JPWO2017068678A1 - Camera and code amount control program - Google Patents

Abstract

The camera system (100) includes a plurality of cameras (200) that generate encoded data (202) of video, and a video recording device (120) that records the encoded data of each of the plurality of cameras. The camera receives code amount information (204) for specifying the code amount of the encoded data generated by another camera. Next, the camera uses the code amount specified by the received code amount information to calculate a target amount that is a target of the code amount of its own encoded data. The camera then generates encoded data having a code amount close to the target amount by setting the target amount in its own encoder.

Description

  The present invention relates to a technique for stabilizing the code amount of video communicated by a camera system having a plurality of cameras.

In a conventional monitoring system using a large number of cameras, a control device that controls the entire system is provided.
Each camera requests permission from the control device to improve the image quality of the video, and the control device responds to each camera with permission or rejection in consideration of the request from each camera.
This improves the image quality of a specific camera while stabilizing the operation of the entire system.

  Patent Document 1 describes messages exchanged between each camera and the control device as means for constructing the monitoring system as described above.

  As described above, a conventional monitoring system requires a control device that controls the entire system. Each camera needs to request permission from the control device in order to improve the image quality of the video. Furthermore, it is necessary to design a message for exchanging between each camera and the control device.

JP 2000-0669455 A

  It is an object of the present invention to stabilize the code amount of video communicated by a camera system having a plurality of cameras.

The camera of the present invention is one of a plurality of cameras.
The camera
An image sensor for generating first video data;
An encoder that encodes the first video data according to a target amount to generate first encoded data;
A receiver that receives code amount information that specifies the code amount of other encoded data generated by another camera for each other camera of the plurality of cameras;
A target amount calculation unit that calculates a code amount target of the first encoded data as the target amount using the code amount specified by the received code amount information.

  According to the present invention, the code amount of the first encoded data can be adjusted according to the code amount of the other encoded data. Therefore, it is possible to stabilize the code amount of video communicated by the camera system.

1 is a configuration diagram of a camera system 100 according to Embodiment 1. FIG. FIG. 2 is a schematic diagram of a configuration of a camera 200 according to Embodiment 1. 2 is a configuration diagram of a camera 200 in Embodiment 1. FIG. 4 is a flowchart of a first code amount control method according to the first embodiment. 6 is a flowchart of target amount calculation processing (step S130) in the first embodiment. 5 is a flowchart of a second code amount control method according to the first embodiment. FIG. 6 is a configuration diagram of a camera 200 according to Embodiment 2. 10 is a flowchart of a first code amount control method according to the second embodiment. FIG. 10 is a configuration diagram of a camera 200 according to Embodiment 3. 10 is a flowchart of a first code amount control method according to Embodiment 3. 10 is a flowchart of a second code amount control method according to Embodiment 3. FIG. 10 is a configuration diagram of a camera 200 according to Embodiment 4. 10 is a flowchart of a first code amount control method according to the fourth embodiment. FIG. 10 is a configuration diagram of a camera 200 according to Embodiment 5. 10 is a flowchart of a first code amount control method according to the fifth embodiment. 10 is a flowchart of a second code amount control method according to the fifth embodiment. FIG. 10 is a configuration diagram of a camera 200 according to Embodiment 6. 18 is a flowchart of a first code amount control method according to the sixth embodiment. The hardware block diagram of the camera 200 in embodiment.

Embodiment 1 FIG.
A camera system 100 having a plurality of cameras 200 will be described with reference to FIGS.

*** Explanation of configuration ***
The configuration of the camera system 100 will be described with reference to FIG.
The camera system 100 includes a plurality of cameras 200, a hub 110 to which the plurality of cameras 200 are connected, and a video recording device 120 connected to the hub 110.
The camera system 100 can be used for a monitoring system or a security system.

The camera 200 is a photographing device that captures an image. Specifically, the camera 200 is a video camera that captures moving images.
The camera 200 transmits encoded data 202 generated by encoding video data to the video recording apparatus 120 via the hub 110. The encoded data 202 is compressed video data. The video is an image displayed on the display, and the video data is digital video data.
Further, the camera 200 communicates with other cameras 200 code amount information 204 that specifies the code amount of the encoded data 202. The code amount corresponds to the data amount of the encoded data 202.

The code amount of the encoded data 202 changes as the image changes. Specifically, when a person enters or exits the range captured by the camera 200, the code amount of the encoded data 202 increases or decreases.
Also, the code amount of the encoded data 202 can be adjusted by changing the encoding method for generating the encoded data 202. Specifically, the code amount of the encoded data 202 can be adjusted by changing the value of the quantization parameter or the macroblock type.

The hub 110 is a relay device that relays data.
The hub 110 receives the encoded data 202 transmitted from the camera 200 and transmits the received encoded data 202 to the video recording device 120.

The video recording device 120 is a device having a function of recording the encoded data 202. Specifically, the video recording device 120 is a viewer or a recorder.
The video recording device 120 receives the encoded data 202 transmitted from the hub 110 and records the received encoded data 202. The video recording apparatus 120 serving as a viewer restores an image using the encoded data 202 and displays the restored image on a display.

