JP5131954B2 - Video recorder and camera system - Google Patents

Description

  The present invention relates to a technology that enables storage and live display of video captured by a camera on a video recorder.

  2. Description of the Related Art Conventionally, CCTV (Closed Circuit Television) type camera systems are widely used for surveillance camera applications and the like.

  In the CCTV camera system, an image captured by the CCTV camera can be transmitted to a video recorder, and the video recorder can store the image or display it live on a display device such as a CRT (Cathode-ray Tube) or liquid crystal.

  Up to now, analog CCTV cameras that convert and output video captured by an imaging device such as a CCD (Charge Coupled Device) into, for example, NTSC (National Television System Committee) video have been widely used.

  Many analog CCTV cameras output video signals captured at 30 fps (frame per second). In live display in which video captured by a CCTV camera is displayed almost in real time, video at 30 fps is used. In order to reduce the recording capacity, the video to be recorded and stored is often used with a frame rate lower than that of live display, such as 10 fps.

  Since the analog CCTV camera always outputs a video signal of 30 fps, it is possible to suppress the frame rate of the video to be recorded and saved by thinning out a part of this video signal while performing live display at 30 fps.

  On the other hand, with the development of computer devices and network environments, digital CCTV cameras that output digital data such as JPEG (Joint Photographic Experts Group) and MPEG (Moving Picture Experts Group) are increasing recently. .

  Digital CCTV cameras have various advantages over conventional analog systems.

  For example, there is no worry that the recorded video will deteriorate. In addition, since connection using a network is possible, introduction, management, maintenance, and the like are easy. It is also possible to easily distribute captured images using the Internet, analyze imaging data to detect abnormalities, and notify users using e-mail when abnormalities are detected. .

  In the digital CCTV camera that outputs still image data such as JPEG, a 30fps still image is output, and a 30fps video is displayed live as in the case of a conventional analog CCTV camera. Still images can be recorded and saved.

  Therefore, it is possible to obtain the advantage as digital data while realizing the same usage method as the conventional analog CCTV system.

  As techniques related to the present invention, techniques using two compression methods are disclosed in Patent Document 1 and Patent Document 2.

Japanese Patent Laid-Open No. 2005-247461 JP 2005-244762 A

  However, still image data such as JPEG has a large data capacity and a high load on the network that transmits the data.

  Since a plurality of CCTV cameras are often used, it is necessary to effectively use a limited communication band.

  For this purpose, it is advantageous to use moving image data such as MPEG that can output data having a smaller data capacity while maintaining the same image quality as a still image.

  However, a digital CCTV camera that outputs moving image data such as MPEG compresses and encodes a video imaged at 30 fps by taking a difference between frames.

  For this reason, for example, 10 fps moving image data cannot be recorded and saved by a process that simply thins out part of the frame data as in the case of still image data. Specifically, it is necessary to perform a process of once decompressing and decoding a video that has been compression-encoded in the MPEG format, thinning out some frame data, and then compression-encoding it again.

  Therefore, there is a problem that the processing load on the video recorder for recording the captured video increases even if the data capacity is reduced and the load on the network is suppressed.

  In order to solve this, a moving image of, for example, 10 fps to be recorded and saved on the video recorder side on the digital CCTV camera side may be generated, and this may be recorded and saved as it is on the recorder side.

  According to this method, the advantage as digital data can be used, and the load on all of the processing in the digital CCTV camera, the network bandwidth, and the processing in the video recorder can be suppressed.

  However, in this case, there is a problem that the video displayed live is also 10 fps.

  As described above, the conventional analog CCTV camera system can record and save at 10 fps while displaying live at 30 fps, but if a new digital CCTV camera system is introduced, recording and saving at 10 fps is possible. The live display also becomes 10 fps, and the impression that the specs have been reduced becomes strong for the user.

  In order to solve this, for example, on the CCTV camera side, a moving image of 30 fps is generated for live display, a moving image of 10 fps is generated for recording storage, and both moving image data are output. is there.

  According to this method, it is possible to record and save a 10 fps moving image as it is while performing live display with a 30 fps moving image.

  However, in this case, there is a problem that the processing load on the digital CCTV camera side is high, and the moving image data of two specifications is transmitted and received, so that the load on the network is high.

  In addition, in order for the digital CCTV camera to output two specifications of moving images at the same time, two independent processing circuits are required, which increases the manufacturing cost of the camera.

