JP2002112341A - Radio communication system, data communication unit and data communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system that can ensure the continuity of data and surely transfer the data to a receiver side even on the occurrence of interruption of a radio wave on the way of communication. SOLUTION: In the radio communication system consisting of an image pickup device 10a and recording and reproducing device 20, the image pickup device 10 transmits video data to the recording and reproducing device 20 through radio communication. In this case, a temporary storage device 16 of the image pickup device 10 stores the data at that time and transfers the data to a recorder 15 by regarding the data as unarrived data when the image pickup device 10 cannot detect an acknowledgement signal sent form the recording and reproducing device 20 in a prescribed time. At the restoration to a communication enabled state, the image pickup device 10 transmits data sent in real time including the unarrived data in the recorder 15. Thus, the recording and reproducing device 20 can obtain the video data in a complete form and can correctly reproduce the video data in time sequence by assembling the received video data on a time base later.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system for transferring video information photographed by a photographing device to a recording / reproducing device by wireless communication, and recording and reproducing the video information on the recording / reproducing device side. The present invention relates to a data communication device and a data communication method used in the wireless communication system.

[0002]

2. Description of the Related Art In recent years, IrDA, Bluetooth,
Wireless communication systems in the personal area such as HomeRF are receiving attention. In particular, Bluetooth and Home
eRF has advantages such as lack of directivity and high transparency compared to infrared communication systems such as IrDA, and is expected to be greatly developed and spread in the future. In addition,
Bluetooth is a short-range wireless communication standard,
2.4GHz ISM (Industrial Science Medica)
l) Wireless communication within 10 m or 100 m is realized by using a band.

[0003] Wireless communication systems such as Bluetooth and HomeRF can connect to a plurality of devices at the same time and have a relatively long transmission distance of, for example, 10 to 100 m as compared with an infrared communication system such as IrDA. This is also one of the major features.

Conventionally, assuming that such a wireless communication system is used, video data photographed by a photographing device (video camera) is transferred to a recording and reproducing device by wireless communication, and the recording and reproducing device records the video data. There is known a recording / playback system for performing playback.

[0005]

In the above-described photographing / recording / reproducing system, when video data is being transferred from the photographing apparatus to the recording / reproducing apparatus, the connection between the two is temporarily lost for some reason such as a normal situation. It may be possible to be cut off. In such a case, there is a problem that the video data is lost on the way and the receiving side cannot process the data completely.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and when transferring data having continuity such as video data by wireless communication, the continuity of the data is maintained even if the wireless connection is interrupted. It is an object of the present invention to provide a wireless communication system, a data communication device, and a data communication method, which can ensure the transfer of data to the receiving side and reliably transfer the data to the receiving side.

[0007]

SUMMARY OF THE INVENTION According to the present invention, data having continuity obtained by a first device is transmitted to a second device by wireless communication.
In the wireless communication system for transferring to the first device,
The device does not detect a response signal sent from the second device at a predetermined timing during transmission of the data having continuity, and regards the data being transmitted at that time as unarrived data. The data is stored in a storage unit, and data transmitted in real time according to the communication status is transmitted by including the unarrived data in the storage unit.

[0008] With this, data having continuity is transmitted from the first device to the second device in real time, and when the radio between the devices is cut off, the data being transmitted at that time is transmitted. Is stored on the first device side, and is sent together with real-time data when the communication device returns to the communicable state.
Therefore, on the second device side, all of the data having continuity can be obtained, and by assembling them on the time axis, it is possible to correctly reproduce the data in chronological order.

The present invention also relates to a wireless communication system for simultaneously transferring data having continuity obtained by a first device to a plurality of second devices by wireless communication, wherein the first device comprises: If the number of response signals sent from each of the second devices is not detected at a predetermined timing during transmission of data having the characteristic at a predetermined timing, the data being transmitted at that time is regarded as unarrived data. The data is stored in a storage unit, and data transmitted in real time according to the communication status is transmitted by including the unarrived data in the storage unit.

As described above, when data is transmitted to a plurality of second devices, if the number of response signals is not detected in a predetermined number or more, it is determined that data transmission has failed, and the data being transmitted at that time is unsuccessful. It is held on the first device side, and is sent together with real-time data when it returns to a state where it can communicate with a predetermined number or more of second devices. As a result, the second device can obtain all of the data having continuity, and by assembling them on the time axis, it is possible to correctly reproduce the data in chronological order.

However, when the number of response signals is detected to be equal to or more than a predetermined number, normal data transmission is performed as it is.
Some second devices may not receive the data. Therefore, after the data transmission is completed, the first device inquires of each of the second devices about the data reception result, and according to the response result, the data is missing in each of the second devices. It is necessary for the device to acquire the data from another device having the data, transfer the data to the device, and complement the data.

Further, the present invention provides a wireless communication system for transferring data having continuity obtained by a first device to a second device by wireless communication, wherein the first device comprises:
When the data having the continuity is transmitted in a predetermined unit, and the data transmitted at that time is temporarily stored in a temporary storage unit, and a signal indicating unarrived data is received from the second device. The data to be transmitted next is compressed according to the amount of the unarrived data, and is transmitted together with the unarrived data read from the temporary storage means.

Thus, data having continuity is transmitted from the first device to the second device in a predetermined unit, and if unreachable data exists during the transmission, the next data to be transmitted is transmitted. The compression ratio is adjusted and sent together with the unreachable data. Therefore, although the data is sent while being adjusted in a predetermined unit, there is some delay, but the continuity of the data can be maintained and given to the second device.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a diagram showing a configuration as a video recording / reproducing system to which a wireless communication system of the present invention is applied.

This video recording / reproducing system includes a photographing device 1
0 and the recording / reproducing device 20. Note that the photographing apparatus 10 and the recording / reproducing apparatus 20 can be connected by wire, but the description will be limited to a wireless connection. As wireless communication in this case, for example, Bluetooth
oth is used. That is, the imaging device 10 and the recording / reproducing device 20 each have a Bluetooth communication function, and can perform bidirectional data communication with each other using radio waves in a predetermined radio frequency band.

The photographing device 10 has a video camera function, and here, transfers video data obtained by the video camera function to the recording / reproducing device 20. The photographing apparatus 10 includes an imaging unit 11 that converts a video image captured by a camera into an electric signal, a signal processing unit 12 that performs signal processing such as encoding the electric signal in a predetermined format, and a predetermined time period. A small-capacity temporary storage device 16 (cache memory) capable of temporarily storing video data, a large-capacity recording device 15 (HDD or the like) capable of recording video data of a predetermined capacity, and data modulation / demodulation processing. And an antenna 18 for transmitting and receiving radio waves.

