JP2006115412A - Data recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain high quality for comparatively new data and to enable old data to be stored for a long time. <P>SOLUTION: A data storage region is divided into storage regions EA, EB, EC and received image data are firstly stored in the storage region EA at a full rate. If there is no space in the storage region EA, frames of the oldest image data stored in the storage region EA are thinned at a thinning rate 1/2 and moved to the storage region EB, and newly received image data are overwritten and stored in an empty region that is produced in the storage region EA by said data move, at the full rate. Furthermore, if there is no space in the storage regions EB, EC, the oldest image data are sequentially moved while being thinned similarly to the case of the storage region EA, and storage target frames of the storage regions EB, EA are sequentially moved to the regions which are made empty by the move. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data recording apparatus for storing image data obtained by a camera in a memory.

  In recent years, for example, various systems for monitoring an intruder or an entering object using a camera have been developed, and some of them have been put into practical use. For example, in the surveillance camera system described in Patent Document 1, a camera is installed in an area to be monitored, image data captured by the camera is transmitted to a monitoring center via a network, and recording provided in the monitoring center is performed. It is memorized by the device.

  However, since the capacity of the recording device is fixed, only a certain amount of data can be stored. For this reason, when the capacity of the recording device becomes full, it is necessary to stop the subsequent data storage or to erase the data recorded in the recording device in the oldest order and store new monitoring data instead. is there.

JP 2003-319378 A

  However, in the conventional recording apparatus, old data is unconditionally erased when the capacity of the recording apparatus becomes full. For this reason, when the capacity of the recording device cannot be increased sufficiently, the storage period of each monitoring data is shortened, and when it is necessary to verify past monitoring data, all the target monitoring data has already been erased. This causes a problem that verification cannot be performed at all.

  On the other hand, in order to store as much monitoring data as possible within a limited storage capacity, various techniques for reducing the data amount by reducing the frame rate and image quality of monitoring data have been proposed. However, with this type of technology, all the monitoring data becomes a quasi-moving image or a still image, or an image with reduced resolution. For this reason, for example, in a normal monitoring operation in which the administrator or the viewer reproduces the monitoring data immediately after recording and confirms the status of the monitoring area, the quality of the monitoring data is low, and detailed confirmation becomes difficult.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is to provide a data recording apparatus that maintains high quality for relatively new data and enables long-term storage of old data There is to do.

  In order to achieve the above object, the present invention provides a data recording apparatus for sequentially storing a plurality of data input in time series in a storage medium, wherein the input data is stored in the storage medium with a first quality. 1 and when the amount of data stored in the storage medium reaches a predetermined upper limit, the data stored in the storage medium is converted to a second quality lower than the first quality. The second means for continuing the storage and the third means for storing the newly input data with the first quality in the free space generated by the quality conversion process. is there.

  Therefore, according to the present invention, relatively new data is stored while maintaining a high quality, and the quality is lowered and stored as it gets older. For this reason, it is possible to save for a long time compared to the case where all data is continuously stored in a high quality state, while the high quality storage is possible compared to the case where all data is stored in a state in which the quality is reduced from the beginning. Various processes based on the data are possible.

  For example, in an apparatus that records image data captured by a surveillance camera, high-quality image data is obtained in a normal surveillance operation in which an administrator or a viewer reproduces surveillance data immediately after recording to check the status of the surveillance area. It is possible to perform detailed confirmation work using the data, while when it becomes necessary to verify the monitoring data retroactively, it is possible to retrieve desired old data stored for a long time.

The following can be considered as a specific configuration for realizing the present invention.
In the first configuration, the data storage area of the storage medium includes a first storage area and a second storage area, and the input data is stored in the first storage area with a first quality. When the amount of data stored in the first storage area reaches a predetermined upper limit value, the first quality data stored in the first storage area is converted into the second quality data. After the conversion, it is moved to the second storage area. Then, the newly input data is stored with the first quality in the empty area generated in the first storage area by the movement of the data to the second storage area.
With this configuration, each data is always stored collectively in units of data, so that address management on the storage medium can be simplified.

In the second configuration, when a data storage area and an address management area are provided in the storage medium, the input data is stored in the data storage area with the first quality and stored in the data storage area. A data storage address is stored in the address management area. When the amount of data stored in the data storage area reaches a predetermined upper limit value, the storage address of the first quality data stored in the data storage area is intermittently stored in the address management area. The first quality data is indirectly converted into second quality data. The newly input data is stored with the first quality in the empty area generated in the data storage area by the intermittent address deletion, and the storage address of the data before the deletion is stored as the storage address of the empty area. To the storage address of the newly stored data.
With this configuration, it is possible to realize an extended data storage process that involves quality conversion by changing the storage address of the data without physically moving the data in the data storage area.