  For this reason, there has been a demand for the appearance of a digital CCTV camera system having a live display performance similar to that of a conventional analog CCTV camera system, but having a small load on a communication band and a small processing load on a CCTV camera or recorder.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a digital CCTV camera with a small load on a network band and a load on video signal processing while maintaining a live display performance equivalent to that of a conventional analog CCTV camera system.

According to a first aspect of the present invention, a first compression process and a second compression having a higher compression ratio than the first compression process for the first frame data and the second frame data divided from the moving image data, respectively. Communication means for receiving first data and second data obtained by processing, storage means for storing only the first data without storing the second data, and the first compression A third data obtained by performing a first decompression process corresponding to the process on the first data, and a second decompression process corresponding to the second compression process obtained by applying the second data to the second data. Video processing means for synthesizing the fourth data and outputting the fifth data.

The second invention is a video recorder according to the first invention, further comprising video display means for displaying a moving image based on the fifth data.

The third invention is a video recorder according to the first or second invention, wherein a plurality of the first frame data and the second frame data are alternately selected from the moving image data. Features.

A fourth aspect of the present invention is a camera, and a video recorder according to any one of the first to third invention, the camera includes an imaging means for obtaining a moving image data by capturing an image, the moving image data Is divided into first frame data and second frame data, the first frame data is subjected to a first compression process to generate first data, and the second frame data is subjected to the first frame data. A signal processing unit that generates a second data by performing a second compression process having a compression rate higher than that of the first compression process, and a communication unit that transmits the first data and the second data, The first data and the second data are transmitted from the camera to the video recorder.

A fifth aspect of the present invention is a camera, and a video recorder according to any one of the first to third invention, the camera includes an imaging means for obtaining a moving image data by capturing an image, the moving image data Is divided into first frame data and second frame data, the first frame data is subjected to a first compression process to generate first data, and the second frame data is subjected to the first frame data. A signal processing unit that generates a second data by performing a second compression process having a compression rate higher than that of the first compression process, and a communication unit that transmits the first data and the second data, The communication means receives control information, and the signal processing means, based on the control information, classifies the first frame data and the second frame data, as well as the first compression process and the first frame data. 2. Compression processing Determining the volumes of the first data and the second data is transmitted from the camera to the video recorder, the communication means of the video recorder, and transmits the control information to the camera .
A sixth invention is a camera system according to the fourth or fifth invention, wherein a plurality of the first frame data and the second frame data are alternately selected from the moving image data in the camera. It is characterized by that.

According to the video recorder of the first invention, the fifth data can be used for live display. Since the compression rate of the second compression process is higher than that of the first compression process, the load on the communication path is reduced compared to the case where only the first compression process is employed as the compression process and moving image data is transmitted. it can. In addition, since only the first frame data is stored, the storage capacity required for the storage unit can be reduced.

According to the video recorder of the second invention, the fifth data can be reproduced and displayed to confirm the content of the moving image data.

According to the video recorder according to the third invention and the camera system according to the sixth invention, even when the video is reproduced and displayed based on the data stored in the storage means, the displayed moving image is one continuous video in the video. It is easy to grasp the contents of the video because it is thinned out with a gap instead of a part.

According to the camera system of the fourth aspect of the invention, the video recorder outputs two systems of video data, recording video data compressed at a low compression rate and display complementary video data compressed at a high compression rate. Only recording video data with little image quality deterioration can be stored, and live display using a high frame rate video obtained by synthesizing the recording video data and display complementary video data can be performed. Since only the recording video data is stored, the storage capacity of the video recorder is suppressed, and the display supplement data compressed at a high compression rate is transmitted and received, so that the load on the communication path can be reduced.

According to the camera system of the fifth aspect of the invention, since the specification of video data output from the camera from the video recorder side can be remotely controlled, the camera outputs data suitable for data processing on the video recorder side. Can control the data processing load on the video recorder side.

  The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

It is a block diagram of the CCTV camera system which concerns on one embodiment of this invention. It is a figure which shows operation | movement of the CCTV camera system which concerns on one embodiment of this invention.

  FIG. 1 is a basic configuration diagram showing a camera system according to an embodiment of the present invention. The camera system is a CCTV type camera system, and as shown in FIG. 1, a digital CCTV camera 1 (hereinafter referred to as CCTV camera) and a digital video recorder 5 (hereinafter referred to as DVR) which are digital CCTV cameras. It consists of.

  The CCTV camera 1 and the DVR 5 are connected via the network 10, and images captured by the CCTV camera 1 can be transmitted / received via the network 10 and recorded and stored in the DVR 5.