The photographing apparatus 10 has an operation unit 1 comprising a group of buttons for operating various functions of the apparatus.
4 or an LCD (Liquor
A display unit 13 such as an id Crystal Display) is provided.

On the other hand, the recording / reproducing device 20 which is a receiving side of the photographing device 10 has a function of recording and reproducing the video data by receiving the video data transferred from the photographing device 10. The recording / reproducing device 2
As 0, a dedicated device for recording and reproducing video data may be used, or an information processing device such as a personal computer may be used.

The recording / reproducing apparatus 20 includes an antenna 27 for transmitting / receiving a radio wave, a modulation / demodulation section 26 for performing data modulation / demodulation processing, a large-capacity recording apparatus 21 capable of recording video data of a predetermined capacity, Is provided with a signal processing unit 23 for performing signal processing such as decoding. The recording / reproducing apparatus 20 includes an operation unit 24 including, for example, a keyboard, and an LCD for mainly displaying video data.
(Liquid Crystal Display), an input / output terminal 22 for an external device 28, and the like.

In such a configuration, an electric signal (video signal) of a video composed of an image and a sound obtained from the image pickup unit 11 of the photographing apparatus 10 is encoded by the signal processing unit 12 in a predetermined format. The video data obtained by the encoding is stored in a temporary storage device 16 (cache), modulated by a modulation / demodulation unit 17 and transmitted as a radio wave by an antenna 18. When data cannot be transmitted, the video data at that time is stored in the recording device 15.

On the other hand, the recording / reproducing apparatus 20 receives the video data from the photographing apparatus 10 via the antenna 27 by radio waves.
Demodulation is performed by the modulation / demodulation unit 26. The demodulated video data is stored in the large-capacity recording device 21. The video data stored in the large-capacity recording device 21 is decoded by the signal processing unit 23 and displayed on the display unit 25. In this case, depending on the user's request, it is possible to store the video data in the large-capacity recording device 21 and display the video data on the screen by decoding so that the captured video can be viewed in real time. Also, real-time appreciation can be performed by the external device 28 via the input / output terminal 22.

The above is the basic processing flow.

Here, the processing when the connection between the apparatuses is temporarily interrupted during data transfer will be described on the assumption that the photographing apparatus 10 transfers video data to one recording / reproducing apparatus 20. I do.

The processing on the photographing apparatus 10 side is composed of three processing modes, "normal processing", "disconnection processing",
This is "return processing". Details of each process are shown below.

FIG. 2 shows a photographing apparatus 1 according to the first embodiment.
0 is a flowchart showing the normal processing operation of FIG.
FIG. 4 is a flowchart showing a processing operation at the time of disconnection of the imaging device 10 according to the first embodiment, and FIG. 4 is a flowchart showing a return processing operation of the imaging device 10 according to the first embodiment.

First, normal processing will be described with reference to FIG.

When photographing is started by activating the imaging unit 11 of the imaging device 10, a signal output from the imaging unit 11 is coded by a predetermined compression process or the like in the signal processing unit 12 to become video data ( Steps 201 to 203). This video data is transmitted to the recording / reproducing device 20 via the modulation / demodulation unit 17 and the antenna 18 (step 204), and is simultaneously written to the temporary storage device 16 (cache memory) in the photographing device 10 (step 205).

Here, when the recording / reproducing apparatus 20 is able to receive the video data, it transmits a reception completion signal to the photographing apparatus 10 at regular intervals or at regular intervals. The photographing apparatus 10 expects the reception completion signal to be periodically transmitted from the recording / reproducing apparatus 20. At the timing when a timer that operates according to the interval of the reception completion signal is activated (step 206). Yes), confirm the reception completion signal from the recording / reproducing device 20 (step 20).
7).

If the reception completion signal can be confirmed (Yes in step 207), the video data at that time (specifically, several frames of the video data transmitted at the interval of the reception completion signal) is correctly recorded and reproduced. 20, the recording / reproducing device 20 discards the video data held in the temporary storage device 16 (step 208), and repeats the processing from step 201. On the other hand, if the reception completion signal cannot be confirmed (N in step 207)
o), it is determined that the video data was not correctly transferred to the recording / reproducing device 20, and the process proceeds to the disconnection process while the video data at that time is retained in the temporary storage device 16 (step 20).
9).

Next, the disconnecting process will be described with reference to the flowchart of FIG.

When the photographing device 10 detects the disconnection state based on the reception completion signal (step 301), it transfers the video data currently stored in the temporary storage device 16 to the large-capacity recording device 15 (step 302). This recording device 1
As 5, for example, an HDD is used. Note that a configuration in which video data is held in the recording device 15 from the beginning may be used. However, if the recording device 15 is constantly activated, power consumption increases, so that the video data is temporarily cached in the small-capacity temporary storage device 16. In addition, it is more preferable to transfer the data from the temporary storage device 16 to the recording device 15 when the disconnection state is detected.

Here, even when "disconnected", the input video is not different from that in the normal state, so that it is necessary to perform the same processing as in the "normal state".

That is, the photographing operation is continuously performed, and the image photographed by the image pickup section 11 is encoded by the signal processing section 12 by a compression process or the like to generate image data (steps 303 to 305). ). Then, the transmission of the video data to the recording / reproducing device 20 is continued even at the time of disconnection (step 306). In this case, the storage destination is the temporary storage device 16 in the "normal time", but is directly written in the recording device 15 in the "disconnection" (step 307).

Further, since data transmission is performed even at the time of disconnection, when the connection is restored and the recording / reproducing apparatus 20 receives video data of a predetermined time or a predetermined number of frames again, a reception completion signal is issued. The photographing apparatus 10 checks the presence or absence of the reception completion signal using the above-described timer every time (step 308). Then, when the reception completion signal from the recording / reproducing device 20 has been confirmed (Yes in step 308)
s), the imaging device 10 determines that the connection has been restored, and shifts to a return process (step 309). If the reception completion signal cannot be confirmed (No in step 308), the disconnection process from step 303 is repeated until the signal is received.

During the disconnection process, the user may be notified of this fact.

FIG. 13 shows a notification example at the time of disconnection. 1 in the figure
01 is an apparatus main body of the photographing apparatus 10, 102 is a finder,
103 is a display unit. The screen of the display unit 103 displays the video image being captured. For example, a message 104 such as “disconnected” is displayed on the screen of the display unit 103 to notify the user that the connection with the recording / reproducing apparatus 20 is disconnected.

