Speech privacy system and/or associated method
View Patent ↗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;
detecting whether the original speech signal includes fundamental building blocks of speech; and
conditioned on the detection of fundamental building blocks of speech in the original speech signal:
generating an intelligibility-disrupting masking signal from the original speech signal, the intelligibility-disrupting masking signal being different from the original speech signal by virtue of being generated to have (a) a time delay relative to the original speech signal, (b) the time delay changing according to an oscillation frequency, and (c) an amplitude that is modulated; and
causing the intelligibility-disrupting masking signal to be outputted through a speaker to reduce the level of intelligibility of the original speech signal.
2. The method of claim 1 , wherein the oscillation frequency is constant.
3. The method of claim 1 , wherein the oscillation frequency varies within a predefined range.
4. The method of claim 1 , wherein the oscillation frequency varies in accordance with an algorithm.
5. The method of claim 1 , wherein the fundamental building blocks of speech comprise formants.
6. The method of claim 1 , wherein the fundamental building blocks of speech comprise consonant sounds.
7. The method of claim 1 , wherein the generation of the intelligibility-disrupting masking signal comprises including in the intelligibility-disrupting masking signal frequency ranges that smear the fundamental building blocks of speech in the original speech signal.
8. The method of claim 1 , wherein the generation of the intelligibility-disrupting masking signal comprises including in the intelligibility-disrupting masking signal frequency ranges that smear fundamental building blocks of speech at a rate matching an expected rate of occurrence for such fundamental building blocks in ordinary speech.
9. The method of claim 1 , wherein the amplitude of the intelligibility-disrupting masking signal is modulated so that it is no more than double a corresponding amplitude in the corresponding original speech signal.
10. The method of claim 1 , wherein the amplitude of the intelligibility-disrupting masking signal is modulated so that perceivable loudness is increased by no more than 10%.
11. The method of claim 1 , further comprising applying a filter to the original speech signal and modulating the amplitude in generating the intelligibility-disrupting masking signal to cause no appreciable increase in loudness upon output of the intelligibility-disrupting masking signal.
12. A speech intelligibility disrupting device, comprising:
control circuitry configured to:
receive, from a microphone, an original speech signal;
generate an intelligibility-disrupting masking signal from the original speech signal, the intelligibility-disrupting masking signal being different from the original speech signal by virtue of being generated to have (a) a time delay relative to the original speech signal, (b) the time delay changing according to an oscillation frequency, and (c) an amplitude that is modulated; and
cause the intelligibility-disrupting masking signal to be outputted through a speaker to reduce the level of intelligibility of the original speech signal,
wherein the control circuitry is further configured to:
detect whether the original speech signal includes fundamental building blocks of speech; and
condition the generation of the intelligibility-disrupting masking signal on the detection of fundamental building blocks of speech in the original speech signal.
13. The device of claim 12 , wherein the oscillation frequency varies within a predefined range.
14. The device of claim 12 , wherein the generation of the intelligibility-disrupting masking signal comprises including in the intelligibility-disrupting masking signal frequency ranges that simulate fundamental building blocks of speech.
15. The device of claim 12 , wherein the generation of the intelligibility-disrupting masking signal comprises including in the intelligibility-disrupting masking signal frequency ranges that smear the fundamental building blocks of speech that occur in the original speech signal.
16. The device of claim 12 , wherein the amplitude of the intelligibility-disrupting masking signal is modulated.
17. A speech intelligibility disrupting system, comprising:
a microphone;
a speaker; and
control circuitry configured to:
receive, from the microphone, an original speech signal;
generate an intelligibility-disrupting masking signal from the original speech signal, the intelligibility-disrupting masking signal being different from the original speech signal by virtue of being generated to have (a) a time delay relative to the original speech signal, (b) the time delay changing according to an oscillation frequency, and (c) an amplitude that is modulated; and
cause the intelligibility-disrupting masking signal to be outputted through the speaker to reduce the level of intelligibility of the original speech signal, wherein:
the control circuitry is further configured to:
detect whether the original speech signal includes fundamental building blocks of speech;
condition the generation of the intelligibility-disrupting masking signal on the detection of fundamental building blocks of speech in the original speech signal; and
modulate the amplitude of the intelligibility-disrupting masking signal, avoiding appreciable increases in loudness beyond a loudness consistent with the original speech signal; and
the generation of the intelligibility-disrupting masking signal comprises including in the intelligibility-disrupting masking signal frequency ranges that simulate fundamental building blocks of speech.
18. The system of claim 17 , wherein the fundamental building blocks of speech comprise formants and/or consonant sounds.
19. The system of claim 17 , wherein the amplitude of the intelligibility-disrupting masking signal is modulated so that perceivable loudness is increased by no more than 10%.
20. The system of claim 17 , wherein the oscillation frequency varies within a predefined range and/or in accordance with an algorithm.