Abstract:
In a device for sensing and informing danger which is held by a person to be protected without requiring any active actions from the person to be protected, the number of false reports and miss-detections is reduced. A function of comparing the audio signals acquired from the microphone with the audio signal model of the person to be protected that has been stored inside, and a function of calculating the degree of danger from the speech intervals from the person to be protected and the speech intervals from the person not to be protected are provided in the device.

Description:
CLAIM OF PRIORITY 
       [0001]    The present application claims priority from Japanese application JP 2006-250239 filed on Sep. 15, 2006, the content of which is hereby incorporated by reference into this application. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a portable device that senses danger to the owner from the sound received and informs it. 
       BACKGROUND OF THE INVENTION 
       [0003]    A device preventing crimes against the weak including school children and infants (hereinafter referred to as those to be protected) is socially in demand and a burglar alarm (included one of the functions of a cellular phone) has been used commonly as a typical example. However, since an active action is required by those to be protected, such as pressing a switch to operate the device, such a device does not function under the situation wherein those to be protected are restrained or frightened. If there is a mechanism for sensing and informing danger using a variety of sensors without requiring any active actions from those to be protected, a device coping with a variety of situations can be implemented. 
         [0004]    As the conventional invention having such mechanism, a device disclosed in JP-T No. 2004-531800 is known. In this device, the information from a variety of sensors for audio, images and temperature is determined in order to detect abnormalities in infants or to detect invaders. 
       SUMMARY OF THE INVENTION 
       [0005]    When implementing a device that is owned by those to be protected for sensing and informing danger without requiring any active actions from those to be protected, if the art mentioned in the aforementioned JP-T No. 2004-531800 is applied, false reports and/or miss-detections may be easily occurred since no mechanism is available for a variety of variance factors in the activities of those to be protected. 
         [0006]    In order to solve the problems, a danger sensing information device according to an embodiment of the present invention is provided with a function for comparing the audio signals acquired from a microphone with the audio signal model of those to be protected and a function for calculating a degree of danger from the speech intervals of those to be protected and the speech intervals of those who are not protected. This is a necessary information for determining the case that is considered to be dangerous in the activities of those to be protected, and by integrating such information, a danger sensing information device with limited false reports and miss-detections can be implemented. 
         [0007]    According to an embodiment of the present invention, the crime prevention effect is superior to that of the prior art due to limited false reports and miss-detections. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a configuration diagram of a danger sensing information device according to an embodiment of the present invention; 
           [0009]      FIG. 2  is a configuration diagram of a danger audio detection unit of a danger sensing information device according to an embodiment of the present invention; 
           [0010]      FIG. 3  is a configuration diagram of a child audio detection unit of a danger sensing information device according to an embodiment of the present invention; 
           [0011]      FIG. 4  is a configuration diagram of a noise volume measurement unit of a danger sensing information device according to an embodiment of the present invention; 
           [0012]      FIG. 5  is a graph showing the function of the degree of noise danger; and 
           [0013]      FIG. 6  is a flowchart of a danger decision unit of a danger sensing information device according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    A danger sensing information device according to an embodiment of the present invention is explained below with reference to the drawings. 
         [0015]      FIG. 1  shows a structure of a danger sensing information device  10  according to an embodiment of the present invention. 
         [0016]    The danger sensing information device  10  is composed of an audio input unit  100 , a danger sensing unit  200 , and a danger information unit  900 . The audio input unit  100  is provided with a microphone  110  and an A/D converter  120  wherein air vibrations due to the sound of a voice are captured and then converted to digital signals which are stored as input voice  240  in the memory device as will be explained later. The danger sensing unit  200  is composed of a processor  210 , a memory device  220 , and an external status input device  230 . The memory device  220  contains each of programs such as a danger audio detection program  300 , a child audio detection program  400 , a noise volume measurement program  500 , a danger determination program  600 , an input voice  240 , a danger audio volume  350 , a child audio volume  420 , a noise danger  520 , danger audio weight  345 , a noise threshold value  515 , an active audio model  325 , an inactive audio model  335 , and a child audio model  415 . The processor  210  performs a processing of input voice  240  using each program and transfers the results to the danger information unit  900 . The details of the operation of each program will be explained later. The danger information unit  900  is provided with a communication device  910  which transmits the results of the danger sensing unit  200  to the outside. 
