Binaural Room Rendering With Anchored Head Tracking
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Solution Overview
Problem
Existing binaural rendering technologies face challenges in accurately replicating the acoustic characteristics of a user's listening environment, particularly due to lengthy and sensitive direct measurement of binaural room impulse responses (BRIRs), and head orientation tracking issues such as IMU drift.
Innovation Solution
Utilize impulse response (IR) measurements to generate binaural filters quickly and adapt reference filters using room acoustic characteristics, and anchor IMU to a playback device for accurate head orientation estimation by combining time-of-flight measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement of binaural room impulse responses (BRIRs) is used to achieve accurate acoustic characteristics, then measurement precision is improved, but measurement time increases significantly and the process becomes sensitive to environmental factors
Solution Approach 1:
The patent uses impulse response measurements from a single microphone position to generate binaural filters that copy the acoustic characteristics of the listening environment. Instead of performing direct BRIR measurements, the system creates synthetic binaural representations by adapting reference filters to match the measured room impulse response, thereby achieving accurate acoustic reproduction without the time-consuming direct measurement process
Solution Approach 2:
The system transforms the measurement approach by changing from direct BRIR measurement to impulse response measurement followed by filter adaptation. By measuring only the room impulse response at a single position and then adapting binaural reference filters to match these characteristics, the system achieves accurate acoustic reproduction while significantly reducing measurement time and environmental sensitivity
2Ease of operation
If IMU data is used for head orientation tracking, then ease of operation is improved, but accuracy deteriorates due to IMU drift over time
Solution Approach 1:
The patent introduces an intermediary reference frame anchored to the playback device that mediates between the IMU data and the final head orientation calculation. By transforming IMU measurements into this stable reference frame and using it to adjust the binaural rendering, the system maintains the ease of IMU-based tracking while compensating for drift to preserve accuracy
Solution Approach 2:
The system implements feedback by continuously monitoring head orientation through IMU data and dynamically adjusting the binaural rendering accordingly. The anchored reference frame provides a stable baseline that feeds back into the rendering process, allowing the system to maintain accurate spatial audio presentation despite IMU drift by constantly correcting based on the stable reference
3Reliability
If binaural rendering is implemented to simulate listening environment, then realism is improved, but computational complexity increases
Solution Approach 1:
The patent performs preliminary actions by pre-computing and storing binaural reference filters that capture the essential acoustic characteristics of typical listening environments. These pre-computed filters are then adapted to match the specific room impulse response, avoiding the need for complex real-time binaural rendering calculations while maintaining simulation accuracy
Solution Approach 2:
The system uses copying by adapting reference binaural filters to match the measured room characteristics rather than performing full binaural rendering from scratch. This approach copies the essential spatial audio characteristics into the reference filters and then applies them to the audio content, significantly reducing computational complexity while maintaining realism
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
Enhances binaural rendering by accurately simulating audio as if originating from the listening environment, maintaining immersive effects over time and various head positions, and improving computational efficiency and accuracy.
Implementation Method 1
combining time-of-flight measurements
Data Source
AI summary
Spatial audio may be played on on wearable playback devices, such as headphone and earbuds. Spatial audio may include forms of binaural rendering of audio, which is played back on the wearable playback devices. Such technologies may create or enhance an immersive listening experience which, to the listener, does not sound like you are listening on a wearable device, but are instead listening to a well-tuned, well-place, three-dimensional audio system of loudspeakers in a particular listening environment, such as the listener's actual living room.