Patent Publication Number: US-2017364152-A1

Title: Input detection method, computer-readable recording medium, and device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International application PCT/JP2015/056510 filed on Mar. 5, 2015 and designated the U.S., the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The present invention is related to an input detection method, a computer-readable recording medium, and a device for detecting an input of a user. 
     BACKGROUND 
     In recent years, a small-scale device such as a watch type wearable terminal, which is capable of not only displaying information but also inputting information, has become widespread. 
     Since a watch type device or the like is limited in size, buttons and an input area used for inputs are limited. Therefore, conventionally, a technology for enabling input of vibrations to the device is known, in addition to an input surface such as a device touch panel or the like. 
     Patent Document 1: Japanese National Publication of International Patent Application No. 2012-522324 
     SUMMARY 
     According to one aspect of an embodiment, there is provided an input detection method by a device to be worn on an arm by a band, the method including: acquiring output information of an acceleration sensor included in the device; and determining, based on the output information, upon detecting a change corresponding to restraining by the band, the change to be an input, in which the change represents a vibration caused by an impact applied to the device, the vibration alternately repeating a first motion of the device moving in a direction of the impact and a second motion of the device being pulled back in an opposite direction to the direction due to the restraining by the band. 
     The aforementioned steps may be performed by function parts realizing respective steps, a method by a computer to perform a process to realize the respective steps, and a computer-readable recording medium storing a program, which causes the computer to perform the process to realize the respective steps. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram for explaining a terminal apparatus of a first embodiment; 
         FIG. 2  is a diagram for explaining a state of inputting to a device of the first embodiment; 
         FIG. 3  is a diagram for explaining a case in which the vibration is applied as the input to the device of the first embodiment; 
         FIG. 4  is a diagram for explaining a restraint of the device by a belt; 
         FIG. 5A  and  FIG. 5B  are diagrams for explaining a first example of a reference waveform; 
         FIG. 6A  through  FIG. 6C  are diagrams for explaining a second example of the reference waveform; 
         FIG. 7A  and  FIG. 7B  are diagrams for explaining the reference waveform data; 
         FIG. 8  is a diagram illustrating an example of a hardware configuration of the device; 
         FIG. 9  is a diagram for explaining the function of the device  200  of the first embodiment; 
         FIG. 10  is a flowchart for explaining an operation of the device of the first embodiment; 
         FIG. 11  is a diagram for explaining a fitting threshold; 
         FIG. 12  is a diagram for explaining the matching of the waveform; 
         FIG. 13A  and  FIG. 13B  are diagrams for explaining an adjustment waveform; 
         FIG. 14  is a diagram for explaining a function of the device in a second embodiment; 
         FIG. 15  is a diagram illustrating an example of a screen prompting to input of waveform data, used to generate adjustment waveform data; 
         FIG. 16  is a flowchart for explaining an acquisition process of the adjustment waveform data in the second embodiment; and 
         FIG. 17  is a flowchart for explaining an operation of the device of the second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     In a conventional watch type device, in a case of inputting vibration, since its size is minimized, compared with a larger device in size than the watch type device, a displacement or an acceleration received by the watch type device increases due to the vibration. Also, in the watch type device, by movements and the like such as moving a body part such as an arm apart from the vibration applied as the input, accelerations occur with various degrees and directions corresponding to usage. 
     As a result, it is difficult for the conventional watch type device to distinguish a change in the acceleration due to a regular usage and a change in the acceleration intended as an input. 
     In one aspect, an objective of a method, a program, and a device is to provide an input detection method, an input detection program, and a device capable of selectively determining an input as the input intended by a user. 
     First Embodiment 
     Embodiments are described with reference to drawings.  FIG. 1  is a diagram for explaining a terminal apparatus of a first embodiment. 
     A terminal apparatus  100  of the first embodiment is a watch type wearable terminal, and includes a device  200 , and a belt (band)  300 . 
     In the device  200  of the terminal apparatus  100  of the first embodiment, one part (an upper side face) on a side face and another part (a lower side face) opposite to the one part are connected to an end portion of the belt  300 . In an example in  FIG. 1 , one part of the side surface connected to the belt  300  is defined as an upper side surface  201  of the device  200 , and another part at a position opposite to the upper side face  201  is defined as a lower side face  202  of the device. 
     For the device  200  of the first embodiment, a screen  203  is provided on a surface, which faces outside, when the device  200  is worn on an arm or the like of a user of the terminal apparatus  100 . The screen  203  includes a display function for displaying various information items, and an input function for receiving an input to the device  200 . 
     Also, the device  200  of the first embodiment receives vibrations applied to lateral faces  204  and  205  as inputs. 
