JP3125709B2 - Digital data recording device and recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data recording apparatus capable of continuously recording digitized image data for a long time and a digital data recording / reproducing apparatus capable of recording / reproducing digital data for a long time. Related to the device.

[0002]

2. Description of the Related Art For example, when recording an image signal obtained by photographing with a monitoring video camera such as a road or an automatic cash dispenser, it is required to record for a long time of 24 hours or more. For example, if the data rate is 4 megabits /
In a monitoring system using moving images (or continuous still images) of seconds (= 500 kilobytes / second), the data amount for one day is 500 KB / sec × 60 × 60 × 24 = 43.2.
It can be gigabytes. Therefore, HDDs (hard disk drives) and MODs (magneto-optical disk drives) have a recording capacity of about several gigabytes, and are not suitable for such long-time recording. For this reason, for example, a conventional HD as disclosed in JP-A-8-237600 is disclosed.
A system using D or the like responds by lowering the data rate by lowering the image quality and suppressing the overall capacity.

[0003] A time-lapse VTR (video tape recorder), which enables long-time recording by performing intermittent recording, has been conventionally used for recording an image signal of a surveillance video camera.

[0004]

First, HDD, MOD
In a data recording device using such a device, if a 1 GB removable HDD is used, the image quality is not reduced.
For recording 43.2 gigabytes of data for one day, 44 hard disk cassettes are required, and it takes time and effort to store and organize past data, and there is a problem that the operation cost of the system is high. Further, when the data amount is reduced, there is a problem that image quality is deteriorated.

[0005] The time-lapse VTR is convenient for storage because a large amount of data can be recorded in one cassette, but has the disadvantage that necessary scenes (moments) for intermittent recording may not be recorded. The time required to search for and display the desired part, that is, the access time is long, and when the same part of the tape is reciprocated many times, the part is deteriorated (dropout, flaws, noise, etc. ).

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a digital data recording apparatus capable of continuously and reliably recording a large amount of image data at low cost and capable of easily searching for a necessary scene. And a recording / reproducing apparatus.

[0007]

According to a first aspect of the present invention, there is provided a digital data recording apparatus for recording input digitized image data on a recording medium. Recording / reproducing means for recording digital data on a first recording medium and reproducing the recorded digital data; and storing the digital data on a second recording medium having a longer access time and a larger recording capacity than the first recording medium. Recording means for recording; and endless recording of the input image data on the first recording medium by the recording / reproducing means, and digest data including frame-based extracted image data extracted from the input image data to the first storage medium. A first recording operation for recording on the first recording medium; and a first recording operation for recording on the first recording medium by the first recording operation. Every time the data amount reaches a predetermined amount equal to or less than the recording capacity of the first recording medium, the image data recorded on the first recording medium is reproduced and recorded on the second recording medium by the recording means. Reproducing the digest data recorded on the first recording medium by the first recording operation, and discriminating the digest data from the image data recording area of the second recording medium by the recording means. And control means for executing the third recording operation for recording in the specified area in a time-division manner.

According to a second aspect of the present invention, in the digital data recording apparatus according to the first aspect, the control unit extracts the extracted image data from the input image data every predetermined sample time. It is characterized by comprising. According to a third aspect of the present invention, in the digital data recording apparatus according to the first aspect, the control means extracts the extracted image data from the input image data by extracting continuous image data for a predetermined continuous time. It is characterized by doing.

According to a fourth aspect of the present invention, in the digital data recording apparatus according to the first aspect, the recording means is configured so that the second recording medium is replaceable, and the control means includes When an instruction to remove the second recording medium is issued, the third recording operation is executed,
Thereafter, the second recording medium can be taken out.

According to a fifth aspect of the present invention, in the digital data recording apparatus according to the first or fourth aspect, the control means may be arranged so that the predetermined area in which the digest data is recorded is located on the second recording medium. The recording start position of the image data is controlled so as to be secured near the head position of the recordable range.

According to a sixth aspect of the present invention, in the digital data recording apparatus according to any one of the first, fourth and fifth aspects, the control means includes:
It is characterized by including recording position information indicating a recording position of the corresponding image data on the second recording medium.

According to a seventh aspect of the present invention, there is provided a digital data recording / reproducing apparatus which records input digitized image data on a recording medium and reproduces the recorded image data. A first recording / reproducing means for recording digital data on a recording medium and reproducing the recorded digital data; and a second recording medium having a longer access time and a larger recording capacity than the first recording medium. And a second recording / reproducing means for reproducing the recorded digital data, and an endless recording of the input image data on the first recording medium by the first recording / reproducing means, A first recording operation of recording digest data including extracted image data in frame units extracted from the first recording medium on the first recording medium; Each time the amount of data recorded on the first recording medium by the first recording operation reaches a predetermined amount equal to or less than the recording capacity of the first recording medium, the image recorded on the first recording medium is reduced. A second recording operation for reproducing data and recording the data on the second recording medium by the second recording / reproducing means; and reproducing the digest data recorded on the first recording medium by the first recording operation. And the second
A third recording operation of recording in a predetermined area of the second recording medium, which is distinguished from a recording area of the image data, by the recording / reproducing means, and recording on the second recording medium by the second recording / reproducing means. The first recording / reproducing means reproduces the reproduced image data and records the data on the first recording medium by the first recording / reproducing means.
Reproduction operation and the second recording / reproduction means
Playback of the digest data recorded on the recording medium of
A second reproducing operation for recording the first recording medium on the first recording medium by the first recording / reproducing means; and an image data or a digest data recorded on the first recording medium by the first or the second reproducing operation. A third reproducing operation for reproducing and outputting the contained extracted image data and a control unit for executing the third reproducing operation in a time-division manner. According to an eighth aspect of the present invention, in the digital data recording / reproducing apparatus according to the seventh aspect, the second recording / reproducing means is configured so that the second recording medium can be replaced. The second reproducing operation is executed when the second recording medium is inserted into the second recording / reproducing means. According to a ninth aspect of the present invention, in the digital data recording / reproducing apparatus according to the eighth aspect, the control means includes a recording unit which indicates a recording position of the image data corresponding to the digest data on the second recording medium. It is characterized by including location information.