The configuration of the camera 200 will be described based on FIG.
The camera 200 includes hardware such as a computer 900, an image sensor 921, and an encoder 922.

The image sensor 921 generates video data 201. Specifically, the image sensor 921 is a CCD image sensor or a CMOS image sensor. CCD is an abbreviation for Charge-Coupled Device. CMOS is an abbreviation for Complementary MOS, and MOS is an abbreviation for Metal Oxide Semiconductor. Video data 201 is input to encoder 922.
The encoder 922 generates the encoded data 202 by encoding the video data 201 according to the target amount 205. The encoded data 202 is input to the computer 900.
The computer 900 transmits the encoded data 202 generated by the encoder 922 to the video recording device 120 via the hub 110. Further, the computer 900 transmits code amount information 204 for specifying the code amount of the encoded data 202 to the other camera 200. Further, the computer 900 receives the code amount information 204 from the other camera 200 and calculates a target amount 205 that is a target of the code amount of the encoded data 202. The target amount 205 is input to the encoder 922.

Based on FIG. 3, the configuration of a computer 900 provided in the camera 200 will be described.
The computer 900 includes hardware such as a processor 901, a memory 902, an auxiliary storage device 903, and a communication device 910. The processor 901 is connected to other hardware via a signal line.

The processor 901 is an IC (Integrated Circuit) that performs processing, and controls other hardware. Specifically, the processor 901 is a CPU, DSP, or GPU. CPU is an abbreviation for Central Processing Unit, DSP is an abbreviation for Digital Signal Processor, and GPU is an abbreviation for Graphics Processing Unit.
The memory 902 is a volatile storage device. The memory 902 is also called main memory or main memory. Specifically, the memory 902 is a RAM (Random Access Memory). The data stored in the memory 902 is saved in the auxiliary storage device 903 as necessary. The data saved in the auxiliary storage device 903 is loaded into the memory 902 as necessary. The memory 902 functions as a storage unit that stores data.
The auxiliary storage device 903 is a nonvolatile storage device. Specifically, the auxiliary storage device 906 is a ROM, HDD, or flash memory. ROM is an abbreviation for Read Only Memory, and HDD is an abbreviation for Hard Disk Drive. The auxiliary storage device 903 functions as a storage unit that stores data.
The communication device 910 includes a receiver 911 and a transmitter 912. Specifically, the communication device 910 is a communication chip or a NIC (Network Interface Card). The communication device 910 functions as a communication unit that communicates data, the receiver 911 functions as a reception unit that receives data, and the transmitter 912 functions as a transmission unit that transmits data.

The memory 902 stores data used, generated or input / output by the computer 900.
Specifically, the memory 902 stores a target total amount 291, an adjustment coefficient 292, a ratio coefficient 293, a code amount 203, and the like. The contents of each data will be described later.

The auxiliary storage device 903 stores programs that realize the functions of “units” such as a code amount calculation unit 210, a target amount calculation unit 221, a target amount setting unit 222, and a communication management unit 230. A program that realizes the function of “unit” is loaded into the memory 902 and executed by the processor 901. The function of “part” will be described later.
Further, the auxiliary storage device 906 stores an OS (Operating System).
At least a part of the OS is loaded into the memory 902, and the processor 901 executes a program that realizes the function of “unit” while executing the OS.
The computer 900 may include a plurality of processors 901, and the plurality of processors 901 may execute a program that realizes the function of “unit” in cooperation with each other.

A program that realizes the function of “unit” can be stored in a nonvolatile storage medium such as a magnetic disk, an optical disk, or a flash memory.
The result of the “part” processing is stored in the memory 902, the auxiliary storage device 903, a register in the processor 901, or a cache memory in the processor 901.

Hardware in which the processor 901, the memory 902, and the auxiliary storage device 903 are collected is referred to as a “processing circuit”.
“Part” may be read as “process”, “procedure”, or “processing”. The function of “unit” may be realized by firmware.

*** Explanation of operation ***
The operation of the camera 200 corresponds to a code amount control method. The procedure of the code amount control method corresponds to the procedure of the code amount control program. The code amount control method is a general term for the Xth code amount control method.

The procedure of the first code amount control method for controlling the code amount 203 of the first encoded data 202, which is the encoded data 202 generated by the encoder 922 in the camera 200, will be described based on FIG.
The procedure of the first code amount control method is executed every time code amount information 204 is transmitted from another camera 200.

Step S110 is information reception processing.
In step S <b> 110, the receiver 911 receives the code amount information 204 transmitted from the other camera 200.

Specifically, the other camera 200 transmits a packet including the code amount information 204 and a camera identifier for identifying itself to the network between the cameras by multicast. The packet includes a header and a payload, and the code amount information 204 and the camera identifier are set in the payload.
The code amount information 204 included in this packet is information for specifying the code amount 203 of the other encoded data 202 that is the encoded data 202 generated by the other camera 200.
In the first embodiment, the code amount information 204 of the other camera 200 is the code amount 203 of the other encoded data 202. The specific code amount 203 is a bit rate representing the data amount of the encoded data 202 to be transmitted. The bit rate indicates the number of bits per second.
The receiver 911 receives a packet including the code amount information 204 and the camera identifier.