     Next, referring to  FIG. 2  through  FIG. 4 , a case will be described, in which the device  200  receives the input in a state in which the terminal apparatus  100  of the first embodiment is worn on the user. 
       FIG. 2  is a diagram for explaining a state of inputting to the device of the first embodiment. The terminal apparatus  100  of the first embodiment is the watch type as depicted in  FIG. 2 , for instance, and is worn on the arm of the user. 
     A state_ 1  illustrated in  FIG. 2  represents that the user wears the terminal apparatus  100 , and a position of the screen  203  is not fixed. That is, the state_ 1  is a state in which information displayed on the screen  203  is confirmed or a movement (for instance, walking or the like) occurs while the user wears the terminal apparatus  100 . 
     A state_ 2  illustrated in  FIG. 2  represents that the user wears the terminal apparatus  100 , and the position of the screen  203  of the terminal apparatus  100  is fixed by the user. That is, the state_ 2  represents that the user views the screen  203  or the user attempts to conduct an operation such as the input or the like onto the screen  203 . 
     When the user lifts his/her arm, and the position of the terminal apparatus  100  is moved from a position of the state_ 1  to a position of the state_ 2 , the state_ 1  transitions to the state_ 2 . The device  200  of the first embodiment detects a motion of the arm of the user based on the acceleration, an angle, and the like of the device  200  itself, and detects a transition from the state_ 1  to the state_ 2 . Moreover, the device  200  of the first embodiment detects the transition from the state_ 2  to the state_ 1 , whichever of the state_ 1  and the state_ 2  is a current state, or the like. 
     When detecting the transition from the state_ 1  to the state_ 2 , the device  200  of the first embodiment may display predetermined information on the screen  203 . The predetermined information may be information indicating time, or information set beforehand. Moreover, when detecting the transition from the state_ 2  to the state_ 1 , the device  200  of the first embodiment may erase display on the screen  203 . In the following explanation, the state_ 1  is called “regular motion state”, and the state_ 2  is called “input preparation state”. 
     Next, referring to  FIG. 3 , a case will be described, in which the vibration to the device  200  of the first embodiment is input.  FIG. 3  is a diagram for explaining a case in which the vibration is applied as the input to the device of the first embodiment. 
     The device  200  of the first embodiment receives the vibration, which is generated by the user tapping either one of the lateral face  204  or  205 , as the input. The tap of the first embodiment represents an operation lightly hitting either one of the lateral faces  204  and  205  by a finger of the user. 
       FIG. 3  depicts a case in which the device  200  being in the input preparation state is tapped. In this case, since the device  200  is restrained to the arm of the user by the belt  300 , vibration in a direction restraining the device by the belt  300  is restricted. With respect to the above, vibration in a direction orthogonal to the direction restraining the device  200  by the belt  300  has an effect of a rebound against restraint by the belt  300 . 
     In the first embodiment, this point is focused on, and the vibration, in which the rebounding of the belt  300  is reflected, is detected as the tap. In detail, the device  200  of the first embodiment records the change in acceleration indicating the vibration in the direction orthogonal to the direction restraining the device  200  by the belt  300 . When the change in the acceleration is detected to match the vibration indication reference waveform data, the change is detected as the tap. 
     In the following, referring to  FIG. 4 , the restraint of the device  200  by the belt  300  will be further described.  FIG. 4  is a diagram for explaining the restraint of the device by the belt. 
     As illustrated in  FIG. 4 , the device  200  of the first embodiment is restrained by the belt  300  in a Y axis direction in coordinate axes for the device  200 . Accordingly, when the device  200  receives an impact (the tap) in a Y1 arrow direction in this state, the motion (the vibration) in the Y axis direction is restrained. 
     In contract, with respect to the motion (the vibration) in an X axis direction of the device  200 , when the impact (the tap) in the arrow Y1 direction is received, one motion in the Y1 arrow direction and another motion pulling back in an opposite direction to the Y1 arrow direction due to the restraint in the Y axis direction occur. Hence, in a case of tapping the device  200  of the first embodiment, the one motion in the Y1 arrow direction and the motion pulling back in the opposite direction to the Y1 arrow direction are alternately repeated in the vibration in the X axis direction of the device  200 . 
     In the first embodiment, the waveform data indicating the change in the acceleration of the device  200  due to this vibration are recorded as the reference waveform data, it is determined by matching the change in the acceleration of the device  200  with the reference waveform data whether the vibration is caused by a tap, and the tap attempted by the user is selectively determined as the input. 
     That is, in the first embodiment, among the axes of the device  200 , only the change in the acceleration in the X axis is referred to, and it is detected whether the vibration applied to the device  200  is a tap. 