  In the present embodiment, one CCTV camera is illustrated, but the present invention is not limited to this, and a mode in which a plurality of CCTV cameras 1 are connected and used may be used. Similarly, a mode in which a plurality of DVRs 5 are used may be used.

  Moreover, although the aspect which comprises a camera system by CCTV camera 1 is shown, this invention is not limited to this, For example, if it has the function mentioned later, a network camera connected to the internet, digital The same effect can be obtained even if the camera system is configured by a video recorder or a computer device.

  The sensor unit (imaging means) 2 converts an image of an object incident via an optical system (not shown) such as a lens into an electrical signal by an imaging element such as a CCD or a CMOS (Complementary Metal Oxide Semiconductor). Has a function to output.

  The signal processing unit (signal processing means) 3 has a function of processing the electrical signal output from the sensor unit 2, converting it into a digital signal of a predetermined method, and outputting the digital signal. The processing performed here is processing for obtaining an appropriate video signal such as AGC (Auto Gain Control), pixel interpolation, color adjustment such as white balance, and gamma correction, and the obtained video signal is separated into two systems. This refers to a process of dividing and a process of compressing and converting each of the two divided video signals into digital data of a predetermined system such as JPEG or MPEG.

  In other words, the signal processing unit 3 has a function of separating the video signal picked up by the sensor unit 2 and outputting two types of video data for recording and display complementation that are further compressed and converted. Details of these processes will be described later.

  The communication unit (communication means) 4 is connected to the network 10 and has a function of transmitting the two systems of video data output from the signal processing unit 3 via the network 10.

  Further, the communication unit 4 can transmit and receive information for determining the specifications of video data to be output with the DVR 5.

  The DVR 5 includes a communication unit 6, a video processing unit 7, a video display unit 8, and a storage unit 9.

  The communication unit (communication means) 6 is connected to the network 10 and has a function of receiving video data transmitted from the CCTV camera 1. Of the two received video data, the video data for recording is output to the storage unit 9 and the video data for both recording and display complement is output to the video processing unit 7.

  Moreover, the communication part 6 can transmit / receive the information etc. which concern on the specification of a video data with the CCTV camera 1 as mentioned above.

  The video processing unit (video processing means) 7 uses the two systems of video data input from the communication unit 6 to perform processing for complementing recording video data with video data for display complementation. The captured image is reproduced, converted into a video signal that can be reproduced and displayed on the video display unit 8, and output. Details of these processes will be described later.

  The video processing unit 7 can also read video data recorded and stored in the storage unit 9, convert it into a video signal that can be reproduced and displayed on the video display unit 8, and output the video signal.

  The video processing unit 7 can also synthesize video signals and output them to the video display unit 8 so that a single screen is composed of a plurality of videos.

  In addition, the video processing unit 7 can perform various processes related to the video signal such as conversion of the frame size, the frame rate, the compression rate, and the like of the video signal, for example, according to the user's specification.

  The video display unit (video display means) 8 is a display device using a CRT (Cathode-ray Tube), a liquid crystal or the like, and reproduces the video data input from the video processing unit 7 so that the user can visually check it. It has a function to display.

  The storage unit (storage unit) 9 is a storage device such as a hard disk drive, for example, and has a function of recording and saving video data for recording input from the communication unit 6. Each video data is managed, for example, for each CCTV camera, for each date and time, etc. so that the user can confirm later if necessary.

  FIG. 2 is a schematic diagram showing processing in the CCTV camera 1 of the captured video signal and processing in the DVR 5. Hereinafter, the operation of the CCTV camera system will be described with reference to FIGS. 1 and 2.

  In the CCTV camera 1, a video signal captured with a frame size of 640 × 480 pixels VGA (Video Graphics Array) and a frame rate of 30 fps (frame per second) is converted from the sensor unit 2 to the signal processing unit 3 as moving image data. Is input.

  The signal processing unit 3 first performs processing such as AGC, pixel interpolation, color tone adjustment, and gamma correction on the video signal to generate an appropriate video signal that can be used for recording and display.

  Next, the signal processing unit 3 separates and classifies the video captured at 30 fps into two systems for recording and display complementation for each frame data.

  The recording video data is video data in a format that can be recorded and saved as it is after being received on the DVR 5 side. Since the contents of the data may be confirmed later, it is desirable that the frame size is large and the compression rate is low so that the details of the video can be confirmed.