With such a configuration, for example, the photographing apparatus 1
0 battery capacity or the recording / reproducing device 20
The user can take action for restoring the connection, such as checking the power supply state of the other device or reducing the interval with the recording / reproducing device 20, and can restore the connection as soon as possible to return to the normal state. The present invention is not limited to the display of such a message, and may be configured to notify the user by, for example, turning on an LED or generating an alarm sound.

Next, the return process will be described with reference to the flowchart of FIG.

When the photographing device 10 detects the restoration of the connection based on the reception completion signal (step 401), it first transmits the video data obtained from the image pickup section 11 to the recording / reproducing device 20 (steps 402 to 405). At the same time, the transmission data is stored in the temporary storage device 16 (step 40).
6).

Here, the photographing apparatus 10 has room for transmitting the video data which could not be transmitted before together with the current video data to be transmitted in real time in the transmission band between the photographing apparatus 10 and the recording / reproducing apparatus 20. It is checked whether or not there is (step 407). That is, the amount of data that can be transmitted between the two devices is determined by the frequency band used by the present system. By comparing the amount of data that can be transmitted with the amount of video data that is currently being shot, it is determined whether extra data can be sent.

If there is no margin in the transmission band (No in step 407), the process proceeds to the next process. On the other hand, if it is determined that there is room in the transmission band (step 4).
(Yes in 07), the imaging device 10 transmits an amount of data stored in the recording device 15 at the time of “disconnection” in accordance with the margin of the transmission band (step 408), and transmits the transmitted data portion. Delete from the recording device 15 (step 4
09).

Further, the photographing apparatus 10 checks whether or not there is a reception completion signal from the recording / reproducing apparatus 20 by using a timer which operates at a predetermined time or at an interval of a predetermined number of frames (step 411). If no reception completion signal is detected (N in step 411)
o), the processing shifts to the disconnection processing of FIG. 3 again (step 41).
3).

When the reception completion signal is detected (Yes in step 411), the photographing device 10
6 are discarded (step 41).
2) At that time, it is checked whether or not data in the recording device 15 remains (step 414). Recording device 1
If no data remains in the storage device 5, the process proceeds to the normal process of FIG. 2 (step 415). If data exists in the recording device 15, the process returns to step 402 and the return process is continued. Do it.

Next, the processing when photographing is completed will be described.

FIG. 5 shows a photographing apparatus 1 according to the first embodiment.
9 is a flowchart illustrating an operation of a shooting end process of No. 0.

When the photographing end is instructed through the operation unit 14 of the photographing apparatus 10 (step 501), the photographing apparatus 10 checks whether or not there is data in the recording device 15 owned by the photographing apparatus 10 (step 502). In this case, for example, when photographing ends before all data is retransmitted in the return processing of FIG. 4, data to be retransmitted still remains in the recording device 15. Then, when the remaining data is confirmed, the photographing device 10 transmits the remaining data in the recording device 15 before disconnecting the connection with the recording / reproducing device 20 (step 503). Then, when all the remaining data is transmitted, the photographing apparatus 10 notifies the recording / reproducing apparatus 20 of the end of the photographing, and at this point, the entire photographing process ends (step 504).

On the other hand, as the processing on the recording / reproducing device 20 side, when receiving the video data transmitted from the photographing device 10, a reception completion signal is transmitted to the photographing device 10. In this case, when data of a predetermined amount or more can be received within the unit time in a unit of time, or data of a predetermined number of frames or more can be received in the unit number of frames in a unit of a certain number of frames. At this time, a reception completion signal is transmitted as reception success.

Further, the received video data is sequentially stored in the large-capacity recording device 21 of the recording / reproducing device 20. Finally, each data held in the large-capacity recording device 21 is not inconsistent on the time axis. To fix it. Thus, even if the connection between the devices is interrupted, video data can be finally obtained in a completed form without data loss and the like, and can be reproduced.

It is also possible to perform a reproducing operation such as displaying the received data on the display unit 25 at the time of data reception in real time. However, if the connection between the devices is disconnected, the video during that period cannot be reproduced. In the case of reproducing in a completed form, the data stored in the large-capacity recording device 21 is edited after the video on the imaging device 10 ends.

FIG. 6 shows, as a specific example corresponding to the first embodiment, a time-series data flow when 64 frames are photographed under the following conditions.

Unit time (interval at which a reception completion signal is issued)
8 frames at a time. -The temporary storage device 16 is a cache memory (high-speed memory)
And The recording device 15 is an HDD (fixed disk). As for the “communication status” in FIG. 6, “６” indicates a status where transmission and reception are possible, “×” indicates a status where transmission and reception are not possible,
In the case of “○”, it is assumed that the number of corresponding frames equal to or more than a predetermined ratio can be transmitted.

The item "previous frame-1" in the item "reception complete signal" indicates that "-1" is a magic number and that this signal is from the first frame group.

As shown in FIG. 6, when video data is transmitted to the recording / reproducing apparatus 20 in units of eight frames, if the communication becomes impossible during the transmission, the data is transferred to the photographing apparatus 10.
In the recording device 15 (HDD), and when communication becomes possible, in addition to the eight frames of video data to be transmitted at that time, the data stored in the recording device 15 (that is, Untransmitted video data).

By the way, the capacity of the recording device 15 of the photographing device 10 is limited, and if the disconnected state continues for a long time, data may not be stored in the recording device 15. In this case, a method for reducing loss of video will be described.

(1) First, a method of maximizing data quality is considered. In other words, this is a method of maintaining the image quality even if the frame is truncated. This includes the method of truncating old data and the recording device 1 written at the time of disconnection.
5, there is a method of giving priority to the data at the beginning of storage and not storing the latest video data that cannot be stored.

(2) The following is a method for preventing loss of transmission video data on the time axis due to disconnection at the expense of some data.

First, when it is detected that the remaining capacity of the recording device 15 in the photographing device 10 has become small, a recalculation for reducing the bit rate of the data stored at the present stage is performed and the data is stored again. As a result, the capacity per unit time used for the video is reduced, thereby increasing the relative recording time.

Second, the stored video is divided in units of time such that the contents are not lost, and its representative image is determined. Then, in the case of re-saving, the format is “representative image + display seconds”. If the division time can be determined according to the situation in this way, the capacity occupied by the image data can be arbitrarily determined, so that a flexible response can be made. Also, for example, when a lecture scene is being photographed, sound is more important than video, or if there is sound, the scene can be complemented to some extent even if the image is slightly lost.
In consideration of such a case, a method of reducing the storage capacity by erasing the image data using only the audio data in the video data may be considered.

