JP2009130820A - Information processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily match the timing at which video signals output from an information processing apparatus are displayed by an external video display device and the timing at which sound signals are output by an external sound output device. <P>SOLUTION: By a time difference between the output of test video signals from the information processing apparatus and the input of the test video signals, "video delay time" is calculated. By a time difference between the output of test sound signal from the information processing apparatus and the output of the test sound signals in an external apparatus, "sound delay time" is calculated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an information processing apparatus, and more particularly to an information processing apparatus that can reproduce and output a video signal and an audio signal.

  Conventionally, an information processing apparatus such as a video camera capable of reproducing and outputting a video signal and an audio signal is known. This type of information processing apparatus can output a video signal to a display or the like that is an external video display device, and can output an audio signal to a speaker or the like that is an external audio output device. However, when outputting a video signal or an audio signal from this type of information processing device to an external video display device or audio output device, if the video playback device and the audio playback device are separate devices, for example, video is displayed. The timing at which the sound is output and the timing at which the sound is output may be shifted. This timing shift is caused by a difference in processing capability of each device in a process of processing a video signal or an audio signal.

In order to solve such problems, some conventional information processing apparatuses have a function that allows a user to manually change the output timing of audio and video (for example, Patent Document 1).
JP 2001-043063 A

  In such an information processing apparatus, the user's manual operation relies on the user's sense to determine whether the video display timing and the audio output timing match, so correction to match this timing is not possible. It was difficult.

  The present invention has been made in view of such problems, and the timing at which a video signal output from an information processing device is displayed on an external video display device, and the audio signal is output by an external audio output device. An object of the present invention is to provide an information processing apparatus that can easily match the timing.

  In order to solve such problems, an information processing apparatus according to the present invention includes a distance measuring unit that measures a distance from an object, and a focus that is adjusted based on distance information obtained by the distance measuring unit. Imaging means for picking up an optical image and obtaining a video signal; sound collecting means for collecting sound and obtaining a sound signal; recording means for associating the video signal and the sound signal and recording them on a recording medium; An information processing apparatus comprising: video output means for reproducing a video signal and outputting it at a first timing; and audio output means for reproducing an audio signal from the recording medium and outputting it at a second timing. Video generation means for outputting a video signal to an external device capable of displaying video, and video detection for detecting that the video corresponding to the predetermined video signal displayed by the external device capable of video display is captured by the imaging means. And a first time from when the predetermined video signal is output by the video generation unit to when it is detected that the video corresponding to the predetermined video signal is captured by the imaging unit by the video detection unit A first calculating means for calculating the sound, a sound generating means for outputting a predetermined sound signal to an external device capable of outputting sound, and a sound corresponding to the predetermined sound signal output by the external device capable of outputting sound. A sound detecting means for detecting that the sound is collected by the sound collecting means; and a sound corresponding to the predetermined sound signal by the sound detecting means after the predetermined sound signal is output by the sound generating means. Calculating a second time until it is detected that the sound is collected by the means, and the sound propagates the distance from the object based on the distance from the object obtained by the distance measuring means. That calculates a third time, and having a second calculating means for calculating a difference between the third time and the second time.

  According to the present invention, when the video signal and the audio signal output from the information processing device are displayed on the external video display device and output from the audio output device, the display timing of the video and the output timing of the audio are shifted. The possibility of being lost can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  An information processing apparatus capable of capturing video and collecting audio and outputting a video signal and an audio signal to the outside will be described.

  FIG. 1 is a block diagram of the video camera of this embodiment.

  In FIG. 1, reference numeral 101 denotes a control unit that controls each block in accordance with various functions of the video camera. Reference numeral 102 denotes an operation unit for inputting an external instruction to the video camera. The operation unit 102 includes a power switch, a selection switch for selecting a recording mode and a reproduction mode, a button for instructing start / end of shooting, and the like. Reference numeral 103 denotes a control signal bus through which a control signal from the control unit 101, an instruction signal from the operation unit 102, and the like come and go. Reference numeral 104 denotes an image / audio data bus through which image data and audio data pass between the blocks.