According to a tenth aspect of the present invention, in the digital data recording / reproducing apparatus according to the ninth aspect, the user refers to the extracted image data included in the digest data to obtain image data corresponding to the digest data. Operating means for instructing reproduction of the second recording / reproducing means, wherein the control means refers to recording position information included in the digest data for which the user instructed the reproduction, and the second recording / reproducing means performs the second recording / reproduction. And performing an access operation for accessing the image data on the recording medium, and then executing the first and third reproduction operations to output corresponding image data.

According to an eleventh aspect of the present invention, in the digital data recording / reproducing apparatus according to the tenth aspect, the input image data is temporally continuous image data;
When executing the reproducing operation according to the recording position information, the control means starts the first operation from the image data slightly earlier than the image data corresponding to the recording position information.
, So that the reproduction operation is started.

According to a twelfth aspect of the present invention, in the digital data recording / reproducing apparatus according to the tenth aspect, the control means converts the extracted image data into continuous image data for a predetermined continuous time from the input image data. It is characterized by extracting and configuring. According to a thirteenth aspect of the present invention, in the digital data recording / reproducing apparatus according to the twelfth aspect, the input image data comprises a plurality of programs, and the control means stores the extracted image data in the first of the plurality of programs. When the reproduction instruction is given by the user during the reproduction and output of the extracted image data, the access operation and the first reproduction are performed during the reproduction and output of the extracted image data. The operation is performed.

According to a fourteenth aspect of the present invention, in the digital data recording / reproducing apparatus according to the tenth aspect, the input image data comprises a plurality of programs, and the control means transmits the extracted image data to the input image data. Thinned image data configured by extracting image data for each predetermined sample time from image data, and partial continuous image data configured by extracting continuous image data for the first predetermined continuous time of each of the plurality of programs; It is characterized by comprising.

According to a fifteenth aspect of the present invention, in the digital data recording and reproducing apparatus according to the fourteenth aspect, when the user gives the reproduction instruction with reference to the thinned image data, For the partial continuous image data corresponding to the thinned image data, the first
And performing a third reproducing operation, and after the first reproducing operation on the partial continuous image data is completed, the first reproducing operation on the image data corresponding to the partial continuous image data.
Perform a reproducing operation, and, following the third reproducing operation for the partial continuous image data, the third reproducing operation for the image data temporally continuous with the partial continuous image data.
Is performed.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a configuration of a digital data recording / reproducing apparatus according to a first embodiment of the present invention. The apparatus according to the present embodiment is a device in which a digital image signal obtained by digitizing an image signal captured by a monitoring video camera is used as an input digital signal, and the digital signal is recorded and reproduced. This device uses MPEG (Motion Pic
an image compression processing unit 1 that performs image compression processing conforming to the standards of the Virtual Experts Group (CPU) and a CPU (Central Processing).
A control unit 2 including a CPU buffer 5 composed of a RAM (Random Access Memory), an image decompression processing unit 3 that performs an image decompression process corresponding to the image compression process in the image compression processing unit 1, and a first Hard disk drive (hereinafter referred to as “HD
D) 6, a data tape recorder (hereinafter referred to as “DTR”) 7 as second recording / reproducing means (or recording means or reproducing means), and a DTR buffer for temporarily storing data to be recorded / reproduced by the DTR 7 8 and
Operation unit 21 for the user to give instructions such as recording and reproduction
The control unit 2, the HDD 6, and the DTR buffer 8 are provided with an interface bus (for example, SCSI (Small)).
Computer System Interface) 2) 10
Connected to each other. The control unit 2 includes a ROM (not shown) storing a control program and an arithmetic RA
M (not shown), and is configured to be able to control the operations of the HDD 6 and the DTR 7 via the interface bus 10 according to a control program stored in the ROM.

As is well known, the HDD 6 writes (records) data on a magnetic disk (first recording medium) called a hard disk and reads (reproduces) the written data. FIG. 2 is an explanatory diagram for explaining data writing and reading by the HDD 6. Data is sequentially written on the magnetic disk in the order of regions R1, R2, R3,... And data can be written endlessly. Reading is performed in the regions R1, R
2,..., Or, for example, the regions R1 to R3 can be collectively read. FIG. 2 is an explanatory diagram and does not necessarily mean that data is written in a sector-shaped area of the magnetic disk.

The DTR 7 has a larger recording (storage) capacity than a magnetic disk and a lower cost per unit data amount, but records data on a magnetic tape (second recording medium) having a long access time. The reproduced data is reproduced. As the DTR 7, for example, a DTR based on the D-VHS (registered trademark) standard is adopted. D-VHS
A DTR conforming to the standard is capable of recording and reproducing digital data at a data rate of 13.8 Mbps (megabits / second) as a standard, and uses a mechanism similar to the VTR of the VHS (registered trademark) standard. The data is recorded and reproduced by obliquely scanning the magnetic tape with a magnetic head. Details of the DTR conforming to the D-VHS standard are disclosed in, for example, Japanese Patent Application Laid-Open No. 8-275102. That is, the recording / reproducing data rate DR2 of the DTR 7 is 13.8 Mbps in the present embodiment.

FIG. 4 is a diagram for explaining the operation when recording the input digital data. The recording operation of the apparatus shown in FIG. 1 will be described with reference to FIG. The operation described below is executed by the control unit 2 controlling the HDD 6 and the DTR 7. In FIG. 1, an image compression processing unit 1 performs a compression process on an input image signal, and converts the processed digital data into a data rate DR1 (for example, 1.38).
(Mbps) to the CPU 4 (see FIG. 4A). The CPU 4 transmits the input data to the data rate DR 3 via the CPU buffer 5 and the interface bus 10.
(For example, 20 Mbps), and
Writes data on the magnetic disk (see FIG. 4B). Here, the data rate DR3 is very large (about 15 times) with respect to the input data rate DR1.
A predetermined data amount DA1 (for example, 40 Mbi) is stored in the U buffer 5.
t) Every time the data is accumulated (every time T1), writing to the HDD 6 is performed in a short time T3 (FIG. 4B). At this time, the write unit of the HDD 6 is the area R shown in FIG.
1, R2,... Respectively.