Step S120 is a code amount storage process.
In step S120, the communication management unit 230 stores the code amount 203 of the other encoded data 202 in the memory 902.

Specifically, the code amount 203 of the other encoded data 202 is stored in the memory 902 as follows.
The communication management unit 230 acquires the code amount information 204 and the camera identifier of the other camera 200 from the received packet. The acquired code amount information 204 is the code amount 203 of the other encoded data 202.
Then, the communication management unit 230 stores the code amount 203 of the other encoded data 202 in the memory 902 in association with the camera identifier of the other camera 200. When the code amount 203 associated with the same camera identifier is already stored in the memory 902, the communication management unit 230 overwrites the code amount 203 stored in the memory 902 with the acquired code amount 203.

Step S130 is a target amount calculation process.
In step S130, the target amount calculation unit 221 calculates the target of the code amount 203 of the first encoded data 202 as the target amount 205, using the code amount 203 specified by the received code amount information 204. That is, the target amount calculation unit 221 calculates the target amount 205 using the code amount 203 of the other encoded data 202.

Specifically, the target amount calculation unit 221 calculates the target amount 205 using the target total amount 291 and the code amount of the other encoded data 202 for each of the other cameras 200.
The target total amount 291 is a target value of the total code amount of the first encoded data 202 and the other encoded data 202 for each other camera. Specifically, the target total amount 291 is a bit rate allowed for the entire camera system 100.

More specifically, the target amount calculation unit 221 calculates the target amount 205 using the target total amount 291, the code amount of the other encoded data 202 for each other camera 200, and the ratio coefficient 293.
The ratio coefficient 293 is a value indicating a target of the ratio of the code amount of the first encoded data 202 to the total code amount of the encoded data 202 of each of the plurality of cameras 200.

The details of the target amount calculation process (step S130) will be described with reference to FIG.
The memory 902 stores a code amount of the first encoded data 202 and a code amount 203 of other encoded data 202 for each of the other cameras 200.

  In step S131, the target amount calculation unit 221 calculates the current total amount by adding the code amount of the first encoded data 202 and the code amount of the other encoded data 202 for each of the other cameras 200. The current total amount is the sum of the code amount of the first encoded data 202 and the code amount of the other encoded data 202 for each of the other cameras 200. When the camera system 100 includes the first to third cameras 200, the current total amount includes the code amount of the encoded data 202 generated by the first camera 200 and the encoding generated by the second camera 200. This is the sum of the code amount of the data 202 and the code amount of the encoded data 202 generated by the third camera 200.

  In step S132, the target amount calculation unit 221 calculates a difference amount by subtracting the current total amount from the target total amount 291. The difference amount is a value obtained by subtracting the current total amount from the target total amount 291. That is, when the current total amount is smaller than the target total amount 291, the difference amount becomes a positive value. If the current total amount is larger than the target total amount 291, the difference amount becomes a negative value.

  In step S133, the target amount calculation unit 221 calculates the adjustment amount by multiplying the difference amount by the adjustment coefficient 292. The adjustment amount is a value obtained by multiplying the difference amount by the adjustment coefficient 292. The adjustment coefficient 292 is a positive coefficient for adjusting the difference amount. A specific adjustment coefficient 292 is 1/2. That is, the adjustment amount is ½ of the difference amount. When the difference amount is a positive value, the adjustment amount is a positive value, and when the difference amount is a negative value, the adjustment amount is a negative value.

  In step S134, the target amount calculation unit 221 calculates the adjustment total amount by adding the adjustment amount to the current total amount. The adjusted total amount is a value obtained by adding the adjusted amount to the current total amount.

  In step S135, the target amount calculation unit 221 calculates the target amount 205 by multiplying the adjustment total amount by the ratio coefficient 293. The target amount 205 is a value obtained by multiplying the adjustment total amount by the ratio coefficient 293. The specific ratio coefficient 293 can be expressed by 1 / N using the number N of cameras 200 included in the camera system 100. That is, when N = 3, the target amount 205 is 1/3 of the total adjustment amount.

Returning to FIG. 4, the description will be continued from step S140.
Step S140 is a target amount setting process.
In step S <b> 140, the target amount setting unit 222 sets the target amount 205 in the encoder 922.
Specifically, the target amount setting unit 222 generates a setting code including the target amount 205 and inputs the generated setting code to the encoder 922. Then, the encoder 922 overwrites the target amount 205 included in the input setting code with the target amount 205 set in the memory in the encoder 922.
After the target setting process (step S140), the encoder 922 generates the first encoded data 202 according to the newly set target amount 205.

  According to the first code amount control method described above, when the code amount 203 of the other encoded data 202 increases, the code amount 203 of the own encoded data 202 decreases and the code amount 203 of the other encoded data 202 decreases. When the code number decreases, the code amount 203 of its own encoded data 202 increases.

Based on FIG. 6, the procedure of the second code amount control method for controlling the code amount 203 of the other encoded data 202 will be described.
The procedure of the second code amount control method is executed every time the information transmission interval elapses. The information transmission interval is a predetermined time. A range in which the image sensor 921 in the camera 200 captures an image is referred to as a first capturing range.

