JP4795007B2 - Wireless imaging system and channel control method - Google Patents

Description

  The present invention relates to a wireless imaging system and a channel control method used in a recording studio, for example.

  There is a demand for wireless cameras used in recording studios. As a result, there is no need to route cables or the like, which improves the safety in the studio. In addition, there are fewer restrictions on the program set, and diversification of shooting methods can be expected. Since wireless cameras can shoot while moving freely, when the cameras approach each other, an image to be transmitted and received may be disturbed or interrupted due to the influence of interference or the like.

  For example, in a wireless communication system, a method of preferentially allocating high-quality channels by registering the superiority or inferiority order of line channels in advance is provided (see, for example, Patent Document 1).

JP 2004-297243 A

As described above, in a wireless imaging system using a wireless camera, an image to be transmitted / received may be disturbed or interrupted due to the influence of interference or the like when the imaging devices approach each other.
The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide a wireless imaging system and a channel control method capable of transmitting and receiving captured images and the like even when the cameras are close to each other. is there.

  In order to achieve the above object, the present invention provides a wireless imaging system and a channel control method comprising: a plurality of imaging devices having a wireless communication function; and a wireless communication channel assigned to each of the plurality of imaging devices. A wireless connection device that performs wireless communication by frequency division multiplexing, wherein the plurality of imaging devices include position detection means for detecting position information of the own device, and position information detected by the position detection means. Position transmitting means for transmitting to the wireless connection device. In addition, the wireless connection device is configured to receive a positional information transmitted from the plurality of imaging devices, and a distance between the imaging devices based on the positional information received by the positional information receiving unit. Is assigned to the imaging device when it is determined by the approach determining unit that there is an imaging device approaching within a certain distance. And a channel assignment changing means for changing the wireless communication channel to a wireless communication channel separated by a certain frequency interval or more.

  In the above configuration, the wireless connection device monitors the position of each imaging device, and when the distance between the imaging devices approaches within a certain distance, the wireless communication channel assigned to the imaging device is equal to or greater than a certain frequency interval. Change to a separated wireless communication channel. As a result, even when each imaging device approaches and affects the adjacent channel, the wireless connection device changes the channel according to the position information, thereby causing interference on the upstream and downstream signals of each imaging device. Etc. can be minimized.

  Therefore, according to the present invention, it is possible to provide a wireless imaging system and a channel control method capable of satisfactorily transmitting and receiving captured images and the like even when imaging devices approach each other.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing the configuration of a wireless imaging system according to an embodiment of the present invention.
This system is an example in which three wireless cameras 102-1, 102-2, and 102-3 are connected to the wireless connection apparatus 101 by frequency division multiplexing, and is installed in a recording studio, for example. Each of the wireless cameras 102-1 to 102-3 transmits the captured video to the wireless connection device 101 using the upstream signal (f1, f2, f3), and transmits the compressed on-air video or the like to the downstream signal (F1, F2). , F3) and can be monitored. Further, each of the wireless cameras 102-1 to 102-3 is provided with GPS units 103-1, 103-2, and 103-3 for position detection, and position information detected by the GPS units 103-1 to 103-3. Are transmitted to the wireless connection apparatus 101 using the uplink signals (f1, f2, f3).

  FIG. 2 is a block diagram illustrating a configuration of the wireless connection device 101. The wireless connection device 101 includes an access point unit 1, a channel control unit 2, and a channel information database 3. The access point unit 1 performs a connection process to the wireless cameras 102-1 to 102-3 in accordance with an instruction from the channel control unit 2. The channel information database 3 stores channels in use of the wireless cameras 102-1 to 102-3.