Further, when a situation in which data is likely to be lost due to a shortage of memory is likely to occur, the fact may be notified through a part such as the finder 102 and the display unit 103 which can be easily confirmed by the user as shown in FIG. good. In the example of FIG. 13, the message 104 of “disconnecting” is displayed on the screen of the display unit 103 that is openably and closably attached to the apparatus main body 101 at the time of disconnection. Can warn that data is about to be lost.

The recovery process starts at the moment when the recording / reproducing device 20 receives the transmission data from the photographing device 10 again, issues a reception completion signal, and the photographing device 10 receives the data. In this case, there is a time during which data is stored in the recording device 15 even though the recording / reproducing device 20 has started re-receiving. Therefore, if all the stored data is transmitted at the time of the return processing, the data is transmitted twice, which is inefficient. Therefore, the reception completion signal has a meaning to improve the efficiency. Information shown in FIG. 7 is added to the reception completion signal.

The information to be specifically given is first the number of the received frame group. This is the start and end number of the frame number received within the corresponding unit time or unit frame. The second is a frame number received before receiving the frame group. This is the end number of the most recently received frame group. By transmitting this, when a frame is lost, it is possible to easily know which frame has been lost. Third,
This is a retransmission frame group number. This returns the frame number received at the time of the return processing, and transmits the start and end frame numbers. Fourth, an ID for specifying the recording / reproducing device 20 itself. This is identification information for communicating so as not to be confused when there is another device in the vicinity, and is uniquely assigned to each device.

As described above, when the connection between the devices is cut off during the transmission of the video data, the video data at that time is stored in the photographing device 10 and the data is stored when returning. By transmitting the video data together, the recording / reproducing apparatus 20 reassemble the data on the time axis after the end of shooting with the shooting apparatus 10 so that the video data can be completely formed (without data loss, continuous Playback). Further, at the time of reception, the recording / reproducing apparatus 20 can reproduce and receive the received data at that time in real time, even if it is intermittent.

(Second Embodiment) Next, a second embodiment of the present invention will be described.

In the second embodiment, one photographing device 10
It is assumed that a plurality of recording / reproducing devices 20 are connected wirelessly. Note that the photographing device 10 can communicate with an arbitrary number of the recording / reproducing devices 20, and can select a communication partner. Further, the recording / reproducing device 20 can communicate with one photographing device 10 at the same time, but this need not be a unique photographing device 10.

In this case, since there are a plurality of recording / reproducing apparatuses 20, a reception completion signal corresponding to the number of recording / reproducing apparatuses 20 exists. Further, even when one recording / reproducing device 20 has succeeded in receiving, the other recording / reproducing device 20 may have failed in receiving. Based on such a situation, similarly to the first embodiment, description will be made separately for each process of “normal time”, “disconnection time”, and “return process”.

FIG. 8 shows a photographing apparatus 1 according to the second embodiment.
0 is a flowchart showing the normal processing operation, and FIG.
FIG. 10 is a flowchart showing a processing operation at the time of disconnection of the imaging device 10 according to the second embodiment, and FIG. 10 is a flowchart showing a return processing operation of the imaging device 10 according to the second embodiment.

First, normal processing will be described with reference to FIG.

When photographing is started by activating the imaging unit 11 of the imaging device 10, a signal output from the imaging unit 11 is encoded by a predetermined compression process or the like in the signal processing unit 12 to become video data ( Steps 801 to 803). This video data is transmitted to all the recording / reproducing devices 20 permitted as communication partners via the modem unit 17 and the antenna 18 (step 804), and simultaneously to the temporary storage device 16 (cache memory) in the photographing device 10. It is written (step 805).

Here, when each recording / reproducing device 20 can receive the video data, it transmits a reception completion signal to the photographing device 10 at regular intervals or at regular intervals. On the photographing apparatus 10 side, the reception completion signal is transmitted to each recording / reproducing apparatus 2.
It is expected to be sent periodically from 0. At the timing when the timer that operates according to the interval of the reception completion signal is activated (Yes in step 806), the reception completion from each recording / reproducing device 20 is completed. The signals are confirmed, and the number of the signals is measured (step 807).

Note that the photographing apparatus 10 has a function of distinguishing and receiving the reception completion signal from each recording / reproducing apparatus 20 by an ID unique to each apparatus.

If a predetermined number or more of the reception completion signals can be confirmed (Yes in step 808), the video data stored in the temporary storage device 16 (specifically, the number of video data transmitted at the interval of the reception completion signal) Are discarded (step 809). In other words, even if there is a device that cannot confirm the reception completion signal, if the number is small depending on the setting, it is regarded as “normal time”. on the other hand,
If a predetermined number or more of the reception completion signals cannot be confirmed (step 808), it is determined that the data has not been correctly transferred to the set number of recording / reproducing devices 20, and the video data at that time is stored in the temporary storage device 16. Then, the process proceeds to the processing at the time of disconnection while holding the data (step 810).

Next, the disconnecting process will be described with reference to the flowchart of FIG.

When the photographing device 10 detects the disconnection state based on the reception completion signal (step 901), it transfers the video data currently stored in the temporary storage device 16 to the large-capacity recording device 15 (step 902).

Here, even when "disconnected", the input image is not different from that in the normal state, and therefore, it is necessary to perform the same processing as in the "normal state".

That is, the photographing operation is continuously performed, and the image photographed by the image pickup unit 11 is encoded by the signal processing unit 12 by a compression process or the like to generate image data (steps 903 to 905). ). Then, the transmission of the video data to the recording / reproducing device 20 is continued even at the time of disconnection (step 906). In this case, the storage destination is the temporary storage device 16 in the "normal time", but is directly written in the recording device 15 in the "disconnection" (step 907).

Further, since data transmission is performed even at the time of disconnection, if the connection is restored and the recording / reproducing apparatus 20 receives image data of a certain time or a certain number of frames again, it issues a reception completion signal. The imaging device 10 checks the number of arrivals of the reception completion signal using the above-described timer every time (step 908). If a predetermined number or more of the reception completion signals can be confirmed (Yes in step 909), the imaging device 10 determines that the connection has been restored again, and shifts to the restoration process (step 910). If a predetermined number or more of the reception completion signals cannot be confirmed (No in step 909),
Until the signal is received, the disconnection processing from step 903 is repeated.

As in the first embodiment, the user may be informed of the fact during the disconnection process (see FIG. 13).

Next, the return process will be described with reference to the flowchart of FIG.

When the photographing device 10 detects the restoration of the connection based on the reception completion signal (step A01), it first transmits the video data obtained from the image pickup section 11 to all the recording / reproducing devices 20 (steps A02 to A05). ) At the same time, the transmission data is stored in the temporary storage device 16 (step A06).