Step S210 is a video data generation process.
In step S <b> 210, the image sensor 921 generates first video data 201 that is digital data of a video in which the first shooting range is reflected, and outputs the generated first video data 201. The output first video data 201 is input to the encoder 922.
The image sensor 921 generates and outputs the first video data 201 every time the shooting interval elapses. The shooting interval is a predetermined time. When the frame rate is 10 frames / second, the shooting interval is 0.1 seconds.
Since the operation of the image sensor 921 is the same as the operation of the conventional image sensor, the details of the video data generation process (step S210) will be omitted.

Step S220 is an encoded data generation process.
In step S220, the encoder 922 encodes the first video data 201 according to the target amount 205 to generate the first encoded data 202, and outputs the generated first encoded data 202. The output first encoded data 202 is input to the computer 900.
Specifically, the encoder 922 selects a quantization parameter value and a macroblock type according to the target amount 205 set in the memory in the encoder 922. Then, the encoder 922 encodes the first video data 201 using the selected quantization parameter value and macroblock type. Accordingly, encoded data 202 having a code amount close to the target amount 205 is generated as the first encoded data 202. The quantization parameter value is a quantization parameter value, and the macroblock type is a macroblock coding type.
The encoder 922 generates and inputs the first encoded data 202 every time the first video data 201 is input.
Since the operation of the encoder 922 is the same as the operation of the conventional encoder, the details of the encoded data generation process (step S220) will be omitted.

Step S230 is an encoded data transmission process.
In step S230, the transmitter 912 transmits the first encoded data 202 to the video recording device 120.

Specifically, the first encoded data 202 is transmitted as follows.
The communication management unit 230 generates a payload including the first encoded data 202, the shooting time, and the camera identifier, and inputs the generated payload to the transmitter 912. Specifically, the shooting time is the time when the first video data 201 is generated.
Then, the transmitter 912 generates a packet including the input payload, and transmits the generated packet to the video recording device 120 via the hub 110. The transmitted packet is received by the video recording device 120, and the first video data 201 is recorded in the video recording device 120 in association with the shooting time and the camera identifier.

Step S240 is a code amount calculation process.
In step S240, the code amount calculation unit 210 calculates the code amount 203 of the first encoded data 202. Specifically, the code amount calculation unit 210 calculates the bit rate of the first encoded data 202 as the code amount 203 of the first encoded data 202.
Then, the code amount calculation unit 210 stores the calculated code amount 203 in the memory 902 in association with the camera identifier of the camera 200. When the code amount 203 associated with the same camera identifier is already stored in the memory 902, the code amount calculation unit 210 overwrites the code amount 203 stored in the memory 902 with the calculated code amount 203.

Step S250 is information transmission processing.
In step S <b> 250, the transmitter 912 transmits the first code amount information 204 to the other camera 200.

Specifically, the first code amount information 204 is transmitted as follows. The first code amount information 204 is the code amount 203 of the first encoded data 202.
The communication management unit 230 generates a payload that includes the code amount 203 of the first encoded data 202 and the camera identifier of the camera 200, and inputs the generated payload to the transmitter 912.
Then, the transmitter 912 generates a packet including the input payload, and transmits the generated packet to the network between the cameras by multicast. The transmitted packet is received by each other camera 200.

  According to the second code amount control method described above, when the code amount 203 of its own encoded data 202 increases, the code amount 203 of the other encoded data 202 decreases and the code amount 203 of its own encoded data 202 decreases. When the number decreases, the code amount 203 of the other encoded data 202 increases.

*** Effect of the embodiment ***
The camera 200 decreases the code amount 203 of its own encoded data 202 when the code amount 203 of the other encoded data 202 increases, and changes its own amount when the code amount 203 of the other encoded data 202 decreases. The code amount 203 of the encoded data 202 can be increased. Further, the camera 200 decreases the code amount 203 of the other encoded data 202 when the code amount 203 of the own encoded data 202 increases, and decreases the code amount 203 of the own encoded data 202. The code amount 203 of the other encoded data 202 can be increased. Therefore, the camera 200 can stabilize the entire code amount of the encoded data 202 communicated by the camera system 100.
That is, the camera system 100 can stabilize the entire code amount without having a control device that controls the plurality of cameras 200. Therefore, it is not necessary to design a message exchanged between the plurality of cameras 200 and the control device.

*** Other configurations ***
The camera system 100 may include two cameras 200 or four or more cameras 200.
The camera 200 may transmit the encoded data 202 directly to the video recording device 120 without using the hub 110.
The encoded data 202 and the code amount information 204 may be communicated either by wire or wirelessly.
The first code amount control method and the second code amount control method may be executed at an arbitrary timing.
The target amount 205 may be calculated by a method different from the method described in the target amount calculation process (step S130).

Embodiment 2. FIG.
A mode in which the operation of the other camera 200 is stopped when the code amount 203 of the other encoded data 202 is abnormal will be described with reference to FIGS. 7 and 8. However, the description which overlaps with Embodiment 1 is abbreviate | omitted.