  The channel control unit 2 includes a position acquisition unit 21, an approach determination unit 22, an adjacent channel determination unit 23, and a channel allocation unit 24. The position acquisition unit 21 acquires position information of the wireless cameras 102-1 to 102-3. The approach determination unit 22 determines whether there is a camera whose distance between the cameras is within a certain distance based on the position information acquired by the position acquisition unit 21. The adjacent channel determination unit 23 refers to the channel information database 3 and determines whether or not the frequency of the channel used by the camera determined to be approached by the approach determination unit 22 is adjacent. The channel allocation unit 24 changes the channel used by each camera so that the frequency of the channel used by the approaching camera is separated by a certain frequency interval or more based on the acquired position information, and updates the channel information database 3. .

Next, the operation of the wireless imaging system configured as described above will be described. FIG. 3 is a flowchart showing the channel control procedure of the wireless connection apparatus 101 and its contents.
In step S <b> 1, the position acquisition unit 21 of the wireless connection apparatus 101 acquires position information of each of the wireless cameras 102-1 to 102-3 at regular time intervals, for example. In step S <b> 2, the approach determination unit 22 determines whether there is a camera whose distance between the cameras approaches within a certain distance among the wireless cameras 102-1 to 102-3 based on the position information acquired by the position acquisition unit 21. Determine whether or not.

  If it is determined in step S2 that there is a camera whose camera distance is within a certain distance, the process moves to step S3, and the adjacent channel determination unit 23 refers to the channel information database 3. It is determined whether the frequency of the channel used by the determined camera is adjacent. If it is determined by this determination that the frequencies being used are adjacent to each other, the channel allocation unit 24 determines that the frequency of the channel used by the camera that is approaching based on the acquired position information is equal to or greater than a certain frequency interval. The channel used by each camera is changed so as to be separated, and the channel information database 3 is updated. Then, in step S4, the channel control unit 2 supplies the changed channel information to the access point unit 1, whereby the access point unit 1 transmits a channel control signal to the corresponding camera.

Here, an example of channel change will be described with reference to the drawings.
FIG. 4 shows a camera arrangement example in which the wireless cameras 102-1 to 102-3 are sufficiently separated from each other. FIG. 5 shows the spectrum of each channel in the camera arrangement shown in FIG. 4 as an ideal shape. Thus, when the cameras are separated from each other by a certain distance or more, the intensity of the spectrum becomes almost equal.

  On the other hand, consider the case where the position of the wireless camera is as shown in FIG. That is, the wireless camera 102-1 and the wireless camera 102-3 are close to each other. The spectrum of each channel in the camera arrangement in this case is as shown in FIG. The transmission spectrum f3 of the upstream signal output by the wireless camera 102-3 itself is the largest, and then becomes the spectrum f1 of the upstream signal of the wireless camera 102-1 located next to each other, and each spectrum is at a distance from the wireless camera 102-3. It is getting smaller. The spectrum of the downstream signal is smaller than that of the upstream signal due to attenuation in the propagation path, and is smaller according to the distance as in the upstream signal. That is, the spectrum of the downstream signal of F3 is the largest, and decreases in the order of F1 and F2.

  Here, in FIG. 6, each spectrum is schematically shown as an ideal shape. However, in general, since various noise components are included in the transmission signal, the spectrum is actually as shown in FIG. Accordingly, when the positional relationship of the camera is as shown in FIG. 1, the upstream signal f1 of the nearby wireless camera 102-1 greatly affects the downstream signal F3 of the wireless camera 102-3, and the wireless camera 102 -3 may not be received correctly.

  Therefore, in the present invention, in such a case, as shown in FIG. 8, the channel control unit 2 switches the use channels of the wireless camera 102-1 and the wireless camera 102-2. That is, channel 2 ′ is allocated to the upstream signal f1 of the wireless camera 102-1, and channel 1 ′ is allocated to the upstream signal f2 of the wireless camera 102-2. By doing so, it is possible to minimize the influence of the uplink signal f1 on the downlink signal F3, so that it is possible to perform good communication in both uplink and downlink.