FIG. 4 does not show a state in which recording is started from the time on the vertical axis on the time axis (horizontal axis) (the time at the intersection of the time axis and the vertical axis) in FIG. (A timing at which data is transferred from the HDD 6 to the DTR buffer 8) is extracted and shown.

FIG. 3 is a diagram for explaining the conversion of the data rate using the buffer. The data is written into the buffer with a write clock corresponding to the input data rate (in the case of the CPU buffer 5, DR1), and the output data is output. The data rate can be converted by reading data from the buffer with a read clock corresponding to the rate (DR3 in the case of the CPU buffer 5).

The data written in the HDD 6 is transferred to the DTR buffer 8 at a data rate DR3 during a period in which writing from the CPU buffer 5 to the HDD 6 is not executed, every time the total amount of data reaches the predetermined amount DA2. Recording is performed by the DTR 7 (FIG. 4C).
(D)). It is necessary to set the predetermined amount DA2 at most to be equal to or less than the recording capacity (storage capacity) DHDMAX of the HDD 6. However, in the present embodiment, the recording operation and the reproduction operation described later are executed in a time-division manner. The maximum value is set to a value of about 1/2 of the recording capacity DHDMAX. In the example shown by a solid line in FIGS.
Write operation 10 to HDD 6 at time T3 shown in (b)
One write operation to the DTR buffer 8 at time T4 is performed. As described above, the recording data rate DR2 by the DTR 7 is 13.8 Mbps, which is lower than the data rate DR3.
Is performed over time T2 (> T4).
Here, DR2 × T2 = DR3 × T4.

Since the DTR 7 uses a magnetic tape as a recording medium, it is preferable to perform a recording operation for a certain time rather than a recording operation for a very short time (about several tens of seconds). As shown by the broken lines in c) and (d), writing to the DTR buffer 8 at time T4 may be performed twice consecutively for 20 times of writing to the HDD 6 at time T3. In this case, time T4 (= T2 × DR2 / DR) is set so that time T2 = time T1.
By setting 3), as shown in FIG.
Recording from the DTR buffer 8 to the DTR 7 (solid line operation and broken line operation) can be continued.

It should be noted that the times T6 and T7 in FIG.
This is a time (seek time) for switching processing between reading and writing of the DD 6 and varies depending on a read address and a write address. Therefore,
The times T1 and T4 are set in consideration of the maximum seek time.

Data rates DR1 to DR3 and time T1
T4 is, for example, DR1 = 1.38 Mbps, DR2 =
13.8 Mbps, DR3 = 20 Mbps, T1 = T2
= 29 seconds, T3 = 2 seconds, and T4 = 20 seconds. In this case, the minimum capacity of the DTR buffer 8 is DR2 × (T
2-T4), which is 125 Mbit.

Next, the operation during reproduction will be described with reference to FIG. The example shown in the figure shows a case where the DTR 7 is played back for the time T2, and the data rate of the playback data played back from the magnetic tape by the DTR 7 is changed by the DTR buffer 8 and written to the HDD 6 (see FIG. a)
(B)). At this time, the recording of the input data input at the data rate DR1 is also continued, so that the HDD at the time T3 of the recording data at the time T1 as shown in FIG.
6 is also being executed. Therefore, the writing of the reproduction data to the HDD 6 is performed during the period when the writing of the recording data is not executed. As described above, in the present embodiment, the recording capacity DHDMAX of the HDD 6 is used.
The half of the capacity DHDREC is used for writing the recording data, and the other half of the capacity DHDDPB is used for writing the reproducing data. Can be performed in splits.

The reproduction data written in the HDD 6 is read as shown in FIG. That is, a read operation at time T11 (≦ T3) is executed every time T12, and the read reproduction data is written to the CPU buffer 5 (data flows in the opposite direction to the above-described recording). Then, the reproduction data is output from the control unit 2 to the image decompression processing unit 3 at the data rate DR1 with a delay of the time T15 required for the CPU processing from the end of the write operation of the HDD 6 immediately before. The image decompression processing unit 3 performs decompression processing of input data, and outputs an image signal after the processing. The output image signal is supplied to, for example, a CRT display,
Displayed on the screen. In this case, the CPU 4 can compose one screen by arranging the image signal being recorded and the image signal being reproduced, and display the input image signal being recorded and the reproduced image signal side by side on a CRT display. desirable.
Of course, depending on the user's selection, display of only the input image signal during recording, display of only the reproduced image signal, or display of an image in which both are displayed may be switched and displayed. Further, if the reproduction data is overwritten on the confirmed area of the DHDPPB after the reproduction data is transferred to the DHDPPB, the data at another position (different time) on the tape can be displayed continuously.

If the processing time of the reproduction operation becomes long, the recording data amount exceeds the storage capacity DHDREC of the HDD 6 for recording data.
For example, when the recording data amount is a recording data storage capacity DHDDR.
At the time when 80% of EC is reached, a caution signal for notifying the user of that is output. This attention signal is preferably combined with the output image signal and displayed on a display. The caution signal is not limited to the one displayed on the display, but may be, for example, an audio signal. Note that these controls are performed by, for example, the CPU 4.

FIG. 6 is a diagram for explaining a modification of the reproducing operation shown in FIG. In this modification, the write operation from the DTR buffer 8 to the HDD 6 is performed at time T16 for three times.
It is designed to be executed separately. Thus, after the user starts the reproduction operation, the output of the reproduction data from the CPU 4 can be actually started from a point in time delayed by the time T15 from the end of the first write operation to the HDD 6 ( FIG. 6 (e). That is, the time from the reproduction instruction by the user to the output of the reproduced image can be reduced as compared with FIG. 5, and the usability can be improved.