  An imaging unit 105 includes an imaging lens that captures an optical image of a subject, an aperture that controls the amount of light, and an imaging device that converts the optical image into an electrical signal. The imaging unit 105 inputs a video signal and an image signal. Reference numeral 106 denotes a video processing unit that converts the video signal input from the imaging unit 105 to an appropriate signal level, converts it into digital data, and performs processing necessary for the video recording method. The video processing unit 106 can generate video data and still image data. Reference numeral 107 denotes a distance measuring unit that measures the distance to the subject and transmits the subject distance information to the imaging unit 105. The imaging unit 105 performs focus adjustment based on information from the distance measuring unit 107. The distance measuring unit 107 may determine the distance from the image of the imaging unit 105.

  Reference numeral 108 denotes a microphone that captures sound. An audio processing unit 109 adjusts the sound collected by the microphone 108 to an appropriate level, converts the obtained audio signal into digital data, performs processing necessary for the audio recording method, and obtains audio data. .

  110 displays a video corresponding to the video data obtained from the video processing unit 106 during recording, and displays a video played back by a video playback processing unit 114 (to be described later) during playback and displays various menus. It is a display part that can. Reference numeral 111 denotes a display control unit for controlling the display of the display unit 110.

  Reference numeral 112 denotes a hard disk (hereinafter referred to as a recording medium) for recording video data, still image data obtained from the video processing unit 106, audio data obtained from the audio processing unit 109, and other data in association with each other as necessary. , HDD). An access unit 113 accesses the HDD 112 to read / write the video data, still image data, audio data, and other data.

  Reference numeral 114 denotes a video reproduction processing unit that processes the video data of the HDD 112 read by the access unit 113 in accordance with a video recording method and converts it into a predetermined form. Reference numeral 115 denotes a video terminal for outputting the video signal reproduced by the video reproduction processing unit 114 to the outside. In addition, the video reproduction processing unit 114 has a function of adjusting the output timing of the video signal. This function can be realized by providing a memory or the like that can buffer a video signal, or by providing a delay circuit.

  Reference numeral 116 denotes an audio reproduction processing unit that reproduces audio data of the HDD 112 read by the access unit 113 in accordance with an audio recording method. Reference numeral 117 denotes an audio terminal for outputting the audio signal reproduced by the audio reproduction processing unit 116 to the outside. The audio reproduction processing unit 116 has a function of adjusting the output timing of the audio signal. This function can be realized by providing a memory or the like that can buffer an audio signal, or by providing a delay circuit.

  Reference numeral 118 denotes a test video signal generator that outputs a test video signal and a video generation signal for indicating the timing at which the test video is output. This test video signal is displayed by an external device that can display video corresponding to the test video signal, and is used to measure the time until the displayed test video is input to the video camera again. . 119 detects an input when a video corresponding to the test video signal output from the test video signal generation unit 118 is captured by the imaging unit 105, and outputs a video reception signal indicating that the video is input. A test video signal detection unit. Reference numeral 120 denotes a video delay time measurement unit that calculates the difference between the time when the test video signal generation unit 118 outputs the video generation signal and the time when the test video signal detection unit 119 outputs the video reception signal. The video delay time measurement unit compares the time when the test video signal is output by the test video signal generation unit 118 and the time when the test video signal detection unit 119 detects that the video corresponding to the test video signal is input. Thus, the time difference is calculated.

  Reference numeral 121 denotes a test sound signal generator that outputs a test sound signal and outputs a sound generation signal for indicating the timing at which the test sound is output. The test audio signal is used to measure the time until the audio corresponding to the test audio signal is output by an external device capable of outputting audio and input to the video camera again. Reference numeral 122 denotes a test signal detector that detects that a voice corresponding to the test voice signal output from the test voice signal generator 121 is input and outputs a voice reception signal indicating that the voice has been input. . Reference numeral 123 denotes an audio delay time measurement unit that calculates the difference between the time when the test audio signal generation unit 121 outputs the audio generation signal and the time when the test audio signal detection unit 122 outputs the audio reception signal. The audio delay time measurement unit compares the time when the test audio signal is output by the test audio signal generation unit 121 and the time when the test audio signal detection unit 122 detects that the audio corresponding to the test audio signal is input. Thus, the time difference is calculated.