Here, the photographing device 10 has a margin for transmitting the video data which could not be transmitted before together with the current video data to be transmitted in real time in the transmission band between the photographing device 10 and each recording / reproducing device 20. It is checked whether or not there is (step A07). That is, the amount of data that can be transmitted between the two devices is determined by the frequency band used by the present system. By comparing the amount of data that can be transmitted with the amount of video data that is currently being shot, it is determined whether extra data can be sent. Note that, regarding all the recording / reproducing devices 20, the transmission band with the imaging device 10 is the same.

If there is no margin in the transmission band (No in step A07), the process proceeds to the next process. On the other hand, if it is determined that there is room in the transmission band (step A
(Yes at 07), the imaging device 10 transmits an amount of data stored in the recording device 15 at the time of “disconnection” according to the margin of the transmission band (step A08), and transmits the transmitted data portion. Delete from the recording device 15 (step A
09).

Further, the photographing apparatus 10 checks the arrival number of the reception completion signal from each recording / reproducing apparatus 20 by using a timer which operates at a fixed time or a fixed number of frames (step A10). . If a predetermined number of reception completion signals have not been detected (No in step A12), the process returns to the disconnection processing in FIG. 9 (step A13).

When a predetermined number of reception completion signals have been detected (Yes in step A12), the photographing device 10 discards the data stored in the temporary storage device 16 (step A13) and records the data at that time. It is checked whether data remains in the device 15 (step A15). If no data remains in the recording device 15, the process proceeds to the normal process of FIG. 8 (step A16), but if data exists in the recording device 15, the process returns to step A02, and the return process here is performed. Continue to do so.

Next, the processing when photographing is completed will be described.

FIG. 11 is a flowchart showing the processing operation at the end of photographing of the photographing apparatus 10 in the second embodiment.

When the photographing end is instructed through the operation unit 14 of the photographing apparatus 10 (step B01), the photographing apparatus 10 checks whether or not there is data in the recording device 15 owned by the photographing apparatus 10 (step B02). In this case, when photographing ends before all data is retransmitted in the return process of FIG. 10, data to be retransmitted still remains in the recording device 15. Then, when the remaining data is confirmed, the photographing device 10 transmits the remaining data in the recording device 15 before disconnecting the connection with the recording / reproducing device 20 (step B03).

Next, the photographing device 10 is
Performs complement processing for data that could not be received. this is,
Since the photographing apparatus 10 receives the predetermined number or more of the reception completion signals and continues the “normal operation” processing, there is a possibility that some of the recording / reproducing apparatuses 20 could not receive the data.
This is a process for complementing the data.

The photographing apparatus 10 inquires each recording / reproducing apparatus 20 whether there is any data that could not be received (step B04). If there is any missing data, the recording / reproducing apparatus 20 that has received the inquiry transmits information indicating the range (unit section of data) to the photographing apparatus 10. Thereby, the imaging device 10 can confirm the recording / reproducing device 20 that could not receive a certain range of data (step B05), and inquire of other recording / reproducing devices 20 whether or not they have the data in the range. (Step B06).

The recording / reproducing apparatus 20 having the data in the range corresponding to this inquiry notifies the photographing apparatus 10 of the fact.
Tell Thereby, the photographing apparatus 10 selects one of the recording / reproducing apparatuses 20 having the data of the range (step B07), acquires the data of the range from the selected recording / reproducing apparatus 20, and then acquires the data of the selected data. Is transferred to the recording / reproducing device 20 that requires the data (step B08).

The above processing is repeated until all the missing data is complemented for one recording / reproducing apparatus 20 (step B09). Then, when all the recording / reproducing apparatuses 20 can have the video data in a complete form, the complementing process is completed (step B10), the end of the photographing is notified to each recording / reproducing apparatus 20, and the entire process of photographing is performed. The process ends (step B11).

In order to identify a plurality of recording / reproducing apparatuses 20 in the above-described series of processing, an individual ID is assigned to each apparatus. This ID is included in the reception completion signal as shown in FIG. 7, and the imaging device 10 identifies the recording / reproducing device 20 based on the reception completion signal.

On the other hand, as processing on the recording / reproducing device 20 side, when receiving the video data transmitted from the photographing device 10, a reception completion signal is transmitted to the photographing device 10. In this case, as in the first embodiment, when a predetermined amount of data or more can be received within a unit time in a unit of time, or in a unit of a unit number of frames in a unit of a certain number of frames. When data equal to or more than a predetermined number of frames can be received, a reception completion signal is transmitted as reception success.

The received video data is sequentially stored in the large-capacity recording device 21 of the recording / reproducing device 20. At the end of photographing, if there is any missing data, the data is acquired from another recording / reproducing device 20 via the photographing device 10 to supplement the data, and the large-capacity recording device 21
To save. Finally, each data held in the large-capacity recording device 21 is corrected so that there is no inconsistency on the time axis. Thus, even if the connection between the devices is interrupted, video data can be finally obtained in a completed form without data loss and the like, and can be reproduced.

FIG. 12 shows, as a specific example corresponding to the second embodiment, a time-series data flow when 64 frames are photographed under the following conditions.

Four recording / reproducing devices 20 (each A, B,
C, D). When the reception completion signal is received from two or more recording / reproducing apparatuses 20, the reception is regarded as successful.・ Shooting 8 frames at a time (interval at which a reception completion signal is issued). -The temporary storage device 16 is a cache memory (high-speed memory)
And The recording device 15 is an HDD (fixed disk). In addition, regarding the “reception completion judgment” in FIG.
Indicates that reception was determined to be successful in this system, and “x” indicates that reception was determined to be unsuccessful in this system. Similarly, regarding the “communication status” of each recording / reproducing device 20, “○” indicates a status in which transmission / reception is possible, “×” indicates a status in which transmission and reception are impossible, Is transmitted.

As shown in FIG. 12, when video data is transmitted to four recording / reproducing apparatuses 20 of A to D in units of eight frames, when a reception completion signal is received from two or more recording / reproducing apparatuses 20 , Normal processing is continued as reception success. If no reception completion signal is received from any of the recording / reproducing devices 20, or if one of the recording / reproducing devices 20
If only the reception completion signal is not received, it is determined that reception has failed (that is, communication is not possible), the data is held in the recording device 15 (HDD) of the photographing device 10, and communication is enabled. At this time, in addition to the video data for eight frames to be transmitted at that time, the data held in the recording device 15 (that is, untransmitted video data) is transmitted. Also in this case, communication is possible.
0, and some devices cannot actually receive data.

