JP4373254B2 - Image compression apparatus for controlling amount of compressed data and camera using the same - Google Patents

Description

  The present invention relates to an image compression apparatus that compresses the data amount of a video signal, and more particularly to an image compression apparatus and a camera that are suitable for application to a plurality of surveillance cameras connected to a network.

  With the development of network technology in recent years, surveillance camera systems have become larger. That is, in the conventional system, one opposing camera and monitor are connected by one coaxial cable, but a plurality of cameras and monitors are connected to one network cable by networking. In image transmission using a network, image compression is performed to effectively use a transmission band. There are various image compression techniques depending on the application, but there is typically a Moving Picture coding Experts Group (MPEG) method as a moving image compression method, and a typical JPEG (Joint Photographic image coding) as a still image compression method. Experts Group) method. A device that performs such image compression is generally installed in a surveillance camera.

  In surveillance camera systems, the moving image compression method is often used when importance is attached to the movement of an object shown in a video, and the still image compression method is often used when importance is attached to the resolution of one image. In particular, image data compressed by a still image compression method can be used as a substitute for a photograph for recording a necessary scene because a high-definition image can be recorded independently for each sheet.

  In addition, although the said prior art was described recognizing that the inventor was already known, since the appropriate literature was not found, description of prior art literature information is not described.

  As an example of the surveillance camera system, a system in which a sensor (for example, a sensor for detecting an intruder) is arranged so that an alarm signal from the sensor can be input to the camera is conceivable. In this case, usually, moving picture transmission is performed by a moving picture compression method. When the sensor reacts, still image compression is performed, and high-definition still image data is transmitted together with image transmission by moving image compression.

  An example of the configuration of a camera used in the above system is shown in FIG.

  The camera circuit 35 includes a moving image compression unit 2, a still image compression unit 8, a compression setting unit 30, a network transmission unit 31, a network reception unit 32, and a compressed data output selector 17.

  The moving image compression unit 2 receives a video signal 1 from a photoelectric conversion element (for example, a CCD (Charge Coupled Device) element) (not shown), performs moving image compression processing, and outputs moving image compression data 3. Also, the moving image compression setting data 6 is input from the compression setting unit 30 to set moving image compression processing relating to image quality, bit rate, and the like.

  The still image compression unit 8 receives the video signal 1, performs still image compression processing, and outputs still image compressed data 9. Further, the still image compression setting data 7 is input from the compression setting unit 30 to set the still image compression processing relating to the image quality, the target compression data amount, and the like.

  The compression setting unit 30 inputs the setting data 13 from the network receiving unit 32, analyzes the contents thereof, determines whether the setting data 13 is for a moving image or a still image, and compresses the moving image to the moving image compression processing unit 2. The setting data 6 is output, and the still image compression setting data 7 is output to the still image compression processing unit 8.

  The network transmission unit 31 receives the compressed moving image data 3 output from the moving image compression processing unit 2 and the selected still image compressed data 18 output from the compressed data output selector 17 only in the case described later. The transmission data 14 obtained by combining both data is output to the network 16.

  Since information for determining the compressed data is added to the transmission data 14, the receiving side can determine which compressed data is by analyzing the contents of the data.

  The network receiving unit 32 inputs the received data 15 from the network 16 and outputs it as the setting data 13 to the compression setting unit 30.

  The compressed data output selector 17 normally does not output the data to the network transmission unit 31 even if the still image compressed data 9 output from the still image compression unit 8 is input. However, when the alarm signal 4 is input from the outside of the camera, the still image compressed data 9 is selected, and the same data is output as the selected still image compressed data 18 to the network transmission unit 31. That is, during the normal operation, only the moving image compressed data 3 is input to the network transmission unit 31 and output to the network 16, but when the alarm signal 4 is input from the outside of the camera, the moving image compressed data 3 and the selected still image are selected. The compressed image data 18 is simultaneously input to the network transmission unit 31.

  A configuration example of a surveillance camera system using the camera is shown in FIG. In this system, two display terminals 23 and 24 monitor images 14a and 14b from two cameras 20 and 21 via a network 22, respectively.

