CA2045959C - Speech recognition apparatus - Google Patents

Speech recognition apparatus

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Publication number
CA2045959C
CA2045959C CA002045959A CA2045959A CA2045959C CA 2045959 C CA2045959 C CA 2045959C CA 002045959 A CA002045959 A CA 002045959A CA 2045959 A CA2045959 A CA 2045959A CA 2045959 C CA2045959 C CA 2045959C
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Canada
Prior art keywords
signal
response
recognition
speech
pbr
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA002045959A
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French (fr)
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CA2045959A1 (en
Inventor
Haruyuki Hayashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
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Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Publication of CA2045959A1 publication Critical patent/CA2045959A1/en
Application granted granted Critical
Publication of CA2045959C publication Critical patent/CA2045959C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Telephone Function (AREA)

Abstract

A speech recognition apparatus for a speech recognition answering system which uses telephone channels and having a function of detecting a PB (PUSH BUTTON) signal. A speech recognition unit recognizes a speech signal from an input signal, while a PB detection unit detects a PB signal from an input signal. A control unit automatically determines whether an input signal is a speech signal or whether it is a PB signal on the basis of the outputs of the speech recognition unit and PB detection unit.

Description

SPFECX RECOGNITION APPARATUS

BACKGROUND OF T~: INVENTION
The present invention relates to a speech recognition apparatus for use in a speech recognition answering system and, more particularly, to a speech recognition apparatus having a 5 PB (PUSH BUTTON) signal detecting or recei~ing function.
A conventional speech recognition apparatus of the type described has a speech recognition unit (SRU) and a PB sinal receognition unit or PB receiver ~PBR), but it cannot determine whether an input signal from a telephone channel is a PB signal 10 or whether it is a speech. It has been customary, therefore, to assign an independent telephone channel to each of PB input and speech input. A business application or similar software using the apparatus monitors the telephone channels to determine which of the telephone channels has received a call and 15 commands the apparatus to use only one of the recognition units SRU and PBR associated with the telephone channel of interest.
Moreover, the conventional speech recognition apparatus with a PB receiving function forces the business application to execute processing matching the independent telephone channels.
2 0 On the other hand, the user has to select either on of two '~
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different telephone numbers assigned to speech input and P
input, resulting in limited serviceability. In a system wherein the apparatus is expected to call the user, the user has to register desired one of the speech input and PB input at the 5 system beforehand. Further, since the channels and the kinds of input signals are fixedly held in one-to-one correspondence, an idle channel cannot be efficiently assigned. Specifically, when calls concentrate on either one of the speech input and PB input channels, the user cannot take full advantage of the service.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a speech recognition apparatus capable of automatically determining whether an input signal is a speech signal or whether 15 it is a PB signal.
It is another object of the present invention to provide a generally improved speech recognition apparatus.
A speech recognition apparatus of the present invention comprises a speech reco~nition unit for recognizing a speech 2 0 from an input signal and outputting the result of recognition, a PB signal detection unit for detecting a PB signal from the input signal and outputting the result of detection, and a control unit for controlling the speech recognition unit and PB signal detection unit to automatically determine whether the input signal is a 2 5 speech signal or whether it is a PB signal on the basis of the ~`
.,, ~3~ 2045959 result of recognition and the result of detection which the speech recognition unit and PB signal detection unit output when used at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which:
FIG. 1 is a block diagram schematically showing a speech recognition system implemented with a speech recognition apparatus embodying the present invention;
FIG. 2 is a flowchart demonstrating a specific operation of the system shown in FIG. l; and FIGS. 3, 4 and 5A through 5G are flowcharts showing specific procedures which the embodiment executes for automatic s ~