     It is noted that the device  200  of the first embodiment may receive a tap as an operation corresponding to a backspace (Back Space) when the lateral face  204  is tapped. 
     It is noted that in the first embodiment, it is assumed that the device  200  is attached to a wrist of the user; however, a position at which the device  200  is attached is not limited to the wrist. For instance, the device  200  of the first embodiment may be attached to an upper arm, a forearm, or the like of the user. 
     It is noted that in a case of attaching the device  200  to the upper arm or the forearm, the orthogonal direction to the direction restraining the device  200  by the belt  300  is the X axis direction in the coordinate axes of the device  200 . 
     A first example of a reference waveform will be described with reference to  FIG. 5A  and  FIG. 5B .  FIG. 5A  illustrates a waveform representing the change in the acceleration when the device  200  is tapped in a state in which the device  200  is restrained by the belt  300 .  FIG. 5A  illustrates the reference waveform, which is referred to for a detection of the tap to be described later. 
       FIG. 5B  illustrates the waveform representing the change in the acceleration when the device  200  is tapped in a state in which the device  200  is not restrained by the belt  300 . The state in which the device  200  is not restrained by the belt  300  corresponds to a state in which the terminal apparatus  100  is not attached to the user. In detail, for instance, the state may be a state in which the terminal apparatus  100  is placed on a palm of the user or on a desk. 
     Here, the reference waveform of the first embodiment will be described. In the first embodiment, a waveform in a case in which the device  200  receives the tap while being restrained by the belt  300  is defined as the reference waveform. 
     The reference waveform of the first embodiment is an ideal waveform representing the change in the acceleration of the device  200  in a case of tapping the device  200  in the state in which the terminal apparatus  100  is attached to the arm of the user. The reference waveform of the first embodiment is acquired as a result from conducting an experiment in which multiple users respectively wear and tap the device  200 . 
     When the impact of the tap is applied to the device  200 , the acceleration of the device  200  changes to a peak value P corresponding to a scale of the impact. 
     Next, in the waveform illustrated in  FIG. 5A , the rebound occurs to an extent higher than or equal to the peak value P within a predetermined time after the impact is received. Then, the acceleration, attaining zero from a reverse direction, gradually converges to approach zero. In detail, in the waveform illustrated in  FIG. 5A , the acceleration changes from the peak value P indicating the change at time of receiving the impact to a peak P1 in the reverse direction to that of the change by the impact within 0.1 msec. A change from the peak value P to the peak value P1 is caused by a motion, which pulls back the device  200  in the opposite direction to the direction in which the impact is applied due to the restraint by the belt  300  in the Y axis direction. 
     For instance, in the waveform in  FIG. 5A , when |P| (an absolute value of the peak value P) represents the change in the acceleration by the impact, the change in the acceleration by being pulled back by the belt  300  becomes |P+P1|. Accordingly, in the waveform illustrated in  FIG. 5A , there is the rebound higher than or equal to the change in the acceleration by the impact within a significantly short time after the impact is received. 
     With respect to the above, in the waveform in  FIG. 5B , it takes 30 msec or more to change from a peak value P′ indicating a change at the time of receiving the impact to a peak value P2 where the acceleration is in an opposite direction. Moreover, the peak value P2 is smaller than a peak value P1. Compared with the waveform illustrated in  FIG. 5A , a change of the acceleration from the peak value P′ is gentle. 
     As described above, when the tap is input, the acceleration of the device  200  changes differently depending on whether the device  200  is restrained by the belt  300 . Accordingly, in the first embodiment, it is possible to discriminate the waveform in  FIG. 5B  from the reference waveform illustrated in  FIG. 5A . 
       FIG. 6A  through  FIG. 6C  are diagrams for explaining a second example of the reference waveform.  FIG. 6A  illustrates the reference waveform, which is the same as the waveform illustrated in  FIG. 5A . 
       FIG. 6B  illustrates a waveform representing the change in the acceleration of the device  200  when the user wears the terminal apparatus  100  and walks.  FIG. 6C  illustrates a waveform representing the change in the acceleration of the device  200  when the user wears the terminal apparatus  100  and punches. 
     In a case in which the user walks, the acceleration of the device  200  changes gently depending on a swing of the arm. 
     Moreover, when the user punches with the arm wearing the terminal apparatus, the acceleration of the device  200  greatly changes. However, even in a motion of the punch, a motion of the arm is included in the change in the acceleration. Hence, compared with the tap directly applying the vibration to the device  200 , the change in the acceleration becomes gentle. 
     Accordingly, a waveform, which represents the change in the acceleration when the user is walking or when the user punches, does not includes the waveform which represents a rebound higher than or equal to the change occurred by the impact within the significantly short time after the change in response to the impact as represented in the reference waveform. 
