JP2012085125A - Network camera system, server, control method of the same, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erroneous detection by using a simple structure in image processing such as moving body detection associated with an operation of a universal head and a lens.SOLUTION: The state of a subject in image data is detected from image data from an imaging part. A driving instruction from a client to a server is received. While movement of the subject is detected as the state of the subject, the value of a flag is set to be ON when the driving instruction is received, and the value of the flag is set to be OFF when the driving instruction is not received. In accordance with the set value of the flag, it is restricted to provide the client with event information indicating that detection processing is under execution.

Description

  The present invention relates to an image distribution system and a control method therefor, and more particularly to a network camera system that distributes image data shot at a remote place via a network.

  Many network camera systems have been proposed in which images taken by a camera are distributed via a network such as the Internet or a LAN, and can be monitored by a remote client (computer terminal). In addition to monitoring the camera image, a system that enables the camera angle to be changed by remotely controlling the camera platform and lens, such as camera pan / tilt angle and zoom, is also widely known. It is.

  In addition, a system that makes it possible to shoot with increased sensitivity by automatically removing the infrared cut filter inside the lens at night is also a well-known technology.

  On the other hand, the photographed image data is analyzed for the state change of the object by image processing. By detecting a change in an image by detecting an image change by an inter-frame difference method, a background difference method, or the like and detecting a desired subject movement, it is possible to detect an event such as an intruder or leaving an object.

  There has been proposed a method for preventing erroneous detection of object motion detection caused by camera operations such as panning, tilting, and zooming. Patent Document 1 proposes a method of stopping the function of motion detection during acquisition of a background image or during pan, tilt, and zoom operations.

Japanese Patent No. 4396708

  Since the background image changes during driving of the pan / tilt head or the lens such as zoom and infrared cut filter, the moving object detection and the non-moving object detection result are incorrect. For this reason, in Patent Document 1, moving object detection is stopped during pan, tilt, and zoom operations.

  However, moving object detection is processed in a different part (moving object detection unit) from the control unit, and when moving object detection is stopped, a stop signal must be generated in synchronization with the image frame and supplied to the moving object detection unit. It must be complicated.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a network camera system and server that can prevent erroneous detection of image processing such as moving object detection associated with the operation of a pan head or a lens with a simple configuration. And its control method and program.

In order to achieve the above object, a network camera system according to the present invention comprises the following arrangement. That is,
A network camera system comprising a server including an imaging unit and a client for remotely controlling the imaging unit via a network,
The server
Detection means for detecting a state of a subject in the image data from the image data input by the imaging unit;
Receiving means for receiving a drive command for the server from the client;
When the detection unit detects the movement of the subject as the state of the subject and the reception unit receives the drive command, a flag value is set to ON, and the reception unit performs the drive. A setting means for setting the value of the flag to OFF when no command is received;
Limiting means for limiting notification to the client of event information indicating that detection processing is being performed by the detection means, in accordance with the value of the flag set by the setting means.

  According to the present invention, it is possible to provide a network camera system, a server, a control method therefor, and a program that can prevent erroneous detection of image processing such as motion detection accompanying the operation of a pan head or a lens with a simple configuration.

1 is a configuration diagram of a network camera system of Embodiment 1. FIG. 1 is a functional configuration diagram of a network camera system according to a first embodiment. 3 is a flowchart illustrating the operation of a flag according to the first embodiment. 10 is a flowchart illustrating the operation of a flag according to the second embodiment. 10 is a timing chart illustrating an operation of a flag according to the second embodiment.

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

<Embodiment 1>
FIG. 1 is a configuration diagram of a network camera system according to the first embodiment.

  The network camera system (image distribution system) includes a server 100 including an imaging unit 101 and a client 120 that can remotely control the imaging unit 101 via the server 100. In the server 100, the imaging unit 101 includes a control circuit (not shown) regarding zoom, focus, exposure, and the like, and automatically controls an optical system (lens and the like) to capture an optimal image. The camera platform 102 drives the imaging unit 101 in the pan and tilt directions to position it at a desired angle.

  The server 100 includes an image processing unit 103, an encoding unit 104, a CPU 105, a ROM 106, a RAM 107, a lens control unit 108, and a pan head control unit 109, which are connected through an internal bus. In addition, it has a function of transmitting image data and the state of the apparatus to the network 130 through the communication unit 110 and receiving a control signal.

