Method and system for controlling an external machine by a voice command

Abstract: In a method for controlling an external machine by a voice command, a voice pattern which is extracted from a voice supplied through a microphone is compared with reference voice patterns to pick up one of them which corresponds to a certain voice command to control an external machine, and a similarity between the voice pattern and the reference voice pattern is calculated. Then, a control signal is supplied to the external machine after a waiting time passes. The waiting time is determined dependent on the similarity such that the waiting time is relatively long when the similarity is low and is determined relatively short when the similarity is high, so that an operator has a sufficient time to judge whether the voice command is the desired one.

Description: FIELD OF THE INVENTION This invention relates to a method and a system for controlling an external machine by a voice command, and more particularly to, a method and a system for controlling an external machine by a voice command in which a voice command is analyzed to control an external machine by comparing the voice analyzed patterns with reference voice patterns. BACKGROUND OF THE INVENTION Control systems of external machines by a voice command have been developed in recent years. In a first conventional control system of an external machine by a voice command, a voice command is supplied via a microphone to the control system to control an external machine, and an operator of the control system is informed visually or aurally that the voice command is accepted. If the operator confirms that the accepted voice command is a desired command, the operator supplies a confirmation signal to the control system to supply the machine with a command signal to control, so that the machine is controlled to operate in accordance with the voice command. If the operator recognizes that the accepted voice command is not the desired command, the operator may not supply a confirmation signal, so that the machine may not be controlled to operate by the voice command. In a second known system for controlling an external machine by a voice command, a command signal is supplied to the external machine after a predetermined waiting time passes upon the acceptance of the voice command, so that the machine is controlled to operate automatically unless an operator of the control system supplies a halt command to the system in the predetermined waiting time. A control system such as this for use in a radio telephone apparatus is known from European Patent Application EP-A-0 293 258. According to the first and second known systems for controlling external machines by a voice command, however, there are disadvantages as described below. In the first known system for controlling an external machine by a voice command, it is troublesome for the operator to supply a confirmation signal every time the voice command is accepted, especially when the voice command is a desired one. In the second known system for controlling an external machine by a voice command, after the operator judges whether the accepted voice command is a desired one or not, the operator must supply a halt command to the system in the predetermined waiting time, when the accepted voice command is not the desired one. Therefore, if the waiting time is set to be long, the operation time becomes long. On the other hand, if the waiting time is set to be short, the operator is required to supply the halt command quickly. SUMMARY OF THE INVENTION According to a first aspect of the invention, a method for controlling an external machine by a voice command, comprises the steps of detecting a voice to be converted into an electric signal, extracting a voice pattern from said electric signal, comparing said voice pattern with reference voice patterns to pick up a certain reference voice pattern which corresponds to said voice pattern, calculating a similarity between said voice pattern and said reference voice pattern, setting a waiting time, and supplying a control signal to said external machine to be operated unless a halt command is generated in said waiting time, and is characterised in that in the step of setting the waiting time, the waiting time is set to a time dependent on the resultant of said calculation of similarity. According to a second aspect of the invention, a system for controlling an external machine by a voice command, comprises means for detecting a voice to be converted into an electric signal, means for extracting a voice pattern from said electric signal, means for storing reference voice patterns which correspond to control commands of an external machine to be controlled, means for comparing said voice pattern with said reference voice patterns to pick up one of said reference voice patterns which is similar to said voice pattern, means for calculating a similarity between said voice pattern and said reference voice pattern, means for generating a halt command, and means for controlling said external machine to be operated by supplying a control signal thereto unless a halt command is generated in a preset waiting time, and characterised by means for setting the waiting time in dependence upon the resultant of the calculation of similarity. By use of the invention it is possible to provide a method and a system for controlling an external machine by a voice command in which the operator has a sufficient time to supply a halt command to the system when the accepted voice command is not a desired one. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail, by way of example, in conjunction with appended drawings, wherein: Fig. 1 is a block diagram showing a system for controlling an external machine by a voice command in a preferred embodiment according to the invention; Fig. 2 is a block diagram showing a control unit of the system for controlling an external machine by a voice command in Fig. 1; Fig. 3 is a flow chart explaining a first operation of the system for controlling an external machine by a voice command in the preferred embodiment according to the invention; and Figs. 4A and 4B are flow charts explaining a second operation of the system for controlling an external machine by a voice command in the preferred embodiment according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 shows a block diagram of a system for controlling an external machine by a voice command in a preferred embodiment. The control system comprises a microphone 1 which detects a voice and converts the voice into an