JP7555837B2 - Camera System - Google Patents

Description

The present invention relates to a camera system that uses an imaging device that captures images and a control device that is connected to the imaging device via communication.

An imaging device used for imaging in television broadcasts of digital high-definition broadcasts (4K, 8K, etc.) is actually used as a camera system (system camera) connected to other devices. The configuration of an optical system camera 8, which is an example of such a system, and the signal flow in this case are simplified and shown in FIG. 7(a). Here, an imaging device 70 that uses a solid-state imaging element to perform imaging is combined with a camera control unit (CCU: control device) 80 that controls the imaging device 70. The CCU 80 outputs an image (image signal) captured by the imaging device 70 to the outside, and the CCU 80 outputs a return image signal input from the outside to the imaging device 70. The return image signal is, for example, an image obtained by another imaging device (camera system) or an image signal for the cameraman operating the imaging device 70 to view through the finder of the imaging device 70. By viewing this image, the cameraman can operate the imaging device 70 appropriately. In this case, in order to support high-definition video signals, it is preferable to use optical communication using optical fiber for communication between the imaging device 70 and the CCU 80.

Here, the CCU 80 also issues a control signal to the imaging device 70 to control the imaging device 70. In addition, the imaging device 70 also receives a TALLY signal to control a tally lamp, an intercom signal which is an audio signal, and a PGM audio signal which is a video/audio signal output from this unit and which becomes the image seen by the viewer, all of which are used when the cameraman operates the device. In contrast to the control signal, a return signal is issued from the imaging device 70 when controlling the device.

For this reason, the imaging device 70 and the CCU 80 use a composite optical cable 81 that integrates an optical fiber for transmitting an optical signal with a cable for transmitting an electrical signal. The video signal and return video signal are broadcast SDI (Serial Digital Interface) signals, which flow as optical signals through the composite optical cable 81 (optical fiber). In this way, the CCU 80 functions as an interface between the imaging device 70 and the outside. Note that while only one imaging device 70 is used in FIG. 7(a), in practice multiple imaging devices 70 may each be connected to the CCU 80 via a composite optical cable 81.

On the other hand, the configuration of a wireless camera system 9, which is another form of such a camera system, and the signal flow in this case are shown in Figure 7 (b). Here, the optical composite cable 81 is not used, and the wireless receiver (control device) 90 used instead of the CCU 80 and the imaging device 70 are connected wirelessly (wireless LAN). As described above, video signals, return video signals, control signals for the imaging device 70, etc. are exchanged between the wireless receiver 90 and the imaging device 70, but these signals are transmitted and received through an IP network using a wireless LAN. For this reason, the video signal and return video signal (SDI signal) are IP (Internet Protocol) converted and transmitted as IP signals over the wireless LAN, and the control signal is also transmitted and received as an IP signal. For this reason, the imaging device 70 needs a function to encode the video signal from the IP signal to an SDI signal, or to IP convert (decode) the SDI signal and transmit it as an IP signal, and a transmitter 91 having this function is connected to the imaging device 70. Correspondingly, the wireless receiver 90 is also provided with a function for IP conversion (decoding, encoding) of the received IP signal to obtain a video signal. For the return video signal, the IP conversion, encoding, and decoding are performed in the opposite manner to that for the video signal. The same is true for control signals, return signals, etc., which are IP converted and transmitted over an IP network. For this reason, the wireless receiver 90 and transmitter 91 are each provided with such IP conversion (encoding, decoding) functions. As with the optical system camera 8 described above, multiple sets of imaging devices 70 and transmitters 91 can be used simultaneously.

In this way, in the camera system, other control devices (CCU 80, wireless receiver 90) with functions such as relaying video signals are connected to the imaging device 70, which has the function of capturing images, via wired or wireless communication, and the video signals are emitted from this control device to the outside. The CCU 80 in FIG. 7(a) and the wireless receiver 90 in FIG. 7(b) are common in that they both have the function of relaying various signals, but as the communication method with the imaging device 70 is different as described above, their other functions are significantly different.