         [0017]      FIG. 2  shows processing that is performed by the danger audio detection program  300 . The danger audio detection unit  300  is composed of a basic frequency measurement processing  310 , an active audio model matching detection processing  320 , an inactive audio model matching detection processing  330 , and a weight adjustment processing  340 . 
         [0018]    In the basic frequency measurement processing  310 , a basic frequency of the input voice  240  is calculated by an arbitrary method. 
         [0019]    The active audio model matching detection processing  320  and the inactive audio model matching detection processing  330  calculate a degree of matching of the active audio model Ma and a degree of matching of the inactive audio model Mb, respectively, which indicate the degree of matching of input voice  240  with active audio model  325  and the inactive audio model  335 , respectively. 
         [0020]    For example, the degree of matching of the active audio model Ma is calculated using the following equation: 
         [0000]        Ma =max  Dai  (i=1: Number of active audio models) 
         [0000]        Dai=∥F input− Fai∥   
         [0000]    where Dai indicates a distance between the input voice and the active audio model i, Finput is a characteristic vector of the input voice, Fai is a characteristic vector of the active audio model i. For characteristic vectors, for example, MFCC (Mel Frequency Cepstrum Coefficients), LPC (Linear Prediction Coefficients), and auto relevant functions. As a result, a difference is calculated between the input voice and the active audio model having the closest acoustic characteristic to the input voice. 
         [0021]    Mb is also calculated using the same equation as in the case of Ma. 
         [0000]        Mb =max  Dbi  (i=1: Number of inactive audio models) 
         [0000]        Dbi=∥F input− Fbi∥   
         [0022]    In the weight adjustment processing  340 , the basic frequency f as the results of basic frequency measurement processing, the degree of matching Ma as the results of active audio model matching detection processing  320 , and the degree of matching Mb as the results of inactive audio model matching detection processing  330  are weighted with a danger audio weight  345  and then added to calculate a danger audio volume  350  Cd. The danger audio volume Cd is calculated by the following equation wherein a basic frequency danger function is given by ff, danger audio weights are given by Wf, Wa and Wb: 
         [0000]        Cd=Wf·ff ( f )+ Wa·Ma+Wb·Mb    
         [0000]    where the basic frequency danger function ff is a function having a peak near the mean basic frequency fm of the speech of an adult male. For example, the following value is used: 
         [0000]        ff ( f )=| f−fm|  if f&gt;90 and f&lt;130 
         [0023]    0 otherwise 
       The aforementioned fm, Wf, Wa, Wb are parameters that can be adjusted according to the user situation. 
       [0024]      FIG. 3  shows a processing performed by the child audio detection program. The child audio detection processing  410  determines the degree of similarity between the input voice  240  and the child audio model  415  and outputs it as a child audio volume  420 . 
         [0025]    The child audio volume Cc is calculated by the following equation as in the cases of Ma and Mb. 
         [0000]        Cc =max  Dci  (i=1: Number of child audio models) 
         [0000]        Dci=∥F input− Fci∥   
         [0026]      FIG. 4  shows a processing performed by the noise volume measurement program  500 . The noise volume measurement processing  510  calculates a noise volume of the input voice  240  (decibels, etc.) and compares it with the noise threshold value  515  to the calculated noise danger  520  to be output. 
         [0027]    The noise danger Cs is calculated using the following equation: 
         [0000]        Cs=fs ( N ) 
         [0000]    where N indicates a noise value of the input voice, fs is a function shown in  FIG. 5 . α and β in  FIG. 5  are defined by the noise threshold value  515 . Here, if the degree of noise danger is positive, noise is high and if it is negative, noise is low. The absolute value of the degree of noise danger expresses the respective degree of danger. 
         [0028]      FIG. 6  shows a flowchart of the processing performed by the danger determination program  700 . 