  While the camera 20 and the camera 21 normally perform moving image transmission by moving image compression, they can simultaneously perform still image transmission by still image compression. The display terminal 23 and the display terminal 24 decompress the received moving image compressed data 3 and display the moving image on a monitor or the like.

  A sensor 25 is connected to the camera 20, and a sensor 26 is connected to the camera 21. When the sensor 25 reacts to the intruder 27, the alarm signal 4 is input to the connected camera 20. The camera 20 that has received the alarm signal 4 outputs the selected still image compressed data 18.

  Here, it is assumed that the transmission capacity of the network 16 is 4 Mbps (bits per second), the moving image compressed data output by one camera is 2 Mbps, and the still image compressed data is 1.5 Mbps. The total capacity of the transmission data output from the two cameras 20 and 21 cannot exceed the transmission capacity of the network 16. Accordingly, although the transmission capacity of 4 Mbps is full, the cameras 20 and 21 can simultaneously send compressed video data of 2 Mbps.

  Now, when the alarm signal 4 is input from the sensor connected to the camera 20 or 21, the camera 20 or 21 tries to output the selected still image compressed data 18 in addition to the moving image compressed data 3. However, since the transmission capacity is full for moving image transmission, a still image cannot be sent as it is. Accordingly, whether still image compressed data is output in preference to the moving image compressed data output by the camera 20, and the moving image compressed data used by the system has a smaller data amount (for example, 1.25 Mbps). The system may not output still image compressed data. However, if the data amount of the moving image compressed data is reduced, the image quality of the moving image is lowered or the frame rate of the image is lowered, so that the image quality of the moving image or the motion of the image is deteriorated. When still image compressed data is not output, a high-definition still image when an alarm signal is input cannot be transmitted, and the original purpose cannot be achieved.

  The above-described problem of the present invention is that a video signal is input and a data amount is compressed, thereby a moving image compression unit that outputs moving image compressed data, and a still image compressed data is compressed by compressing the data amount of the video signal. A still image compression unit that outputs, and a transmission unit that outputs transmission data having the still image compression data and the alarm signal when the alarm signal is input from the moving image compression data and an external sensor to an external network. The moving image compression unit can be effectively solved by an image compression device that changes the data amount of the moving image compression data when another alarm signal is input from the external network.

  If a surveillance camera system is configured using a camera equipped with the image compression device, the camera transmits an alarm signal to another camera connected to the same network when the alarm signal is input, and the amount of data output by the other camera is reduced. Restrict. As a result, the amount of transmission data of the camera input with an alarm is secured.

  By using the camera equipped with the image compression apparatus of the present invention, the monitoring image transmission performance at the time of alarm signal input can be maintained even when the transmission data amount of the camera is large and the transmission capacity of the network is not sufficient. A camera system can be realized.

  Hereinafter, an image compression apparatus in which the amount of compressed data according to the present invention is controlled and a camera using the same will be described in more detail with reference to embodiments shown in the drawings.

  FIG. 1 shows the configuration of the image compression apparatus of the present embodiment. The image compression apparatus includes a moving image compression unit 2, a still image compression unit 8, a compression setting unit 5, a network transmission unit 10, a network reception unit 11, and a compressed data output selector 17. The camera according to the present embodiment is configured by combining a lens unit and a photoelectric conversion unit (for example, a CCD) (not shown) with the image compression apparatus shown in FIG.

  A surveillance camera system can be configured using the camera of the present embodiment. Although details of this system will be described later, a sensor is arranged near or attached to the camera, and the sensor is connected to the camera. Examples of the sensor include a sensor for detecting an intruder and a smoke detector. The sensor generates an alarm signal when an object is detected. The alarm signal is input to the camera to which the sensor is connected.

  In FIG. 1, a moving image compression unit 2 receives the video signal 1 from the photoelectric conversion unit, performs moving image compression processing, and outputs moving image compressed data 3. Also, moving image compression setting data 6 is input from the compression setting unit 5 to set moving image compression processing relating to image quality, bit rate, and the like.

  The still image compression unit 8 receives the video signal 1, performs still image compression processing, and outputs still image compressed data 9. Further, the still image compression setting data 7 is input from the compression setting unit 5, and the setting of the still image compression processing relating to the image quality, the target compression data amount, and the like is performed.