  The encoding unit 104 encodes image data. Image data encoding methods include JPEG and H.264. Although there are methods such as H.264, the first embodiment does not depend on the encoding method. The client 120 can display images taken by the server 100 and can remotely control various states of the server 100.

  The lens control unit 108 controls an optical system (such as a lens) of the imaging unit 101 according to the control signal. The pan head control unit 109 controls driving of the pan head unit 102 according to the control signal.

  The client 120 is an information processing apparatus having a hardware configuration (CPU, RAM, ROM, storage device (hard disk), communication unit, display device, etc.) equivalent to the server 100 that is an information processing apparatus.

  Next, FIG. 2 shows functional blocks of hardware viewed from the viewpoint of imaging control processing and image processing. In other words, FIG. 2 shows the flow of image data and control signals in FIG. For this reason, blocks whose functions can be explained by the same expression as in FIG.

  The server 100 includes an imaging unit 101, a pan head unit 102, an image buffer 201, an encoding unit 104, a communication unit 110, a motion detection unit 202, a flag control unit 203, a lens control unit 108, and a pan head control unit 109. Here, the image buffer 201 is physically the RAM 107, and the motion detection unit 202, the flag control unit 203, the lens control unit 108, and the pan head control unit 109 are physically the CPU 105.

  The flow of image data will be described. First, image data is acquired from the imaging unit 101 and stored in the image buffer 201. The image data stored in the image buffer 201 is encoded by the encoding unit 104 and transmitted to the network 130 through the communication unit 110. The client 120 connected to the network 130 can receive the transmitted image data and display it on a display device or store it in a storage device. On the other hand, the image data is also transmitted from the image buffer 201 to the motion detection unit 202, where the image data motion detection processing is performed. By this motion detection processing, it is possible to detect the state of a subject (moving object, presence or absence of movement of a non-moving object, etc.) in image data.

  The image data motion detection process is performed based on, for example, a difference between image data. As the difference method, the difference method between adjacent frames and the background difference method are well known. As the difference calculation of the difference method between adjacent frames, the absolute value of the brightness difference of the pixels having the same coordinates, the absolute value sum of the differences of DCT coefficients in JPEG encoded block units, etc. are used, and these difference results are integrated for the attention area. There is a method in which there is a movement when the obtained value exceeds a predetermined threshold. However, the present invention does not depend on the motion detection method.

  The client 120 transmits a drive command for the camera platform 102 such as pan / tilt of the server 100 and a drive command for the imaging unit 101 such as zoom. A drive command for the pan head unit 102 is transmitted from the communication unit 110 via the flag control unit 203 and the pan head control unit 109. In addition, a drive command for the imaging unit 101 is transmitted from the communication unit 110 via the flag control unit 203 and the lens control unit 108.

  As described above, the server 100 receives the drive command for the drive unit (the imaging unit 101 and the camera platform 102) from the client 120, and the drive unit (the imaging unit 101 and the camera platform 102) according to the drive command. Drive.

  The flag control unit 203 determines whether or not the camera platform 102 is controlled by the client 120 during the subject motion detection process by the motion detection unit 202, and sets a flag value (ON / OFF) according to the determination result. And transmit the data to the encoding unit 104 or the communication unit 110.

  The first embodiment is characterized in that event information such as motion detection is controlled according to the flag information determined by the flag control unit 203, and this processing procedure will be described with reference to the flowchart of FIG.

  In step S <b> 301, the server 100 stores frame image data in the image buffer 201.

  In step S <b> 302, the server 100 causes the motion detection unit 202 to perform subject motion detection processing based on the background difference of the image data.

  In step S <b> 303, the server 100 uses the motion detection unit 202 to determine whether or not the subject has moved. If it is determined that there is no movement (NO in step S303), in step S307, the server 100 sets the flag to OFF in the flag control unit 203, and acquires the next frame image data in step S301.

  On the other hand, if it is determined in step S303 that the subject is moving (YES in step S303), the server 100 transmits motion detection information indicating that the motion of the subject is detected from the motion detection unit 202 to the flag control unit 203. To do.

