Frequency Domain Convolution for Reverberation Processing
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Solution Overview
Problem
Conventional reverberant sound adding apparatuses face high processing costs due to convolution operations performed in the time domain for calculating reverberation.
Innovation Solution
The system reduces processing costs by converting input signals and impulse response signals into the frequency domain, performing convolution, and discarding sampled values, thereby reducing the number of operations required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If convolution operation is performed in the time domain, then the reverberation calculation is accurate, but the processing cost is high
Solution Approach 1:
The patent transforms the convolution operation from the time domain to the frequency domain using Fast Fourier Transform (FFT). This dimensional change allows the convolution to be performed as element-wise multiplication in the frequency domain, significantly reducing computational complexity from O(N²) to O(N log N), thereby resolving the contradiction between accuracy and processing cost.
Solution Approach 2:
The patent applies zero-value processing to sampled impulse response values, setting certain frequency components to zero. This parameter modification reduces the number of non-zero elements that require computation, further decreasing processing cost while maintaining acceptable reverberation quality through selective preservation of important frequency components.
2Manufacturing precision
If all sampled impulse response values are processed, then the output quality is high, but the number of operations is large
Solution Approach 1:
The patent extracts and eliminates unnecessary computational operations by setting sampled impulse response values to zero. By identifying and removing redundant frequency components that contribute minimally to the overall reverberation quality, the system reduces the number of operations required while preserving the essential characteristics of the reverberation effect.
Data Source
AI summary
A system for calculating reverberation, comprising a computer that receives a signal input; stores an impulse response signal; reads out the impulse response signal corresponding to the input signal; converts an input signal and an impulse response signal into an input signal in the frequency domain and an impulse response signal in the frequency domain; samples the input signal and in the frequency domain and the impulse response signal in the frequency domain to an input signal and an impulse response signal after sampling; sets one of values of signals included in the impulse response signal after sampling to zero to obtain an impulse response signal after zero-value processing; performs a convolution operation on the impulse response signal after zero-value processing to obtain a reverberant signal in the frequency domain; and converts the reverberant signal in the frequency domain into a reverberant signal in a time domain.