  Reference numeral 124 denotes an external output terminal that outputs a control signal to the outside. For example, the external output terminal can output a control signal related to the delay signal measured by the delay signal measuring unit 123 to the outside.

  In this embodiment, the HDD 111 is used as a storage medium, but this is not limited to a hard disk, and a magnetic (or magneto-optical) recording medium can be considered.

  Further, an external connection terminal may be further provided, and a terminal capable of inputting / outputting digital data such as an HDMI terminal, a USB terminal, and IEEE1394 is conceivable.

First, the moving image recording operation of the video camera of this embodiment will be described.
In response to the operation of the power switch of the operation unit 102, the video camera enters a shooting standby state. In this state, the user operates the shooting button on the operation unit 102 to instruct the video camera to start moving image shooting. In response to the moving image shooting start instruction, the control unit 101 transmits a shooting start instruction signal to the imaging unit 105, the video processing unit 106, and the like.

  When shooting starts, the distance measuring unit 107 measures the distance to the subject, and the imaging unit 105 performs focus adjustment based on the measured distance. The light from the subject incident through the imaging lens of the imaging unit 105 is controlled in light quantity by the diaphragm and converted into an electrical signal by the imaging element. The electrical signal is adjusted to an appropriate signal level by the video processing unit 106 and converted into digital data. The video signal converted into digital data is adjusted to an appropriate number of pixels by a pixel number adjustment circuit of the video processing unit 106, and is compressed and encoded by a predetermined video recording method to become video data.

  In addition, the audio signal captured by the microphone 108 is adjusted to an appropriate level by the audio processing unit 109 and converted into digital data.

  The control unit 101 synthesizes the video data and the audio data to form a data stream, and outputs the data stream to the access unit 113. Based on an instruction from the control unit 101, the access unit 113 starts writing a data stream of video data and audio data into the HDD 112 as one moving image file under file system management such as UDF or FAT. The file system means a structure system composed of management information and file data for managing files. By sharing this file system, recording and reproduction can be performed on different storage media or recording / reproduction devices.

  The data stream may be displayed on the display unit 110 through the display control unit 111 as necessary.

  Then, when the user operates the shooting button of the operation unit 102 again and the video camera is instructed to end moving image shooting, the control unit 101 ends shooting to the imaging unit 105, the video processing unit 106, and the like. The instruction signal is transmitted.

  In response to receiving the instruction signal for ending the moving image shooting, the imaging unit 105 and the video processing unit 106 end the shooting operation. Under the instruction of the control unit 101, the access unit 113 writes a series of video data and audio data recorded from the start of shooting to the end of shooting as one file in the HDD 112, and ends the recording operation. The control unit 101 shifts the video camera to a shooting standby state.

Next, normal playback operation of the video camera of this embodiment will be described.
The control unit 101 controls the access unit 113 to read out video data and still image data from the HDD 112 in response to the reproduction mode being designated by the selection switch of the operation unit 102. Then, the display control unit 111 is controlled so that a thumbnail screen in which thumbnails of the read video data and still image data are arranged and a file name of the video data and still image data are displayed on the display unit 110. In addition, the display control unit 111 may be controlled so that the last captured video data, still image data, or the like is displayed on the display unit 110.

  Then, when the user operates the operation unit 102 with the thumbnail screen displayed and gives an instruction to reproduce video data or still image data, the control unit 101 controls each block to reproduce each image data. To do.

  When playing back video data, the control unit 101 separates audio data and video data from the content data read from the HDD 112 in response to an instruction from the operation unit 102. Then, the video data is decompressed by the video reproduction processing unit 114 and displayed as video on the display unit 110 by the display control unit 111. At this time, since the video signal is also output from the video terminal 115, a video display device connected through the video terminal 115 can display the video. The audio data is transmitted to the audio reproduction processing unit 116, and the audio signal that has been decoded and expanded into an analog signal is output from the audio terminal 117. As a result, audio is output from the audio output device connected to the audio terminal 117.