The optical system camera 8 and the wireless camera system 9 can both be used in television broadcasts, etc., and which is more preferable is determined according to the mode and situation of use, particularly the communication situation. For this reason, when considering sudden communication failures, it is desirable to have a configuration in which the imaging device 70 is shared and the optical system camera 8 and the wireless camera system 9 can be switched as appropriate. In this case, for example, the CCU 80 and optical composite cable 81 in FIG. 7(a) and the wireless receiver 90 and transmitter 91 in FIG. 7(b) are all provided, and the connections between them can be switched as appropriate. However, when multiple (many) imaging devices 70 are provided as described above, it is necessary to perform this switching simultaneously and appropriately. Technology that facilitates such switching operations is described, for example, in Patent Document 1.

JP 2012-151590 A

Such a switching operation is performed, for example, in the event of a sudden failure as described above, during which the video signal output to the outside is temporarily interrupted. If a storage medium that stores the video signal at all times is provided on the imaging device side, even in the event of a communication failure like this, it is possible to prevent the loss of video during the failure, and at least make it possible to transmit all video signals after the failure is restored. However, in television broadcasts of high-definition broadcasts (4K, 8K, etc.), the capacity of the video signal becomes large, so the storage medium required becomes large, and the camera system itself becomes large. Since the camera system may be mounted on a vehicle, for example, it is not desirable for the camera system to become large in this way.

In addition, when actually switching from the configuration in FIG. 7(a) to the configuration in FIG. 7(b), the optical composite cable 81 and the transmitter 91 must be swapped, i.e., the cable connections must be changed, etc., and the switching operation takes time. During this switching operation, the video signal is no longer transmitted to the outside, resulting in a problem of interruption of the video.

For this reason, there was a demand for technology in camera systems that could switch the communication path between the imaging device and the control device without losing the video signal to be transmitted.

The present invention was developed in light of these circumstances, and aims to solve the above problems.

The present invention relates to
A camera system comprising an imaging device which generates a video signal by imaging, and a control device which is connected to the imaging device by a communication means, wherein the video signal is transmitted from the imaging device to the control device by the communication means, and a return video signal used on the imaging device side is transmitted from the control device to the imaging device by the communication means, wherein both wired communication and wireless communication are available as the communication means, and a control device side communication switching unit is provided on the control device side which selects and sets either the wired communication or the wireless communication as the communication means when the control device receives the video signal. The imaging device side is equipped with an imaging device side communication switching unit that selects and sets either the wired communication or the wireless communication as the communication means when the imaging device receives the return video signal, and the imaging device side is equipped with a video recording unit that stores the video signal before and after the timing at which the imaging device side communication switching unit switches the communication means, and an imaging device side signal degradation recognition unit that recognizes degradation of the received return video signal, and the video recording unit stores the video signal when degradation of the return video signal is recognized by the imaging device side signal degradation recognition unit.
Furthermore, on the imaging device side, a trigger code signal indicating the start and end timings of storing the video signal in the video recording section, and a recording signal in which the trigger code signal is superimposed on the video signal, are generated, and the video recording section may receive the recording signal, recognize the trigger code signal, recognize the period in which the video signal should be stored, and store the video signal.
In addition, the imaging device may be provided with a trigger generation unit that generates the trigger code signal indicating the start of storage of the video signal when degradation is recognized by the imaging device side signal degradation recognition unit, and the end of the storage when the degradation is eliminated.
In addition, the control device may be provided with a control device side signal degradation recognition unit that recognizes degradation of the received video signal, and when degradation of the video signal is recognized by the control device side signal degradation recognition unit, the control device may degrade the return video signal to be transmitted to the imaging device side.
At least one of the control device side communication switching section and the imaging device side communication switching section may switch the communication means in response to a reception level in the communication means.

According to the present invention, in a camera system, it is possible to switch the communication path between the imaging device and the control device without losing the video signal to be transmitted.