*** Explanation of configuration ***
Based on FIG. 7, the configuration of the camera 200 will be described.
The camera 200 includes a computer 900, an image sensor 921, and an encoder 922.
The computer 900 includes a processor 901, a memory 902, an auxiliary storage device 903, and a communication device 910.
The auxiliary storage device 903 includes a program that realizes the functions of “units” such as a code amount calculation unit 210, a target amount calculation unit 221, a target amount setting unit 222, a communication management unit 230, an abnormality detection unit 241, and a stop command unit 242. It is remembered. A program that realizes the function of “unit” is loaded into the memory 902 and executed by the processor 901.

*** Explanation of operation ***
A first code amount control method will be described with reference to FIG.
The method described based on FIG. 8 includes steps S111 and S112 in addition to steps S110 and S120 to S140 described in the first embodiment.

  In step S <b> 110, the receiver 911 receives a packet transmitted from another camera 200. The received packet includes code amount information 204. The code amount information 204 included in the received packet is the code amount 203 of the other encoded data 202.

Step S111 is an abnormality detection process.
In step S111, the abnormality detection unit 241 detects, as abnormality information, code amount information 204 that specifies an abnormal code amount.
Specifically, the abnormality detection unit 241 acquires the code amount 203 as the code amount information 204 from the received packet, and compares the acquired code amount 203 with a code amount threshold. When the code amount 203 is larger than the code amount threshold, the code amount information 204 included in the received packet is abnormality information. The code amount threshold is a predetermined value. A specific code amount threshold is ½ of the target total amount 291.
When the code amount information 204 is detected as abnormality information, the procedure of the first code amount control method proceeds to step S112.
If the code amount information 204 is not detected as abnormality information, the procedure of the first code amount control method proceeds to step S120.

Step S112 is a stop command process.
In step S112, the stop command unit 242 commands the other camera 200 corresponding to the abnormality information to stop the operation.

Specifically, the stop command unit 242 commands the other camera 200 corresponding to the abnormality information to stop the operation as follows.
The stop command unit 242 acquires a transmission source address from the received packet. In addition, the stop instruction unit 242 generates a payload including a stop instruction that instructs to stop the operation. Then, the stop command unit 242 inputs the generated payload and the acquired transmission source address to the transmitter 912.
The transmitter 912 generates a packet including the input payload, sets the transmission source address in the header of the generated packet, and transmits the packet to the network between the cameras. The transmitted packet is received by another camera 200 which is a transmission source of the packet including the abnormality information. Then, the other camera 200 stops its operation according to the stop command. Thereafter, the encoded data 202 and the code amount information 204 are not transmitted from the other cameras 200 that have stopped operating.

*** Effect of the embodiment ***
The camera 200 can stop the operation of the other camera 200 when the code amount 203 of the other encoded data 202 is abnormal. Therefore, the camera 200 can stabilize the entire code amount of the encoded data 202 communicated by the camera system 100.

Embodiment 3 FIG.
A form in which the quantization parameter value having a strong correlation with the code amount 203 is used as the code amount information 204 will be described with reference to FIGS. However, the description which overlaps with Embodiment 1 is abbreviate | omitted.

*** Explanation of configuration ***
Based on FIG. 9, the configuration of the camera 200 will be described.
The camera 200 includes a computer 900, an image sensor 921, and an encoder 922.
The computer 900 includes a processor 901, a memory 902, an auxiliary storage device 903, and a communication device 910.
The auxiliary storage device 903 stores programs that realize the functions of “units” such as a code amount calculation unit 210, a target amount calculation unit 221, a target amount setting unit 222, a communication management unit 230, and an information acquisition unit 250. A program that realizes the function of “unit” is loaded into the memory 902 and executed by the processor 901.

*** Explanation of operation ***
A first code amount control method will be described with reference to FIG.
The method described based on FIG. 10 includes step S121 in addition to step S110, step S130, and step S140 described in the first embodiment.

In step S <b> 110, the receiver 911 receives the code amount information 204 transmitted from the other camera 200.
In Embodiment 3, the code amount information 204 of the other camera 200 is a quantization parameter value used as a quantization parameter value when other encoded data 202 is generated.

Step S121 is a code amount calculation process.
In step S <b> 121, the code amount calculation unit 210 calculates the code amount 203 of the other encoded data 202 using the quantization parameter value that is the code amount information 204 of the other camera 200.

Specifically, the code amount calculation unit 210 calculates the code amount 203 of the other encoded data 202 by calculating the code amount function with the quantization parameter value that is the code amount information 204 of the other camera 200 as an input. .
The code amount function is a function in which an algorithm for calculating the code amount 203 using the quantization parameter value is defined. By calculating the code amount function, the code amount 203 having a magnitude inversely proportional to the magnitude of the quantization parameter value is calculated. That is, the larger the quantization parameter value, the smaller the code amount 203, and the smaller the quantization parameter value, the larger the code amount 203.

  Then, the code amount calculation unit 210 stores the code amount 203 of the other encoded data 202 in the memory 902, like the communication management unit 230 in step S120 in the first embodiment.

In step S <b> 130, the target amount calculation unit 221 calculates the target amount 205 using the code amount 203 of the other encoded data 202.
In step S <b> 140, the target amount setting unit 222 sets the target amount 205 in the encoder 922.

A second code amount control method will be described with reference to FIG.
The method described based on FIG. 11 includes step S261 in addition to steps S210 to S250 described in the first embodiment.