     In the following, the reference waveform data will be described with reference to  FIG. 7 .  FIG. 7A  and  FIG. 7B  are diagrams for explaining the reference waveform data.  FIG. 7A  illustrates the reference waveform data, and  FIG. 7B  illustrates a change of a differential value corresponding to the reference waveform data. 
     In the input preparation state, in the reference waveform at the time when the device  200  receives the tap, the device  200  of the first embodiment defines a portion indicating a characteristic change of the acceleration indicating the vibration by the tap as the reference waveform. 
     More specifically, the device  200  of the first embodiment defines a waveform in a predetermined time from a point where the acceleration is 0, at time the acceleration is changing to the peak value P1 due to the rebound after the acceleration has changed to the peak value P in response to the impact. 
     That is, in the first embodiment, a waveform in the predetermined time as of a point where a value of the acceleration occurring in response to the impact initially becomes 0 is determined as the reference waveform data. 
     That is, reference waveform data N of the first embodiment is a waveform, which is extracted from time t 1  when the value of the acceleration initially becomes 0 after the peak value P of the acceleration in response to the impact, to time t 2  at the endpoint of the predetermined time, in the reference waveform. 
     In the reference waveform data N of the first embodiment, the change in the acceleration from the time t 1  is the greatest, and after the time t 1 , the change in the acceleration does not exceed the change in the acceleration indicating the rebound. The change in acceleration from the time t 1  is caused by the rebound against the impact which the device  200  receives. 
     Therefore, in the reference waveform data N of the first embodiment, an absolute value of a first peak value P1 of the acceleration from the time t 1  where the acceleration is 0 is the greatest. After the first peak value P1, the absolute value of the acceleration does not exceed the absolute value of the peak value P1. 
     Also, in the first embodiment, in order to determine whether the change in the acceleration is caused by the impact of the tap, a tap detection threshold is set to the differential value of the acceleration illustrated in  FIG. 7B . 
     In the first embodiment, when the differential value indicating the scale of the change in the acceleration is greater than the tap detection threshold, it is determined that this change in the accelerations is a change caused by the impact of the tap. 
     It is noted that in an example illustrated in  FIG. 7B , the tap detection threshold is indicated as a negative value; however, the tap detection threshold may be set as an the absolute value. In this case, the tap detection threshold is compared with the absolute value of the acceleration. 
     The tap detection threshold of the first embodiment is a value acquired based on a result from conducting the experiment of tapping the device  200  in a state in which the user in actuality wears the terminal apparatus  100 . A value regarded with respect to a fluctuation band of the acceleration due to the impact of the tap is set as the tap detection threshold. 
     Next, the device  200  of the first embodiment will be described.  FIG. 8  is a diagram illustrating an example of a hardware configuration of the device. 
     The device  200  includes a display operation device  21 , a sensor device  22 , a drive device  23 , an auxiliary storage device  24 , a memory device  25 , an arithmetic processing unit  26 , and an interface device  27 , which are mutually connected via a bus B. 
     The display operation device  21  may be a touch panel or the like, and is used to input and display various signals. The sensor device  22  may include an acceleration sensor, a gyro sensor, or the like, for instance, and detects an angle, the acceleration, and the like of the device  200 . The interface device  27  may include a modem, a LAN card, and the like, and is used to connect to a network. 
     The input detection program to be described later is at the least a part of various programs for controlling the device  200 . For instance, the input detection program may be provided by a distribution of a recording medium  28  and by a download through the network. The recording medium  28  may be any type of a recording medium, which is a non-transitory tangible computer-readable medium including a data structure. For instance, as the recording medium  28  recording the input detection program, various types of recording media may be used: a recording medium, which optically, electronically, or magnetically records information such as a CD-ROM, a flexible disk, a magnetic optical disk, or the like, a semiconductor memory, which electronically records information such as a ROM, a flash memory, or the like. 
     Also, when the recording medium  28  storing the input detection program is set to the drive device  23 , the input detection program is installed into the auxiliary storage device  24  from the recording medium  28  through the drive device  23 . The input detection program, which is downloaded from the network, is installed into the auxiliary storage device  24  through the interface device  27 . 
     The auxiliary storage device  24  stores necessary files, data, and the like as well as the installed input detection program. The memory device  25  stores the input detection program, which is read out from the auxiliary storage device  24  when a computer is activated. Then, the arithmetic processing unit  26  realizes various processes to be described later, in accordance with the input detection program stored in the memory device  25 . 
     Next, referring to  FIG. 9 , functions of the device  200  of the first embodiment will be described.  FIG. 9  is a diagram for explaining the functions of the device  200  of the first embodiment. 