In short, in the present invention, data input in time series is sequentially stored in the storage medium with the first quality, and when the data amount of the storage medium reaches the upper limit value, the data stored in the storage medium is stored in the first medium. The second quality lower than the first quality is converted and stored, and the newly input data is stored in the first quality in the surplus storage area generated by the quality conversion process.
Therefore, according to the present invention, it is possible to provide a data recording apparatus that maintains high quality for relatively new data and enables long-term storage for old data.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a monitoring system including a data recording apparatus according to the first embodiment of the present invention.
This monitoring system connects a plurality of monitoring cameras CM1 to CMr arranged in a monitoring target area to a monitoring server device SV via a communication network NW, and communicates a plurality of browsing terminals to the monitoring server device SV. Connection is possible via the network NW.

  The communication network NW includes, for example, a computer network represented by a LAN (Local Area Network) or the Internet, and a subscriber network for connecting the computer network and a browsing terminal. It is also possible to separately configure a network connecting the monitoring cameras CM1 to CMr and the monitoring server device SV and a network connecting the browsing terminal and the monitoring server device SV.

  The browsing terminal is used by a manager of the facility to be monitored or a browser such as an owner, and is composed of fixed terminals PC1 to PCk and mobile communication terminals MS1 to MSj. The fixed terminals PC1 to PCk are composed of personal computers, for example, and are connected to the communication network NW via a subscriber line or a wired line such as a wired LAN. The mobile communication terminals MS1 to MSj are composed of mobile phones, PDAs (Personal Digital Assistants), and portable personal computers, and are connected to the communication network NW via a wireless line.

The monitoring server device SV is provided with a database DB, and the monitoring server device SV and the database DB constitute a data recording device.
The database DB uses a hard disk as a storage medium, and includes a data storage area and a management information storage area. The data storage area is divided into storage areas EA, EB, and EC as shown in FIG. The storage area EA is used for storing relatively new monitoring data captured by the monitoring cameras CM1 to CMr at a full rate. The storage area EB is used for storing the monitoring data that has become obsolete among the monitoring data stored in the storage area EA at half the full rate. The storage area EC is used to store image data that is older in the image data stored in the storage area EB at 1/4 of the full rate.

  A storage area management table is stored in the management information storage area. The storage area management table is provided corresponding to each of the storage areas EA, EB, and EC, and stores management information of monitoring data stored in the storage areas EA, EB, and EC, respectively. The management information includes a monitoring data name (data identification number), a number of a plurality of frames constituting the monitoring data, a head storage address of each frame, a data length of each frame, and a recording time. An example is shown in FIG.

  On the other hand, the monitoring server device SV is configured as follows. FIG. 2 is a block diagram showing the configuration of the monitoring server device SV. The monitoring server device SV includes a central processing unit (CPU) 11, and a program memory 13, an image encoder 14, and an image decoder 15 are connected to the CPU 11 via a bus 12. Further, the CPU 11 includes a database interface (database I / F) 16, a network interface (network I / F) 17, an input / output interface (input / output I / F) 18, and a serial communication interface (serial communication). I / F) 19 are connected to each other.

  The database I / F 16 writes and reads monitoring data and management information to and from the database DB under the control of the CPU 11. The network I / F 17 is connected to the communication network NW, and transmits and receives remote control signals and monitoring data to and from the monitoring cameras CM1 to CMr under the control of the CPU 11. In addition, the monitoring data and the browsing request thereof are transmitted and received between the fixed terminals PC1 to PCk and the mobile communication terminals MS1 to MSj. In the following, a case where the monitoring data is image data will be described. However, the monitoring data may include audio data in addition to the image data image data.

  An input unit 20 and a display unit 21 are connected to the input / output I / F 18. The input unit 20 includes a keyboard and a mouse, for example, and is used to input a control command for monitoring control. The display unit 21 is composed of, for example, a liquid crystal display and displays display data such as a monitoring video output from the input / output I / F 18. The input / output I / F 18 is also provided with various connectors, and sensors and the like are connected to these connectors. The serial communication I / F 19 is used for serial data communication with an external serial device.

  The image encoder 14 and the image decoder 15 are configured by, for example, a DSP (Digital Signal Processor). The image encoder 14 compresses and encodes the image data received by the network I / F 17. The image decoder 15 decompresses and decodes the encoded image data read from the database DB and reproduces the original image data.

The program memory 13 stores a data storage control program 131, an address management program 132, and a data reproduction control program 133 as control programs according to the present invention.
The data storage control program 131 controls the storage of image data in the storage areas EA, EB, and EC of the database DB. The received image data is first stored in the storage area EA at a full rate, for example, 30 frames per second (30 fps). Remember me. Next, when there is no more free space in the storage area EA, the frame image data stored in the storage area EA is thinned out to ½ of the full rate, for example, 15 fps in order from the oldest recording time. The image frame that should not be moved is moved and stored in the storage area EB. Further, when there is no more free space in the storage area EB, the image data stored in the storage area EB is thinned out to ¼ of the full rate in order from the oldest frame, for example, 7.5 fps. The image frame that is not the object is moved and stored in the storage area EC.

