JP2999990B2 - Digital VTR - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital VTR.
About.

[0002]

2. Description of the Related Art A VTR has been developed which records an image picked up by a surveillance camera on a video tape intermittently (time lapse) at a ratio of one field to a predetermined number of fields.

In this type of VTR, a rewind operation (RWD) is automatically performed when recording to the tape end is completed, and a recording operation (repeat recording) is automatically started again when rewinding to the tape top. Is done.

[0004] In such a VTR, even when a very important scene in security is recorded,
There is a problem that data is erased by repeat recording.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a VTR capable of preventing important scenes from being erased during repeat recording.

[0006]

According to a digital VTR according to the present invention, when a video tape reaches the vicinity of a tape end during a recording process, the video tape is automatically rewound to the tape top and the recording process is restarted. V
In the TR, an image data storage means for intermittently writing an image captured by a video camera into a memory, and every time predetermined one recording unit of image data is stored in the memory, the image data of one recording unit is transferred from the memory. Image data recording means for reading and recording on a video tape together with external information or rank information determined on the basis of an operator's designation among a plurality of importance ranks; Means for recording a rank change position signal indicating a rank change position by using the information, and each time the recording operation of the image data for one recording unit is completed, the importance rank information and the rank change position signal are used. The recording location of the next one recording unit does not overlap with the recording location where image data of a predetermined importance rank or higher is recorded. , Characterized in that it comprises a key scene erase prevention processing means for controlling the writing position.

[0007]

The important scene erasure prevention processing means includes, for example, a first means for performing reproduction processing for one recording unit, and whether or not rank information obtained by the reproduction processing includes rank information of a predetermined rank or more. The second means for determining whether the rank information obtained by the reproduction processing does not include rank information equal to or higher than the predetermined rank, and the third means for rewinding by one recording unit, If the rank information includes rank information equal to or higher than a predetermined rank, the video tape is sent to the position where the next rank change position signal is recorded, and then a reproduction process for one recording unit is performed. Fourth means for determining whether or not the rank information obtained by the processing includes rank information equal to or higher than a predetermined rank; If the rank information higher than the predetermined rank is not included, the same processing as the third means is performed. If the rank information obtained by the reproduction processing includes the rank information equal to or higher than the predetermined rank, the fourth processing is performed. What has the 5th means which performs the same process as a means is used.

In the case where the importance rank information recorded by the image data recording means indicates either the first rank with high importance or the second rank with low importance, the important scene erasure prevention processing means For example, 1
First means for performing a reproduction process for a recording unit, second means for determining whether rank information of the first rank is included in the rank information obtained by the reproduction process, rank information obtained by the reproduction process Does not include the rank information of the first rank, the third means for rewinding by one recording unit, and the rank information obtained by the reproduction processing includes the rank information of the first rank. In this case, the one provided with the fourth means for sending the video tape up to the point where the next rank change position signal is recorded is used.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a time lapse digital VTR for intermittently recording a video taken by a surveillance camera on a video tape and reproducing an image recorded on the video tape. FIG. 1 shows only a circuit for recording an image.

As is well known, a time-lapse digital VTR is an A / D converter 1 for converting an image signal from a surveillance camera (video camera) into a digital signal.
A memory 2 for temporarily storing digital image data obtained by the D converter 1, an image compression circuit 3 for performing image compression such as JPEG or MPEG on an image stored in the memory 2, an image compression circuit 3 An error correction code adding circuit 4 for adding an error correction code to the coded data obtained from, a SYNC etc. code adding circuit 5 for adding codes such as SYNC (synchronous) and ID (identification), and recording coding The circuit 6 is provided.

The image compression circuit 3 and the memory 2 are controlled by a microcomputer (microcomputer) 10.
Also, as is well known, the microcomputer 1
0 is connected to a CTL signal recording / reproducing circuit 11. Further, in this embodiment, a sensor (not shown) for detecting an intruder or the like is provided around the monitoring area.
When an intruder or the like is detected by the sensor, an alarm signal is output from the sensor. The alarm signal output from the sensor is input to the microcomputer 10.

In this example, the A / D converter 1 supplies 6
An image signal for 0 fields is input. The memory 2 has a capacity to store image data for 240 fields, and the image data is written at a rate of one field per second.

Every time image data for 240 fields (image data for one recording unit) is stored in the memory 2, that is, every four minutes, the data is read out, and the image compression circuit 3 Correction code addition circuit 4, SYN
Through a C-addition code adding circuit 5 and a recording coding circuit 6,
Recorded on videotape. In this embodiment, a flying erase head is provided as an erase head instead of a full-width erase head. The time required to record image data for 240 fields on a video tape is about 4 seconds. Even during this recording operation (during the reading period), the writing of the image data is performed.