-2~4~

DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 of the drawings, a speech recognition system implemented with a speed recognition apparatus embodying the present invention is shown. As 5 shown, a subscriber's telephone 6 is connected to a channel control 1 via first and second exchanges 7 and 8. The channel control 1 sends an input signal to a speech recognition apparatus 10 under the control of a business application 2. The speech recognition apparatus 10 has a speech recognition unit (S~U~ 3, 10 a PB signal or dial tone recognition unit (PBR), and a control unit 5.
The operation of the system will be described with reference also made to FIG. 2. When a person using the system originates a call on the telephone 6, the call is sent to the channel control 1 via the exchanges 7 and 8 (step 2 01 ) . In response, the channel control 1 informs the business application 2 of the arrival of the call. On receiving a call termination command from the business application 2, the channel control 1 connects the channel to the speech recognition apparatus 10 2 0 (step 2 0 2 ) and then informs the business application 2 of the end of call termination. In response, the business application 2 notifies the control unit 5 of the apparatus 10 of the number of words of an input signal to be recognized (step 2 0 3 ) . The number of kinds of input signals to be recognized at the 2 5 same time are equal to the number of kinds of PB dials of the telephone, and ~' ~5~ 2045959 most of them are numerals. Hence, in the illustrati~e embodiment, let the number of words be treated as figures or digits hereinafter.
On recei~ing the digit command from the business application, the control unit 5 enables the SRT 3 and PBR 4 (step 204) so as to recognize input signals from the channel control 1 at the same time, thereby automatically discriminating the input signals (step 2 0 5 ) . When the predetermined number of figures have been recognized, the control unit 5 delivers the results of recognition to the business application 2 (step 206).
The automatic discrimination of input signals which is the characteristic feature of the present invention will be described in detail. Preconditions for the automatic identification are as follows:
(1 ) The detection rate of the PBR 4 is substantially 100 % while the recognition rate of the SRU 3 is less than 100 %;
and (2) There is no user who uses speech and PB together.
FIG. 3 shows the details of the automatic discrimination step 205 of FIG. 2 which the control unit 5 of the apparatus 10 executes. Implemented by a microProcessor, for example, the control unit 5 enables the SRU 3 and PBR 4 for the first digit in order to effect simultaneous recognition (step 204, FIG. 2).
Then, the control unit 5 sets a predetermined time (Tl ) in a timer built therein. If the result of recognition of the first digit ~'~
.

is returned from the PBR 4 first (step 302), the control unit 5 immediately determines that it is the result of simultaneous recognition of the first digit (step 311) since the recognition rate of the PBR 4 is considered to be 100 %. At this instant, the 5 control unit 5 disenables the SRU 3. In the event of multi-figure input, the control unit 5 determines that the second and successive digits are not a speech on the basis of the previously stated precondition (2) and, therefore, executes the processing only with the PBR 4, i. e., without simultaneous recognition 10 (step 312). When the result of recognition of the first digit is returned from the SRU 3 first (step 303), the control unit 5 waits a predetermined period of time (T2) to see if a result from the PBR 4 is not really returned. For this purpose, the control unit 5 sets the time T2 in a timer independent of the timer 15 assigned to the time Tl.
The time T2 should not be longer than about 1. 5 seconds at most since it delays the processing time. If the PBR 4 returns an answer to the control unit 5 within the time T2 (step 308), the control unit 5 determines that the SRU 3 has misrecognized 20 due to noise or similar cause. Then, the control unit 5 regards the result from the PBR 4 as the result of simultaneous recognition of the first digit and disenables the SRU 3 (step 311). In the case of multi-figure input, the control unit 5 uses only the PBR 4 in effecting recognition (step 312). If an answer 25 from the BPR 4 is not returned within the time T2 as determined B