  In step S304, the server 100 determines whether the pan / tilt driving is being performed by the flag control unit 203. That is, it receives a drive command for the camera platform 102 from the client 120, and determines whether the camera platform 102 is operating according to the drive command. When it is determined that the pan / tilt drive is not being performed (NO in step S304), in step S308, the server 100 transmits, to the client 120, event information indicating that the subject movement detection process is being performed. In step S307, the server 100 sets the flag to OFF in the flag control unit 203, and acquires the next frame image data in step S301.

  On the other hand, if it is determined in step S304 that the pan / tilt drive is being performed (YES in step S304), the flag control unit 203 sets the flag to ON in step S305. In step S306, since the flag state is ON, the server 100 stops transmitting event information indicating that the subject motion detection process is being performed to the client 120.

  As described above, according to the first embodiment, when the movement of the subject is detected, it is determined whether the pan / tilt is driven, and the pan / tilt driving (driving) is performed according to the determination result. The flag indicating the presence or absence of an instruction is controlled. Depending on the state of this flag, notification of event information to the client can be restricted.

  The present invention is not limited to the above embodiment. In the above-described embodiment, the notification of the event information indicating that the subject motion detection process is being performed is limited, but the present invention can also be applied to unmoving object detection such as leaving an object as image processing.

  In the above-described embodiment, the notification of event information is limited according to the state of the flag. However, the present invention is not limited to this. For example, it is possible to control the transmission of image data in accordance with the state of the flag, notify the client of flag information indicating the state of the flag, display the message, and store the flag information.

<Embodiment 2>
In the second embodiment, the flag is controlled according to the driving state of the camera platform 102 of the imaging unit 101 and the optical system (lens) of the imaging unit 101, and a predetermined delay time is applied to the flag control. Processing will be described.

  The system configuration of the second embodiment is the same as that described in the first embodiment with reference to FIGS. 1 and 2. Therefore, here, the procedure for controlling the flag will be described with reference to the flowchart of FIG.

  In step S <b> 401, the server 100 accumulates frame image data in the image buffer 201.

  In step S <b> 402, the server 100 causes the motion detection unit 202 to perform subject motion detection processing based on the background difference of the image data.

  In step S <b> 403, the server 100 uses the motion detection unit 202 to determine whether or not the subject is moving. If it is determined that there is no motion (NO in step S403), the next frame image data is acquired in step S401.

  On the other hand, when it is determined in step S403 that there is a subject motion (YES in step S403), the server 100 transmits motion detection information indicating that the subject motion is detected from the motion detection unit 202 to the flag control unit 203. To do.

  In step S404, the server 100 uses the flag control unit 203 to determine whether pan / tilt driving is in progress. That is, it receives a drive command for the camera platform 102 from the client 120, and determines whether the camera platform 102 is operating according to the drive command. If it is determined that the pan / tilt drive is selected (YES in step S404), the server 100 sets the flag to ON in the flag control unit 203 in step S410. In step S411, the server 100 stops transmitting event information indicating that the subject motion detection process is being performed to the client 120, and acquires the next frame image data in step S401.

  On the other hand, when it is determined in step S404 that pan / tilt is not being driven (NO in step S404), the server 100 determines whether the lens is being driven by the flag control unit 203 in step S405. That is, it receives a drive command for the imaging unit 101 from the client 120, and determines whether the imaging unit 101 is operating according to the drive command. Here, the lens driving means driving of a lens unit such as a zoom or an infrared cut filter of the imaging unit 101, that is, an optical system.

  When it is determined that the lens is being driven (YES in step S405), in step S410, the server 100 sets the flag to ON in the flag control unit 203. In step S411, the server 100 stops transmitting event information indicating that the subject motion detection process is being performed to the client, and in step S401, acquires the next frame image data.

  On the other hand, if it is determined in step S405 that the lens is not being driven (NO in step S405), it is determined in step S406 whether or not the flag is ON. If it is determined that the flag is OFF (YES in step S406), in step S409, the server 100 transmits event information indicating that the subject movement detection process is being performed to the client 120 in the communication unit 110.