Here, after the photographing is completed, a supplementary process is executed for the recording / reproducing device 20 that could not receive the data. In the example of FIG. 12, the device A receives the frame number “08-1”.
Since the data “5” could not be received, the data is complemented by acquiring the data from the device B via the photographing device 10 after the photographing is completed. Further, since the devices B and C could not receive the data of the frame number “40-47”, the data is complemented by acquiring the data from the device A via the photographing device 10 after the photographing is completed.

The solution to the temporary limit of the capacity of the recording device 15 when the disconnection state continues for a long time is as described in the first embodiment.

As described above, when video data is transferred from the photographing device 10 to a plurality of recording / reproducing devices 20, even if a situation occurs in which video data cannot be transferred to all the recording / reproducing devices 20, even if a situation occurs, the final In each of the recording / reproducing devices 20, the video data is converted to a perfect form (with no data loss,
(In a continuous state). In addition, at the time of reception, each recording / reproducing device 20 can reproduce and receive the received data in real time, even if it is intermittent.

(Third Embodiment) Next, a third embodiment of the present invention will be described.

In the first and second embodiments, it is assumed that data is transmitted and received in real time, and even if video is interrupted at the real time level, the data is maintained in real time and the data to be finally stored is maintained. Can be complemented to be as close as possible when radio waves are not cut. On the other hand, the third embodiment focuses on maintaining the continuity of data so that even if a connection is interrupted during data transfer, a moving image captured by a photographer can be provided without loss. Is what you do.

That is, by utilizing the delay in data transfer to the extent that the viewer does not feel uncomfortable and the fluctuation of the dynamic compression ratio, the risk of radio wave disconnection in wireless communication is absorbed and the continuity of time-series data is reduced. A system that secures and provides optimal moving images is realized.

In this case, one photographing device 10
The description will be made on the assumption that video data captured by the image capturing device 10 is transferred to one recording / reproducing device 20.

The configurations of the photographing device 10 and the recording / reproducing device 20 are basically the same as those in FIG. However, as for the recording / reproducing device 20, as shown in FIG.
Shall be provided.

FIG. 15 is a diagram for explaining a data transfer method according to the third embodiment. Here, the number of frames as a data transmission unit is determined in advance, and the subsequent processing is performed using this as one unit. This unit is expressed as a "block", and when a radio wave is cut off during transmission / reception of a certain block and several frames in the block cannot be received, the frame that could not be transmitted in the previous block at the next block transmission The data is mixed with the block data to be transmitted and transmitted. At this time, it is assumed that the block data to be transmitted is compressed at a compression ratio such that the transmission is completed within a predetermined time even when the data is mixed with the data not transmitted in the previous block.

Here, the processing operations of the photographing apparatus 10 and the recording / reproducing apparatus 20 will be described with reference to FIGS. 16 and 17, while referring to the data transfer in FIG. FIG.
6 is a flowchart showing a processing operation on the photographing apparatus 10 side in the third embodiment, and FIG. 17 is a flowchart showing a processing operation on the recording / reproducing apparatus 20 side in the third embodiment.

The photographing apparatus 10 calculates the data compression ratio in block units (step G01), and compresses and encodes the video obtained by the imaging unit 11 at the compression ratio to generate video data. (Steps G02 to G0
3).

The video data corresponding to the first first block is transmitted to the recording / reproducing device 20 via the antenna 18 (step G06), and at the same time, the data is written to the temporary storage device 16 (step G07).

Here, when the radio wave is interrupted or the like, a predetermined number or more of frames in the first block are stored in the recording / reproducing apparatus 2.
Suppose that it was not sent to 0. On the recording / reproducing device 20 side,
A signal relating to the received information is issued for each block, and the non-arrival information of the frame is returned to the imaging device 10 with reference to the number of the arrived frame. This state is referred to as T1, T in FIG.
It is shown in FIG.

When the non-arrival information of such a frame is returned to the photographing device 10, the photographing device 10
When transmitting the next block, the frame that has not arrived in the first block is mixed with the frame in the second block and transmitted. However, since the bandwidth that can be transmitted is determined, the compression of the data in the second block is performed so that the data of the first block and the data of the second block are mixed to obtain a transmission state equivalent to that in normal transmission. Adjust the rate (Step G
03). In this case, generally, the compression ratio of the second block to be sent is higher. The method of calculating the compression ratio will be described later with reference to FIG.

By adjusting the compression ratio as described above, when mixed data of the first block unreachable frame that was previously transmitted and the data of the second block that is transmitted this time is generated (steps G04 and G05), the mixed data is generated. Temporary storage device 16
(Step G07), and transmitted to the recording / reproducing device 20 (Step G06). This state is shown in FIG.
At T3 and T4. The dotted arrow in the figure indicates the transmission of data corresponding to the unarrived frame of the first block.

On the other hand, when the recording / reproducing device 20 receives the data transmitted from the photographing device 10 (step H04), it separates the data into the first block data and the second block data (step H05). ), And save them in appropriate storage spaces (step H06). Although there is a method of using the large-capacity recording device 21 as the storage space, the temporary storage device 1 of the imaging device 10 is
It is also conceivable to add a function equivalent to 6 to the recording / reproducing device 20 and use it. This is indicated by the temporary storage device 30 in FIG.

When the transmission / reception of the second block between the photographing device 10 and the recording / reproducing device 20 is completed (step G08, step H07), the recording / reproducing device 2
In the case of 0, as in the case of the above-described first block, information indicating the number of the unarrived frame that could not be received in the second block is transmitted to the photographing apparatus 10 (step G09, step H09, T4 in FIG. 15B). ).

Next, in the photographing device 10, the temporary storage device 1
After deleting the data of the first block stored in No. 6, the process moves to the video data corresponding to the third block (steps G10 and G11). The data of the third block is stored in the deleted storage area of the temporary storage device 16 and transmitted to the recording / reproducing device 20 at the same time (step G0).
7, G06). In this case, the photographing apparatus 10 mixes the unarrived frame of the second block and the data of the third block with reference to the information on the unarrived frame of the second block, and transmits the data (steps G04 and G05). This state is shown at T5 and T6 in FIG. The dotted arrows in the figure indicate the transmission of data corresponding to unarrived frames in the second block.

On the other hand, the recording / reproducing device 20 stores the transmitted data in the temporary storage device 30 (steps H04 to H06), and decodes and reproduces the already stored data of the first block. (Step H
01 to H03). Then, the data of the first block is transferred from the temporary storage device 30 to the large-capacity recording device 21 (Step H08). At this time, information indicating the number of the unarrived frame of the third block is transmitted to the imaging device 10 (Step H09).

