Speech privacy system and/or associated method
Certain example embodiments relate to speech privacy systems and/or associated methods. The techniques described herein disrupt the intelligibility of the perceived speech by, for example, superimposing onto an original speech signal a masking replica of the original speech signal in which portions of it are smeared by a time delay and/or amplitude adjustment, with the time delays and/or amplitude adjustments oscillating over time. In certain example embodiments, smearing of the original signal may be generated in frequency ranges corresponding to formants, consonant sounds, phonemes, and/or other related or non-related information-carrying building blocks of speech. Additionally, or in the alternative, annoying reverberations particular to a room or area in low frequency ranges may be “cut out” of the replica signal, without increasing or substantially increasing perceived loudness.
1. A method for disrupting speech intelligibility, the method comprising:
receiving, via a microphone, an original speech signal corresponding to original speech;
generating an intelligibility-disrupting masking signal comprising smeared cues of the original speech in the original speech signal; and
reducing the level of intelligibility of the original speech signal by outputting, through a speaker, the intelligibility-disrupting masking signal comprising the smeared speech cues,
wherein the intelligibility-disrupting masking signal is time delayed relative to the original speech signal,
wherein the intelligibility-disrupting masking signal is generated such that the amplitude of the intelligibility-disrupting masking signal is modulated in time, and
wherein the time delay oscillates in time.
2. The method of claim 1 , wherein the intelligibility-disrupting masking signal is time-delayed by 20-150 ms.
3. The method of claim 1 , wherein the intelligibility-disrupting masking signal is time-delayed by 80 ms.
4. The method of claim 1 , wherein the time delay oscillates in time in relation to the original signal within a range of 80-230 ms.
5. The method of claim 4 , further comprising generating the intelligibility-disrupting masking signal such that gain corresponding to the intelligibility-disrupting masking signal added to the original speech signal is 0.05-0.25%.
6. The method of claim 1 , wherein the time delay oscillates with an oscillation frequency of 1-10 Hz.
7. The method of claim 6 , wherein the time delay oscillates with an oscillation frequency of 2-6 Hz.
8. The method of claim 1 , wherein smeared cues are generated at a frequency of 0.01-20 Hz.
9. The method of claim 8 , wherein smeared cues are generated at a frequency of 2-6 Hz.
10. The method of claim 1 , further comprising outputting, through the speaker, the intelligibility-disrupting masking signal together with a prerecorded mix of multiple voices.
11. The method of claim 10 , wherein the prerecorded mix of multiple voices comprises 2-7 different voices.
12. The method of claim 10 , wherein the prerecorded mix of multiple voices comprises 3 different voices.
13. A speech intelligibility disrupting device, comprising:
control circuitry configured to:
receive, from a microphone, an original speech signal corresponding to original speech;
generate an intelligibility-disrupting masking signal comprising smeared cues of the original speech in the original speech signal, the cues being smeared through control circuitry induced reverberation of the original speech signal; and
cause a speaker to output the intelligibility-disrupting masking signal comprising the smeared speech cues to reduce the level of intelligibility of the original speech signal,
wherein the intelligibility-disrupting masking signal is time delayed relative to the original speech signal, and
wherein the intelligibility-disrupting masking signal is generated such that the amplitude of the intelligibility-disrupting masking signal is modulated in time.
14. The device of claim 13 , wherein the intelligibility-disrupting masking signal is time-delayed by 20-150 ms.
15. The device of claim 13 , wherein the time delay oscillates in time.
16. The device of claim 15 , wherein the time delay oscillates in time in relation to the original signal within a range of 80-230 ms.
17. The device of claim 16 , wherein the intelligibility-disrupting masking signal is generated such that gain corresponding to the intelligibility-disrupting masking signal added to the original speech signal is 0.05-0.25%.
18. The device of claim 15 , wherein the time delay oscillates with an oscillation frequency of 1-10 Hz.
19. The device of claim 13 , wherein smeared cues are generated at a frequency of 2-6 Hz.
20. The device of claim 13 , further comprising outputting, through the speaker, the intelligibility-disrupting masking signal together with a prerecorded mix of multiple voices.
21. The speech intelligibility disrupting device of claim 13 , wherein the reverberation includes temporal phasing and amplitude modulation of the target signal.
22. The speech intelligibility disrupting device of claim 13 , wherein the control circuitry is voice-activated, and wherein the control circuitry is configured to automatically adjusts to psycholinguistic aspects and acoustic-phonetic cues of the original speech in generating the intelligibility-disrupting masking signal.
23. The speech intelligibility disrupting device of claim 13 , wherein the reverberation is generated to disrupt the rhythm of the original speech, mask acoustic cues of overlapping syllables and vowels, and/or eliminate artificially created infra-sound with sub-threshold frequencies that resonate adversely with the brain waves.
24. The speech intelligibility disrupting device of claim 13 , wherein output of the intelligibility-disrupting masking signal causes the original speech signal to be perceivable as an unintelligible foreign language.
25. A speech intelligibility disrupting system, comprising:
a microphone;
a speaker; and
control circuitry configured to:
receive, from the microphone, an original speech signal corresponding to original speech;
generate an intelligibility-disrupting masking signal comprising smeared cues of the original speech in the original speech signal; and
cause the speaker to output the intelligibility-disrupting masking signal comprising the smeared speech cues to reduce the level of intelligibility of the original speech signal,
wherein the intelligibility-disrupting masking signal is time delayed relative to the original speech signal, the time delay oscillating in time, and
wherein the intelligibility-disrupting masking signal is generated such that the amplitude of the intelligibility-disrupting masking signal oscillates in time.
26. An acoustic wall, comprising the system of claim 25 .