  On the other hand, when it is determined in step S406 that the flag is ON (YES in step S406), in step S408, the server 100 determines whether or not a predetermined time has elapsed. If the predetermined time has not elapsed (NO in step S407), the process waits until the predetermined time elapses. On the other hand, if the predetermined time has elapsed (YES in step S407), the server 100 sets the flag to OFF in the flag control unit 203 in step S408. In step S <b> 409, the server 100 transmits event information indicating that the subject movement detection process is being performed by the communication unit 110 to the client 120.

  Next, the flag setting delay processing in step S407 will be described with reference to the timing chart of FIG.

  In FIG. 5, reference numeral 501 denotes a pan head control time, which is a pan / tilt drive control time determined in step S404. Reference numeral 502 denotes a lens control time, which is a lens drive control time determined in step S405. Reference numeral 503 denotes a flag which is turned OFF when both the pan head control and the lens control are stopped, but is turned OFF after a predetermined delay time 504 has elapsed when switching from ON to OFF. This delay time can be changed by setting a timer such as a timer included in the server 100. For example, the delay time can be set in consideration of a time for generating a background image necessary for motion detection.

  As described above, according to the second embodiment, in addition to the effects described in the first embodiment, it is possible to restrict notification of event information to the client while securing a time necessary for appropriate motion detection processing. It becomes possible.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (7)

A network camera system comprising a server including an imaging unit and a client for remotely controlling the imaging unit via a network,
The server
Detection means for detecting a state of a subject in the image data from the image data from the imaging unit;
Receiving means for receiving a drive command for the server from the client;
When the detection unit detects the movement of the subject as the state of the subject and the reception unit receives the drive command, a flag value is set to ON, and the reception unit performs the drive. A setting means for setting the value of the flag to OFF when no command is received;
A network camera system comprising: restriction means for restricting notification to the client of event information indicating that detection processing by the detection means is being performed according to a flag value set by the setting means . The server
According to the flag value set by the setting means, further comprising: transmission means for transmitting flag information indicating the value to the client;
The client
Receiving means for receiving the flag information;
The network camera system according to claim 1, further comprising display means for displaying a message of flag information received by the receiving means. The server
According to the flag value set by the setting means, further comprising: transmission means for transmitting flag information indicating the value to the client;
The client
Receiving means for receiving the flag information;
The network camera system according to claim 1, further comprising storage means for storing flag information received by the receiving means. It further comprises a time measuring means for setting the delay time,
The network camera system according to claim 1, wherein the setting unit sets the flag to OFF in accordance with the delay time set by the time measuring unit. A server in a network camera system comprising a server including an imaging unit and a client for remotely controlling the imaging unit via a network;
Detection means for detecting a state of a subject in the image data from the image data from the imaging unit;
Receiving means for receiving a drive command for the server from the client;
When the detection unit detects the movement of the subject as the state of the subject and the reception unit receives the drive command, a flag value is set to ON, and the reception unit performs the drive. A setting means for setting the value of the flag to OFF when no command is received;
And a restricting means for restricting notification to the client of event information indicating that detection processing by the detecting means is being performed in accordance with a flag value set by the setting means. A server control method in a network camera system comprising a server including an imaging unit and a client for remotely controlling the imaging unit via a network,
A detecting step for detecting a state of a subject in the image data from the image data from the imaging unit;
A receiving step for receiving a drive command for the server from the client;
If the setting means detects the movement of the subject as the state of the subject and the reception step receives the drive command, the setting means sets a flag value to ON and the reception A setting step of setting the value of the flag to OFF when the step does not receive the drive command;
A restricting unit comprising: a restricting step of restricting notification to the client of event information indicating that detection processing by the detecting step is being performed according to a value of the flag set in the setting step. Server control method. A server computer in a network camera system comprising a server including an imaging unit and a client for remotely controlling the imaging unit via a network;
Detection means for detecting a state of a subject in the image data from the image data from the imaging unit;
Receiving means for receiving a drive command for the server from the client;
When the detection unit detects the movement of the subject as the state of the subject and the reception unit receives the drive command, a flag value is set to ON, and the reception unit performs the drive. A setting means for setting the value of the flag to OFF when no command is received;
According to a flag value set by the setting unit, the program functions as a limiting unit that limits notification to the client of event information indicating that detection processing by the detection unit is being performed. .

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