  Each time new image data is stored in the storage area EA by the data storage control program 131, the address management program 132 generates management information for the image data and stores it in the storage area management table. Each time image data is moved and stored from the storage area EA to the storage area EB and from the storage area EB to the storage area EC, the management information of the image data is rewritten.

  The data reproduction control program 133 is based on the management information stored in the storage area management table when an image data browsing request is sent from the browsing fixed terminals PC1 to PCk or the mobile communication terminals MS1 to MSj. Relevant image data is selectively read from the storage areas EA, EB, and EC. Then, the read image data is transmitted from the network I / F 17 to the requesting terminal together with header information in which the frame rate and the like are inserted. If the terminal does not have an image playback function corresponding to the frame rate, the read image data is subjected to speed conversion processing and frame interpolation processing for playback of the image before thinning processing, The image data after the reproduction process may be transmitted to the terminal.

Next, the image data recording operation by the data recording apparatus configured as described above will be described. FIG. 6 is a flowchart showing the control procedure and control contents.
Each time one frame of image data is sent from the monitoring cameras CM1 to CMr, the CPU 11 of the monitoring server apparatus SV fetches the image data from the network I / F 17 in step 6a. When the image data is captured, the CPU 11 first compresses and encodes the image data with the image encoder 14. When audio data is sent together with image data from the monitoring cameras CM1 to CMr, the audio data is compressed and encoded by an audio encoder (not shown).

  Next, in step 6b, the CPU 11 determines the free capacity of the data storage area EA of the database DB. As a result of the determination, if it is confirmed that the free space necessary for storing the compression-encoded image data exists in the storage area EA, the process proceeds to step 6n, where the storage area EA The compressed and encoded image data is stored in the empty area. Then, after the storage process is completed, the management information of the newly stored image data is generated in step 6o, and the generated management information is additionally stored in the storage area management table corresponding to the storage area EA.

  For example, when one frame of image data fa1 is received with all the storage areas EA being empty, the received one frame of image data fa1 is compression-encoded and then stored in the storage area EA as shown in FIG. To remember. Then, the management information is stored in the storage area management table as shown in FIG. Similarly, when frame image data fa2, fa3,... Are received subsequent to the frame image data fa1, the frame image data fa2, fa3,... Are compressed and encoded as shown in FIG. The data is sequentially stored in the storage area EA. Then, the management information is stored in the storage area management table as shown in FIG.

  On the other hand, it is assumed that there is no free space in the storage area EA for storing the compression-encoded image data of one frame. In this case, the CPU 11 proceeds to step 6c, and selects the image data with the oldest recording time from the frame image data stored in the storage area EA based on the management information in the storage area management table. Then, after confirming whether or not the selected oldest frame image data is a storage target, a process for moving to the storage area EB is executed.

  That is, first in step 6d, it is determined whether or not the oldest frame image data is to be saved. Whether or not the image is to be saved is determined by a frame thinning rate when moving the frame image data from the storage area EA to the storage area EB. For example, if the thinning rate is ½, the frames to be stored are set every other frame.

  If it is determined in step 6d that the frame is to be stored, the CPU 11 subsequently determines in step 6e whether or not there is a free space necessary for storing the frame image data to be stored in the storage area EB. As a result of this determination, if it is confirmed that there is free space, the CPU 11 moves to step 6m, and moves the frame image data to be saved from the storage area EA to the free area of the storage area EB. In step 6n, the compression-encoded image data of one frame is stored in the storage area EA that is substantially vacant by the movement. On the other hand, frames that are not to be saved are not moved to the storage area EB. Then, the process proceeds to step 6n, where the one frame of compressed and encoded image data is overwritten and saved in the area where the frame image data not to be saved is stored in the storage area EA.

For example, as shown in FIG. 4, if the recording time is old and the thinning rate is 1/2 in the order of the frame image data fa1, fa2, fa3, fa4,..., The frame image data fa1, fa2, fa3, .. out of fa4,... are selected as the frame image data to be stored in the oldest order and moved to the storage area EB. On the other hand, the even frame image data fa2, fa4, fa6,... Are not moved because they are not the frame image data to be stored. In the area after the image data fa1, fa3, fa5,... Of the odd frame are moved, and in the area in which the image data fa2, fa4, fa6,. The received frame image data fi1, fi2, fi3,... Are sequentially overwritten and saved.
Then, after the overwriting is completed, the management information of the corresponding frame image data in the storage area management table is rewritten in step 6o.