  The compression setting unit 5 receives the alarm signal 12 in addition to the setting data 13 from the network receiving unit 11 and analyzes the contents of the alarm signal 12 and the setting data 13. From the analysis result, the moving image compression setting data 6 is output to the moving image compression processing unit 2, and the still image compression setting data 7 is output to the still image compression processing unit 8.

  The network transmission unit 10 receives the compressed moving image data 3 output from the moving image compression processing unit 2, and further receives the selected still image compressed data 18 output from the compressed data output selector 17 only when described later. The alarm signal 4 is input, and both data and the alarm signal 4 are output as transmission data 14 to the external network 16.

  Since the transmission data 14 is added with information for determining the compressed data and the alarm signal 4, the receiving side can determine which compressed data or the alarm signal 4 is by analyzing the contents of the data. Can do.

  The network receiving unit 11 inputs received data 15 from the network 16. The reception data 15 includes setting data 13 or an alarm signal 12. The setting data signal 13 is data transmitted from the receiving side to the camera, for example, when the receiving side monitor wants to change settings such as image quality and bit rate. The alarm signal 12 is a signal corresponding to the alarm signal 4 output from a camera having the same configuration as that of this embodiment connected to the network 16. The network receiving unit 11 outputs the setting data 13 or the alarm signal 12 extracted from the input received data 15 to the compression setting unit 30.

  The compressed data output selector 17 normally does not output the data to the network transmission unit 10 even if the still image compression data 9 output from the still image compression unit 8 is input. However, when the alarm signal 4 is input from the outside of the camera, the still image compressed data 9 is selected, and the same data is output as the selected still image compressed data 18 to the network transmission unit 31. That is, during the normal operation, only the moving image compressed data 3 is input to the network transmission unit 31 and output to the network 16, but when the alarm signal 4 is input from the outside of the camera, the moving image compressed data 3 and the selected still image are selected. The compressed image data 18 is simultaneously input to the network transmission unit 31. Although the alarm signal 4 is also input, since the data amount of the alarm signal 4 is very small, the influence on the data amount of the transmission data 14 is small.

  The output destination of the alarm signal 4 is a camera having the same configuration as that of the present embodiment connected to the network 16. Which camera the alarm signal is output to is set in advance in the network transmission unit 10.

  Accordingly, the network reception unit 11 receives an alarm signal from a similar camera connected to the network 16 by the reception data 15 and outputs it as the alarm signal 12 to the compression setting unit 5.

  When the alarm signal 12 is input to the compression setting unit 5, the compression setting unit 5 sets a moving image compression setting data 6 as a moving image compression setting data 6 as a moving image compression setting data 6. Output to the compression unit 2. In order to reduce the data amount of the moving image compressed data 3, for example, there are methods of deteriorating the image quality, lowering the frame rate, and reducing the image size to be compressed.

  A configuration example of a surveillance camera system using the above cameras is shown in FIG. The surveillance camera system monitors two camera images with two display terminals.

  The camera 20 and the camera 21 are both connected to the display terminal 23 and the display terminal 24 on the receiving side via the network 22. While the camera 20 and the camera 21 normally perform moving image transmission by moving image compression, they can simultaneously transmit still images by still image compression. The display terminal 23 and the display terminal 24 decompress the received moving image compressed data 3 and display the moving image on a monitor or the like. The display terminals 23 and 24 are, for example, personal computers incorporating image decompression software, and display the decompressed images on a personal computer monitor.

  A sensor 25 is connected to the camera 20, and a sensor 26 is connected to the camera 21. By inputting the alarm signal 4 when the sensor has reacted to the camera to which the sensor is connected, the camera outputs still image compression data 18.

  The sensors 25 and 26 have a function for cooperating with the cameras 20 and 21 and are of various types. For example, when the monitoring application is intruder detection, a sensor that outputs an alarm signal 4 when an object crosses the front is used. When the sensor generates an alarm signal 4, the intruder's figure is transmitted as a high-definition still image. In this system, the sensor 25 reacts to the intruder 27 to generate the alarm signal 4, and the camera 20 outputs the still image compressed data 18.