1 is a diagram showing an overall configuration of a camera system according to an embodiment; FIG. 2 is a diagram showing a configuration of an imaging device in a camera system according to an embodiment. FIG. 2 is a diagram showing a configuration of a control device side in a camera system according to an embodiment. 5 is a flowchart showing a communication means switching operation in the camera system according to the embodiment. 2 is a diagram showing a circuit configuration of a signal degradation recognition unit used in the camera system according to the embodiment. FIG. 4 is a diagram showing a circuit configuration of a trigger generation unit used in the camera system of the embodiment. FIG. 1A and 1B are diagrams showing two typical configurations of a conventional camera system.

Next, a specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of a camera system 1 according to an embodiment of the present invention. This camera system 1 also uses an imaging device 10 that generates a video signal by capturing an image with an image sensor, similar to the imaging device 70 described above. As will be described later, the imaging device 10 is provided with functions that are not available in the imaging device 70.

Also, like the optical system camera 8, the camera system 1 uses a camera control unit (CCU: control device) 20, which also has the same functions as the wireless receiver 90 in the wireless camera system 9. Correspondingly, a transmitter 30 is also used on the imaging device 10 side. For this reason, video signals, return video signals, control signals, return signals, etc. are exchanged between the imaging device 10 and the CCU 20 via a wireless LAN. As a result, video signals are transmitted from the CCU 20 to the outside and are also used for broadcasting.

However, like the optical system camera 8 described above, the imaging device 10 and the CCU 20 are connected by the same optical composite cable 81 described above. This allows video signals, return video signals, control signals, etc. to be exchanged between the imaging device 10 and the CCU 20 via the optical composite cable 81, and also allows video signals to be transmitted from the CCU 20 to the outside.

Therefore, this camera system 1 can be used in place of the wireless camera 9 using wireless communication (wireless LAN) and the optical system camera 8 using wired communication. However, this camera system 1 uses either wired communication or wireless communication in the default state, for example, and switches to the other communication if a failure occurs. At this time, loss of video signals during this switching is suppressed. For this reason, the CCU 20 does not simply have both the components (or functions) of the CCU 80 and wireless receiver 90, but is given functions that the CCU 80 and wireless receiver 90 do not have, as in the case of the imaging device 10. The configuration of such imaging device 10, CCU 20, etc. will be described below.

Figure 2 shows the configuration of the imaging device 10 used here and the transmitter 30 connected thereto. As mentioned above, control signals, return signals, TALLY signals, etc. used to control the imaging device 10 are also exchanged between the transmitter 30 and the imaging device 10, but here, the components related only to such signals (signals related to control) other than the video signal and return video signal are omitted, and the flow of such signals is also omitted. These signals are transmitted between the imaging device 10 and the CCU 20 using the same communication method as the return video signal and video signal. The flow of these signals within the imaging device 10 is different from that of video signals, etc., but in this respect there is no difference from the conventional case (Figures 7 (a) (b)).

As described above, a video signal converted to an SDI signal from the imaging device 10 is input to the transmitter 30, which supports wireless communication (wireless LAN). This signal is IP converted by the encoder 31 to an IP signal and transmitted to the CCU 20 side via the wireless LAN. Conversely, the transmitter 30 receives a return video signal converted to an IP signal from the CCU 20 side, and the decoder 32 IP converts this to a return video signal (SDI signal) and transmits it to the imaging device 10 side.

In the imaging device 10, light that passes through the optical system 11 is captured by the imaging element 12 to generate a video signal, which is an electrical signal. This video signal is input to the signal input/output unit 14 via the signal processing unit 13, and is output from the signal input/output unit 14 with an appropriate intensity. This video signal is also input to the viewfinder 15, which is a display adjacent to the imaging device 10, allowing the cameraman operating the imaging device 10 to visually view the image generated by this video signal.

As described above, the return video signal is input to the imaging device 10 from the CCU 20 via the transmitter 30. This return video signal is also input to the viewfinder 15 via the signal processing unit 13 and the signal input/output unit 14. The cameraman can switch between the video signal and the video image based on the return video signal as appropriate, or split the screen to view them on the viewfinder 15.