As described above, in the apparatus of this embodiment, the operation of writing the input image data to the HDD 6 and the operation of reading the data and recording the data on the DTR 7 when the data written to the HDD 6 is collected to some extent are performed in a time-division manner. Since the processing is executed, data input continuously for a long time can be reliably recorded at low cost. In other words, there is no problem that the recording medium becomes enormous as in the case of recording using only the conventional HDD, and there is no problem such as the lack of necessary data at the required moment due to intermittent recording such as in a time-lapse VTR. A high-performance digital data recording device can be realized.

Since the reproducing operation is always executed via the HDD 6, even when the same part is repeatedly reproduced, the HD
Since the reproduction process is performed on D6, the magnetic tape of the DTR 7 does not deteriorate. In addition, the access time for repeated reproduction can be significantly reduced.

Further, since the reproducing operation is also performed by the recording operation and time division, the recorded data can be reproduced without interrupting the recording operation. Further, the recorded image and the reproduced image can be simultaneously displayed on the display. Further, in the above data example, since the input data rate DR1 = 1.38 Mbps and the recording / reproducing data rate DR2 = 13.8 Mbps of DTR6, for example, if the recording operation of DTR7 is performed for about 3 minutes during 30 minutes, Since all input data can be recorded continuously,
The MTBF of the DTR 7 (mean time between failures), especially the life of the magnetic head, can be greatly extended in comparison with the use time.

(Second Embodiment) In the second embodiment, the hardware configuration and the basic recording / reproducing operation are the same as those in the first embodiment, and the operation for realizing the RAW (Read After Write) function is performed. , Under the control of the control unit 2. Hereinafter, this operation will be described with reference to FIGS.

That is, using the above data example,
Since DR2 = 10 × DR1, the input data for 30 minutes is recorded on the magnetic tape by the DTR 7 in about 3 minutes (FIG. 8, process P1), and the remaining 27 minutes (hereinafter “non-recording time”)
DTR7 is stopped. Therefore, in this embodiment, the data recorded on the magnetic tape during this non-recording time is reproduced (FIG. 8, process P2), and the reproduced data is transferred to the HD.
D6, the original data corresponding to the reproduced data and the reproduced data remaining in the HDD 6 are written to the CPU 6.
4 (FIG. 7 (b), time T17), and the CPU 4 compares these data (process P3). Then, as a result of the collation, when it is confirmed that the data is correctly recorded on the magnetic tape (when the reproduced data is the original data),
Transition to the stop state, and the DTR
7 is performed (process P1). On the other hand, as a result of matching,
When there is an error in the reproduced data (when the reproduced data is the original data), the operation of recording the original data again by the DTR 7 (process P4) and the re-verification operation of the re-recorded data (process P5, P6) To perform the recording operation of the DTR 7 at the next recording operation timing (process P1). When re-recording, the magnetic tape may be recorded at another position on the magnetic tape in consideration of the possibility that the magnetic tape has a defect such as a flaw.

In the above collation, the original data recorded in the HDD 6 is naturally overwritten (erased).
Must be run before. Therefore, it is desirable that the collation be performed immediately after one recording operation by the DTR 7 is completed. Here, a general DTR is disclosed in Japanese Unexamined Patent Application Publication No. 8-27510.
As described in Japanese Patent Laid-Open Publication No. 2 (1999), recording is performed by adding error correction code data to recording data, and data errors during reproduction (magnetic tape errors due to relatively small dropouts, flaws, etc.) are corrected by error correction codes. And output the reproduced data. The correction capability tends to be higher as the amount of error correction code data is larger. However, a data error due to a large dropout may not be completely corrected by the error correction code described above, resulting in an error in reproduced data.

On the other hand, the fact that the correction code could not be corrected, as represented by the parity code, can be specified from the error correction operation. That is, the presence or absence, the number, the scale, and the like of errors in the reproduced data can be confirmed by the error display in the correction code calculation during the DTR reproduction process.

Therefore, a means for confirming the above-mentioned error display is added to the DTR 7 so that errors in the reproduced data can be detected by the DTR 7.
7 to confirm that the correct recording has been performed, transfer of the reproduction data to the HDD 6,
Reserve area for writing reproduction data in DD6, HDD
Needless to say, the process of collating the original data with the reproduced data in 6 may be omitted.

FIG. 8 shows an example in which accurate recording on a magnetic tape has been performed by executing the re-recording / re-verification process once. Repeat the record rematch process. In that case, the recording operation (for example, a recording operation for 3 minutes for 30 minutes) is not prevented.

As described above, according to the present embodiment, a conventionally expensive RAW function can be realized at low cost without adding any hardware. In addition, DTR7
TRE required to record a certain amount of data
Since C and the time TPB required to reproduce the data are substantially equal, the data rate DR2 must be at least twice as large as the data rate DR1 in order to perform the above-described collation operation in a recording operation and time division. is necessary. Further, when it is determined by collation that the data has not been correctly recorded, it takes an additional time TREC to enable the re-recording operation to be performed once. Therefore, the data rate DR2 is at least larger than three times the data rate DR1. It is necessary.

(Third Embodiment) The first and second embodiments described above
In the embodiment, since there is no so-called cueing function of the image data recorded on the magnetic tape, when recording image data from a monitoring camera, for example, necessary image data cannot be easily searched from the recorded magnetic tape.

Therefore, in this embodiment, the hardware configuration and the basic recording / reproducing operation are the same as those in the first embodiment, and furthermore, a function for facilitating retrieval of image data required when image data is recorded. Is added, and realized by the processing of the control unit 2. That is, the digest data including the extracted image data formed by extracting a part of the input image data is transferred to the HD together with the input image data.
At the time of reproduction, the digest data is recorded from the magnetic tape and written to the HDD 6 by the DTR 7 via the D6, and is written to the HDD 6 by the user. The image data can be easily searched. Hereinafter, a more detailed description will be given with reference to FIGS.