  Usually, when outputting a video signal and an audio signal to the outside, the audio signal is output in accordance with the first timing at which the video signal is output so that the timing of the signal output from the output terminal of the video camera matches. The output is controlled at the second timing.

  In a state where the video terminal 115 is connected to a device capable of outputting video and the audio terminal 117 is connected to a device capable of outputting audio, the user operates the selection switch of the operation unit 102 to designate the reproduction mode. When the playback mode is designated, the control unit 101 shifts to the playback standby state as described above. At this time, when the user further operates the operation unit 102, the control unit 101 can further shift to the delay time measurement mode. it can.

  Next, the delay time measurement mode will be described. In the delay time measurement mode, the control unit 101 controls the display control unit 111 so that the display unit 110 displays the delay time measurement mode and displays the measurement start button. Good.

  First, in the video camera of this embodiment, a method for measuring the time from when a video signal is output until a device capable of displaying a video corresponding to the output video signal is displayed will be described with reference to FIG. To do. Here, the time from when an apparatus capable of displaying an image displays an image until the displayed image reaches the video camera is approximated to 0 seconds. This is because the image arrives at approximately 0 seconds within the video camera shooting range because the image arrives at the speed of light.

  In the delay time measurement mode, a test video signal is output from the video terminal 115 of the video camera to a device capable of displaying video, and a video corresponding to the test video signal is displayed by the device capable of displaying video. Then, an image corresponding to the test video signal displayed by the device capable of displaying video is captured by the imaging unit 105. Then, the “video delay time” is measured by measuring the time from the test video signal output to the imaging of the video corresponding to the test video signal. Since the time until the displayed video arrives at the video camera after the video display device displays the video is approximated to 0 seconds, this “video delay time” is calculated after the video signal is output. The time until the image is displayed on a device capable of displaying an image is shown.

  When the delay time measurement mode is set, the control unit 101 shifts the test video signal generation unit 118 and the imaging unit 105 to a standby state in order to measure “video delay time”.

  Next, in response to the user operating the operation unit 102 so as to start the delay time measurement, the test video signal generation unit 118 outputs a test video signal to the video terminal 115. Here, for example, a test video signal for displaying an image whose luminance changes abruptly is output. This may be any test video signal as long as it is a signal for displaying a video that can be easily detected by the test video detection unit 119.

  At this time, the test video signal generation unit 118 outputs a video generation signal indicating the time when the test video signal is output to the video delay time measurement unit 120.

  The test video signal output from the video terminal 115 is displayed as a video by a device capable of video display.

  The video corresponding to the test video signal displayed by the video displayable device is picked up again by the image pickup unit 105 provided in the video camera of this embodiment, converted into a video signal, and an optimum value in the video processing unit. And is output to the test video detection unit 119. The test video detection unit 119 detects whether or not the video signal obtained by the imaging unit 105 is a signal indicating a video displayed by a device capable of displaying a video corresponding to the test video signal. When the video signal obtained by the imaging unit 105 is detected as a signal indicating a video displayed by a device capable of displaying a video corresponding to the test video signal, the video reception signal is measured as a video delay time. To the unit 120.

Through the above process, the video delay time measurement unit 120 receives the video generation signal and the video reception signal, and calculates the difference between the input time of the video generation signal and the video reception signal. “Video delay time” can be obtained.
Then, the video delay time measurement unit 120 transmits “video delay time” to the control unit 101.

  Next, in the video camera of this embodiment, a method for measuring the time from when an audio signal is output until the device capable of outputting the audio corresponding to the output audio signal is output will be described with reference to FIG. explain. At this time, the distance measuring unit 107 of the video camera is set to a state in which the distance from the device capable of outputting sound can be measured.

  In the delay time measurement mode, a test audio signal is output from the audio terminal 117 of the video camera to a device that can output audio, and audio corresponding to the test audio signal is output from the device that can output audio. Then, the microphone 108 receives the sound corresponding to the test sound signal output by the device capable of outputting sound. Further, the distance measuring unit 107 of the video camera measures the distance between the audio reproduction device and the video camera. Next, measure the time difference from the test audio signal output to the input of the audio corresponding to the test audio signal, and subtract the time obtained by dividing the distance between the video camera and the audio output device by the sound speed. Measure. This “audio delay time” indicates the time from the output of an audio signal to the output from a device capable of outputting audio.