~7~ 204~959 in the step 3 0 8, the control unit 5 determines that the input signal is a speech (step 3 0 9 ) and recognizes the second and successive digits only by the SRU 3 (step 310). On completing the recognition of the predetermined number of figures, the 5 control unit 5 sends the results to the business application 2 (step 2 0 6 ) . If the SRU 3 does not return an answer as determined in the step 3 0 3, the control unit 5 determines whether the time T1 has expired or not (step 304) and, if it has expired, ends the processing while informing the business 10 application 2 of the expiration (step 306). If the time Tl has not expired as determined in the step 304, the program returns to the step 3 0 2 to see if the PBR 4 or the SRU 3 returns an answer.
By the above procedure, input signals are automatically 1 5 discriminated.
As stated above, the illustrative embodiment recognizes the first digit and, base on the result of this recognition, recognizes the second and successive digits by either one of the SRU 3 or the PBR 4. This is successful so long as only the 2 0 recognition unit associated with the input signal responds correctly. In practice, however, it sometimes occurs that both of the recognition units respond. Then, this embodiment effecting simultaneous recognition would malfunction.
Generally, the two different recognition units may respond at the 25 same time under either one of the following two situations:

B~

(a) The PBR 4 also responds to a speech input; and (b) The SRU 3 also responds to a PB input.
The above occurrence (a) is unavoidable although rare.
Hence, considering that the probability that the occurrence (a) 5 continues is low, it is determined that the input signal is PB if the PBR 4 responds within a predetermined plurality of digits.
In the event of the occurrence (b), the input signal is determined to be PB since the recognition rate of the PBR 4 is considered to be 10 û %. However, when PB involving noise or speech is 10 recognized by the SRU 3, the PBR 4 is apt to return a result after the SRU 3. To eliminate this problem, a result from the PB~ 4 may be waited for after the return of a result from the SRU 3. However, this implementation is not fully satisfactory since the waiting time delays the response and, therefore, 15 cannot exceed a certain limit. A procedure which promotes more accurate automatic identification consists in determining, every time the SRU 3 returns a result, whether or not the PBR 4 returns an answer and regarding the input as PB if the PBR 3 has returned an answer as to two or more digits. FIG. 4 shows a 20 sequence of steps for practicing such a procedure.
The procedure shown in FIG. 4 corresponds to the step 205 shown in FIG. 2. Specifically, both the SRU 3 and the P~3R 4 are enabled. First, the control UIlit 5 sets in a first timer an input time T0 associated with the number of figures which is 25 instructed by the business application 2. If the PBR 4 returns a ~.
, .~

g result of recognition of the first digit before the SRU 3 (step 402), the control unit 5 regards it as a result of simultaneous recognition on the first digit by considering that the recognition rate of the PBR 4 is 100 %. If it is the SRU 3 that has returned 5 a result first (step 403), the control unit 5 waits a predetermined period of time (Tl) to see if the PBR 4 does not really return an answer (step 406). Again, this waiting time T1 should not be longer than about 1. 5 second so as not to delay the processing. If the PBR 4 returns an answer within the period 10 of time T1, the control unit 5 regards the result from the PBR as a result of simultaneous recognition of the first digit by determining that the SRU 3 has misrecognized due to noise or similar cause (step 411).
If the first digit is PB as determined in the step 411, the 15 answer of a step 412 is NO without exception since the number of times that the PBR 4 answers is unconditionally once. Then, the next digit is recognized (step 413) . At this time, the control unit 5 does not enable the SRU 3 and waits for a result from the PBR 4 for a given period of time (T2) (step 414). Assuming 20 that the user of the telephone 6 presses the keys on the telephone 6 slowly, the period of time T2 is the interval between the successive operations of the keys, e. g. 1 second to 3 seconds.
If the PBR 4 returns a result within the period of time T2, the control unit 5 regards it as a result of simultaneous recognition 25 of the second digit (step 417). If the result of recognition from ..t --1 o--the PBR is not on the last digit (step 418 ), the control unit 5 recognizes the succeeding digit or digits with the PBR 4 only, i. e., it does not execute simultaneous recognition (step 419).
If the PBR 4 does not return a result within the period of time T2 as determined in the step 414 and if the SRU 3 has returned a result on the first digit (step 415), the control unit 5 replaces the result on the first digit with the result from the SRU (step 416) and enables the SRU 4 (step 410).
On the other hand, if the SRU 3 has returned a result on the first digit first (step 403) and if the PBR 4 has not returned a result within the waiting time T1 (step 406), the control unit determines that the input is not PB since the PBR 4 is free from misrecognition. Then, the control unit 5 regards the result from the SRU 3 as a result of simultaneous recognition of the first digit (step 407).
In the illustrative embodiment, when the answers from the SRU 3 and PBR 4 exist together, the results of recognition are replaced with each other, depending on the situation, as follows:
(i) First replacement: When the PBR 4 returns an answer as to two or more digits during the recognition of a plurality of digits, the results having been returned from the PBR
4 are substituted for the results of recognition; and (ii) Second replacement: Assume that after a result from the PBR 4 on a given digit has been regarded as a result of .
.. ~