  Similarly, as long as there is free space in the storage area EB, the image data of the frame to be saved among the frame image data stored in the storage area EA is moved to the free area in the storage area EB in order of oldest recording time. . Then, the newly received frame image data is sequentially overwritten and stored in the storage area before the movement of the moved storage target frame and the storage area of the frame not to be stored.

  On the other hand, in step 6e, it is determined that there is no free space in the storage area EB. In this case, the CPU 11 proceeds to step 6f, where each frame image data stored in the storage area EB is selected in order from the oldest recording time, and whether or not the frame image data is to be saved is stored. A process for moving to the area EC is executed.

  That is, in step 6g, the CPU 11 first selects the oldest frame image data in the storage area EB, and determines whether or not this frame image data is a storage target. In this case as well, whether or not the image is to be saved is determined by the frame thinning rate when moving the frame image data from the storage area EB to the storage area EC. For example, if the thinning rate is ½, the frames to be stored are set every other frame.

  If it is determined in step 6g that the frame is to be stored, the CPU 11 determines in step 6h whether or not there is a free space necessary for moving the frame image data to be stored in the storage area Ec. As a result of this determination, if it is confirmed that there is free space, the CPU 11 proceeds to step 6k, and moves the frame image data to be saved from the storage area EB to the free area of the storage area EC. Then, after this moving process, the process proceeds to step 6m, where the frame image data to be saved stored in the storage area EA is moved to the area of the storage area EB which has become substantially empty by the moving process. Then, in step 6n, the newly received frame image data is stored in the storage area EA which has become substantially empty due to the data movement to the storage area EB. Finally, in step 6o, the management information of the corresponding frame image data in the storage area management table is rewritten.

  On the other hand, image data of a frame that is not a storage target of the storage area EB is not moved to the storage area EC. Then, the process proceeds to step 6m, where the image data of the odd-numbered frame to be stored, which has been stored in the storage area EA, is overwritten and stored in the storage area of the frame image data not to be moved. Then, after this overwrite storage is completed, the management information of the corresponding image data in the storage area management table is rewritten in step 6o.

For example, as shown in FIG. 4, if the recording times are old in the order of the frame image data fk1, fk3, fk5,... And the thinning rate is 1/2 in the storage area EB, the frame image data fk1, fk3, .. among the odd-numbered frame image data fk1, fk5, fk9,... of fk5,. On the other hand, the even-numbered frame image data fk3, fk7,... Are not moved and are not moved. In the area after the odd-numbered frame image data fk1, fk5, fk9,... Have moved, and in the area in which the even-numbered frame image data fk3, fk7,. The odd frame image data fa1, fa3, fa5,... Stored in the area EA are moved. .. Are newly received in the area where the image data fa1, fa3, fa5,... Of the odd frames are moved and the area where the image data fa2, fa4, fa6,. The frame image data fi1, fi2,.
Further, after the overwriting is completed, the management information of the corresponding frame image data in the storage area management table is rewritten in step 6o.

  Similarly, as long as there is free space in the storage area EC, the frames to be stored stored in the storage area EB are moved to the free area in the storage area EC in the order of the oldest recording time. Then, the storage target frame image data stored in the storage area EA is stored in the storage area EB in the area that is substantially vacant by the movement and in the area in which the non-save target frame is stored. Moved from oldest to newest. Further, the newly received frame image data is sequentially overwritten and stored in the storage area EA in the area that has become substantially empty due to the above movement and the area in which the frame image data that is not to be saved is stored.

  In step 6h, it is determined that there is no free space in the storage area Ec. In this case, the CPU 11 proceeds to step 6i, where the frame image data stored in the storage area EC is selected in order of oldest recording time. Then, the frame image data to be saved in the storage area EB is moved to the area of the storage area EC where the selected frame image data was stored (step 6k). Then, in step 6m, the frame image data to be stored in the storage area EA is moved to the storage area EB, and the newly received frame image data is stored at the end of the storage area EA that has become substantially free by this movement. .

  For example, in the example shown in FIG. 4, the frame image data fs1, fs5, fs9,... Stored in the storage area Ec are selected in order from the oldest recording time, and in the area where the selected frame image data is stored, The frame image data fk1, fk5, fk9,... To be stored in the storage area EB are moved in order of oldest recording time. Then, the storage target frames fa1, fa3, fa5,... In the storage area EA are moved to the area after the movement of the storage area EB in order from the oldest recording time, and further received in the area after the movement of the storage area EA. The frame image data fi1, fi2,... Are sequentially overwritten and saved.

On the other hand, the image data stored in the data storage areas EA, EB, EC of the database DB as described above is reproduced as follows.
That is, when an image data browsing request arrives from the browsing fixed terminals PC1 to PCk and the mobile communication terminals MS1 to MSj, the CPU 11 of the monitoring server device SV extracts the playback start time designated by the viewer from the received browsing request. To do. Then, the management information of the image data recorded at the corresponding time is read from the storage area management table based on the extracted reproduction start time, and stored based on the storage address included in the read management information. The areas EA, EB, and EC are selectively accessed to read out the corresponding frame image data.