         [0029]    Initially, the degree of noise danger  510  is analyzed in the determination  710 . The distinction analysis is carried out as follows using the threshold values θa and θb. 
       S 1  if (θa&lt;Cs and Cs&lt;θb) 
     S 2  if (θb≦Cs) 
     S 3  if (Cs≦θa) 
       [0030]    If the degree of noise danger is determined to be within the safe range (S 1 ), a safe state is output ( 780 ). If the degree of danger is determined to be high due to the fact that the state with high noise continued for a fixed time (S 2 ), the control shifts to the decision  740 . If the degree of danger is determined to be low due to the fact that the state with low noise continued for a fixed time (S 3 ), the control shifts to the decision  720 . This processing is based on the hypotheses that in a place with abnormally high noise, dangers such as accidents or natural disasters are approaching the child or there is a high possibility of these, or that in a place with less noise, the number of passersby is less so that there is a higher possibility of running into an event of kidnapping. 
         [0031]    In the decision  720 , a distinction analysis is carried out for the danger audio volume input  350 . For example, such distinction analysis is carried out as follows using the threshold values θd, θt and θ T , 
       S 4  if ((Σ( t=t−θt ˜Now) d (θ d≦Cdt ))&lt;θ T ) 
     S 5  otherwise 
       [0032]    where d (x) is a function of 1 when equation x is true and 0 when equation x is false. Cdt is a value of Cd at a time t. 
         [0033]    If the state with a high danger audio volume does not continue for a fixed time (S 4 ), a safe state ( 780 ) is output. If the state with a high danger audio volume continues for a fixed time (S 5 ), the control is shifted to the decision  730 . 
         [0034]    The threshold values θd, θt and θ T  are set up in the parameter setting unit  900 . This is a processing performed by the danger audio detection program  300  for a brief voice. This is based on the hypothesis that if an audio danger state continues for a fixed time, it should be decided as dangerous 
         [0035]    In the decision  730 , a distinctive analysis is performed for the input child audio volume  410 . The distinctive analysis is carried out as follows using the threshold values θe, θc and θ c , 
       S 6  if ((Σ( t=t−θc ˜Now) d (θ e≦Cct ))≧θ c ) 
       [0036]    S 7  otherwise where d(x) is a function of  1  when equation x is true and 0 when equation x is false. Cct is a value of Cc at a time t. 
         [0037]    If the state with a high child audio volume lasts for a fixed time (S 6 ), a safe state ( 780 ) is output. If the state with a high child audio volume does not last for a fixed time (S 7 ), the control is shifted to the decision  740 . This is a processing performed by the danger audio detection program  300  for brief voice. This is based on the hypothesis that when the child audio volume lasts for a fixed time, that is, in such a state that the child is determined to be talking to a dangerous voice, there is a high probability that the person is acquainted with the child so that the degree of danger is determined to be not as high. 
         [0038]    In the decision  740 , a decision is made based on the locked state of the device acquired from the external state input unit  600 . If the device is locked in order to prevent false reports, a safe state is output ( 780 ). If it is not locked, a danger state is output ( 790 ). 
         [0039]    The locking function of the device has the advantage of reducing the number of false reports, but it also interferes with regular communication. In that case, the locking function is excluded. In this case, the decision  740  immediately outputs a danger state ( 790 ). 
         [0040]    The following methods are available for outputting the danger state: 
       1. Alarm Output Using a Speaker 
     2. Emergency signal output by radio transmission 
     3. Calling a curator (parent) by radio transmission 
     4. Calling a service center by radio transmission 
       [0041]    As one of embodiments of a danger sensing information device  10  of the present invention, software mounting on the cellular phone is possible. If a microphone  110  and an A/D converter  120  in the audio input unit  100 , a processor  210 , a memory device  220  and an outer state input device  230  in the danger sensing unit and a communication device  910  in the danger information unit  900  are provided from those used in the calling functions and data communication functions of the cellular phone, programs and data in the memory device  220  can be newly introduced so that the advantage is that the product cost can be maintained to be low. In addition, for cellular phone users, the advantage is that there is no need of owning additional cellular terminals.