JPS6331794B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plosive sound detection device for detecting plosive sounds.

Conventionally, plosive sounds can be reliably, easily, and
There is no known method for real-time detection.
The present invention provides a plosive sound detection device that detects plosive sounds simply and in real time.

Experiments have revealed that the oral airflow that accompanies speech can be detected and that plosive sounds can be reliably detected from the oral airflow. However, when a plosive is in the middle of a continuous utterance, in addition to the oral airflow corresponding to the plosive, an oral airflow similar to that for a plosive may be generated at the end of the vowel, and only the plosive is unique. It has become clear that this poses a hindrance to effective detection.

Accordingly, another object of the present invention is to provide a plosive sound detection device that reliably detects oral airflow corresponding to a plosive sound even when the plosive sound is present in a word of continuous speech. The present invention will be described in detail below using Examples.

The plosive sound detection device according to the present invention basically consists of a flow velocity detector 1 for detecting oral airflow as shown in FIG.
, a sound detector 2 that detects sound, and a signal processing circuit 3 that controls the output signal of the flow velocity detector 1 with the output signal of the sound detector 2 and extracts only the oral air flow of a plosive. The flow velocity detector 1 detects the flow velocity of oral airflow during speech, changes in flow velocity (acceleration), etc., and is composed of, for example, a hot wire type wind velocity detector, a microphone with a windshield removed, or the like. The flow velocity detector 1 is placed in front of the speaker's mouth at a position where it can detect the oral airflow associated with speech. The voice detector 2 detects the voice when speaking, and is composed of, for example, a close-talk type microphone. Similarly, the voice detector 2 is also placed at a position near the speaker's mouth where the voice can be detected. The signal processing circuit 3 controls the output signal of the flow velocity detector 1 using the output signal of the voice detector 2. For example, the signal processing circuit 3 controls the amplitude of the output signal of the flow velocity detection means for a certain period after the end of the vowel of the voice signal. configured to do so.

The signal processing circuit 3 includes a detection circuit 31 that detects the output of the audio detector 2 at a certain level or higher, and a control circuit 3.
4. It consists of a monostable multivibrator (MM) 32 and an RS flip-flop (FF) 33 for generating a control signal for the control circuit 34 from the output of the detection circuit 31.

FIG. 2 shows signal waveforms at various parts to explain the operation of the embodiment shown in FIG. 1. Waveform A shows a typical example of a voice signal when a plosive sound detected by the voice detector 2 is in a word of continuous speech. Waveform B shows a typical example of an oral airflow signal when the above-mentioned plosive sound detected by the flow velocity detector 1 is in the middle of a continuous utterance. Here, an example is shown in which |apa| is uttered.

According to experiments, when a plosive sound is present in the word of a continuous utterance, when |apa| is uttered, the oral airflow signal B becomes a pulse-like pulse with a characteristic steep rise corresponding to the plosive sound |p|. A mouth airflow signal having a waveform (hereinafter referred to as a rupture mouth airflow signal α) and a mouth airflow signal (hereinafter referred to as a closed mouth airflow signal β) having a waveform similar to that of the rupture mouth airflow signal α are generated. The mouth closure airflow signal β occurs at the end of the vowel |a| preceding the plosive, which corresponds to a time just before the lip closure point. Thereafter, there is a closure period of the plosive sound |p|, during which the intraoral pressure increases and the plosive orifice airflow signal α is generated almost simultaneously with the opening point. Closure airflow signal β
varies depending on the speaker, speech method, and type of plosive, but its occurrence period is within several tens of milliseconds preceding a closing period of 100 to 200 milliseconds. Therefore, when a plosive sound is present in a word of continuous speech, it is difficult to accurately detect only the plosive sound using only the oral airflow signal.

According to the plosive sound detection device shown in FIG. 1, the signal processing circuit 3 By suppressing the oral airflow signal B for a certain period after the end of the vowel of the speech, only the oral airflow of the plosive is extracted as shown in FIG. 2C.

