VOCAL’s speech dereverberation software has been extensively studied using real world voice recordings and comprehensive computational modeling. Tests have demonstrated the software can effectively handle tonal and impulse interference at 8kHz and 16kHz sampling rates with reverberation of up to one second in length. The extensive testing has resulted in a robust speech dereverberation solution for a wide variety of acoustic environments.
VOCAL’s speech dereverberation software may be licensed as source code or binary, either standalone or as part of our comprehensive Voice Quality Enhancement System which also includes echo cancellation, noise reduction, and gain control. In addition, custom solutions are available from VOCAL. Please contact us to discuss your specific speech dereverberation application requirements.
In any environment where the speaker is not located near the microphone, dereverberation of speech signals can improve speech intelligibility by removing the environmental effects of the room impulse response. Similar to acoustic echo cancellation, speech dereverberation models the room impulse response transfer function and filters it from the received microphone signal. However, in this case the problem is more complex because we do not have access to the original sound source.
A sound source located a distance from a microphone will have its direct path signal arrive at the microphone and then reflections of the original signal will be captured. As the distance from the source to the microphone increases, the signal to reverberation ratio and, as a result, the effect of reverberation will also increase. To a listener, late reflections sound like noise while early reflections introduce speech coloration and distance perception.
Speech reverberation can be a significant problem especially in free-space systems, such as with laptops, tablets and videoconferencing where environmental echoes can be disruptive to conversations. With these systems, it is not the responsibility of the user to move closer to the microphone, but for engineers to develop speech enhancement systems that provide the freedom users desire in these environments.
- Speech Dereverberation using Spectral Subtraction
- Voice Activity Detection for Dereverberation of Speech
- Reverberation Cancellation versus Suppression
- Combination of dereverberation and adaptive beamforming
- Variable Tap Length Filters for Acoustic Echo Cancellation
- Octave Banks for Acoustic Filtering