Also provided is a video recording device (video recording section) 16, which is a storage medium (hard disk, non-volatile memory, etc.) that records (stores) the video signal. For this reason, the video signal is also input from the signal input/output section 14 to the video recording device 16 as a recording signal. However, this recording is not performed all the time, but is recorded only during periods that are deemed necessary. For this reason, the video recording device 16 does not need to have a large storage capacity, and the video recording device 16 can be made smaller. For this reason, although the video recording device 16 is separate from the imaging device 10 in FIG. 2, the video recording device 16 may be provided within the imaging device 10. The same applies to the viewfinder 15.

As described above, since the camera system 1 also operates as an optical system camera, the signal input/output unit 14 outputs a video signal (SDI signal) as an optical signal via the optical composite cable 81, and the signal input/output unit 14 also receives a return video signal via the optical composite cable 81. However, here, a reception level detection unit 17 for recognizing the reception strength (reception level) of the optical signal is provided on the path for receiving the return video signal. Therefore, the signal input/output unit 14 can select either the return video signal obtained by wired communication via the optical composite cable 81 or the return video signal by wireless communication via the transmitter 30 (decoder 32) according to the reception level recognized by the reception level detection unit 17, and output it to the signal processing unit 13. Therefore, the signal input/output unit 14 can set whether to use the return video signal obtained by wired communication or wireless communication according to the reception level recognized for the wired communication. In other words, the signal input/output unit 14 also functions as an imaging device side communication switching unit that switches the communication means on the imaging device 10 side.

Whether or not the video signal is recorded in the video recording device 16 is determined by the video degradation determination circuit (signal degradation recognition unit: imaging device side signal degradation recognition unit) 131 provided in the signal processing unit 13 analyzing the input return video signal and recognizing the presence or absence of degradation in the return video. If degradation is recognized, a recording start trigger code (trigger code signal) is generated by the trigger generation circuit (trigger generation unit) 132, and if it is recognized that the degradation has disappeared after that, a recording end trigger code (trigger code signal) is generated by the trigger generation circuit 132. The specific content of the degradation of the return video signal evaluated here will be described later. The recording start trigger code and recording end trigger code are superimposed on the video signal by the synthesis unit 133 and input to the signal input/output unit 14 as a recording signal separate from the video signal output to the transmitter 30 side, and this recording signal is input to the video recording device 16 side. The video recording device 16 recognizes the recording start trigger code, recording end trigger code, and video signal in this recording signal, and can select and record the video signal between when the recording start trigger code is generated and when the recording end trigger code is generated. The recorded video signal can then be transmitted from the imaging device 10 to the CCU 20 while communication with the CCU 20 is good.

If the currently available return video signal is obtained from the transmitter 30 (decoder 32), this degradation occurs due to the degradation of the communication conditions when it is transmitted to the imaging device 10 side by wireless LAN. However, as described later, in reality, depending on the communication conditions, the return video signal itself does not degrade, but when degradation is recognized in the video signal obtained by the CCU 20 from the imaging device 10 side, such degradation may be added to the return video signal. For this reason, when degradation is recognized in either the return video signal on the imaging device 10 side or the video signal on the CCU 20 side, recording is performed by the video recording device 16. Similarly, when the currently available return video signal is obtained via the optical composite cable 81, there is degradation that occurs during transmission in the optical communication cable 81 and degradation that is added on the CCU 20 side as described above.

Figure 3 shows the configuration of the CCU (control unit) 20 in correspondence with Figure 2. On the imaging device 10 side of the CCU 20 (left side in the figure), an IP conversion unit 21 is provided that performs IP conversion of video signals and return video signals in correspondence with the transmitter 30. In the IP conversion unit 21, a decoder 21A that converts a video signal received as an IP signal into an SDI signal, and an encoder 21B that converts a return video signal that has been made an SDI signal into an IP signal, are provided in correspondence with the encoder 31 and decoder 32. In addition, on the opposite side of the CCU 20 from the imaging device 10 (right side in the figure), a signal input/output unit 22 is provided for outputting a video signal to the outside and obtaining a return video signal from the outside.