In the present embodiment, as shown in FIG.
An image data area ROD for writing input image data and image data reproduced from the DTR 7 on the magnetic disk D6, and a recording digest data area for writing digest data including extracted image data extracted from the input image data RDJA and a reproduction digest data area RDJB for writing reproduction digest data reproduced from the magnetic tape by the DTR 7 are secured. Recording digest data area RDJ
The A and the reproduction digest data area RDJB both have a sufficient capacity to record the longest magnetic tape that can be recorded and reproduced by the DTR 7 for one magnetic tape. FIG. 9 is an explanatory diagram similar to FIG. 2 and does not necessarily mean that the areas ROD, RDJA, and RDJB are secured on different magnetic disks. The writing of the digest data to the HDD 6 is executed at substantially the same timing as the writing of the corresponding image data.

FIG. 10 is a view for explaining the recording position of the digest data on the magnetic tape. In this embodiment, the digest data recording area TR1 is secured from the top position TPS of the recordable area of the magnetic tape. From the end position TP1 to the position TP2 of the digest data recording area TR1, a non-recording area T where no signal is recorded is recorded.
The area from R2 to the end position TPE of the magnetic tape recordable area is set as the image data recording area TR3. Therefore, the control unit 2 avoids the digest data recording area TR1 and the non-recording area TR2 in advance and moves the position T
The DTR 7 is controlled to record image data from P2. The recording position of the digest data is not limited to this. For example, when the image data is recorded from the leading position TPS, and when the user instructs to take out the magnetic tape, the recording position of the digest data is set after the recording end position of the image data. Digest data may be recorded. However, it is desirable to secure a digest data recording area near the head position TPS. This is because the process of reproducing the digest data and writing it to the HDD 6 can be performed quickly.

FIG. 11 is a diagram for explaining the structure of the digest data. The digest data includes an area RDJ1 for storing identification data indicating the digest data, and a recording position indicating the recording position on the magnetic tape. An area RDJ2 for storing information NRP, an area RDJ3 for storing information indicating recording date and time, and an area RDJ4 for storing extracted image data. In the present embodiment, D
VISS (Video Index Search System) defined by the VHS (registered trademark) standard for home VTRs as TR7
The recording position information NRP
Is the NRP-th VISSI from the beginning of the magnetic tape
The position corresponding to the D signal is shown.

The VISSID signal is a marking signal recorded in a control signal area RCTL for recording a control signal of the magnetic tape as shown in FIG.
By counting from the PS, the absolute address of the magnetic tape can be specified, and by counting from any position on the magnetic tape, the relative address from that position can be specified. By referring to the VISSID signal, it is possible to access the designated position on the magnetic tape at a speed 100 to 200 times faster than the normal reproduction.

The recording position information NRP is information indicating the position from the head position of the magnetic tape. Therefore, if there is no data already recorded on the magnetic tape from which recording is started,
It is determined by sequentially incrementing from "1", and when there is already recorded data, the digest data recorded on the magnetic tape is first reproduced to obtain the maximum value of the recording position information NRP, and It is determined by sequentially incrementing from a value obtained by adding “1”.

In FIG. 12, RAD is an audio signal area for recording a linear audio signal and the like, RVD is a data signal area for recording a compressed image and audio signal,
For example, VISSID (k-1), VISSID (k), VISS
ID (k + 1) and corresponding image data DV (k-1),
The positional relationship between DV (k) and DV (k + 1) is as shown in FIG.

When the input image data is temporally continuous image data such as an output signal of a surveillance camera, the control unit 2 generates one frame of image data (thinned-out image data) at regular intervals from the input image data. Is extracted as extracted image data (RDJ4), and additional information RDJ1 to 3 are added to the extracted image data to constitute digest data.
For example, if the data example shown in the first embodiment is used as it is, the recording operation by the DTR 7 is executed in a unit of time T2 = 29 seconds (hereinafter, referred to as “DTR recording unit RU”). Of data for 4 minutes and 50 seconds (13.8 Mbps × 29 / 1.38 Mbps = 29)
0 seconds and the frame rate of the input image data is 30 frames / second, which is equivalent to 8700 frames of data). Therefore, the first frame is extracted for each DTR recording unit RU to form extracted image data. in this case,
As shown in FIG. 12, image data corresponding to the extracted image data (hereinafter referred to as “main image data” to distinguish from the extracted image data) DV (k−1), DV (k), DV (k + 1) Are arranged at equal intervals (29-second intervals in terms of time) on the magnetic tape.

The operation of reading out the recorded digest data written in the recorded digest data area RDJA of the HDD 6 and recording it in the area TR1 on the magnetic tape is as follows.
Executed immediately before the removal operation when the user instructs the removal of the magnetic tape (cassette tape) of the DTR 7 via the operation unit 21, or when the recording of the image data to the end position TPE of the magnetic tape is completed. Is executed.

When the input image data is composed of a plurality of programs such as a broadcast program, the extracted image data is a part of the plurality of programs instead of the thinned-out image data and has a predetermined continuous time TCONT. Image data (partial continuous image data) (for example, image data for the first 5 minutes of each program). Even when the input image data is a long-time continuous signal like the output image data of the monitoring camera, for example, a partial continuous image for a predetermined continuous time TCONT from the time when the intrusion of the suspicious person is detected by the ultrasonic sensor or the like. The data may constitute the extracted image data. Furthermore, the extracted image data is
The data may be composed of both the thinned-out image data of one frame every fixed time and the partial continuous image data.

The recording operation including the recording of the digest data described above is summarized as follows. (Step S1) Digest data including extracted image data obtained by extracting a part of the input image data is formed and written to the HDD 6 together with the image data.

(Step S2) The image data is stored in the HDD 6
From the magnetic tape by the DTR7.
R3 is sequentially recorded. (Step S3) Immediately before the removal of the magnetic tape or when the recording of the image data is completed up to the end position of the magnetic tape, the digest data is read out from the HDD 6 and read.
The data is recorded in the area TR1 of the magnetic tape by TR7.

Next, the operation during reproduction will be described. (Step S11) First, when the magnetic tape is inserted into the DTR 7, the control unit 2 reproduces the digest data recorded in the area TR1 of the magnetic tape by the DTR 7,
A reproduction initial operation for writing to the reproduction digest data area RDJB of the HDD 6 is executed. This reproduction initial operation is executed prior to other operations.