     The device  200  of the first embodiment includes a storage part  210 , and an input detection processing part  220 . For instance, the storage part  210  of the first embodiment stores various information items to be described later, in storage areas provided in the memory device  25 , the auxiliary storage device  24 , and the like. 
     The input detection processing part  220  is realized by the arithmetic processing unit  26  executing the input detection program stored in the memory device  25  or the like. 
     The storage part  210  of the first embodiment stores tap detection threshold data  211 , reference waveform data  212 , fitting threshold data  213 , and the like. 
     The tap detection threshold data  211  of the first embodiment is a threshold for determining whether the change in the acceleration of the device  200  is caused by the impact of the tap. The tap detection threshold data  211  is a threshold which is set beforehand. 
     The reference waveform data  212  is as described above, and is matched with the waveform data indicating change in the acceleration of the device  200  in response to an input. 
     The fitting threshold data  213  of the first embodiment is a threshold for determining whether the waveform data indicating the change in the acceleration of the device  200  indicates a vibration due to the tap. The fitting threshold data  213  of the first embodiment is compared with a fitting degree resulting from matching the reference waveform data  212  with the waveform data indicating the change in the acceleration of the device  200 . 
     The fitting threshold data  213  of the first embodiment includes first threshold data  214  and second threshold data  215 . A value indicated by the first threshold data  214  is set to be greater than a value indicated by the second threshold data  215 . 
     In the following, a value indicated by the tap detection threshold data  211  may be called “tap detection threshold”, and a value indicated by the fitting threshold data  213  may be called “fitting threshold”. Also, in the following, values indicated by the first threshold data  214  and the second threshold data  215  may be called “first threshold” and “second threshold”, respectively. 
     The input detection processing part  220  of the first embodiment detects an input to the device  200  by the vibration applied to the device  200 . 
     The input detection processing part  220  of the first embodiment includes an acceleration detection part  221 , a differential value calculation part  222 , an input state determination part  223 , a threshold selection part  224 , a differential value determination part  225 , a waveform matching part  226 , and a tap determination part  227 . 
     The acceleration detection part  221  detects the acceleration in the X axis direction of the device  200 , which is detected by the sensor device  22  included in the device  200 . 
     The differential value calculation part  222  calculates the differential value of the detected acceleration. The input state determination part  223  determines a state of the device  200 . In detail, the input state determination part  223  determines, by the sensor device, whether the state of the device  200  is in the input preparation state (refer to  FIG. 2 ). 
     The threshold selection part  224  selects and sets the fitting threshold in response to a determination result by the input state determination part  223 . 
     The differential value determination part  225  determines whether the differential value of the acceleration calculated by the differential value calculation part  222  exceeds the tap detection threshold (the absolute value). 
     When it is determined by the differential value determination part  225  that the differential value of the acceleration exceeds the tap detection value, the waveform matching part  226  matches the reference waveform data  212  with the waveform data indicating the change in the acceleration due to the vibration applied to the device  200 . 
     The tap determination part  227  determines whether the vibration applied to the device  200  is caused by the tap, in response to a comparison result between the fitting degree acquired by the waveform matching part  226  and the fitting threshold. 
     Next, referring to  FIG. 10 , an input detection process of the device  200  of the first embodiment will be described.  FIG. 10  is a flowchart for explaining an operation of the device of the first embodiment. 
     The device  200  of the first embodiment acquires an acceleration_a of the device  200 , which the sensor device  22  detects by the acceleration detection part  221  of the input detection processing part  220  (step S 1001 ). 
     Next, the input detection processing part  220  calculates the differential value da/dt of the acquired acceleration_a by the differential value calculation part  222  (step S 1002 ). Subsequently, the device  200  determines, by the input state determination part  223 , whether the state of the device  200  is the input preparation state (step S 1003 ). 
     When the state of the device  200  is the input preparation state with respect to step S 1003 , the threshold selection part  224  sets the first threshold to the fitting threshold (step S 1004 ), and advances to step S 1006 , which will be described later. When the state of the device  200  is not the input preparation state in step S 1003 , the threshold selection part  224  sets the second threshold to the fitting threshold (step S 1005 ), and advances to step S 1006 , which will be described later. 
     That is, in the first embodiment, when the state of the device  200  is the input preparation state, the fitting threshold is set to be higher. When the state of the device  200  is the regular motion state, which is not the input preparation state, the fitting threshold is set to be lower than the case of the input preparation state. 
     Next, the input detection processing part  220  determines, by the differential value determination part  225 , whether the differential value is greater than the tap detection threshold (step S 1006 ). 
     When the differential value is less than or equal to the tap detection threshold in step S 1006 , the input detection processing part  220  goes back to step S 1001 . 