The CCU 20 is also provided with a signal processing unit 23 corresponding to the signal processing unit 13 in the imaging device 10. The signal processing unit 23 receives a video signal from the imaging device 10 (left side in the figure) and a return video signal from the signal input/output unit 22 (right side in the figure). As with the return video signal in the signal input/output unit 14 in the imaging device 10, the signal switching unit (controller side communication switching unit) 24 selects either the video signal via the IP conversion unit 21 (decoder 21A) or the video signal input via the optical composite cable 81 as the video signal. As with the case of the signal input/output unit 14, a reception level detection unit 25 that recognizes the reception level of the video signal is provided between the optical composite cable 81, which is the path of the video signal, and the signal switching unit 24. Therefore, depending on the recognized reception level, the signal switching unit 24 can recognize whether to use the video signal obtained by wired communication or wireless communication depending on the recognized reception level for wired communication.

In the signal processing unit 23, the input video signal is branched into two paths, and one of these paths (the path at the bottom in the figure) is provided with a video degradation judgment circuit (signal degradation recognition unit: control device side signal degradation recognition unit) 231, which has a judgment function similar to that of the video degradation judgment circuit 131 in the imaging device 10. Therefore, it is the video signal input to the signal processing unit 23 that is evaluated for degradation here. In addition, the return video signal input from the signal input/output unit 22 to the signal processing unit 23 is branched into two paths in the signal processing unit 23, and one of these paths (the path at the bottom in the figure) is provided with a degradation adding circuit 232 that degrades the return video signal. Both of these two paths are input to a switch 233, and the selected path is connected to the signal switching unit 24. The switching operation by the switch 233 will be described later.

In this camera system 1, the video signal is transmitted from the imaging device 10 to the CCU 20, and the return video signal is transmitted from the CCU 20 to the imaging device 10. The route used for this is wired communication via an optical composite cable 81, or wireless communication via a wireless LAN. In the above configuration, the imaging device 10 can determine which of the return video signals should be used based on the reception level of the wired communication recognized by the reception level detection unit 17. Also, the CCU 20 can determine which of the video signals should be used based on the reception level of the wired communication recognized by the reception level detection unit 25. Depending on the result of this determination, the communication means for receiving the video signal and the return video signal can be switched between wired communication and wireless communication.

Figure 4 is a flowchart showing an example of this switching operation when the CCU 20 receives a video signal in a case where wired communication is adopted in the default state. Here, first, the reception level in the current state (a state in which a video signal obtained by one communication (wired communication) is output to the signal processing unit 23 side) is evaluated by the reception level detection unit 25. The signal switching unit 24 judges whether this reception level is equal to or lower than a preset reference level (warning level) (S1). If the reception level is equal to or lower than the warning level (S1: Yes), it judges whether the other communication (wireless communication) is established (S2). This judgment can be made by the IP conversion unit 21 or the signal switching unit 24. If it is established (S2: Yes), the signal switching unit 24 switches the path of the video signal to be output to the signal processing unit 23 side to wireless communication (the other communication) (S3). If the reception level exceeds the warning level (S1: No) or the other communication (wireless communication) is not established (S2: No), communication switching is not performed.

A similar operation can be performed when receiving a return video signal on the imaging device 10 side. In this case, the reception level detection unit 17 is used instead of the reception level detection unit 25, and the signal input/output unit 14 is used instead of the signal switching unit 24. That is, such a communication means switching operation can be performed on either the CCU 20 or the imaging device 10 side. In addition, in the above configuration, the reception level detection units 25 and 17 are used to evaluate the reception level of wired communication, but by providing a means for evaluating the reception level of wireless communication in the wireless communication path, it is also possible to switch from wireless communication to wired communication in the same manner as above. This makes it possible to quickly and automatically switch to the other communication when a failure occurs in one communication.