  In response to the user operating the operation unit 102 to start the delay time measurement, the test audio signal generation unit 121 outputs a test audio signal to the audio terminal 117. The test sound signal is, for example, a sine wave having a single frequency. Further, the waveform of the test sound signal may be changed so that a sound having a higher sound level than that of the external sound is output.

  At this time, the test signal generator 121 outputs a sound generation signal indicating the timing at which the test sound signal is output to the sound delay time measurement unit 123.

  The audio signal output from the audio terminal 117 is output as audio by a device capable of outputting audio.

  Audio corresponding to the test audio signal reproduced by a device capable of audio output is collected again by the microphone 108 provided in the video camera of this embodiment and converted into an audio signal.

  The audio signal obtained by the microphone 108 is adjusted to an appropriate level by the audio processing unit 109 and transmitted to the test audio signal detection unit 122. The test signal detection unit 122 detects whether or not the sound signal obtained by the microphone 108 is a signal indicating sound output by a device that can output sound corresponding to the test sound signal. For example, when the test audio signal is a 1 KHz sine wave, it is possible to detect whether or not the sound corresponds to the test audio signal by extracting the 1 KHz sine wave and determining the level. When it is detected that the sound signal obtained by the microphone 108 is a signal indicating sound output by a device capable of outputting sound corresponding to the test sound signal, the sound reception signal is sent to the sound delay time measuring unit 123. Output.

  Through the above steps, the sound generation time signal and the sound reception signal are input to the sound delay time measurement unit 123.

  Next, the video camera uses the distance measuring unit 107 to measure the distance to the object. That is, the distance from the video camera to the audio playback device is measured. The time obtained by dividing the distance from the video camera to the audio reproduction device by the speed of sound is the time until the audio output from the audio reproduction device reaches the video camera.

  Therefore, in the audio delay time measurement unit 123, the time obtained by subtracting the time until the audio output from the audio reproduction device reaches the video camera from the difference between the input times of the audio generation signal and the audio reception signal is: It becomes “voice delay time”.

  Then, the audio delay time measurement unit 123 transmits a signal indicating “audio delay time” to the control unit 101.

  Upon receiving these “video delay time” and “audio delay time”, the control unit 101 shifts the video camera mode from the delay time measurement mode to the normal playback mode.

  Then, the “video delay time” and “audio delay time” calculated by the video delay time measurement unit 120 and the audio delay time measurement unit 123 are notified. For example, it may be displayed on the display unit 110, an audio signal indicating “video delay time” and “audio delay time” may be output from the audio terminal, and “video delay time” and “audio delay time” may be output from the video terminal. May be output. In this way, the user can know how much the voice is delayed.

  The user can match the video display timing and the audio output timing by adjusting the output timing of the video signal and the audio signal while confirming the “video delay time” and the “audio delay time”.

  Moreover, even if it is a case where it is made not to alert | report, you may make it adjust automatically as follows. When the moving image data recorded on the HDD 112 is reproduced in the reproduction mode, a video signal is output from the video terminal 115 and an audio signal is output from the audio terminal 117. At this time, for example, when the “video delay time” is 3 seconds and the “audio delay time” is 4 seconds, the audio reproduction processing unit 116 outputs the audio signal one second ahead of the video signal. To do. That is, when the “audio delay time” is larger than the “video delay time”, the audio reproduction processing unit 116 outputs the audio signal first by the difference time between the “video delay time” and the “audio delay time”. To control. Conversely, when the “audio delay time” is smaller than the “video delay time”, the audio reproduction processing unit outputs the audio signal later by the difference time between the “video delay time” and the “audio delay time”. 116 is controlled.

  Further, when the “audio delay time” is larger than the “video delay time”, the video reproduction processing unit 114 is configured to output the video signal later by the difference time between the “video delay time” and the “audio delay time”. You may make it control. Conversely, when the “audio delay time” is smaller than the “video delay time”, the video playback processing is performed so that the video signal is output first by the difference between the “video delay time” and the “audio delay time”. The unit 114 may be controlled.

