Method for generating sound masking signal based on time reversal

A technology of time reversal and signal generation, which is applied in the direction of sound producing equipment, speech analysis, instruments, etc., can solve the problems of low masking efficiency, reduced speech intelligibility of the target sound source, and increased voice annoyance, so as to reduce speech intelligibility High degree, suitable for real-time processing, and the effect of protecting call privacy

CN102110441AInactive Publication Date: 2011-06-29INST OF ACOUSTICS CHINESE ACAD OF SCI
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2011-06-29
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a method for generating a sound masking signal based on time reversal. In the method, a corresponding sound masking signal is acquired according to a target sound source signal and has a long-time amplitude spectrum similar to that of the target sound source signal and extremely low speech intelligibility. The method comprises the following steps of: picking up the target sound source signal by using a microphone or a microphone array and performing preprocessing to acquire a clean target sound source signal; performing framing based on a specific time window length according to the acquired target sound source signal; and performing time reversal on a time domain of each frame of signal according to y(t)=x(-t) to acquire the sound masking signal corresponding to a target sound source, wherein x(t) represents a frame of signal, and the y(t) represents an output signal of the frame. The time reversal sound masking signal has the long-time amplitude spectrum similar to that of the target sound source signal; the method has advantages in energy masking; and the time reversal sound masking signal is completely unintelligible or is partially intelligible and cannot become a new interference sound source.
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Description

technical field

[0001] The invention relates to a method for generating a sound masking signal, in particular to a method for generating a sound masking signal based on time reversal. Background technique

[0002] Studies have shown that speech is the most disturbing sound signal in the room, and the speech intelligibility of speech signals will reduce work efficiency. In some occasions, due to the high speech intelligibility, the privacy of personal calls cannot be guaranteed, and there is an urgent need for a method that can reduce the speech intelligibility and protect the privacy of personal calls. Sound masking refers to the method of adding a natural or artificially synthesized sound into the environment, covering the sound of the target sound source through auditory masking, and reducing the intelligibility of the target sound source signal. At present, acoustic masking technology based on acoustic masking signals is considered to be one of the necessary measures to ...

Examples

specific Embodiment

[0031] The signal processing process of this embodiment is simulated in MATLAB software, and the speech intelligibility is evaluated through auditory subjective experiments on the processing results. Assume that a clean target sound source signal has been obtained, such as figure 2 shown, then to figure 2 The medium signal is divided into frames with 200ms as a frame, such as figure 2 The dotted line shown is the frame boundary, and then the time reversal process is performed on each frame signal, such as image 3 As shown, at this time, there is a discontinuity between frames. In order to eliminate the discontinuity, the Tukey window function is added for smoothing. The MATLAB expression of the window function is "tukeywin(L, 0.2)", where L is the number of sampling points in the frame, Finally, the time-reversed sound masking signal of the target sound source signal is obtained, such as Figure 4 shown. Adjust target sound source signal figure 2 Harmonic masking sig...