Such operation of the signal switching unit 24 and the signal input/output unit 14 (communication switching unit) can lengthen the time during which communication is established, thereby preventing the loss of the video signal that should be received by the CCU 20 and the return video signal that should be received by the imaging device 10.

In addition, when a video signal or return video signal is transmitted between the imaging device 10 and the CCU 20, degradation of video quality may occur depending on the communication conditions. Such degradation is recognized by the video degradation determination circuit 131 for the return video signal on the imaging device 10 side, and by the video degradation determination circuit 231 for the video signal on the CCU 20 side.

The specific configuration of such image degradation determination circuits 131, 231 (signal degradation recognition units) will be described below. Figure 5 shows the configuration of the image degradation determination circuit 131 (231). Here, this degradation is performed by recognizing the total number of line start codes (start of line: sol) and line end codes (end of line: eol) corresponding to each line of the effective pixel area in the return image (image). For example, if the number of lines in the effective pixel area in the image is 1100, the number of sols and the number of eols in one frame are 1100, respectively, and the total number of these is 2200.

5, a sol detection circuit 41 that outputs a pulse when sol is recognized, and an eol detection circuit 42 that outputs a pulse when eol is recognized are used, and the output pulses of an OR circuit 43 that receives these as inputs are counted by a counter 44. When this counting is performed for each frame, if all sol and eol are recognized, this number (count value) will be 2200 in the above case. If a part of sol and eol is missing due to deterioration of the return video signal (video signal), an image cannot be obtained properly in this frame, and the count value will be smaller than 2200. Therefore, the count value is compared with its reference value (2200 in the above case) by a comparator 45, and the comparator 45 can output the result of the judgment of the presence or absence of deterioration as a judgment signal (deterioration judgment signal). The deterioration judgment signal can be, for example, a 1-bit signal in which the count value = reference value (no deterioration) is "0" and the count value < reference value (deterioration) is "1".

The operation of the trigger generation circuit 132 using this deterioration determination signal in the imaging device 10 will be described. FIG. 6 is a diagram showing the configuration of the trigger generation circuit 132. Here, trigger codes for instructing the start and end of recording are generated as described above. The start recording trigger code, which is issued when it is recognized that deterioration has occurred, is generated by the start recording trigger code generation unit 51, and the end recording trigger code, which is issued when it is recognized that this deterioration has disappeared, is generated by the end recording trigger code generation unit 52. The start recording trigger code and the end recording trigger code are output when the switches 53 and 54 are turned on, respectively. The specific contents of the start recording trigger code and the end recording trigger code can be set appropriately as long as they can be superimposed on the video signal by the synthesis unit 133.

When the deterioration judgment signal is set as described above, the switch 53 is turned on when the deterioration judgment signal is "1". That is, when it is recognized that there is deterioration in the return video signal, the recording start trigger code is output. On the other hand, the deterioration judgment signal is also input to the recovery judgment circuit 55, which recognizes the change of the deterioration judgment signal from "1" to "0". When this change is recognized, the recovery judgment circuit 55 turns on the switch 54 to output the recording end trigger code. Since the deterioration judgment signal is generated for each frame, these operations are also performed for each frame. The recording start trigger code and the recording end trigger code are not generated at the same time, but are input to the OR circuit 56, and the output is input to the synthesis unit 133 as a trigger code signal (recording start trigger code or recording end trigger code), which is superimposed on the video signal and input to the video recording device 16 as a recording signal. The video recording device 16 can recognize and store the video signal from when the recording start trigger code is recognized to when the recording end trigger code is recognized. It is also possible to use the video signal and the signal indicating the period of time to be recorded in the video signal separately, rather than generating a recording signal in which the trigger code signal and video signal are superimposed in this way. However, by using a recording signal in which the two are superimposed in this way, the configuration of the video recording device 16 can be simplified.

The end recording trigger code is issued after the start recording trigger code, but the above-mentioned switch between wired and wireless communication may occur after the start recording trigger code is issued. In this case, when degradation of the return video signal is recognized when one of wired or wireless communication is used, and then the communication method is switched to the other method, the end recording trigger code is issued when the degradation of the return video signal disappears. For this reason, the video signal is recorded for a period before and after the timing of the switch in communication method.