204~959 recognition, the PBR 4 does not return an answer as to the next digit within the period of time T2. Then, if all the results of recognition up to the digit of interest are the results from the SRU 3, the results from the SRU 3 are substituted for the results of recognition.
A reference will be made to FIGS. 5A through 5G for describing the answers from the SRU 3 and PBR 4 and the results of recognition on the assumption that five digits are sequentially recognized. As shown, when the SRU 3 answers first as to the first digit (step 403) and the PBR 4 does not answer within the period of time T1 (step 406), the result S1 from the SRU 3 is determined to be the result of recognition of the first digit (step 407 and FIG. 5A). As the SRU 3 answers first as to the second digit also and the PBR 4 does not answer, the output S2 of the SRU 3 is determined to be the result of recongnition of the second digit (FIG. 5B). However, regarding the third digit, the PBR 4 answers before the SRU 3 (step 402), so that the output P1 of the PBR 4 is determined to be the result of recognition of the third digit (step 41 and FIG. 5C). Since the PBR 4 answers only once, the step 412 is followed by the step 413 for recognizing the next digit. Assume that thepBR 4has not returned an answer within the period of time T2 (step 414). Then, the control unit 5 determines whether or not the SRU 3 has responded to the third digit (step 415). If the answer of the step 415 is YES, the above-mentioned replacement (i) is effected to substitute all of . . .

the outputs of the SRU 3 having been returned from the results of recognition up to third digits (step 416 and FIG 5D). Since the SRU 3 has to be enabled digit by digit, the control unit 5 enables it to process the next digit (step 410). Assume that the 5 PBR 4 has responded as to the next digit also (step 4 0 2 ) .
Then, the result from the PBR 4 is selected as a result of recongition of the digit of interest (step 411). Since the PBR has responded twice as counted from the beginning of the processing, the control unit 5 determines that the input signals 10 are PB and, therefore, effects the replacement (i) (steps 412 and 417 and FIG. 5E). After such a decision, the control unit 5 executes recognition with the succeeding digits by using only the PBR 4, i. e., without enabling the SRU 3 (step 419 and FIG.
5F). On determining the results of recognition of five digits (step 418 and FIG. 5G), the control unit 5 sends them to the business application (step 2 0 6 ) . Such a procedure enhances more accurate identification of input signals. It is to be noted that the number of digits to which the PBR responds as determined in the step 412 is not limited to two and may be three 20 or more.
In summary, it will be seen that the present invention provieds a speech recognition apparatus which has a speech recognition unit for identifying a speech from an input signal, a PB recognition unit for detecting a PB signal from an input 2 5 signal, and a control unit capable of automatically determining ! B

-13- 2045~59 whether an input signal is a speech signal or whether it is a PB
signal. The apparatus, therefore, makes it needless for a business application which controls it to discriminate a PB signal and a speech signal. As a result, the customer intending to use S an inquiry service, for example, does not have to discriminate the telephone number for voice input and the telephone number for PB input. In the case of information service, it is not necessary for the customer to register at the system regarding the PB/voice input. Hence, the apparatus enhances the 10 serviceability of the system. Further, the system sets up efficient traffic since both of PB input processing and voice input processing are implemented by a single telephone channel, exhibiting the processing ability to the full extend.
Various modifications will become possible for those 15 skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.