electric signal, a voice analyzing unit 2 which extracts a voice pattern (input voice pattern) from the voice, a matching unit 3 which checks the matching between the input voice pattern and a reference voice pattern to pick up a reference voice pattern which corresponds to the input voice pattern, a reference voice pattern memory 4 which stores reference voice patterns corresponding to voice commands, a control unit 5 which judges a degree of similarity between the input voice pattern and the reference voice pattern and controls an external machine 6 such as a telephone set, a facsimile machine, etc. to be controlled in accordance with the degree of the similarity, and a halt signal key 7 for generating a halt signal to halt the control of the external machine 6. Fig. 2 shows a block diagram of the control unit 5. The control unit 5 comprises a similarity calculating unit 51 which calculates the similarity between the input voice pattern and the reference voice pattern, a similarity judging unit 52 which judges the degree of the similarity between the input voice pattern and the reference voice pattern by the similarity calculating result, a similarity indicating unit 53 which indicates the voice command and a content of the voice command such as a called party, a telephone number of the called party, etc. by an LCD display, a speaker, etc., a waiting time control unit 54 which sets a waiting time determined by the degree of the similarity, and a control signal unit 55 for generating a control signal to control operation of the external machine 6 in consideration of the waiting time and the halt signal. In operation, it is supposed that the external machine 6 is a telephone set in which dialing of a number is carried out by a voice command. In this case, when an operator makes a voice such as "TOKYO" which corresponds to a voice command to dial a number of a person in Tokyo toward the microphone 1, an electric signal converted from the voice by the microphone 1 is supplied to the voice analyzing unit 2, where a voice pattern (input voice pattern) is extracted from the voice. This input voice pattern is compared to check as to the matching with the reference voice patterns in the matching unit 3 to pick up a certain reference voice pattern which corresponds to the input voice pattern. Then, the compared results are supplied to the similarity calculating unit 51 of the control unit 5 to calculate a similarity between the input voice pattern and the reference voice pattern. The similarity may be provided as a distance in the similarity calculating unit 51 if the Dynamic Program matching method is used in the matching unit 3. The Dynamic Program matching method is described in U.S.P. No. 4,059,725 entitled "AUTOMATIC CONTINUOUS SPEECH RECOGNITION SYSTEM EMPLOYING DYNAMIC PROGRAMMING". In this case, the two voice patterns are more similar the shorter the distance is. Thus calculated similarity, that is, a calculated distance is supplied to the similarity judging unit 52, where it is judged whether the distance is longer than a predetermined distance. Then, the result of the judgement in the similarity judging unit 52 is supplied to the similarity indicating unit 53, so that the voice command and a called party and a telephone number corresponding thereto are displayed on the LCD screen and/or voiced by the speaker. On the other hand, the result of the judgement in the similarity judging unit 52 is also supplied to the waiting time control unit 54, in which the waiting time is set to be a predetermined time dependent on the degree of the similarity. If a halt signal is not supplied from the halt signal key 7 to the control signal unit 55 in the waiting time, the telephone set (the external machine 6) is controlled to call the called party designated by the voice command "TOKYO" by a control signal supplied from the control signal unit 55. On the other hand, if the distance is too long and the operator judges that the similarity between the input voice pattern and the reference voice pattern is not sufficient, the operator can stop operation of the control system by supplying a halt command from the halt signal key 7 to the control signal unit 55 in the waiting time which is thought to be sufficient for the operator to judge the similarity. Instead, the halt command may be supplied as a voice command such as "STOP" which is supplied to the microphone 1, so that the system will stop calling the called party when the voice command is recognized as the halt command. Fig. 3 shows a flow chart of first operation in the control system in the preferred embodiment in which the waiting time of the halt command is determined automatically in accordance with the degree of the similarity. At first, a step 100 for input of a voice command is carried out, then matching operation is carried out (not shown in Fig. 3). After calculating of the similarity is carried out in a step 101, it is judged whether the similarity is over a predetermined value or not in a step 102. If it is so, then a step 103 is carried out, and if it is not so, then the result of the judgement in the step 102 is informed to the operator visually or aurally in a step 108, and then the operation is restarted from the step 100. In the step 103, it is judged whether the similarity is quite high or not. If the the similarity is high, a step 104 is carried out. On the other hand, if the similarity is not high, then a step 109 is carried out. In the step 104, the result of the judgement in the step 103, along with the corresponding voice command and the called party and the telephone number thereof, are informed to the operator visually or aurally, and then a step 105 is carried out, where it is checked whether a halt command is supplied. If an input of the halt command is recognized in the step 105, the operation is restarted from the step 100. And if an input of the halt command is not recognized, then it is checked whether a first predetermined waiting time which is relatively short, that is 3 seconds for instance, passes or not in a step 106. If not, the operation is repeated in a loop comprising the steps 105 and 106 until the first predetermined waiting time passes. If the first predetermined waiting time passes, the control signal is supplied to the external machine in a step 107, so that the machine is controlled in accordance with the voice command. In the step 109, the result of the judgement in the step 103 is also informed to the operator visually or aurally like in the step 104. After that, it is checked whether a halt command is supplied in a