Thereafter, similarly, T7 and T7 shown in FIG.
As shown in 8, the above processing is repeated. If there is no reception completion signal due to radio wave disconnection or the like even after retransmission of unarrived data, it is processed as missing data.

As described above, when the video data captured by the photographing device 10 is transferred to the recording / reproducing device 20, if data that could not be transmitted to the recording / reproducing device 20 due to radio wave conditions or the like occurs, the photographing device 10 Then, the compression ratio of the data to be transmitted next is adjusted so that the data is transmitted together with the unreachable data. As a result, although some delay occurs, it is possible to transmit the video data to the recording / reproducing apparatus 20 while maintaining continuity.

In the example shown in FIG. 15, the video data captured by the image capturing device 10 is transmitted by the recording and reproducing device 20 corresponding to two blocks from the actual time. Instead of allowing such a delay, continuity can be maintained as a moving image.

It is assumed that a compression ratio equal to or higher than the predetermined ratio is not performed, and when compression higher than the predetermined ratio becomes necessary, retransmission data one block before is deleted and transmitted. This is to guarantee a moving image of a constant quality.

FIG. 18 shows a calculation example of the compression ratio.

At each time point, data is transmitted using the entire band. Also, 12 frames are converted to 1
It is a block unit.

Assume that transmission of data for three frames has failed when data for 12 frames of block 1 has been transmitted. In such a case, unarrived data (untransmitted data) for three frames in the block 1 is transmitted at the timing of the block 2. When these data are averaged and sent, 3 frames / 12 frames = 0.25, which means that a 25% bandwidth per frame can be used. Therefore, in block 2, 2
Coding is performed by adjusting the compression ratio so as to reduce the information amount by 5%.

Next, in block 2, it is assumed that there are two frames whose transmission has failed. By the way, since the data was created with a high compression ratio in the block 2, if the data is averaged and sent at the timing of the block 3, it becomes (2 frames / 12 frames) × 0.75 = 0.125. 12.5% block per frame 2
May be used for retransmission of the message. Therefore, the encoding of the block 3 is performed by adjusting the compression ratio so that the information amount is reduced by 12.5% from the normal time.

It should be noted that this calculation sequence is an example of a simplified model, and in fact, the fact that the amount of information differs for each frame and redundancy must be considered.

By adjusting such a compression ratio, it becomes possible to transmit data including unreachable data, and although there is some delay, continuity as video data can be maintained. As in the second embodiment, the data can be reproduced and viewed without requiring editing work such as assembling each received data on the time axis on the receiving side (recording / reproducing device 20).

In each of the above embodiments, the photographing device 10
The case where video data is transferred by wireless communication using the recording and reproducing apparatus 20 has been described as an example, but the present invention is not limited to the transfer of video data, and time-series data is transferred in real time and recorded on the receiving side. If it is a system that reproduces, it can be applied to all of them.

[0128]

As described above in detail, according to the present invention, when the radio between the devices is interrupted while transmitting data having continuity from the first device to the second device. , The data at that time is held on the first device side,
Since the data is sent together with the real-time data when the communication is restored, the second device can obtain all the continuous data, and assembling these on the time axis, Reproduction can be performed correctly in order.

When transmitting data to a plurality of second devices, if the number of response signals is not detected in a predetermined number or more, it is determined that data transmission has failed and the data at that time is transmitted to the first device. And the data is transmitted together with the real-time data when the communication device returns to a state in which communication with a predetermined number or more of the second devices is possible. Therefore, the second device obtains all the data having continuity. By assembling these on the time axis, it is possible to reproduce the data correctly in chronological order.

Further, after the data transmission is completed, the second
Inquiry of the data reception result to the device of the second device, according to the response result, for the device in which data is missing in each of the second devices, obtain the data from another device having the data, By transferring the data to the above-described device, the data can be complemented for the second device that has not received the data.

Further, data having continuity is transmitted from the first device to the second device in a predetermined unit, and if there is unarrived data during the transmission, the data to be transmitted next is compressed. Since the rate is adjusted and sent together with the unreachable data, the amount of data sent while adjusting in predetermined units,
Although there is some delay, the data continuity is maintained and the second
Device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration as a video recording / reproducing system to which a wireless communication system of the present invention is applied.

FIG. 2 is a flowchart illustrating a normal processing operation of the imaging device according to the first embodiment;

FIG. 3 is a flowchart illustrating a processing operation at the time of disconnection of the image capturing apparatus according to the first embodiment.

FIG. 4 is a flowchart illustrating a return processing operation of the image capturing apparatus according to the first embodiment.

FIG. 5 is a flowchart illustrating an operation of a photographing end process of the photographing apparatus according to the first embodiment.

FIG. 6 shows a specific example corresponding to the first embodiment, 64
FIG. 6 is a diagram showing a time-series data flow in a case where a frame is shot.

FIG. 7 is a diagram showing information added to a reception completion signal in the first embodiment.

FIG. 8 is a flowchart illustrating a normal processing operation of the image capturing apparatus according to the second embodiment.

FIG. 9 is a flowchart illustrating a disconnection processing operation of the image capturing apparatus according to the second embodiment.

FIG. 10 is a flowchart illustrating a return processing operation of the image capturing apparatus according to the second embodiment.

FIG. 11 is a flowchart illustrating a processing operation at the end of image capturing of the image capturing apparatus according to the second embodiment.

FIG. 12 is a view showing, as a specific example corresponding to the second embodiment, a time-series data flow in a case where 64 frames are shot under the following conditions.

FIG. 13 is a diagram illustrating an example of a notification during disconnection in the imaging device.

FIG. 14 is a block diagram illustrating a configuration of a recording / reproducing device according to a third embodiment.

FIG. 15 is a view for explaining a data transfer method according to the third embodiment;

FIG. 16 is a flowchart illustrating a processing operation on the imaging device side according to the third embodiment.

FIG. 17 is a flowchart showing a processing operation on the recording / reproducing device side in the third embodiment.