As described above, the video signal that the CCU 20 transmits to the outside is obtained from the imaging device 10 by a selected communication method, either wired communication or wireless communication. If degradation is found in the return video signal received by the imaging device 10 by one of these communications, there is a high probability that the video signal received by the CCU 20 from the imaging device 10 is also degraded. In addition, if the communication situation changes gradually, there is a high possibility that the communication method will be switched after a short period of time due to a decrease in the reception level as described above. With the above configuration, the video signal that may be lost in such a case is stored in the video recording device 16. The stored video signal can then be transmitted from the imaging device 10 to the CCU 20 during a period of good communication conditions.

Here, the video signal is recorded in the video recording device 16 only during the period from when the recording start trigger code is issued until the recording end trigger code is issued, i.e., while degradation is recognized in the return video signal. This allows the data capacity of the video signal recorded in the video recording device 16 to be reduced to the minimum necessary. Note that in the imaging device 10, the video signal may be temporarily stored in a semiconductor memory or the like before it is transmitted from the signal input/output unit 14. In this case, the recording start trigger code can be added to the video signal before degradation is recognized in the return video signal, for example, several seconds before, to use it as a recording signal. This makes it possible to more reliably prevent the video signal from being lost when the communication means is switched.

In the above operation, the deterioration of the return video signal in the imaging device 10 is recognized, but as described above, this deterioration corresponds to a deterioration in the communication conditions from the CCU 20 to the imaging device 10. In contrast, the communication conditions from the CCU 20 to the imaging device 10 may be good (there is no deterioration in the return video signal), but the communication conditions from the imaging device 10 to the CCU 20 may deteriorate, causing the video signal received by the CCU 20 to deteriorate. In such cases, it is preferable to record the video signal in the video recording device 16 as described above, but it is generally difficult for the imaging device 10 to recognize such a situation.

In such a case, the signal processing unit 23 in the CCU 20 operates to record the video signal in the video recording device 16 on the imaging device 10 side. In FIG. 3, such degradation of the video signal on the CCU 20 side is recognized by the video degradation determination circuit 231 configured as shown in FIG. 5. That is, here, the presence or absence of degradation of the video signal is determined by the numbers of sol and eol, as in the case of the return video signal described above. In FIG. 3, when the degradation determination circuit 231 outputs "0" (no degradation), the switch 233 sets the upper path in the figure, so that the return video signal (normal return video signal) obtained by the signal input/output unit 22 is input directly to the signal switching unit 24. On the other hand, when the degradation determination circuit 231 outputs "1" (degraded), the switch 233 sets the path via the degradation adding circuit 232 on the lower side in the figure.

The degradation adding circuit 232 processes the return video signal so that the return video signal without degradation becomes a return video signal with degradation as described above. Specifically, at least one sol or eol in the frame at this point is removed. As a result, the processed return video signal (degradation added return video signal) is recognized by the imaging device 10 in the same way as a normal return video signal, and the degradation thus added is recognized by the video degradation determination circuit 131, which causes a degradation determination signal, a recording start trigger code, and a recording end trigger code to be issued in the same way as described above, and the video signal from when the recording start trigger code is issued to when the recording end trigger code is issued is recorded in the video recording device 16 in the same way as described above.

As described above, such operation of the signal processing unit 23 is particularly effective when there is degradation in the video signal received by the CCU 20 but no degradation in the return video signal received by the imaging device 10, thereby allowing the video signal while it is degraded to be reliably recorded by the video recording device 16.

In the above example, the above-mentioned recording start trigger code and recording end trigger code were used as trigger code signals for recording the video signal in the video recording device 16, but the specific content of the trigger code signal can be set as appropriate, so long as it can indicate the period during which recording should be performed in correspondence with the video signal. In this case, it is preferable that the trigger code signal be superimposed on the video signal as described above, since this simplifies the device configuration and clarifies the correspondence with the actual video signal.