  In this way, it is possible to easily match the timing at which the video signal output from the information processing device is displayed on the external video display device and the timing at which the audio signal is output from the external audio output device. .

  In this embodiment, the output timings of the video signal and the audio signal are adjusted by the video camera. The display and audio output timing may be adjusted.

  In this embodiment, the output timing of the video signal and the audio signal is adjusted by the video camera. However, in the access unit 113, the timing of reproducing the audio signal and the video signal based on the “video delay time” and “audio delay time” The playback timing may be controlled.

  Further, the test audio signal may be output a plurality of times with different amplitude levels instead of being output only once. By doing this, it is possible to reduce the possibility of failing the “voice delay time” measurement even if there is noise in the surroundings or the volume of the device that can output voice is reduced. .

  Further, when the test audio signal is output a plurality of times, the audio delay time can be measured more efficiently by gradually increasing the amplitude level.

  In this embodiment, the “video delay time” and “audio delay time” may be measured simultaneously.

(Other examples)
In the embodiments, the video camera has been described as an information processing apparatus that can reproduce moving image data and collect sound. However, other devices can also reproduce moving image data and collect sound. Any device having a function to perform the above can be applied.

  Needless to say, the object of the present invention can also be achieved by supplying a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus. At this time, the computer (or CPU or MPU) of the supplied system or apparatus reads and executes the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, the OS (basic system or operating system) running on the computer performs part or all of the processing based on the instruction of the program code, and the functions of the above-described embodiments are realized by the processing. Needless to say, cases are also included.

  Further, the program code read from the storage medium may be written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, and the functions of the above-described embodiments may be realized. Needless to say, it is included. At this time, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

1 is a block diagram of a video camera according to Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Control part 102 Operation part 103 Control bus 104 Image / audio bus 105 Imaging part 106 Video processing part 107 Distance measuring part 108 Microphone 109 Sound processing part 110 Display part 111 Display control part 112 Hard disk 113 Access part 114 Video reproduction processing part 115 Video | video Terminal 116 Audio reproduction processing unit 117 Audio terminal 118 Test video signal generation unit 119 Test video signal detection unit 120 Video delay time measurement unit 121 Test audio signal generation unit 122 Test audio signal detection unit 123 Audio delay time measurement unit 124 External output terminal

Claims (4)

A distance measuring means for measuring the distance to the object;
Imaging means for adjusting the focal point based on the distance information obtained by the distance measuring means to capture an optical image of the object and obtaining a video signal;
Sound collecting means for collecting sound and obtaining sound signals;
Recording means for recording the video signal and the audio signal in association with each other on a recording medium;
Video output means for reproducing a video signal from the recording medium and outputting it at a first timing;
An information processing apparatus having audio output means for reproducing an audio signal from the recording medium and outputting the audio signal at a second timing,
Video generation means for outputting a predetermined video signal to an external device capable of video display;
Video detection means for detecting that the video corresponding to the predetermined video signal displayed by the external device capable of video display is imaged by the imaging means;
A first time from when the predetermined video signal is output by the video generation unit to when it is detected by the imaging unit that the video corresponding to the predetermined video signal is detected by the video detection unit is calculated. First calculating means;
Sound generating means for outputting a predetermined sound signal to an external device capable of outputting sound;
Voice detection means for detecting that the voice corresponding to the predetermined voice signal output by the external device capable of voice output is collected by the sound collection means;
A second time from when the predetermined sound signal is output by the sound generation means until the sound detection means detects that the sound corresponding to the predetermined sound signal is collected by the sound collection means. And calculating a third time for the sound to propagate the distance from the object based on the distance from the object obtained by the distance measuring means, and calculating the second time and the third time. And a second calculating means for calculating the difference between the information processing apparatuses.   The audio output means changes the second timing for outputting the audio signal from the first timing, the first time, the second time, and the third time. The information processing apparatus according to claim 1.   The video output means changes the first timing for outputting the audio signal from the second timing, the first time, the second time, and the third time. The information processing apparatus according to claim 1.   The information processing apparatus according to claim 1, further comprising a notifying unit that notifies a difference between the first time, the second time, and the third time.

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