  Next, the read frame image data is transmitted from the network I / F 17 to the browsing request source terminal together with a header including management information such as the frame rate of the frame image data. Thereafter, similarly, the frame image data is read from the storage areas EA, EB, and EC in the order of recording time, and the read frame image data is transmitted to the browsing request source terminal together with the header including the management information. This image data transmission operation ends when a browsing end request is received from the terminal.

  As described above, in the first embodiment, the data storage area is divided into three physically different storage areas EA, EB, and EC, and the received frame image data is first stored in the storage area EA at the full rate. To do. When the storage area EA runs out of space, the frame image data stored in the storage area EA is thinned out at the thinning rate 1/2 in the order of the oldest recording time, and the frame image data to be saved is stored in the storage area EB. The newly received frame image data is overwritten and saved at the full rate in the empty area generated in the storage area EA by this data movement. Also, when there are no more free areas in the storage areas EB and EC, the frame image data stored in the storage area EA is thinned out at the thinning rate 1/2 in the order of the oldest recording time as in the case of the storage area EA. The frame image data is sequentially moved, and the frames to be stored in the storage areas EB and EA are sequentially moved to an area which becomes empty by this movement.

  Accordingly, relatively new image data immediately after reception is stored while maintaining high quality, and as the image data becomes older, the quality is lowered and storage is continued. For this reason, it is possible to store for a long time compared to the case where all the image data is continuously stored in a high quality state, while the quality is higher than the case where all the image data is stored in a state in which the quality is reduced from the beginning. Can be processed based on the image data. For example, in a monitoring system, an administrator or a viewer can check the status of a monitoring area in detail using relatively new image data immediately after recording. On the other hand, when it becomes necessary to verify image data retroactively, desired image data can be read from the old image data stored for a long time and verified.

(Second Embodiment)
In the first embodiment, the data storage area is divided into three physically different storage areas EA, EB, and EC, and the storage data is thinned out in units of frames each time there is not enough space in the upper storage area. Physically moved to the lower storage area sequentially while processing.
On the other hand, in the second embodiment of the present invention, a data storage area and a storage management table are provided in a database, and received frame image data is sequentially stored in the data storage area. Then, when there is not enough space in the data storage area, the frame image data stored is not physically moved, and the frame image data is thinned out. The newly received frame image data is stored in the area.

7 to 11 are views for explaining a second embodiment of the present invention. The configuration of the monitoring server device SV is the same as that shown in FIG.
The database DB is provided with a data storage area and a storage management table. The received frame image data is fixedly stored in the data storage area. FIG. 7 shows an example of this, and shows a state in which frame image data fa1, fa2,..., Fan,... Are stored in order in the data storage areas represented by addresses “0000” to “FFFF”.

  On the other hand, management information of each frame image data stored in the data storage area is stored in the storage management table. The management information includes a frame number of frame image data, a head storage address, a tail storage address, a data length, a recording time, whether a rate is changed, and a frame rate (fps). An example is shown in FIG.

Similar to the first embodiment, the program memory 13 of the monitoring server device SV stores a data storage control program, an address management program, and a data reproduction control program.
The data storage control program performs storage control of image data in the data storage area of the database DB. When there is an empty area in the data storage area, the received frame image data is sequentially stored in the data storage area. On the other hand, when there is no free space in the data storage area, the newly received frame image data is written into the free space generated by the thinning process.

  Each time frame image data is newly stored in the data storage area, the address management program generates management information and address information related to the stored frame image data, and additionally stores them in the storage management table. When there is no more free space in the data storage area, a plurality of frame image data stored in the data storage area are selected in order of oldest recording time based on the management information stored in the storage management table. Then, it is determined whether or not the selected frame image data is a frame to be stored, and the storage address of the frame image data that is not the storage target is a free area, and the newly received frame image data is written and not the storage target The management information of the frame image data is rewritten to the management information of the newly written frame image data. On the other hand, for the frame image data to be saved, the storage area is not physically moved, the frame rate of the management information is changed to ½ of the full rate, and the rate change item is changed from “No” to “Yes”. Change to

  When a browsing request for image data is sent from the browsing fixed terminals PC1 to PCk or the mobile communication terminals MS1 to MSj, the data playback control program corresponds to the corresponding recording time according to the playback start time included in the browsing request. Are sequentially read from the frame image data. Then, the read frame image data is transmitted from the network I / F 17 to the browsing request source terminal together with a header including the frame rate and the like.