(Step S12) Next, the extracted image data included in the digest data is read from the HDD 6, subjected to image expansion processing, output, and displayed on a CRT display. At this time, the recording position information NRP and the recording date and time included in the digest data are read out, and superimposed on the reproduced extracted image and displayed.

(Step S13) The reproduction of the corresponding main image data is performed by referring to the extracted image data reproduced by the user.
When instructed via the operation unit 21, the control unit 2
In R7, a position (VISSID (k−)) which is temporally one VISSID signal earlier than the recording position indicated by the recording position information NRP (= k) corresponding to the reproduced extracted image data.
The operation of reproducing the main image data from the position 1)) and writing it to the HDD 6 is started, and the DTR 7 is controlled so that the operation is continued until the main image data to which VISSID (k + 1) is added (FIG. 12). PBP range). That is, the DTR is calculated from the main image data slightly earlier (4 minutes and 50 seconds in the above data example) than the image data designated by the user.
7 is started. DTR7 is VIS
When the reproduction operation of the main image data corresponding to SID (k + 1) is completed, the operation is stopped and the apparatus enters a standby state. At this time, the tape
Stop at the position where VISSID (k + 2) is detected.

(Step S14) The main image data written in the HDD 6 is sequentially read and output. (Step S15) When the user further instructs reproduction of the main image data corresponding to VISSID (k-2) via the operation unit 21, the DTR 7 stops at the position corresponding to VISSID (k + 2). Since the control unit 2 has the VISSID
= 4 (relative address) causes the DTR 7 to execute the reproduction operation.

The instruction by the user in (Step S13) is, for example, the recording position information NR displayed on the screen.
This is performed by inputting P or the recording date and time from the operation unit 21 or by displaying a desired image in a still image and inputting a trigger signal (for example, clicking with a mouse) from the operation unit 21 in that state.

The above is a description of the case where the extracted image data is thinned image data. If the extracted image data is partially continuous image data, the above-described (step S13) uses D
The TR 7 starts reproduction from the position indicated by the recording position information NRP, and after the reproduction of the extracted data is completed, continues the operation of sequentially reproducing the main image data recorded on the magnetic tape.

When the input image data is composed of a plurality of programs and the extracted image data is composed of thinned-out image data and partially continuous image data, the following operation is performed. Note that the partial continuous image data is image data of a time corresponding to the first DTR recording unit RU of each program (4 minutes and 50 seconds of input image data using the above-described data example). The operation until the extracted image data is displayed on the CRT display is basically the same as the above (Step S11) (Step S12), but the thinned image data is displayed first of the two types of extracted image data. The subsequent operation is as follows.

(Step S21) When the user looks at the reproduced thinned-out image data and instructs the reproduction of the corresponding main image data, the control unit 2 first reads out the partial continuous image data written in the HDD 6, and During the output, the main image data on the magnetic tape is reproduced from the position corresponding to the (NRP + 1) th VISSID obtained by adding “1” to the recording position information NRP of the digest data including the partial continuous image data. The DTR 7 is controlled to execute the operation of writing to the HDD 6. Here, the reason why the (NRP + 1) -th is set is that the image data for the first 1 DTR recording unit RU of the main image data is the same as the partially continuous image data.

(Step S22) The output of the main image data written in the HDD 6 is started immediately after the end of the output of the partial continuous image data, and the partial continuous image data of the selected program is continuously output to the main image data. . As described above, in the present embodiment, the digest data including the extracted image data together with the image data is recorded on the magnetic tape, so by referring to the extracted image data in the digest data at the time of reproduction, a large amount of image data can be obtained. Desired image data can be quickly searched from inside.

When the reproduction of the main image data is instructed with reference to the thinned-out image data included in the index data, the reproduction is started from the main image data slightly earlier than the instructed main image data. As a result, it is possible to improve the convenience when confirming images before and after a desired point in time in the input image data that is temporally continuous.

Further, by forming the extracted image data with the partial continuous image data, the corresponding main image data is accessed during the output of the partial continuous image data, and is temporally continuous with the partial continuous image data. Since the main image data is output, when the input image data is composed of a plurality of programs, the usability when searching and reproducing a desired program from the plurality of programs can be improved.

In the above-described embodiment, the extracted image data is recorded in the area TR1 of the magnetic tape, and the main image data including the extracted image data is recorded in the area TR3, that is, corresponding to the extracted image data. The image data is recorded in two places in an overlapping manner.
, The main image data excluding the extracted image data may be recorded. By doing so, the magnetic tape required for recording can be saved.

The time of the partial continuous image data is not limited to about 5 minutes as described above, but may be any time sufficient for the user to confirm the contents. However, in order to access the main image data following the partial continuous image data and output the main image data following the partial continuous image data, the maximum access time to the main image recording position on the magnetic tape is required. It is desirable to secure a time slightly longer than the value.

In this embodiment, it is desirable that the image compression method conforms to the JPEG (Joint Photographic Experts Group) standard. Consists of a frame.

(Other Embodiments) The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, in the configuration of FIG. 1 described above, the entire storage capacity of the HDD 6 is almost divided into two, and about half of the capacity is used for writing recording data, and the remaining half is used for writing reproduction data. However, the present invention is not limited to this, and the input data rate, the total storage capacity of the HDD 6,
The setting may be made in accordance with the cost and the needs of the apparatus in consideration of the continuous playback time, the time interval of the recording operation of the DTR 7, and the like. Further, as shown in FIG. 13A, an HDD 11 may be added to the configuration of FIG. 1, and one may be used for recording data and the other may be used for reproduction data. FIG.
In the configuration of (a), one of the HDDs 6 is dedicated to writing and the other HDD 11 is dedicated to reading only.
After the writing to all the areas is completed, the HDD 11 may be used for writing only and the HDD 6 may be used for reading only, and thereafter, the writing HDD and the reading HDD may be switched and used in the same manner.