step 110 like in the step 105. If an input of the halt command is recognized in the step 110, the operation is restarted from the step 100. And if not, then it is checked whether a second predetermined time which is relatively long, that is 5 seconds for instance, passes in a step 111. If not, the operation is repeated in a loop comprising the steps 110 and 111 until the second predetermined waiting time passes. If the second predetermined waiting time passes, the step 107 whose operation is explained above is carried out. Next, Figs. 4A and 4B shows flow charts of second operation in the control system in the preferred embodiment in which it is selected whether the waiting time of the halt command is set automatically or manually by an operator in a step 200 in Fig. 4A. If the automatical set of waiting time is selected, then steps 100 to 111 which are the same operation as in Fig. 3 are carried out. If the manual set of waiting time is selected, then a step 201 is carried out in Fig. 4B, where a time of waiting for an input of a halt command is determined manually by the operator. Then, a step 202 for input of a voice command is carried out, then matching operation is carried out (not shown in Fig. 4B). After calculating of the similarity is carried out in a step 203, it is judged whether the similarity is over a predetermined value or not in a step 204. If it is so, then a step 205 is carried out, and if it is not so, then the result of the judgement in the step 203 is informed to the operator visually or aurally in a step 209, and the operation is restarted from the step 202. In the step 205, the result of the judgement in the step 203 is informed to the operator visually or aurally, and then a step 206 is carried out, where it is checked whether a halt command is supplied. If an input of the halt command is recognized in the step 206, the operation is restarted from the step 202. And if not, then it is checked whether the predetermined time which is set in the step 201, that is 5 seconds for instance, passes in a step 207. If not so, the operation is repeated in a loop comprising the steps 206 and 207 until the predetermined time passes. If the predetermined time passes, the control signal is supplied to the external machine in a step 208, so that the external machine is controlled in accordance with the voice command.

Claims: A method for controlling an external machine by a voice command, comprising steps of: detecting a voice to be converted into an electric signal; extracting a voice pattern from said electric signal; comparing said voice pattern with reference voice patterns to pick up a certain reference voice pattern which corresponds to said voice pattern; calculating a similarity between said voice pattern and said reference voice pattern; setting a waiting time; and supplying a control signal to said external machine to be operated unless a halt command is generated in said waiting time; characterised in that in the step of setting the waiting time, the waiting time is set to a time dependent on the resultant of said calculation of similarity. A method for controlling an external machine by a voice command according to claim 1, further characterised in that said comparing step comprises the step of carrying out the Dynamic Program method. A method for controlling an external machine by a voice command according to claim 1, further characterised in that, in the step of setting the waiting time, the waiting time is set to be a first time when said similarity is high, and the waiting time is set to be a second time longer than the first time when said similarity is low. A method for controlling an external machine by a voice command according to claim 1, further characterised in that, in the step of setting the waiting time, the waiting time is set to be long when said similarity is over a higher predetermined limit, and the waiting time is set to be short when said similarity is below a lower predetermined limit. A method for controlling an external machine by a voice command according to claim 1, further characterised in that, in the step of setting the waiting time, the waiting time is set to be almost null when said similarity is over a higher predetermined limit. A method for controlling an external machine by a voice command according to claim 1, further characterised in that said supplying step comprises the step of halting the supplying of said control signal to said external machine when said similarity is below a lower predetermined limit. A method for controlling an external machine by a voice command according to claim 6, further characterised in that said halting step is carried out in response to a first signal generated by a voice command or a second signal generated by a key operation. A system for controlling an external machine by a voice command, comprising: means (1) for detecting a voice to be converted into an electric signal; means (2) for extracting a voice pattern from said electric signal; means (4) for storing reference voice patterns which correspond to control commands of an external machine to be controlled; means (3) for comparing said voice pattern with said reference voice patterns to pick up one of said reference voice patterns which is similar to said voice pattern; means (51) for calculating a similarity between said voice pattern and said reference voice pattern; means (7) for generating a halt command; and means (5) for controlling said external machine to be operated by supplying a control signal thereto unless a halt command is generated in a preset waiting time; and characterised by means (54) for setting the waiting time in dependence upon the resultant of the calculation of similarity. A system for controlling an external machine by a voice command according to claim 8, further characterised in that said comparing means comprises means for carrying out the Dynamic Programming method. A system for controlling an external machine by a voice command according to claim 8, further characterised in that said controlling means comprises: means (52) for judging whether said similarity is higher than a predetermined level; means (54) for determining a waiting time dependent on an output signal of said judging means; and means (55) for generating said control signal unless said halt command is generated in said waiting time dependent on said output signal.

Inventors: NAKANO FUMIO, NAKANO, FUMIO, NAKANO, FUMIO, C/O NEC CORPORATION
Applicants: NIPPON ELECTRIC CO, NEC CORPORATION
Application year: 1991
Main classification: G10L5
IPC codes: G10L11, H04M1, G10L15