     When the differential value is greater than the tap detection threshold in step S 1006 , the input detection processing part  220  determines, by the waveform matching part  226 , whether the acceleration_a becomes 0 or more within the predetermined time (step S 1007 ). In the first embodiment, for instance, the predetermined time is set to be 30 msec. 
     When the acceleration_a does not become 0 within the predetermined time (step S 1007 ), the input detection processing part  220  goes back to step S 1001 . 
     When the acceleration_a becomes 0 within the predetermined time (step S 1007 ), the input detection processing part  220  records, by the waveform matching part  226 , the waveform data representing the change in the acceleration of the device  200  due to the vibration (step S 1008 ). 
     Next, the input detection processing part  220  matches, by the waveform matching part  226 , the recorded waveform data with the reference waveform data  212  (step S 1009 ). Subsequently, the input detection processing part  220  determines, by the tap determination part  227 , whether the fitting degree between the recorded waveform data and the reference waveform data  212  is greater than the fitting threshold (step S 1010 ). It should be noted that the matching of the waveform data by the waveform matching part  226  will be described later in detail. 
     When the fitting degree is greater than the fitting threshold in step S 1010 , the input detection processing part  220  determines, by the tap determination part  227 , that the waveform data correspond to the reference waveform data  212 . Next, the tap determination part  227  determines that the change in the acceleration_a detected by the device  200  is caused by the tap to the device  200  (step S 1011 ), and terminates this process. 
     The fitting threshold of the first embodiment will be now described. 
     In the first embodiment, in response to whether the terminal apparatus  100  is in the input preparation state, the fitting threshold is modified. 
     When the terminal apparatus  100  is in the input preparation state, since the position of the screen  203  is fixed, it is predicted that a waveform indicating vibration due to the tap may become similar to the reference waveform. Hence, in the first embodiment, when the terminal apparatus  100  is in the input preparation state, the fitting threshold is set as the first threshold. When the terminal apparatus  100  is not in the input preparation state, that is, when the terminal apparatus  100  is in the regular motion state, the fitting threshold is set as the second threshold, being lower than the first threshold. 
     In the first embodiment, it is possible to improve a recognition accuracy of the tap by setting the fitting threshold as described above, regardless of the state of the device  200 . 
     In the following, the fitting threshold of the first embodiment will be described with reference to  FIG. 11 .  FIG. 11  is a diagram for explaining the fitting threshold. In  FIG. 11 , a method for setting the first threshold and the second threshold to be the fitting threshold of the first embodiment will be described. 
     A value acquired from a distribution of the fitting degree, which is obtained by an experiment of tapping the terminal apparatus  100  for the input preparation state is applied to the first threshold of the first embodiment. Also, a value acquired from a distribution of the fitting degree, which is obtained by an experiment of tapping the terminal apparatus  100  for the regular motion state is applied to the second threshold of the first embodiment. 
     A curve L 1  depicted in  FIG. 11  represents a distribution of the fitting degree of a result from comparing the waveform data, which is acquired by tapping the device  200  being in the input preparation state multiple times with the reference waveform data. Also, a curve L 2  represents a distribution of the fitting degree of a result from comparing the waveform data, which is acquired by tapping the device  200  being in the regular motion state multiple times with the reference waveform data. 
     In  FIG. 11 , a fitting degree THa denotes an average value of a distribution L 1 , and σ 1  denotes a standard deviation of the distribution L 1 . Also, a fitting degree THb denotes an average value of a distribution L 2 , and σ 2  denotes a standard deviation of the distribution L 2 . 
     In the first embodiment, a fitting degree TH 1 , which is acquired by deducting a standard deviation σ 1  from a fitting degree THa, is set to the first threshold, and a fitting degree TH 2 , which is acquired by deducting a standard deviation σ 2  from a fitting degree THb, is set to the second threshold. 
     It is noted that when there is no input for a predetermined time after the device  200  becomes in the input preparation state, the fitting threshold may be changed from the first threshold to the second threshold. 
     Next, the matching by the waveform matching part  226  will be described with reference to  FIG. 12 .  FIG. 12  is a diagram for explaining the matching of the waveform. 
     In the first embodiment, for instance, the reference waveform data N may be divided into multiple sets of the waveform data, and the fitting threshold may be set for each of the multiple sets of the waveform data divided from the reference waveform data N. 
       FIG. 12  illustrates an example of dividing the reference waveform data N at time when a direction of the change in the acceleration changes. 
     In the first embodiment, the reference waveform data N is divided into such waveform data N 1 , N 2 , N 3  as illustrated in  FIG. 12 . 