  The display complement data is data for complementing frame data that is not sufficient for recording video data when the DVR 5 side reproduces and displays a 30 fps image captured by the CCTV camera 1 in almost real time. Since it is only necessary to visually confirm the imaging content of the CCTV camera 1, the frame size may be smaller and the compression rate may be higher than the recording video data.

  The CCTV camera 1 is set to output, for example, 10 fps recording video data as an initial setting value.

  In this case, as shown in FIG. 2, only the frame data indicated by the oblique lines in the 30 fps captured video is separated and used as 10 fps recording data (first frame data). The other frame data is used as display complement data (second frame data).

  Note that the frame rate of the recording data is set to 10 fps, and it is possible to change the frame rate as will be described later. The frame rate of the recording video data can be set to a value up to 30 fps that does not exceed the performance of the sensor unit 2.

  At this time, each frame data is assigned a sequential number, which is a serial number indicating the front-rear relationship of the frames, so that the DVR 5 can reproduce the same video as the captured video captured by the CCTV camera 1 as a display video. .

  In the signal processing unit 3, compression processing (compression processing 1 and 2 in FIG. 2) is separately performed on each separated frame data based on the set content.

  Specifically, since there is a case where the contents of the recorded video are later confirmed in detail in the recording data, the compression processing (first processing) is performed with the setting content with emphasis on image quality that suppresses the degradation of the image quality of the video. Compression process). For example, the image may be compressed and converted into the JPEG format with the VGA frame size, or may be compressed and converted into a format such as MPEG1 or MPEG4 having a low compression rate (high bit rate). This is output as recording video data (first data).

  In addition, since it is only necessary to confirm the content of the image being captured by the digital CCTV camera 1 as display complement data, the data capacity is emphasized so as to suppress the data capacity in order to reduce the load on the communication band at the time of data transmission. The compression process (second compression process) is performed with the set contents. For example, after the frame size is reduced to a QVGA size of 320 × 240 pixels, it is compressed and converted into a format such as MPEG1 or MPEG4 having a high compression rate (low bit rate). This is output as display-complementary video data (second data).

  The recording video data and the display complementing video data compressed by the signal processing unit 3 are transmitted from the communication unit 4 to the DVR 5 via the network 10.

  The communication unit 6 of the DVR 5 that has received the two systems of video data outputs only the recording video data to the storage unit 9 and outputs both the recording video data and the display complementing video data to the video processing unit 7.

  The storage unit 9 to which the recording video data is input records and stores the input recording video data. Since the recording video data is a video signal in a format suitable for storage in the storage unit 9, the input video data is recorded and saved in the storage unit 9 as it is.

  However, it is also possible to record and save after processing the video data for recording by setting as necessary. For example, when the video processing unit 7 of the DVR 5 is compatible with specifications such as a frame size, a frame rate, and a compression rate that cannot be handled by the signal processing unit 3 of the CCTV camera 1, the video signal received from the CCTV camera 1 is It can be recorded and saved in the storage unit 9 after being converted into those specifications.

  The video data stored in the storage unit 9 is managed in association with information such as the imaging date and time and the CCTV camera 1, and is read and used later when it is desired to check the video captured by the CCTV camera 1. In this case, the data read from the storage unit 9 is converted into a video signal that can be displayed on the video display unit 8 by the video processing unit 7, input to the video display unit 8, and reproduced and displayed.

  In the video processing unit to which two types of video data of recording video data and display complementary video data are input, each video data is subjected to decompression processing corresponding to the content of the compression processing (decompression processing 1 and 2 in FIG. 2). ) Is given. That is, the recording video data subjected to the first compression processing is decompressed by the first decompression processing corresponding to the first compression processing to obtain 10 fps frame data (third data), and the second The display-complementing video data that has been subjected to the compression process is decompressed by a second decompression process corresponding to the second compression process to obtain 20 fps frame data (fourth data). Each frame data obtained at this time is converted so that its frame size and the like match.

  Then, the obtained frame data is synthesized based on the sequential number attached to each frame data, and the captured image captured by the CCTV camera 1 is reproduced. In other words, each frame data obtained from 10 fps recording video data and 20 fps display complementing video data is synthesized, and display video data having a frame rate of 30 fps (like the captured video captured by the CCTV camera 1) ( 5th data) is generated.

  The generated display video data is output to the video display unit 8. At this time, the video processing unit 7 can also synthesize video signals and output the video signals to the video display unit 8 so as to generate a so-called multi-screen in which videos captured by the plurality of CCTV cameras 1 form one screen.

  The video display unit 8 reproduces and displays the input display video data on a CRT or a liquid crystal display.