....~

Claims (3)

1. A speech recognition apparatus comprising:
speech recognizing means for recognizing a speech from an input signal and outputting the result of recognition;
PB signal detecting means for detecting a PB signal from the input signal and outputting the result of detection; and control means for controlling said speech recognizing means and said PB signal detecting means to automatically determine whether the input signal is a speech signal or whether said input signal is a PB signal on the basis of the result of recognition and the result of detection which said speech recognizing means and said PB signal detecting means output when used at the same time.
2. An apparatus as claimed in claim 1, wherein said control means determines that the input signal is a speech signal when a first response which is the response of said speech recognizing means precedes a second response which is the response of said PB signal detecting means and if said second response does not appear within a predetermined period of time after said first response, or determines that said input signal is a PB signal when said second response appears within said predetermined period of time or when said second response precedes said first response.
3. An apparatus as claimed in claim 1, wherein said control means determines that the input signal is a PB signal when a first response which is the response of said speech recognizing means precedes a second response which is the response of said PB signal detecting means and another second response appears within a first predetermined period of time after said second response, when said first response precedes said second response and said second response appears within a second period of time after said first response and another second response appears within said first predetermined period of time after said second response, or when said second response appears more than a predetermined number of times during a plurality of times of recognition of the input signal.
CA002045959A 1990-07-02 1991-06-28 Speech recognition apparatus Expired - Fee Related CA2045959C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2174801A JP2734750B2 (en) 1990-07-02 1990-07-02 Voice recognition device
JP2-174801 1990-07-02

Publications (2)

Publication Number Publication Date
CA2045959A1 CA2045959A1 (en) 1992-01-03
CA2045959C true CA2045959C (en) 1996-04-02

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CA002045959A Expired - Fee Related CA2045959C (en) 1990-07-02 1991-06-28 Speech recognition apparatus

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CA (1) CA2045959C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11854570B2 (en) 2013-01-07 2023-12-26 Samsung Electronics Co., Ltd. Electronic device providing response to voice input, and method and computer readable medium thereof

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5956675A (en) 1997-07-31 1999-09-21 Lucent Technologies Inc. Method and apparatus for word counting in continuous speech recognition useful for reliable barge-in and early end of speech detection
US6405051B1 (en) 1999-06-10 2002-06-11 Telefonaktiebolaget Lm Ericsson (Publ) Method and apparatus for using a B-answer signal to prevent a voice announcement in a group call
JP3837061B2 (en) 2001-11-28 2006-10-25 富士通株式会社 Sound signal recognition system, sound signal recognition method, dialogue control system and dialogue control method using the sound signal recognition system
FI20085371A0 (en) 2008-04-25 2008-04-25 Pellonpaja Oy Process for the treatment and / or pretreatment of liquid manure or reject from biogasver for the elimination of pollutants, in particular nitrogen, phosphorus and odor molecules

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Publication number Priority date Publication date Assignee Title
JPS59111529A (en) * 1982-12-17 1984-06-27 Hitachi Ltd Identifying system for input device of audio response unit
JPS6160055A (en) * 1984-08-31 1986-03-27 Toshiba Corp Voice recognition response device
JPS6356055A (en) * 1986-08-27 1988-03-10 Oki Electric Ind Co Ltd User identification circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11854570B2 (en) 2013-01-07 2023-12-26 Samsung Electronics Co., Ltd. Electronic device providing response to voice input, and method and computer readable medium thereof

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Publication number Publication date
JP2734750B2 (en) 1998-04-02
JPH0462600A (en) 1992-02-27
CA2045959A1 (en) 1992-01-03

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