Audio Reverberation Extraction Using Estimated Impulse Response
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Solution Overview
Problem
Current technologies face challenges in modifying the reverberation component of an audio signal without direct measurement of the acoustic space, particularly in separating and altering the direct sound and reverberant components, which is essential for various applications such as audio processing, speech recognition, and film production, where inappropriate reverberation affects signal clarity and authenticity.
Innovation Solution
The method involves estimating the impulse response of the reverberant system using block-based magnitude responses derived from the audio signal, allowing for the extraction and alteration of the reverberant component without direct measurement, and applying these characteristics to modify the signal appropriately for its intended application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If artificial reverberation devices are used to add reverberant energy, then the recording can have more reverberation, but the reverberation does not sound natural and does not complement the existing reverberation
Solution Approach 1:
The patent extracts the impulse response from the existing recording to create a model of the acoustic space, then uses this copied model to generate additional reverberation that matches the original characteristics. This copying approach ensures the added reverberation sounds natural and complements the existing reverberation rather than sounding artificial.
Solution Approach 2:
The patent introduces an impulse response model as an intermediary between the dry signal and the reverberant output. This intermediary captures the acoustic characteristics of the space and mediates the reverberation generation process, ensuring natural-sounding results that are consistent with the original recording environment.
2Reliability
If directional microphones or microphone arrays are used to reduce reverberation, then the direct sound can be enhanced, but the system complexity and hardware resources increase
Solution Approach 1:
The patent replaces the mechanical approach of using directional microphones or microphone arrays with a signal processing approach. By extracting the impulse response and using it to separate and process direct and reverberant components digitally, the system achieves similar clarity enhancement without the hardware complexity of specialized microphones or arrays.
Solution Approach 2:
The patent extracts the impulse response characteristics from the recording and uses this extracted information to separate the direct sound from the reverberation. This extraction approach allows for reverberation reduction without requiring complex hardware, as the necessary information is derived from the signal itself.
3Reliability
If the entire impulse response is used for signal processing, then complete reverberant characteristics are preserved, but computational complexity and processing time increase
Solution Approach 1:
The patent divides the impulse response into multiple blocks or segments, processing each block separately rather than handling the entire impulse response at once. This segmentation reduces computational complexity and processing time while preserving the essential reverberant characteristics through systematic block-wise processing.
Solution Approach 2:
The patent processes only the most significant portions of the impulse response that contain the essential reverberant characteristics, rather than processing the entire impulse response in detail. This partial action approach maintains adequate acoustic space representation while reducing computational burden and processing time.
Data Source
AI summary
A method and apparatus for extracting and changing the reverberant content of an input signal is provided. The method of estimating an impulse response for a reverberant system includes sampling a signal from a reverberant system, having an impulse response, into a sequence of blocks, for each block of the sequence, determining a magnitude in dependence upon a magnitude of a previous block, forming an estimate of the impulse response using determined magnitudes as parameters for a finite impulse response filter. The method of creating a multi-channel signal using a signal with fewer channels from a reverberant system includes sampling the signal from a reverberant system, having an impulse response, into a sequence of blocks, for each block of the sequence, determining a magnitude in dependence upon a magnitude of a previous block, forming an estimate of the impulse response using determined magnitudes as parameters for a finite impulse response filter, applying an inverse of the estimated impulse response to the signal to derive at least one of a direct signal component and a reverberant signal component, and recombining the direct signal component and the reverberant signal component to create a multi-channel signal.