In step S210, the image sensor 921 generates first video data 201.
In step S <b> 220, the encoder 922 encodes the first video data 201 according to the target amount 205 to generate first encoded data 202.
In step S230, the transmitter 912 transmits the first encoded data 202 to the video recording device 120.
In step S240, the code amount calculation unit 210 calculates the code amount 203 of the first encoded data 202, and stores the calculated code amount 203 in the memory 902.
After step S240, the procedure of the second code amount control method proceeds to step S261.

Step S261 is information generation processing.
In step S261, the information acquisition unit 250 acquires the first code amount information 204.

Specifically, the first code amount information 204 is acquired as follows. The first code amount information 204 is a quantization parameter value used as a quantization parameter value when the first encoded data 202 is generated.
The information acquisition unit 250 requests the encoder 922 for a quantization parameter value.
The encoder 922 returns the quantization parameter value set in the memory in the encoder 922 to the information acquisition unit 250.
Then, the information acquisition unit 250 receives the returned quantization parameter value.
After step S261, the procedure of the second code amount control method proceeds to step S250.

  In step S <b> 250, the transmitter 912 transmits the first code amount information 204 to the other camera 200.

*** Effect of the embodiment ***
The camera 200 can stabilize the entire code amount of the encoded data 202 communicated by the camera system 100, as in the first embodiment.

Embodiment 4 FIG.
A mode in which the operation of the other camera 200 is stopped when the code amount 203 of the other encoded data 202 is abnormal will be described with reference to FIGS. 12 and 13. However, the description which overlaps with Embodiment 3 is omitted.

*** Explanation of configuration ***
Based on FIG. 12, the configuration of the camera 200 will be described.
The camera 200 includes a computer 900, an image sensor 921, and an encoder 922.
The computer 900 includes a processor 901, a memory 902, an auxiliary storage device 903, and a communication device 910.
The auxiliary storage device 903 includes functions of “units” such as a code amount calculation unit 210, a target amount calculation unit 221, a target amount setting unit 222, a communication management unit 230, an abnormality detection unit 241, a stop command unit 242, and an information acquisition unit 250. A program for realizing is stored. A program that realizes the function of “unit” is loaded into the memory 902 and executed by the processor 901.

*** Explanation of operation ***
The first code amount control method will be described with reference to FIG.
The method described based on FIG. 13 includes step S113 and step S114 in addition to step S110 and steps S121 to S140 described in the third embodiment.

  In step S <b> 110, the receiver 911 receives a packet transmitted from another camera 200. The received packet includes code amount information 204. The code amount information 204 included in the received packet is a quantization parameter value used as a quantization parameter value when other encoded data 202 is generated.

Step S113 is an abnormality detection process.
In step S113, the abnormality detection unit 241 detects, as abnormality information, code amount information 204 that identifies an abnormal code amount.
Specifically, the abnormality detection unit 241 acquires a quantization parameter value that is the code amount information 204 from the received packet, and compares the acquired quantization parameter value with a parameter threshold value. When the quantization parameter value is smaller than the parameter threshold value, the code amount information 204 included in the received packet is abnormal information. The parameter threshold value is a predetermined value.
When the code amount information 204 is detected as abnormality information, the procedure of the first code amount control method proceeds to step S114.
If the code amount information 204 is not detected as abnormality information, the procedure of the first code amount control method proceeds to step S121.

Step S114 is a stop command process.
In step S114, the stop instruction unit 242 instructs the other camera 200 corresponding to the abnormality information to stop the operation.
This stop command process (step S114) is the same as the stop command process (step S112) described in the second embodiment.

*** Effect of the embodiment ***
Similarly to the second embodiment, the camera 200 can stabilize the entire code amount of the encoded data 202 communicated by the camera system 100.

Embodiment 5. FIG.
A mode in which a macroblock type having a strong correlation with the code amount 203 is used as the code amount information 204 will be described with reference to FIGS. However, the description which overlaps with Embodiment 1 is abbreviate | omitted.

*** Explanation of configuration ***
Based on FIG. 14, the configuration of the camera 200 will be described.
The camera 200 includes a computer 900, an image sensor 921, and an encoder 922.
The computer 900 includes a processor 901, a memory 902, an auxiliary storage device 903, and a communication device 910.
The auxiliary storage device 903 stores programs that realize the functions of “units” such as a code amount calculation unit 210, a target amount calculation unit 221, a target amount setting unit 222, a communication management unit 230, and an information acquisition unit 250. A program that realizes the function of “unit” is loaded into the memory 902 and executed by the processor 901.

*** Explanation of operation ***
The first code amount control method will be described based on FIG.
The method described based on FIG. 15 includes step S122 in addition to step S110, step S130, and step S140 described in the first embodiment.

In step S <b> 110, the receiver 911 receives the code amount information 204 transmitted from the other camera 200.
In the fifth embodiment, the code amount information 204 of the other camera 200 is a macroblock type used when other encoded data 202 is generated.

Step S122 is a code amount calculation process.
In step S <b> 122, the code amount calculation unit 210 calculates the code amount 203 of the other encoded data 202 using the macroblock type that is the code amount information 204 of the other camera 200.