Next, a data recording operation in the apparatus configured as described above will be described. FIG. 9 is a flowchart showing the control procedure and control contents.
Every time frame image data is sent from the monitoring cameras CM1 to CMr, the CPU 11 of the monitoring server device SV fetches the frame image data from the network I / F 17 in step 10a. When the frame image data is captured, the CPU 11 first compresses and encodes the captured frame image data with the image encoder 14. When audio data is attached to the frame image data, the audio data is also compressed and encoded by an audio encoder (not shown).

  Next, in step 10b, the CPU 11 determines the free capacity of the virtual area VA among the two virtual areas VA and VB logically set in the data storage area of the database DB. The virtual areas VA and VB are areas set in advance according to the frame rate of the image data for managing free space in the data storage area, and the virtual area VA stores full-rate frame image data. The area and virtual area VB are defined as areas for storing frame image data whose rate has been lowered by the thinning process.

  FIG. 10 is a flowchart showing the processing contents for calculating the total amount of data stored in the virtual areas VA and VB. When determining the free capacity of the virtual area VA, the CPU 11 first refers to the item “frame rate” of the stored data management table (FIG. 8) in step 11b, and the frame rate of each frame image data is the full rate (30 fps). It is determined in step 11c whether or not. If the result of this determination is the full rate, the data amount of the full rate data is sequentially accumulated and added in step 11d. When it is confirmed in step 11a that the above processing has been completed for all the frame image data managed in the storage management table, the CPU 11 ends the calculation processing of the total storage data amount in the virtual area VA.

  Next, the CPU 11 determines whether or not there is a free area in the virtual area VA in step 10c based on the calculation result of the total storage data amount in the virtual area VA. As a result of this determination, if it is confirmed that the free space necessary for storing the compression-encoded frame image data exists in the virtual area VA, the process proceeds to step 10k, where the virtual area VA The compression-encoded frame image data is stored in an empty area. Then, after the storage process is completed, management information of the newly stored frame image data is generated in step 101, and the generated management information is additionally stored in the storage management table (FIG. 8). As described above, the management information includes a frame number, a head storage address and a tail storage address, data length, recording time, presence / absence of rate change, and frame rate (fps).

  On the other hand, it is assumed that there is no free space in the virtual area VA for storing the compression-encoded frame image data. In this case, the CPU 11 proceeds to step 10d and selects the frame image data with the oldest recording time from the frame image data stored in the virtual area VA based on the management information in the storage management table. Then, with respect to the selected oldest frame image data, it is determined whether or not the data is a frame to be saved, and recognition processing as a free area or frame rate change processing is executed.

  That is, first, in step 10e, it is determined whether or not the oldest frame image data is a storage target frame. Whether or not the frame is a storage target frame is determined by a preset frame thinning rate. For example, if the thinning rate is ½, the frames to be stored are set every other frame. When it is determined in step 10e that the oldest frame image data is not a frame to be saved, the CPU 11 proceeds to step 10k and newly acquired in the area where the oldest frame image data is stored. Store image data. In step 101, the management information of the newly stored frame image data is stored in the storage management table.

  On the other hand, if it is determined in step 10e that the oldest frame image data is a storage target frame, the CPU 11 proceeds to step 10f and updates the management information of the storage target frame. For example, if the frame image data fa1 is selected as the oldest frame image data and the data is a frame to be saved, the frame rate of the management information corresponding to the frame image data is “15” as shown in FIG. And the rate change presence / absence is updated from “No” to “Yes”.

  Subsequently, in step 10g, the CPU 11 performs a calculation process of the total storage data amount of the virtual area VB. This calculation process is also performed according to the procedure shown in FIG. 10 in the same manner as the calculation process for the virtual area VA described above. When the calculation result of the total storage data amount in the virtual area VB is obtained in this way, the CPU 11 determines whether or not there is a free capacity necessary for storing the acquired data in the virtual area VB based on the calculation result. The determination is made at step 10h. As a result of this determination, if it is confirmed that there is a free capacity, the CPU 11 proceeds to step 10j and stores the acquired data in the free area in the virtual area VB. Then, after the storage process is completed, management information of the newly stored frame image data is generated in step 101, and the generated management information is additionally stored in the storage management table.

On the other hand, in step 10h, it is determined that there is no free space in the virtual area VB. In this case, the CPU 11 proceeds to step 10i where the frame image data with the oldest recording time is selected from the frame image data stored in the virtual area VB. Then, the process proceeds to step 10j, where the acquired data is stored in the storage area of the selected frame image data, and the management information is updated in step 101 after the storage of the acquired data is completed.
Thereafter, similarly, the above processing is repeatedly executed every time frame image data is received.

As described above, in the second embodiment, when there is no more free space in the data storage area, the frame image data is indirectly obtained by performing recognition processing as a free space or frame rate change processing on the storage management table. Therefore, new image data is stored in units of frames in an area that is substantially freed by the thinning process.
Therefore, it becomes possible to perform extended storage processing of image data including thinning processing by changing management information, which eliminates the need for physical movement processing of image data in the data storage area, thereby reducing the processing procedure accordingly. Thus, the processing can be simplified and speeded up.