Also, as shown in FIG. 3B, a DTR 12 and a DTR buffer 13 are added to the configuration of FIG. 1 so that one DTR is used for recording and the other DTR is used for reproduction. You may. In order to reproduce a tape different from the tape being recorded by one DTR, it is necessary to replace the tape during a period in which no recording operation is being performed and to reproduce the tape. Even when playing back, when performing the recording operation,
The playback operation needs to be interrupted, but according to the configuration shown in FIG. 13 (b), such replacement of cassettes and interruption of playback can be eliminated.

The data amount compression processing in the image compression processing unit 1 is not limited to the one conforming to the MPEG standard.
A method based on the PEG standard or another method may be used, or an image thinning processing unit that performs pixel thinning processing instead of compression processing may be used, or these may be used in combination.

In the above-described embodiment, the case where the data rate DR1 after the compression processing is constant is shown. However, the case where the compression rate in the image compression processing unit 1 is constant and the data rate DR1 fluctuates depending on the content of the image. Needless to say, this is fine. The amount of data stored in the CPU buffer 5 may be monitored, and the write time interval T1 and the write time T3 for the HDD 6 may be changed as appropriate.

In the first and second embodiments, the input digital data is not limited to a digitized image signal. For example, text information transmitted / received via a communication line may be transmitted to the apparatus of the present invention. The present invention may be applied to a general digital data monitoring apparatus including the above, and used for recording and reproducing general digital data. Alternatively, a combination of a digitized image signal and audio signal may be used as input digital data.

The HDD 6 may be replaced with a large-capacity semiconductor memory (RAM). In the above-described embodiment, the control unit 2, the HDD 6, the DTR 7 and the DTR buffer 8 are interconnected by the interface bus 10, but these components are interconnected via a communication line. You may do so.

In the above-described embodiment, the recording / reproducing apparatus for recording and reproducing digital data has been described.
The recording device having only the recording function or the reproducing device having only the reproducing function may be used.

[0076]

As described above in detail, according to the digital data recording apparatus of the first aspect, the input image data and the digest data including the extracted image data extracted from the input image data are recorded on the first recording medium. A first recording operation to be performed, and each time the amount of data recorded on the first recording medium by the first recording operation reaches a predetermined amount equal to or less than the recording capacity of the first recording medium, A second recording operation of reproducing the recorded image data and recording the second image data on the second recording medium by the recording device; and reproducing the digest data recorded on the first recording medium by the first recording operation. And the third recording operation for recording in a predetermined area of the second recording medium which is distinguished from the recording area of the image data is executed in a time-division manner, so that all data input continuously for a long time is reliably recorded. To do Can, moreover by first reproducing the digest data at the time of reproduction, it is possible to quickly find the desired image data.

According to the seventh aspect of the present invention, the first recording operation for recording the input image data and the digest data including the extracted image data extracted from the input image data on the first recording medium, Each time the amount of data recorded on the first recording medium by the recording operation reaches a predetermined amount equal to or less than the recording capacity of the first recording medium, the image data recorded on the first recording medium is reproduced. A second recording operation for recording on the second recording medium, and reproducing the digest data recorded on the first recording medium by the first recording operation, and recording of image data on the second recording medium by the recording means. A third recording operation for recording in a predetermined area distinct from the area, a second recording / reproducing means for reproducing image data recorded on the second recording medium, and a first recording / reproducing means for first recording. Record on media A first reproducing operation, a second reproducing operation of reproducing the digest data recorded on the second recording medium by the second recording / reproducing means, and first recording the digest data on the recording medium by the first recording / reproducing means; And the third reproduction operation for reproducing and outputting the extracted image data included in the image data or the digest data recorded on the first recording medium by the first or second reproduction operation is performed in a time-division manner. It is possible to reproduce the recorded data without interrupting the recording operation, and to output the extracted image data included in the digest data in a shorter time by executing the second reproducing operation first, It is possible to quickly search for desired image data.

According to the eleventh aspect of the present invention, when performing the reproducing operation according to the recording position information, the first image data from the image data slightly earlier than the image data corresponding to the recording position information is obtained. Since the reproduction operation is started, it is possible to improve the convenience when confirming the images before and after the desired point in the time-continuous input image data.

According to the thirteenth aspect of the present invention, the extracted image data is constituted by image data for a first predetermined continuous time of a plurality of programs, and the reproduction instruction is issued by the user during the reproduction and output of the extracted image data. When the extraction image data is reproduced and output, the operation of accessing the corresponding image data on the second recording medium and the first reproduction operation of the image data are performed during the reproduction and output of the extracted image data. The output of the corresponding image data can be performed following the output, and when the input image data is composed of a plurality of programs, the usability when searching and reproducing a desired program from the plurality of programs can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital data recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining endless recording.

FIG. 3 is a diagram illustrating conversion of a data rate by a buffer.

FIG. 4 is a diagram for explaining a recording operation of the apparatus of FIG. 1;

FIG. 5 is a diagram for explaining a reproduction operation of the apparatus of FIG. 1;

FIG. 6 is a diagram for explaining a reproduction operation of the apparatus of FIG. 1;

FIG. 7 is a diagram for explaining a collation operation of the apparatus of FIG. 1;

FIG. 8 is a diagram for explaining a collation operation and a re-recording / re-collation operation of the apparatus of FIG. 1;

FIG. 9 is a diagram for explaining a write / read operation of the hard disk device according to the third embodiment.

FIG. 10 is a diagram for explaining an area on a magnetic tape on which digest data is recorded.

FIG. 11 is a diagram showing a configuration of digest data.

FIG. 12 is a diagram for explaining a relationship between a signal indicating a recording position on a magnetic tape and recording data.