     The waveform data N 1  corresponds to waveform data from time t 1  to time t 11 . The time t 11  is a time when the direction of the change in the acceleration is changed from positive to negative. The waveform data N 2  corresponds to waveform data from time t 11  to time t 12 . The time t 12  is a time when the direction of the change in the acceleration is changed from negative to positive. The waveform data N 3  corresponds to waveform data from time t 12  to time t 13 . The time t 13  is a time when the direction of the change in the acceleration is changed from positive to negative. 
     As described above, in the first embodiment, the waveform data are divided every time the direction of the change of the reference waveform data N is changed. 
     For instance, the fitting thresholds for the waveform data N 1  and the waveform data N 2 , in which change due to the impact of the tap in the reference waveform data N is significantly apparent, may be set to be higher than the fitting threshold for the waveform data as of the waveform data N 3 . 
     Also, in the first embodiment, the first threshold and the second threshold may be set as a plurality of fitting thresholds for each of sets of the divided waveform data. 
     Moreover, in a case in which the fitting degree becomes greater than or equal to the fitting threshold for each of sets of the waveform data in all sets of the divided waveform data from the reference waveform data N, the waveform matching part  226  of the first embodiment may determine that the change in the acceleration_a detected by the device  200  is caused by the tap. 
     As described above, in the first embodiment, it is possible to distinguish between change in the acceleration or the like due to regular usage and change in the acceleration or the like for intended input, and to selectively determine an input as the input intended by a user. 
     Second Embodiment 
     In the following, a second embodiment will be described with reference to drawings. The second embodiment differs from the first embodiment in that adjustment waveform data acquired from the vibration input by the user is referred to when matching the waveform data. In the following explanation of the second embodiment, only differences from the first embodiment will be described, such that parts that are the same as those in the first embodiment are given by the same reference numbers, and the explanations thereof will be omitted. 
       FIG. 13A  and  FIG. 13B  are diagrams for explaining an adjustment waveform.  FIG. 13A  depicts a waveform indicating the change in the acceleration when the device  200  is tapped in a case of tightly fastening the belt  300 .  FIG. 13B  depicts a waveform indicating the change in the acceleration when the device  200  is tapped in a case of loosely fastening the belt  300 . 
     The vibration applied to the device  200  by the tap varies depending on a state of an attachment of the terminal apparatus  100  to the user. For instance, the vibration applied to the device  200  varies depending on a tightness of the belt  300 . 
     It should be noted that a case of tightly fastening the belt  300  corresponds to a state in which the terminal apparatus  100  is fixed to the arm of the user when the user wears the terminal apparatus  100 , and in which the motion in the Y axis direction of the device  200  is restricted. A case of loosely fastening the belt  300  corresponds to a state in which the device  200  is not fixed to the arm of the user when the terminal apparatus  100  is attached, a space exists between the arm of the user and the device  200 , and the motion in the Y axis direction of the device  200  is not readily restricted. 
     In a case in which the user wears the terminal apparatus  100 , when the belt  300  is tightly fastened, the force, with which the belt  300  constrains the device  200  in the Y axis direction becomes greater. Therefore, the impact applied to the device  200  by the tap is more greatly reflected by the change in the acceleration in the X axis direction. Therefore, the waveform indicating the change in the acceleration in this case becomes closer to the reference waveform. 
     Also, in a case in which the user wears the terminal apparatus  100 , when the belt  300  is loosely fastened, the power constraining the device  200  by the belt  300  becomes smaller than a case of tightly fastening the belt  300 . Accordingly, compared with the case of tightly fastening the belt  300 , the change in the acceleration in the Y axis direction easily reflects the impact applied to the device  200  by the tap, and accordingly, the change in the acceleration in the X axis direction tends to become smaller. 
     Accordingly, the change in the acceleration of the waveform depicted in  FIG. 13B  is smaller than the waveform depicted in  FIG. 13A . A wavelength λ is longer than the waveform depicted in  FIG. 13A , and the change is moderate. 
     In the second embodiment, focusing on this point, in allowing the user to tap the device  200  in a state of wearing the terminal apparatus  100 , an adjustment waveform is acquired whereby the manner in which the user wears the terminal apparatus  100  and the like are reflected. Therefore, in the second embodiment, instead of the reference waveform, the adjustment waveform is used in the matching by the waveform matching part  226 , and a discrepancy in an accuracy of an input detection of the tap in response to the user is restricted, such that the accuracy of the input detection is maintained. 
       FIG. 14  is a diagram for explaining functions of the device in the second embodiment. The device  200 A of the second embodiment includes a storage part  210 A, and an input detection process part  220 A. 
     The storage part  210 A of the second embodiment stores the tap detection threshold data  211 , the reference waveform data  212 , the fitting threshold data  213 , and adjustment waveform data  216 . 