In the above example, the degradation of the return video signal and video signal was recognized by the number of sol and eol, but the degradation may be evaluated by other measures. In this case, if the CCU (control unit) is able to add this degradation to the return video signal in the same way as above, the same operation as above is possible. The specific content of the degradation determination signal when this degradation is recognized can also be set appropriately. In the above example, wired and wireless communication were switched depending on the recognized reception level, but this switching may also be performed depending on the presence or absence of degradation of the received signal, or the degree of degradation.

Furthermore, in the above example, the communication means between the imaging device 10 and the CCU (control device) 20 are wired communication via an optical composite cable 81 and wireless communication via a wireless LAN, but the above configuration can be applied in the same way as long as two different types of communication methods are used.

REFERENCE SIGNS LIST 1 Camera system 8 Optical system camera 9 Wireless camera system 10, 70 Imaging device 11 Optical system 12 Imaging element 13, 23 Signal processing unit 14 Signal input/output unit (imaging device side communication switching unit)
15 Viewfinder 16 Video recording device (video recording section)
17, 25 Reception level detection unit 20, 80 Camera control unit (CCU: control device)
21 IP conversion unit 21A, 32 Decoder 21B, 31 Encoder 22 Signal input/output unit 24 Signal switching unit (control device side communication switching unit)
30, 91 transmitter 41 sol detection circuit 42 eol detection circuit 43, 56 OR circuit 44 counter 45 comparator 51 recording start trigger code generation unit 52 recording end trigger code generation unit 53, 54 switch 55 recovery determination circuit 81 optical composite cable 90 wireless receiver (control device)
131 Image degradation determination circuit (signal degradation recognition unit: imaging device side signal degradation recognition unit)
132 Trigger generation circuit (trigger generation unit)
133 Combining unit 231 Video degradation determination circuit (signal degradation recognition unit: control device side signal degradation recognition unit)
232 Degradation giving circuit 233 Switch

Claims (5)

A camera system comprising an imaging device that generates a video signal by imaging, and a control device that is connected to the imaging device by a communication means, wherein the video signal is transmitted from the imaging device to the control device by the communication means, and a return video signal used on the imaging device side is transmitted from the control device to the imaging device by the communication means,
Both wired communication and wireless communication can be used as the communication means,
a control device side communication switching unit for selectively setting either the wired communication or the wireless communication as the communication means when the control device receives the video signal;
an imaging device side communication switching unit for selectively setting either the wired communication or the wireless communication as the communication means when the imaging device receives the return video signal;
Each equipped ,
On the imaging device side,
a video recording unit that stores the video signal before and after the timing of switching the communication means by the imaging device side communication switching unit;
an imaging device side signal degradation recognition unit that recognizes degradation of the received return video signal;
Equipped with
The camera system according to claim 1, wherein the video recording section stores the video signal when the image capturing device side signal degradation recognition section recognizes degradation of the return video signal . On the imaging device side,
a trigger code signal indicating a timing for starting and ending the storage of the video signal in the video recording section, and a recording signal in which the trigger code signal is superimposed on the video signal are generated;
2. The camera system according to claim 1 , wherein the video recording unit receives the recording signal, recognizes the trigger code signal, recognizes a period during which the video signal should be stored, and stores the video signal. On the imaging device side,
The camera system according to claim 2, further comprising a trigger generation unit which generates the trigger code signal indicating the start of storage of the video signal when degradation is recognized by the image capture device side signal degradation recognition unit, and the end of the storage when the degradation is eliminated. The control device includes a control device side signal degradation recognition unit that recognizes degradation of the received video signal,
The camera system according to any one of claims 1 to 3 , characterized in that the control device degrades the return video signal to be transmitted to the imaging device side when degradation of the video signal is recognized by the control device side signal degradation recognition unit. The camera system according to any one of claims 1 to 4 , characterized in that at least one of the control device side communication switching unit and the imaging device side communication switching unit switches the communication means depending on a reception level in the communication means.

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