the angle error, the system can correct for long spatial update latencies and reduce the perceptual impact of such latencies for the user.