FIG. 13 is a block diagram showing a configuration of a modification of the configuration in FIG. 1;

[Explanation of symbols]

Reference Signs List 2 control unit (control means) 4 CPU (Central Processing Unit) 5 CPU buffer 6 hard disk drive (recording / reproducing means, first recording / reproducing means) 7 data tape recorder (recording means, second recording / reproducing means) 8 DTR buffer 10 Interface bus

────────────────────────────────────────────────── ─── Continuing from the front page (72) Koji Suzuki, Inventor 3-12-12 Moriyacho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside (72) Inventor Hiroyuki Kitamura 3--12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa (56) References JP-A-9-224215 (JP, A) JP-A-10-269699 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5 / 91-5/956 G11B 20/10 301

Claims (15)

(57) [Claims] 1. A digital data recording apparatus for recording input digitized image data on a recording medium, wherein the digital data is recorded on a first recording medium which can be recorded endlessly, and the recorded digital data is reproduced. Recording / reproducing means for performing recording; recording means for recording digital data on a second recording medium having a longer access time and a larger recording capacity than the first recording medium;
A first recording operation for recording endlessly on a first recording medium while recording digest data including frame-based extracted image data extracted from the input image data on the first recording medium. Whenever the amount of data recorded on the first recording medium reaches a predetermined amount equal to or less than the recording capacity of the first recording medium, the image data recorded on the first recording medium is reproduced, A second recording operation for recording on the second recording medium by the recording means; and digest data recorded on the first recording medium by the first recording operation, and the recording means reproducing the digest data. Control means for executing, in a time-division manner, a third recording operation for recording in a predetermined area of the recording medium which is distinct from the recording area of the image data. Apparatus. 2. The digital data recording apparatus according to claim 1, wherein said control means is configured to extract said image data from said input image data at predetermined sampling times. 3. The digital data recording apparatus according to claim 1, wherein said control means is configured to extract the extracted image data by extracting continuous image data for a predetermined continuous time from the input image data. . 4. The recording means is configured so that the second recording medium can be exchanged, and the control means controls the third recording medium when an instruction to remove the second recording medium is issued. 2. The digital data recording apparatus according to claim 1, wherein an operation is executed, and thereafter, the second recording medium can be taken out. 5. The image processing apparatus according to claim 1, wherein the control unit starts recording of the image data such that the predetermined area in which the digest data is recorded is secured near a head position of a recordable range of the second recording medium. 5. The digital data recording device according to claim 1, wherein the position is controlled. 6. The recording medium according to claim 1, wherein the control unit includes, in the digest data, recording position information indicating a recording position of the corresponding image data on the second recording medium. The digital data recording device according to any one of the above. 7. A digital data recording / reproducing apparatus for recording input digitized image data on a recording medium and reproducing the recorded image data, wherein the digital data is recorded on a first recording medium which can be recorded endlessly. First recording / reproducing means for recording and reproducing the recorded digital data; and digital data recorded on a second recording medium having a longer access time and a larger recording capacity than the first recording medium. A second recording / reproducing means for reproducing digital data; an endless recording of the input image data on the first recording medium by the first recording / reproducing means; and a frame unit extraction from the input image data. A first recording operation for recording digest data including image data on the first recording medium; and a first recording operation. The amount of data recorded on the first recording medium, the first
Each time a predetermined amount equal to or less than the recording capacity of the recording medium is reached, the image data recorded on the first recording medium is reproduced, and the second recording / reproducing means records the image data on the second recording medium. And reproducing the digest data recorded on the first recording medium by the first recording operation, and recording the image data on the second recording medium by the second recording / reproducing means. A third recording operation for recording data in the discriminated predetermined area, and reproducing the image data recorded on the second recording medium by the second recording / reproducing means, and reproducing the first data by the first recording / reproducing means. A first reproducing operation for recording on the recording medium, and reproducing the digest data recorded on the second recording medium by the second recording / reproducing means.
A second reproducing operation for recording on the recording medium, and reproducing and outputting the extracted image data included in the image data or the digest data recorded on the first recording medium by the first or second reproducing operation. A digital data recording / reproducing apparatus, comprising: control means for executing the third reproducing operation in a time-division manner. 8. The second recording / reproducing means is configured so that the second recording medium is replaceable, and the control means is configured to insert the second recording medium into the second recording / reproducing means. 8. The digital data recording / reproducing apparatus according to claim 7, wherein said second reproducing operation is executed when said operation is performed. 9. The digital data according to claim 8, wherein the control unit includes, in the digest data, recording position information indicating a recording position of the corresponding image data on the second recording medium. Recording and playback device. 10. An operation means for a user to instruct reproduction of image data corresponding to the digest data by referring to the extracted image data included in the digest data, and the control means includes a step of: The second recording / reproducing means executes an access operation for accessing the image data on the second recording medium with reference to recording position information included in the digest data for which the reproduction instruction has been issued, and 10. The digital data recording / reproducing apparatus according to claim 9, wherein the first and third reproducing operations are executed to output corresponding image data. 11. The input image data is temporally continuous image data, and when executing a reproducing operation in accordance with the recording position information, the control means controls the image corresponding to the recording position information. 11. The digital data recording / reproducing apparatus according to claim 10, wherein control is performed such that the first reproducing operation is started from image data slightly earlier than data. 12. The apparatus according to claim 1, wherein the control unit is configured to extract the extracted image data by extracting continuous image data for a predetermined continuous time from the input image data.
2. The digital data recording / reproducing apparatus according to item 0. 13. The input image data comprises a plurality of programs, and the control means comprises the extracted image data as image data for a first predetermined continuous time of the plurality of programs. 13. The digital data according to claim 12, wherein when the reproduction instruction is given by the user during the reproduction output, the access operation and the first reproduction operation are executed during the reproduction output of the extracted image data. Recording and playback device. 14. The input image data comprises a plurality of programs, and the control means converts the extracted image data to thinned-out image data formed by extracting image data from the input image data every predetermined sample time. 11. The digital data recording / reproducing apparatus according to claim 10, wherein the digital data recording / reproducing apparatus comprises partial continuous image data formed by extracting continuous image data for the first predetermined continuous time of each of the plurality of programs. 15. The control means, when the reproduction instruction is issued by a user with reference to the thinned-out image data, the first and third partial continuous image data corresponding to the thinned-out image data. Executing a first reproducing operation on the image data corresponding to the partial continuous image data after the first reproducing operation on the partial continuous image data is completed. 15. The digital data recording / reproducing apparatus according to claim 14, wherein the third reproducing operation is performed on image data temporally continuous with the partial continuous image data, following the third reproducing operation. apparatus.