For this reason, in the signal processing circuit 3, the detection circuit 31 first determines the threshold value of the output A of the audio detector 2.
_One or more time periods are detected and detection pulses are obtained indicative of the time periods. The detection pulse output is FF33.
MM 32 generates a pulse with a pulse width t ₁ from the end of the detection pulse to the time point at which the closure airflow signal β occurs. FF33 is
The output of the detection circuit 31 is inputted as a set input, and the inverted output of the MM32 is inputted as a reset input to generate a control signal D whose pulse period is from the start of the detection pulse indicating the voice section to the end of the output of the MM32.
4 suppresses the output of the oral airflow detector 1 during this pulse period. As a result, only the oral airflow component corresponding to a plosive sound, as shown in FIG. 3E, can be detected as the output of the signal processing circuit 3.

FIGS. 4 and 5 show other embodiments of the plosive sound detection device according to the present invention. The configuration of FIG. 4 is the same as that of FIG. 1 except for the signal processing circuit 3. The signal processing circuit 3 includes a delay circuit 41 that delays the output of the audio detector 2 by t ₂ , an envelope detection circuit 42 , an integration circuit 43 and a control circuit 44 .

In this embodiment, a delay circuit 41 using a charge transfer element such as a CCD or a BBD provides a signal obtained by delaying the output A of the audio detector 2 by _t2 . The positive polarity portion of the delayed audio output is detected by an envelope detection circuit 42 and integrated by an integrating circuit 43, to obtain a signal representing the power of the audio detection signal, as shown in FIG. The signal G representing this power is applied as a control signal to the control circuit 44, and as in FIG. 1, the signal L from the flow velocity detector 1 is suppressed when the signal G is at a level above a predetermined threshold. Here, the number of stages and the clock frequency of the charge transfer elements constituting the delay circuit 41 are such that the above-mentioned closed mouth airflow signal β is input to the voice detection output after the delay.
It is set to provide a delay time that completely includes the rupture port airflow signal α and does not include the rupture port airflow signal α.
Further, the control circuit 44 includes a gain control amplifier whose gain decreases as the control signal increases.

In this configuration, the envelope detection circuit 42 and the integration circuit 43 obtain a signal T representing the power to the delayed audio signal, and the magnitude of the power is large at |a|, corresponding to the utterance of |apa|. , |p| becomes zero. Therefore, the control circuit 44 operates to suppress the output A from the flow velocity detector 1 when the power signal level is large |a|, and to pass it as is when the power signal is |p|. As a result, the aforementioned closed mouth airflow signal β is removed from the output of the control circuit 44, and only the mouth airflow corresponding to the plosive sound can be detected.

As is clear from the above description, according to the present invention, even when a plosive sound is present in a word of continuous speech, only the oral airflow corresponding to the plosive sound can be reliably detected. In addition, the configuration of the plosive detection device is simple,
Real-time detection becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of a plosive detection device according to the present invention, FIGS. 2 and 3 are diagrams showing waveforms of each part of FIG. 1, and FIG. A block diagram showing the configuration of another embodiment of the detection device, FIG. 5 is a diagram showing waveforms of various parts in FIG. 4. DESCRIPTION OF SYMBOLS 1... Flow velocity detector, 2... Sound detector, 3... Signal processing circuit, 31... Detection circuit, 32... Monostable multivibrator, 33... R-S flip-flop, 34... Control circuit.

Claims (1)

[Claims] 1. A flow velocity detection means for detecting oral airflow, a sound detection means for detecting sound, and an amplitude control for the output signal of the flow velocity detection means for a certain period after the end of the output signal of the sound detection means. and processing means for extracting only the oral airflow of the plosive. 2. In claim 1, the processing means includes a delay section for delaying the output signal of the audio detection means, an amplitude detection section for detecting the power of the output signal of the delay section, and an amplitude detection section for detecting the power of the output signal of the amplitude detection section. A plosive sound detection device comprising a suppressor that reduces the output signal of the flow velocity detection means when the flow velocity detection means becomes large.