Specifically, the code amount calculation unit 210 calculates the code amount 203 of the other encoded data 202 as follows.
Here, it is assumed that the type coefficient table and the reference amount are stored in the memory 902. The type coefficient table is a table including type coefficients associated with macroblock types. The reference amount is a reference code amount.

First, the code amount calculation unit 210 acquires a type coefficient associated with a macroblock type that is the code amount information 204 of another camera 200 from the type coefficient table.
Then, the code amount calculation unit 210 calculates the code amount 203 by multiplying the acquired type coefficient by the reference amount. The code amount 203 is a value obtained by multiplying the reference amount by the type coefficient.

  Then, the code amount calculation unit 210 stores the code amount 203 of the other encoded data 202 in the memory 902, like the communication management unit 230 in step S120 in the first embodiment.

In step S <b> 130, the target amount calculation unit 221 calculates the target amount 205 using the code amount 203 of the other encoded data 202.
In step S <b> 140, the target amount setting unit 222 sets the target amount 205 in the encoder 922.

Based on FIG. 16, the second code amount control method will be described.
The method described based on FIG. 16 includes step S262 in addition to steps S210 to S250 described in the first embodiment.

In step S210, the image sensor 921 generates first video data 201.
In step S <b> 220, the encoder 922 encodes the first video data 201 according to the target amount 205 to generate first encoded data 202.
In step S230, the transmitter 912 transmits the first encoded data 202 to the video recording device 120.
In step S240, the code amount calculation unit 210 calculates the code amount 203 of the first encoded data 202, and stores the calculated code amount 203 in the memory 902.
After step S240, the procedure of the second code amount control method proceeds to step S262.

Step S262 is information generation processing.
In step S262, the information acquisition unit 250 acquires the first code amount information 204.

Specifically, the first code amount information 204 is acquired as follows. The first code amount information 204 is a macroblock type used when the first encoded data 202 is generated.
The information acquisition unit 250 requests the encoder 922 for the macro block type.
The encoder 922 returns the macro block type set in the memory in the encoder 922 to the information acquisition unit 250.
Then, the information acquisition unit 250 receives the returned macro block type.
After step S262, the procedure of the second code amount control method proceeds to step S250.

  In step S <b> 250, the transmitter 912 transmits the first code amount information 204 to the other camera 200.

*** Effect of the embodiment ***
The camera 200 can stabilize the entire code amount of the encoded data 202 communicated by the camera system 100, as in the first embodiment.

Embodiment 6 FIG.
A mode in which the operation of the other camera 200 is stopped when the code amount 203 of the other encoded data 202 is abnormal will be described with reference to FIGS. 17 and 18. However, the description which overlaps with Embodiment 4 is abbreviate | omitted.

*** Explanation of configuration ***
The configuration of the camera 200 will be described based on FIG.
The camera 200 includes a computer 900, an image sensor 921, and an encoder 922.
The computer 900 includes a processor 901, a memory 902, an auxiliary storage device 903, and a communication device 910.
The auxiliary storage device 903 includes functions of “units” such as a code amount calculation unit 210, a target amount calculation unit 221, a target amount setting unit 222, a communication management unit 230, an abnormality detection unit 241, a stop command unit 242, and an information acquisition unit 250. A program for realizing is stored. A program that realizes the function of “unit” is loaded into the memory 902 and executed by the processor 901.

*** Explanation of operation ***
A first code amount control method will be described with reference to FIG.
The method described based on FIG. 18 includes steps S115 and S116 in addition to steps S110 and S122 to S140 described in the sixth embodiment.

  In step S <b> 110, the receiver 911 receives a packet transmitted from another camera 200. The received packet includes code amount information 204. The code amount information 204 included in the received packet is a macroblock type used when other encoded data 202 is generated.

Step S115 is an abnormality detection process.
In step S115, the abnormality detection unit 241 detects code amount information 204 that identifies an abnormal code amount as abnormality information.
Specifically, the abnormality detection unit 241 acquires the macroblock type that is the code amount information 204 from the received packet, and compares the acquired macroblock type with the abnormal type. When the macroblock type is the same as the abnormal type, the code amount information 204 included in the received packet is abnormal information. The abnormal type is a macroblock type used when encoded data 202 having an abnormal code amount is generated.
When the code amount information 204 is detected as abnormality information, the procedure of the first code amount control method proceeds to step S116.
If the code amount information 204 is not detected as abnormality information, the procedure of the first code amount control method proceeds to step S122.

Step S116 is a stop command process.
In step S116, the stop command unit 242 commands the other camera 200 corresponding to the abnormality information to stop the operation.
This stop command process (step S116) is the same as the stop command process (step S112) described in the second embodiment.

*** Effect of the embodiment ***
Similarly to the second embodiment, the camera 200 can stabilize the entire code amount of the encoded data 202 communicated by the camera system 100.

Each embodiment is an example of a preferred embodiment and is not intended to limit the technical scope of the present invention. Each embodiment may be implemented partially or in combination with other embodiments. Specifically, in Embodiments 2, 4, and 6, the processor 901 of the camera 200 may not function as the target amount calculation unit 221 and the target amount setting unit 222.
The procedure described using the flowcharts is an example of the procedure of the camera, the code amount control method, and the code amount control program.