FIG. 18 is a diagram illustrating a calculation example of a compression ratio according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Photographing apparatus 11 ... Imaging part 12 ... Signal processing part 13 ... Display part 14 ... Operation part 15 ... Recording device 16 ... Temporary storage device 17 ... Modulation / demodulation part 18 ... Antenna 20 ... Recording / reproducing device 21 ... Large-capacity recording device 22 ... Input / output terminal 23 ... Signal processing unit 24 ... Operation unit 25 ... Display unit 26 ... Modulation / demodulation unit 27 ... Antenna 28 ... External equipment 30 ... Temporary storage device 101 ... Device body 102 ... Finder 103 ... Display unit 104 ... Message

Continued on the front page F-term (reference) 5C054 AA01 CH01 DA00 DA07 EA01 EA03 EA07 FF02 GA01 GA04 HA00 5C056 FA01 FA03 FA20 HA01 HA04 5K033 AA06 CB04 CB15 DA01 DB13 DB16 5K034 AA05 CC02 CC05 DD01 EE03 FF02H03 H01H03 NN27 5K067 AA23 BB21 DD52 GG02 HH01 HH23

Claims (12)

[Claims] 1. A wireless communication system for transferring data having continuity obtained by a first device to a second device by wireless communication, wherein the first device transmits the data having continuity. Transmitting means; detecting means for detecting a response signal transmitted from the second device at a predetermined timing during data transmission by the transmitting means; and detecting when the response signal is not detected by the detecting means. A storage unit for storing the data being transmitted at that time as unreachable data; and transmitting the data transmitted in real time by the transmission unit in accordance with the communication status, including the unreachable data in the storage unit. A transmission control unit, wherein the second device receives data sequentially transmitted from the first device, and receives data by the reception device. Response means for returning a response signal; storage means for storing each data received by the receiving means; and data editing means for assembling each data stored by the storage means on a time axis. Wireless communication system. 2. The transmission control means judges whether a band that can be transmitted by including the unarrived data can be secured, and if the band can be secured, the unreachable data and the data in real time can be secured. The wireless communication system according to claim 1, wherein data is transmitted. 3. The first device includes: a temporary storage unit for temporarily storing data transmitted by the transmission unit; and a temporary storage unit in the temporary storage unit when the response signal is detected by the detection unit. 2. The data management device according to claim 1, further comprising: data management means for discarding data and holding the data in the temporary storage means as unreachable data in the storage means when the response signal is not detected. Wireless communication system. 4. A wireless communication system for transferring data having continuity obtained by a first device to a plurality of second devices simultaneously by wireless communication, wherein the first device has the data having continuity. Transmitting means for transmitting a response signal transmitted from each of the second devices at a predetermined timing during transmission of data by the transmitting means; and detecting the number of response signals by the detecting means. When a predetermined number or more are not detected, the storage means for storing the data being transmitted at that time as unreachable data, and the data transmitted in real time by the transmission means in accordance with the communication status. Transmission control means for transmitting the unarrived data by including the unarrived data; each of the second devices; receiving means for receiving data sequentially transmitted from the first device; Response means for returning a response signal when data is received by the means; storage means for storing each data received by the receiving means; data editing means for assembling each data stored by the storage means on a time axis A wireless communication system comprising: 5. The data processing apparatus according to claim 1, wherein after the data transmission is completed, the first device inquires each of the second devices about a result of the data reception, and in accordance with a response result of each of the second devices by the inquiry means. Data compensating means for acquiring data from another device having the data and transferring the acquired data to the device, for the device in which data is missing in each of the second devices, 5. The apparatus according to claim 4, wherein each of the devices includes a specific information return unit that returns specific information indicating a range in which data is missing in response to an inquiry from the first device. Wireless communication system. 6. A wireless communication system for transferring data having continuity obtained by a first device to a second device by wireless communication, wherein the first device converts the data having continuity into a predetermined unit. A transmitting means for transmitting data transmitted by the transmitting means; a temporary storing means for temporarily storing data transmitted by the transmitting means; Compression means for compressing the data to be transmitted in accordance with the amount of the non-arrival data; and transmission control means for reading the non-arrival data from the temporary storage means and transmitting the data together with the data compressed by the compression means. The second device comprises: receiving means for receiving data sequentially transmitted in predetermined units from the first device; and unarrived data not received by the receiving means. Wireless communication system comprising: the response means for returning a signal indicating the data, a storage means for storing each data received by the receiving means for each predetermined unit. 7. A data communication apparatus for transferring data having continuity to an external device by wireless communication, comprising: transmitting means for transmitting the data having continuity; and at predetermined timing during transmission of data by the transmitting means. Detecting means for detecting a response signal sent from the external device; and storing means for storing data being transmitted at that time as unreached data when the response signal is not detected by the detecting means; A data communication apparatus, comprising: transmission control means for transmitting data transmitted in real time by the transmission means in accordance with a communication state, by including unarrived data in the storage means. 8. A data communication apparatus for transferring data having continuity to a plurality of external devices simultaneously by wireless communication, a transmission means for transmitting the data having continuity, and a predetermined means for transmitting data by the transmission means. Detecting means for detecting a response signal sent from each of the external devices at the timing of the above; and, if the number of the response signals is not detected by a predetermined number or more by the detecting means, the data being transmitted at that time is not yet detected. Storage means for storing as arrival data; and transmission control means for transmitting data transmitted in real time by the transmission means in accordance with the communication status, including the unarrived data in the storage means. Data communication device. 9. A data communication device for transferring data having continuity to an external device by wireless communication, comprising: transmitting means for transmitting the data having continuity in a predetermined unit; and temporarily transmitting data transmitted by the transmitting means. Temporary storage means for temporarily storing data, and compression means for compressing data to be transmitted next by the transmission means in accordance with the amount of the non-arrival data when receiving a signal indicating unreachable data from the external device. And a transmission control means for reading the unreached data from the temporary storage means and transmitting the read data together with the data compressed by the compression means. 10. A data communication method for transferring data having continuity to an external device by wireless communication, wherein the data having continuity is transmitted, and transmitted from the external device at a predetermined timing during the transmission of the data. When the response signal is detected, if the response signal is not detected, the data being transmitted at that time is stored as unarrived data in the memory, and the data transmitted in real time according to the communication state is stored in the memory. A data communication method comprising transmitting unreachable data in a memory. 11. A data communication method for simultaneously transferring data having continuity to a plurality of external devices by wireless communication, wherein the data having continuity is transmitted, and each of the external devices is transmitted at a predetermined timing during transmission of the data. A response signal sent from the device is detected, and if the number of the response signals is not detected by a predetermined number or more, the data being transmitted at that time is stored in a memory as unarrived data, and according to a communication state. A data communication method, wherein data transmitted in real time includes unarrived data in the memory and transmitted. 12. A data communication method for transferring continuity data to an external device by wireless communication, wherein the continuity data is transmitted in a predetermined unit, and the transmission data is temporarily stored in a memory. Receiving a signal indicating unreachable data from the external device, compressing data to be transmitted next according to the amount of the unreachable data, reading the unreachable data from the memory, and A data communication method characterized by transmitting together with data.