     The adjustment waveform data  216  of the second embodiment are acquired by an acquisition process of the adjustment waveform data to be described later, and stored in the storage part  210 A. 
     The input detection process part  220 A of the second embodiment includes a waveform acquisition part  228  and an adjustment waveform generation part  229 , in addition to the parts  221  through  227  of the input detection processing part  220  of the first embodiment. 
     The waveform acquisition part  228  of the second embodiment acquires the change in the acceleration by the vibration input to the device  200  as the waveform data. The adjustment waveform generation part  229  of the second embodiment generates the adjustment waveform data  216  indicating the adjustment waveform from the acquired waveform data. 
     In the following, the acquisition process of the adjustment waveform data of the second embodiment will be described with reference to FIG.  15  and  FIG. 16 . 
       FIG. 15  is a diagram illustrating an example of a screen prompting to input of waveform data, used to generate the adjustment waveform data. 
     The device  200 A of the second embodiment, for instance, displays a message prompting multiple taps on the screen  203 , in response to receiving an operation for acquiring the adjustment waveform data. 
     When the input of the vibration is received on the screen  203  in a state of displaying a message as illustrated in  FIG. 15 , the device  200 A of the second embodiment starts the acquisition process of the adjustment waveform data. 
       FIG. 16  is a flowchart for explaining the acquisition process of the adjustment waveform data in the second embodiment. 
     Processes in steps S 1601  and S 1602  in  FIG. 16  are similar to those in steps S 1001  and S 1002  in  FIG. 10 , and the explanation thereof will be omitted. 
     Next, in the input detection processing part  220 A of the second embodiment, the threshold selection part  224  selects a value indicated by the second threshold data  215  as the fitting threshold (step S 1603 ). 
     Processes in steps S 1604  through S 1609  in  FIG. 16  are similar to those in steps S 1003  through S 1008  in  FIG. 10 , and the explanations thereof will be omitted. 
     Next, the input detection processing part  220 A retains the waveform data indicating the change in the acceleration, which is determined as the tap by the waveform acquisition part  228  (step S 1610 ). Subsequently, the input detection processing part  220 A determines, by the adjustment waveform generation part  229 , whether a predetermined number of times of the tap is detected (step S 1611 ). 
     When the predetermined number of times of the tap has not been detected (step S 1611 ), the input detection processing part  220 A goes back to step S 1601 . 
     When the predetermined number of times of the tap is detected (step S 1611 ), the input detection processing part  220 A determines, by the adjustment waveform generation part  229 , the adjustment waveform data  216  from the waveform data for the predetermined count, and stores the adjustment waveform data  216  in the storage part  210  (step S 1612 ). In detail, the adjustment waveform generation part  229  of the second embodiment may store an average of sets of the waveform data excluding the waveform data having a lowest fitting degree in the waveform data for the predetermined count as the adjustment waveform data  216 . 
     Next, the input detection process of the device  200 A of the second embodiment will be described with reference to  FIG. 17 .  FIG. 17  is a flowchart for explaining an operation of the device of the second embodiment. 
     Processes from step S 1701  to step S 1708  in  FIG. 17  are similar to processes from step S 1001  to step S 1008  in  FIG. 10 , and the explanation thereof will be omitted. 
     Following step S 1708 , the input detection processing part  220 A matches, by the waveform matching part  226 , the recorded waveform data with the adjustment waveform data  216  (step S 1709 ). 
     Next, the tap determination part  227  determines whether the fitting degree between the recorded waveform data and the adjustment waveform data  216  is greater than the fitting threshold (step S 1710 ). 
     When the fitting degree is greater than the fitting threshold (step S 1710 ), the input detection processing part  220 A regards, by the tap determination part  227 , the waveform data as corresponding to the adjustment waveform data. Then, the tap determination part  227  determines that the change in the acceleration_a detected by the device  200  is caused by the tap to the device  200  (step S 1711 ), and terminates this process. 
     As described above, in the second embodiment, it is determined whether the tap is input as the adjustment waveform depending on the manner in which the user wears the terminal apparatus  100 ; hence, regardless of the manner in which the terminal apparatus  100  is worn, it is possible to selectively determine an input as the input intended by the user. 
     It is noted that the process of the input detection in the above described embodiments is performed by the device  200  included in the terminal apparatus  100  being the watch type; however, it is not limited thereto. For instance, the process of the input detection of each of the embodiments may be conducted by a smartphone or the like capable of being fixed onto the arm or the like of the user. Moreover, the process of the input detection may be performed by an IC (Integrated Circuit) or the like included in the device  200 . 
     According to the above described embodiment, it is possible to selectively determining an input as the input intended by a user. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.