Position-Dependent Extrapolation of Multichannel Room Impulse Responses
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Solution Overview
Problem
Existing methods for generating multichannel room impulse responses require a high measurement effort and data volume for arbitrary spatial locations, leading to significant temporal, timbral, and spatial artifacts, and are not effective in virtual or augmented reality applications where users continuously change positions.
Innovation Solution
A method for position-dependent extrapolation of multichannel room impulse responses by splitting signals into temporal segments, identifying salient peaks, determining sound event positions, and applying gain, directional mapping, and temporal shift to generate responses for arbitrary locations, using a limited set of measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multichannel room impulse responses are measured for every position in space to achieve thorough sound field reproduction, then measurement precision and sound field accuracy are improved, but measurement effort and data volume increase significantly
Solution Approach 1:
The patent segments the room impulse response into multiple temporal segments, each corresponding to a specific sound event with identified start and end times. This segmentation allows selective processing and extrapolation of individual sound events rather than handling the entire impulse response as a single unit, reducing the computational and storage requirements while maintaining accuracy for each segment.
Solution Approach 2:
The patent creates virtual copies of measured multichannel room impulse responses at arbitrary spatial locations through extrapolation algorithms. Instead of physically measuring at every possible position, the system generates synthetic impulse responses by copying and transforming the characteristics of measured responses to unmeasured positions, significantly reducing measurement effort while maintaining reproduction accuracy.
2Adaptability or versatility
If position-dependent weighting is applied to measured multichannel room impulse responses to generate responses at arbitrary locations, then adaptability to different positions is improved, but temporal, timbral, and spatial artifacts increase
Solution Approach 1:
The patent applies position-dependent weighting selectively to specific temporal segments corresponding to individual sound events rather than uniformly across the entire impulse response. Each sound event segment is weighted according to its spatial characteristics and distance from the target position, allowing localized adaptation that preserves the natural temporal and spectral structure of each sound event while reducing artifacts.
Solution Approach 2:
The patent performs preliminary identification and segmentation of sound events before applying extrapolation and weighting operations. By pre-identifying the temporal boundaries and characteristics of each sound event, the system can apply position-dependent transformations in advance, ensuring that artifacts are minimized through proper temporal alignment and segment-specific processing rather than post-processing corrections.
3Measurement precision
If spherical harmonics transformation and spatial translation are applied to recorded microphone signals, then directional information processing is improved, but measurement density requirements increase and temporal structure information is lost
Solution Approach 1:
The patent segments the impulse response into temporal segments corresponding to individual sound events before applying spatial transformation. This segmentation allows the spherical harmonics transformation to be applied to smaller, more manageable segments with distinct temporal characteristics, reducing the complexity requirements for measurement density while preserving directional information within each segment's spatial context.
Solution Approach 2:
The patent changes the temporal parameter representation by identifying and extracting specific sound event segments with defined start and end times, rather than processing the entire impulse response as a continuous signal. This parameter change from continuous to segmented temporal representation allows more efficient use of measurement data and reduces the required measurement density while maintaining directional accuracy through segment-specific processing.
Data Source
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AI summary
The present invention relates to methods and an apparatus for position-dependent extrapolation or interpolation and extrapolation of multichannel room impulse responses resulting from a sound emitted in a room. The method comprises amongst others the steps of: splitting multichannel signals of the at least one input multichannel room impulse response into temporal segments; determining a position corresponding to the sound events; assigning the determined sound event position to each temporal segment of the at least one input multichannel room impulse response; and extrapolating an extrapolated multichannel room impulse response for a desired extrapolation position representing an arbitrary spatial location in the room, comprising the steps of: applying a gain, applying a directional mapping, and applying a temporal shift, to each of the temporal segments of the at least one input multichannel room impulse response, respectively.