  In short, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a schematic diagram showing a configuration of a wireless imaging system according to an embodiment of the present invention. The block diagram which shows the structure of the wireless connection apparatus shown in FIG. The flowchart which shows the procedure of the channel control operation | movement of the wireless connection apparatus shown in FIG. 1, and its content. The figure which shows an example of the camera arrangement | positioning of the wireless imaging system shown in FIG. The figure which shows the spectrum (ideal form) of each channel in the camera arrangement | positioning shown in FIG. The figure which shows the spectrum (ideal form) of each channel in the camera arrangement | positioning shown in FIG. The figure which shows the spectrum before the channel control of each channel in the camera arrangement | positioning shown in FIG. The figure which shows the spectrum after the channel control of each channel in the camera arrangement | positioning shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Wireless connection apparatus, 102-1, 102-2, 102-3 ... Wireless camera, 103-1, 103-2, 103-3 ... GPS antenna, 1 ... Access point part, 2 ... Channel control part, 21 ... Position acquisition unit, 22 ... proximity determination unit, 23 ... adjacent channel determination unit, 24 ... channel allocation unit, 3 ... channel information database, F1, F2, F3 ... downlink signal, f1, f2, f3 ... uplink signal.

Claims (2)

First to third imaging devices having a wireless communication function, first to third upstream wireless communication channels are allocated to the first to third imaging devices, and first to third downstream wireless communication channels are used. A wireless connection device that performs bidirectional video transmission using the frequency division multiplexing method with the first to third imaging devices,
The plurality of imaging devices include:
Position detecting means for detecting position information of the own device;
Position transmitting means for transmitting position information detected by the position detecting means to the wireless connection device;
With
The wireless connection device is:
Position information receiving means for receiving position information transmitted from each of the plurality of imaging devices;
Based on the positional information received by the positional information receiving means, an approach determining means for determining whether there is an imaging apparatus in which the distance between the imaging apparatuses approaches within a certain distance;
When the approach determining means determines that there is an imaging device that has approached within a certain distance, the upstream wireless communication channel assigned to the approaching imaging device is used for the approaching imaging device. Channel assignment changing means for changing to an uplink radio communication channel that is separated from the radio communication channel by a predetermined frequency interval or more;
With
The first to third downlink radio communication channels are assigned to lower frequencies than the first to third uplink radio communication channels;
The change of the uplink radio communication channel is determined that there is the approaching imaging device, and the frequency of the uplink radio communication channel used by one of the approaching imaging devices is the downlink radio communication used by the other When it is determined that the channel frequency is adjacent,
A wireless imaging system that changes by switching an uplink wireless communication channel used by one of the approaching imaging devices and an uplink wireless communication channel used by an imaging device other than the approaching imaging device. . First to third imaging devices having a wireless communication function, first to third upstream wireless communication channels are allocated to the first to third imaging devices, and first to third downstream wireless communication channels are used. Used in a wireless imaging system including a wireless connection device that performs bidirectional video transmission with the first to third imaging devices by frequency division multiplexing.
The plurality of imaging devices include:
A position detecting step for detecting position information of the own device;
A position transmission step of transmitting the position information detected by the position detection step to the wireless connection device,
The wireless connection device is:
A position information receiving step of receiving position information transmitted from each of the plurality of imaging devices;
Based on the position information received by the position information receiving step, an approach determination step for determining whether or not there is an image capturing apparatus in which the distance between the image capturing apparatuses approaches within a certain distance;
When it is determined by the approach determining step that there is an imaging device approaching within a certain distance, the upstream wireless communication channel assigned to the approaching imaging device is used for the approaching imaging device. A channel assignment change step for changing to an uplink radio communication channel that is spaced apart from the radio communication channel by a certain frequency interval , and
The first to third downlink radio communication channels are assigned to lower frequencies than the first to third uplink radio communication channels;
The change of the uplink radio communication channel is determined that there is the approaching imaging device, and the frequency of the uplink radio communication channel used by one of the approaching imaging devices is the downlink radio communication used by the other When it is determined that the channel frequency is adjacent,
A channel control method comprising: changing an uplink radio communication channel used by one of the approaching imaging devices and an uplink radio communication channel used by an imaging device other than the approaching imaging device by switching. .

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