In each embodiment, the function of the camera 200 may be realized by hardware.
FIG. 19 shows a configuration when the function of the camera 200 is realized by hardware.
The camera 200 includes a processing circuit 990. The processing circuit 990 is also called a processing circuit.
The processing circuit 990 is a dedicated electronic circuit that realizes the function of the “unit” described in each embodiment. The “unit” includes a memory unit that functions as the memory 902 and the auxiliary storage device 903.
Specifically, the processing circuit 990 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an ASIC, an FPGA, or a combination thereof. GA is an abbreviation for Gate Array, ASIC is an abbreviation for Application Specific Integrated Circuit, and FPGA is an abbreviation for Field Programmable Gate Array.
The camera 200 may include a plurality of processing circuits 990, and the plurality of processing circuits 990 may realize the function of “unit” in cooperation.

  The function of the camera 200 may be realized by a combination of software and hardware. That is, a part of “part” may be realized by software, and the rest of “part” may be realized by hardware.

  100 camera system, 110 hub, 120 video recording device, 200 camera, 201 video data, 202 encoded data, 203 code amount, 204 code amount information, 205 target amount, 210 code amount calculation unit, 221 target amount calculation unit, 222 Target amount setting unit, 230 communication management unit, 241 abnormality detection unit, 242 stop command unit, 250 information acquisition unit, 291 target total amount, 292 adjustment coefficient, 293 ratio coefficient, 900 computer, 901 processor, 902 memory, 903 auxiliary storage Device, 910 communication device, 911 receiver, 912 transmitter, 990 processing circuit.

Claims (11)

One of a plurality of cameras,
An image sensor for generating first video data;
An encoder that encodes the first video data according to a target amount to generate first encoded data;
A receiver that receives code amount information that specifies the code amount of other encoded data generated by another camera for each other camera of the plurality of cameras;
A camera comprising: a target amount calculation unit that calculates a code amount target of the first encoded data as the target amount using a code amount specified by the received code amount information. The code amount information is a code amount of the other encoded data,
The target amount calculation unit includes a target total amount that is a target of a total code amount of the first encoded data and other encoded data for each other camera, and other encoded data for each other camera. The camera according to claim 1, wherein the target amount is calculated using a code amount. The target amount calculation unit includes the first encoding for the target total amount, the code amount of other encoded data for each of the other cameras, and the total code amount of the encoded data of each of the plurality of cameras. The camera according to claim 2, wherein the target amount is calculated using a ratio coefficient indicating a target of the ratio of the data code amount. The code amount information is a quantization parameter value used as a quantization parameter value when the other encoded data is generated,
The camera includes a code amount calculation unit that calculates a code amount of other encoded data using a quantization parameter value for each other camera,
The target amount calculation unit includes a target total amount that is a target of a total code amount of the first encoded data and other encoded data for each other camera, and other encoded data for each other camera. The camera according to claim 1, wherein the target amount is calculated using a code amount. The target amount calculation unit includes the first encoding for the target total amount, the code amount of other encoded data for each of the other cameras, and the total code amount of the encoded data of each of the plurality of cameras. The camera according to claim 4, wherein the target amount is calculated using a ratio coefficient indicating a target of the ratio of the data code amount. The code amount information is a macroblock type used when the other encoded data is generated,
The camera includes a code amount calculation unit that calculates a code amount of other encoded data using a macroblock type for each other camera,
The target amount calculation unit includes a target total amount that is a target of a total code amount of the first encoded data and other encoded data for each other camera, and other encoded data for each other camera. The camera according to claim 1, wherein the target amount is calculated using a code amount. The target amount calculation unit includes the first encoding for the target total amount, the code amount of other encoded data for each of the other cameras, and the total code amount of the encoded data of each of the plurality of cameras. The camera according to claim 6, wherein the target amount is calculated using a ratio coefficient indicating a target of the ratio of the data code amount. Among the received code amount information, an abnormality detection unit that detects, as abnormality information, code amount information that identifies an abnormal code amount;
The camera according to claim 1, further comprising: a stop command unit that commands other cameras corresponding to the abnormality information to stop the operation. One of a plurality of cameras,
A receiver that receives code amount information that specifies the code amount of other encoded data generated by another camera for each other camera of the plurality of cameras;
Among the received code amount information, an abnormality detection unit that detects, as abnormality information, code amount information that identifies an abnormal code amount;
A camera comprising: a stop command unit that commands other cameras corresponding to the abnormality information to stop the operation. An image sensor for generating first video data;
An encoder that encodes the first video data according to a target amount to generate first encoded data;
For each other camera, a receiver that receives code amount information that specifies the code amount of other encoded data generated by the other camera;
A code amount control program for a camera comprising a computer,
Code amount control for causing the computer to execute a target amount calculation process for calculating the target of the code amount of the first encoded data as the target amount using the code amount specified by the received code amount information program. For each other camera, a receiver that receives code amount information that specifies the code amount of other encoded data generated by the other camera;
A camera control program for a camera comprising a computer,
Among the received code amount information, an abnormality detection process for detecting, as abnormality information, code amount information that identifies an abnormal code amount;
A code amount control program for causing the computer to execute stop command processing for instructing another camera corresponding to the abnormality information to stop operation.

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