(Other embodiments)
In each of the above embodiments, the case where the JPEG (Joint Photographic Experts Group) method is adopted as the image encoding method has been described as an example. However, the present invention is not limited to this, and the present invention can be applied to a case where an MPEG (Motion Picture Experts Group) system is adopted.
Image data encoded by the MPEG system is composed of an I frame (I picture in MPEG1 / 2, called I-VOP in MPEG4), and a plurality of P frames (P picture in MPEG1 / 2, MPEG4). (Referred to as P-VOP). Therefore, if such encoded data is simply thinned out in units of frames as in the above embodiments, the I frame may be deleted and data may not be reproduced.

Therefore, as a thinning method when the MPEG method is adopted,
(1) A method of selectively deleting P frames from behind while leaving I frames (one or more P frames to be deleted are selected continuously without being thinned).
(2) A method of creating an I frame at the position of the target frame and deleting P frames before and after the I frame.
Adopt one of the following.

  FIG. 11 is a diagram for explaining the thinning method (2). In the figure, when the P1n frame between the I1 frame and the I2 frame is set as the target frame position, the P1n frame to the P1n frame are first reflected on the I1 frame in order to create the I1.5 frame at the position of the P1n frame. . Then, the created I1.5 frame is replaced with the P1n frame, and thereafter, the P11 to P1m frames between the I1 frame and the I2 frame are deleted. In this way, it is possible to decode and reproduce the data before the thinning process from the data after the thinning process without damaging the I frame.

  In the first and second embodiments, when the image data is stored in the data storage area at the full rate, and thereafter there is no free area in the data storage area, the image data is thinned out to reduce the amount of information. The memory was continued after decreasing. However, the present invention is not limited to this. For example, a plurality of storage areas having the same storage capacity are prepared. When the received image data is stored, a plurality of image data having different frame rates are generated based on the image data, and the generated plurality of data are stored in parallel in the storage area. . For example, full-rate data, 1/2 / rate data, and 1 / 4-rate data are generated for one piece of received image data, and these three types of data have the same storage capacity. , Stored in the second and third storage areas.

  With this configuration, the first storage area has a short storage period but relatively new image data is stored in a high quality state, while the third storage area has lower quality but the old image data is longer. It can be stored for a period of time. In the second storage area, medium quality image data can be stored for a necessary and sufficient period. In addition, when such a configuration is adopted, it is not necessary to perform physical movement of image data or address change processing after storage, thereby further simplifying image data storage management control. Also, by selecting a storage area when reproducing image data, it is possible to selectively reproduce image data at a desired rate.

  Further, in each of the above embodiments, it is assumed that the information size of all frames is the same size, or a plurality of frame storage areas corresponding to the maximum information size of one frame are fixedly set in the data storage area, A case has been described in which a frame of newly input image data is stored in the frame storage area and a frame to be saved is moved. However, depending on the image encoding method, the information size of each frame is not always constant. In this case, if an attempt is made to store or move a newly input frame of image data or a frame to be stored in the frame storage area having the fixed size, a surplus area may be generated or conversely, the storage area may be insufficient. is there.

  Therefore, first, when a surplus area is generated, the defragmentation process for the data storage area may be executed using the non-monitoring time zone or in parallel with the image data storage processing operation. On the other hand, when the storage area is insufficient in one frame storage area, control is performed so that a frame of newly input image data and a frame to be saved are stored across a plurality of frame storage areas. When an excess storage area is generated as a result of storage in the plurality of frame storage areas, the defragmentation process is executed as described above. In this way, reliable and efficient memory area management can be performed even when the frame information size is variable.

  Furthermore, in the embodiment, when reproducing the image data after the thinning process, the reproduction timing of each frame is adjusted based on the recording time so as to correspond to the speed of the image data before the thinning process. Alternatively, playback may be performed without adjusting the playback timing. In this way, old data is automatically fast-forwarded and replayed, and as a result, past old data can be re-viewed in a short time.

  Furthermore, when the stored image data is reproduced, not only the recording time but also the character data representing the presence / absence of the rate change and the frame rate are superimposed on the image data based on the management information, or the image data A separate display area may be provided and displayed in this area. The frame rate may be displayed by changing the background color of the image data or the color of the display frame instead of using the character data.

  Furthermore, a plurality of image data stored in the data storage area can be edited and displayed in a thumbnail format, and the difference in frame rate can be displayed by changing the character data or color. Also good. In this way, when displaying a list of a plurality of stored image data in the thumbnail format, the frame rate of each image data can be confirmed at a glance.