  Here, it is assumed that the transmission capacity of the network is 4 Mbps, the compressed moving image data output by one camera is 2 Mbps, and the compressed still image data is 1.5 Mbps.

  Usually, since the two cameras output the transmission data 14c and the transmission data 14d having the moving image compression data 3 of 2 Mbps, the total becomes 4 Mbps.

  When the alarm signal 4 is input from the sensor 25 connected to the camera 20, the camera 20 outputs the still image compressed data 18 by the input of the alarm signal 4, and at the same time, the alarm signal 4 is directed to the camera 21 connected to the same network 22. Send.

  The camera 21 to which the alarm signal 12 is input changes the moving image compression setting to a setting that reduces the data amount. In this example, it is assumed that the setting is made so that the data amount is reduced to ¼. With this change, the amount of data output to the network is 2 Mbps for the camera 20 and 0.5 Mbps for the camera 21, and a margin of 1.5 Mbps is generated for the transmission capacity of the network of 4 Mbps.

  At the same time, the camera 20 starts outputting the still image compression data 18 when the alarm signal 4 is input. Since the data amount of the still image compressed data 18 is 1.5 Mbps, the still image compressed data 18 can be transmitted using a 1.5 Mbps band that has an empty transmission capacity of the network 22.

  As described above, the still image compressed data 18 can be output by controlling the amount of data output from a camera other than the camera to which the alarm signal 4 is input from the sensor.

  The camera of this embodiment has a built-in moving image and still image compression processing function. However, the camera and the compression processing function are separated, and the camera is a camera that outputs an uncompressed image. It is possible to employ a configuration in which an image compression apparatus that inputs an uncompressed image and performs image compression processing is combined.

  In this description, the number of cameras used by the surveillance camera system is two. The control of the data amount of each camera when the number of cameras increases or when alarm signals are generated simultaneously from a plurality of sensors may be arbitrarily set according to the actual system setting status. For example, when the number of cameras further increases, moving image compressed data may not be transmitted to cameras other than the camera to which an alarm signal is input from the sensor. In addition, when alarm signals are generated simultaneously from multiple sensors, a predetermined transmission data amount is set according to the transmission capacity of the network and the number of cameras to which alarm signals are input from the sensors. It is possible to assign to each input camera.

  Further, in the above-described embodiment, the moving image transmission is normally performed and the still image transmission is performed only when an alarm signal is input from the sensor. However, the present invention is not limited to this. Image transmission may be performed, and moving image transmission may be performed only when an alarm signal is input from the sensor.

  In the above-described embodiment, for example, an alarm signal is input to the camera from an external sensor. However, the present invention is not limited to this, and for example, an intruding object can be obtained by image recognition processing from a video signal captured by the camera. It is good also as a structure which detects this and generates an alarm signal by this detection.

The block diagram for demonstrating embodiment of the image compression apparatus by which the compressed data amount which concerns on this invention is controlled, and a camera using the same. The block diagram for demonstrating the example of the surveillance camera system using the camera of FIG. The block diagram for demonstrating the image compression apparatus considered prior to this invention, and the camera using the same. The block diagram for demonstrating the example of the surveillance camera system using the camera of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Video input signal, 2 ... Moving image compression part, 3 ... Moving image compression data, 4 ... Alarm signal, 5 ... Compression setting part, 6 ... Moving image compression setting data, 7 ... Still image compression setting data, 8 ... Still Image compression unit, 9 ... still image compressed data, 10 ... network transmission unit, 11 ... network reception unit, 12 ... alarm signal, 13 ... setting data, 14 ... transmission data, 15 ... reception data, 16 ... network, 17 ... compression Data output selector, 18... Selected still image compressed data.

Claims (1)

A video compression unit that outputs video compression data by inputting a video signal and compressing the data amount;
A still image compression unit that compresses the data amount of the video signal and outputs still image compressed data;
A transmission unit that outputs transmission data including the moving image compression data, the still image compression data when an alarm signal is input from an external sensor, and the alarm signal to an external network;
The image compression apparatus, wherein the moving image compression unit changes a data amount of the moving image compression data when another alarm signal is input from the external network.

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