  Note that the user can also set the frame size, frame rate, compression rate, compression format, and the like for the recording video data and display complement video data performed by the signal processing unit 3 in the CCTV camera 1.

  The user setting may be performed directly on the signal processing unit 3 by an operator provided in the CCTV camera 1 or may be set on the DVR 5 side.

  When the setting is performed on the DVR 5 side, control information including the setting content is transmitted from the communication unit 6 of the DVR 5 to the CCTV camera 1 via the network 10. The communication unit 4 that has received the control information notifies the signal processing unit 3 of the setting contents. Then, based on the setting contents, the signal processing unit 3 performs extraction of frame data from the captured video and compression processing of the extracted frame data.

  Moreover, the aspect which transmits not only the aspect which transmits control information from the DVR5 side to the CCTV camera 1 side but the information regarding self to the DVR5 from the CCTV camera 1 side may be sufficient.

  For example, if the camera information including information such as the specifications of the digital CCTV camera, the specifications of the optical system lens provided therein, and the video specifications that can be output can be transmitted from the CCTV camera 1 to the DVR 5, the camera on the DVR 5 side Various settings can be made based on the information.

  Thus, by generating video data for recording on the CCTV camera 1 side, the DVR 5 does not need to convert the video data received from the CCTV camera 1 and can record and save it as it is.

  The video data for recording is a part of the video captured by the CCTV camera 1, but is not extracted from a part of the continuous frame data in the entire video, but is extracted from the entire video at intervals. Therefore, even when the video data for recording is read out and reproduced and displayed later, it is possible to grasp the entire contents of the captured video.

  Also, by generating display-complementary video data on the CCTV camera 1 side, a 30 fps video can always be displayed live on the DVR 5 regardless of the frame rate of the video data to be recorded.

  At this time, for example, if the frame rate of the video data for recording is 10 fps, the frame rate of the video data for display complementation may be 20 fps. Therefore, the CCTV camera 1 is compared with the case where 30 fps video data is separately generated exclusively for display. The processing load and the load on the communication band are reduced.

  In addition, while maintaining the image quality of the video data for recording, only the display complement data is compressed at a high compression rate, thereby reducing the overall volume of data to be transmitted and received and further reducing the load on the communication bandwidth during transmission. can do.

Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

Claims (6)

  Obtained by performing first compression processing and second compression processing with a higher compression ratio than the first compression processing on the first frame data and the second frame data divided from the moving image data, respectively. Communication means (6) for receiving the first data and the second data;
  Storage means (9) for storing only the first data without storing the second data;
  Third data obtained by performing first decompression processing corresponding to the first compression processing on the first data, and second decompression processing corresponding to the second compression processing are performed on the second data. Video processing means (7) for synthesizing the fourth data obtained by applying to the data and outputting the fifth data;
A video recorder comprising:   The video recorder of claim 1, further comprising:
  Video display means (8) for displaying a moving image based on the fifth data;
  A video recorder comprising:   The video recorder according to claim 1 or 2,
  A video recorder wherein a plurality of the first frame data and the second frame data are alternately selected from the moving image data. A camera and the video recorder according to any one of claims 1 to 3 ,
The camera
Imaging means (2) for capturing video and obtaining moving image data;
The moving image data is divided into first frame data and second frame data, a first compression process is performed on the first frame data to generate first data, and the second frame data is converted into the second frame data. Is a signal processing means (3) for generating a second data by performing a second compression process having a higher compression ratio than the first compression process;
(4) communication means for transmitting the first data and the second data;
With
The camera system, wherein the first data and the second data are transmitted from the camera to the video recorder. A camera and the video recorder according to any one of claims 1 to 3 ,
The camera
Imaging means (2) for capturing video and obtaining moving image data;
The moving image data is divided into first frame data and second frame data, a first compression process is performed on the first frame data to generate first data, and the second frame data is converted into the second frame data. Is a signal processing means (3) for generating a second data by performing a second compression process having a higher compression ratio than the first compression process;
(4) communication means for transmitting the first data and the second data;
With
The communication means receives control information;
The signal processing means determines a classification of the first frame data and the second frame data and processing contents of the first compression processing and the second compression processing based on the control information. ,
The first data and the second data are transmitted from the camera to the video recorder;
The camera system, wherein the communication means of the video recorder transmits the control information to the camera.   The camera system according to claim 4 or 5, wherein
  The camera system, wherein a plurality of the first frame data and the second frame data are alternately selected from the moving image data in the camera.

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