  In the first embodiment, three storage areas EA, EB, and EC are provided in the data storage area. From the oldest image data, the storage area EA is changed to the storage area EB, and the storage area EB is changed to the storage area EC. The case where the memory location is moved while thinning out has been described as an example. However, the present invention is not limited to this, and the number of storage areas may be two, or four or more. In addition to providing the plurality of storage areas on the same storage device or the same storage medium, for example, they may be distributed in storage devices of different servers or terminals, and further distributed in different storage media. It may be provided. Similarly, in the second embodiment, the case where two temporary storage areas VA and VB are defined has been described as an example, but three or more temporary storage areas may be set.

  Further, in each of the above embodiments, the configuration example in which the image data obtained by the surveillance camera in the surveillance system is stored in the database of the surveillance server device has been shown. However, as another configuration example, for example, the image data ( The present invention can also be applied to a configuration in which (including still images and moving images) is stored in a storage unit in the digital camera.

  Further, the thinning rate when moving the storage location of the image data between the storage areas is not limited to 1/2, and may be 1/3 or more, and may be adaptively changed according to the number of received image data. May be. Furthermore, as a method for reducing the information quality of image data, thinning processing in units of pixels may be used in addition to thinning out processing in units of frames.

  Further, in each of the above embodiments, the odd-numbered frame is a storage target frame, and the even-numbered frame is a thinning target frame. However, in the monitoring system, for example, a frame in which an abnormality is detected and a predetermined number of frames before and after the frame are set as the storage target frames, and the thinning process may be intermittently performed in the other frames. In this way, it is possible to reliably save a frame in which an abnormality is detected.

  Furthermore, in the first embodiment, the frames having the oldest recording times are selected in order from the storage areas EA, EB, and EC, and after the thinning process is performed, they are moved to the lower storage area. It is not necessary to select from the frame with the oldest recording time, and it may be selected randomly regardless of the recording time. The same applies to the second embodiment.

Furthermore, in the above-described embodiment, the case where image data obtained by a monitoring camera is recorded in the monitoring system has been described as an example. However, not only image data but also measurement data, document data, various calculation data, and the like are recorded. The invention is applicable.
In addition, the configuration of the data recording apparatus, data storage control, address management control and data reproduction control procedures and contents, data types, and the like can be variously modified without departing from the scope of the present invention.

  In short, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows 1st Embodiment of the monitoring system concerning this invention. The block diagram which shows the structure of the monitoring data recording apparatus in the monitoring system shown in FIG. The figure which shows the structure of the monitoring data storage area of the database provided in the monitoring data recording apparatus shown in FIG. The figure for demonstrating the storage control operation | movement of the data with respect to the monitoring data storage area shown in FIG. The figure which shows the structure of the storage area management table provided in the monitoring data recording apparatus shown in FIG. The flowchart which shows the procedure and content of the data storage control by the monitoring data recording device shown in FIG. The figure which shows the structure of the data storage area provided in the monitoring data recording device concerning 2nd Embodiment of this invention. The figure which shows an example of the management information memorize | stored in the memory | storage management table provided in the monitoring data recording apparatus concerning 2nd Embodiment of this invention. The flowchart which shows the procedure and content of the data storage control by the monitoring data recording device concerning 2nd Embodiment of this invention. The flowchart which shows the calculation procedure of the memory | storage data amount in the flowchart shown in FIG. 9, and its content. The figure for demonstrating the frame thinning-out system in the monitoring data recording device concerning other embodiment of this invention.

Explanation of symbols

  CM1 to CMr ... surveillance camera, SV ... surveillance server device, DB ... database, PC1-PCk ... fixed terminal, MS1-MSj ... mobile communication terminal, NW ... communication network, 11 ... CPU, 12 ... bus, 13 ... program memory, DESCRIPTION OF SYMBOLS 131 ... Data storage control program, 132 ... Data storage management program, 133 ... Data reproduction control program, 14 ... Image encoder, 15 ... Image decoder, 16 ... Database interface, 17 ... Network interface, 18 ... Input / output interface, 19 ... Serial Communication interface 20... Input unit 21.

Claims (2)

In a data recording apparatus for sequentially storing a plurality of data input in time series in a storage medium,
First means for storing the input data in the storage medium with a first quality;
When the amount of data stored in the storage medium reaches a predetermined upper limit, the data stored in the storage medium is converted to a second quality lower than the first quality and the storage is continued. A second means;
3. A data recording apparatus comprising: a third means for storing newly input data with the first quality in an empty area generated by the quality conversion. When the data storage area of the storage medium is composed of a first storage area and a second storage area,
The first means stores the input data in the first storage area with a first quality,
The second means reads the first quality data stored in the first storage area when the amount of data stored in the first storage area reaches a predetermined upper limit value. The second quality data, and move the second quality data to the second storage area,
The third means stores the newly input data with the first quality in the empty area generated in the first storage area by moving the data to the second storage area. The data storage device according to claim 1, wherein:

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