As described above, the image data is recorded on the video tape at a predetermined interval every 240 fields. One recording operation is referred to as a recording operation of one recording unit. Therefore, the video tape is also intermittently sent in synchronization with the recording operation of one recording unit. When the video tape reaches the tape end, the same recording processing is performed after the video tape is automatically rewound to the tape top.

When reading image data from the memory 2, the microcomputer 10 adds rank information indicating the importance rank for each field. Therefore, rank information is also recorded on the video tape for each field. Then, at the change of the importance rank, the CTL signal recording / reproducing circuit 11 records the rank change position signal on the control track. As the rank change position signal, a VISS signal (consisting of 60 or more CTL signals representing "1") conventionally used for cueing may be used, or a VASS signal (after the VISS signal). (A control signal to be inserted) may be used. In this example, a VISS signal is used as the rank change position signal.

In this example, the importance rank includes a first rank having a high importance and a second rank having a low importance. At all times, the importance rank is set to the second rank,
Since the scene within a predetermined time after the input of the alarm signal is considered to be an important scene for security, the importance rank is set to the first rank.

Further, the microcomputer 10 has a configuration shown in FIG.
As shown in (1), when the recording operation for one recording unit is not performed, the important scene erasure prevention processing is performed.

FIG. 3 shows an important scene erasure prevention processing procedure.

The data recorded in the recording operation from the tape top to the tape end of the video tape currently being performed is called new data, and the data previously recorded on the video tape is called old data. I do.

When the recording operation of the new data for one recording unit is completed, a reproduction process for one recording unit is performed (step 1). That is, the video tape is caused to run by one recording unit, and the old data for one recording unit is read from the video tape and reproduced.

It is determined whether the rank information obtained by the reproduction process includes the rank information of the first rank (step 2).

When the rank information obtained by the reproduction process does not include the rank information of the first rank, that is,
If all of the rank information obtained by the reproduction processing is the rank information of the second rank, the video tape is rewound by one recording unit (step 3), and the important scene erasure prevention processing of this time ends.

If the rank information obtained by the reproduction process includes the rank information of the first rank, the next V
The video tape is fast-forwarded until an ISS signal (rank change position signal) is recorded (step 4). Then, the important scene erasure prevention process ends.

In the important scene erasure prevention process, when the process of step 3 is performed, in the next recording operation of one recording unit, the new data recorded by the previous recording operation of one recording unit is used. Subsequently, new data is recorded.

In the important scene erasure prevention processing, if the processing of the above step 4 is performed, in the next recording operation of one recording unit, the position where the data was recorded by the previous recording operation of one recording unit. Thus, the data is recorded by skipping the recording position where the old data whose importance rank is the first rank is recorded. That is, it is possible to prevent the new data from being overwritten in a location where a scene important for security is recorded.

In the digital VTR as described above, when repeat recording is repeatedly performed, only data for important scenes remains, and the security check time is shortened.

In the above embodiment, there are two types of importance ranks, but three or more types may be set. Then, the operator may be able to specify a rank for preventing overwriting. The importance rank may be set based on a time zone, various sensors, an input signal input based on an operation of a monitor, and the like.

[0030]

According to the present invention, it is possible to prevent important scenes from being erased during repeat recording.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a digital VTR.

FIG. 2 is a time chart showing timing at which important scene erasure prevention processing is performed.

FIG. 3 is a flowchart illustrating an important scene erasure prevention processing procedure;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 A / D converter 2 Memory 3 Image compression circuit 4 Error correction code addition circuit 5 SYNC etc. code addition circuit 6 Recording / coding circuit 10 Microcomputer 11 CTL signal recording / reproduction circuit

Claims (3)

(57) [Claims] When a video tape reaches the vicinity of a tape end during a recording process, the video tape is automatically rewound to the tape top, and in a digital VTR where the recording process is restarted, an image captured by a video camera is read. Image data storage means for intermittently writing to a memory, each time predetermined one recording unit of image data is stored in the memory, reads out the one recording unit of image data from the memory, and from among a plurality of importance ranks, Image data recording means for recording on a video tape together with rank information determined on the basis of a signal or an operator's designation.
Means for recording a rank change position signal indicating a rank change position using an L signal, and each time a recording operation of image data for one recording unit is completed, the determined rank information, a rank change position signal, Important scene erasure prevention processing means for controlling the writing position so that the recording location of the next one recording unit does not overlap with the recording location where image data of a predetermined rank or higher is recorded. Time-lapse digital V
TR. 2. The important scene erasure prevention processing means includes: first means for performing reproduction processing for one recording unit; and determining whether rank information obtained by the reproduction processing includes rank information equal to or higher than a predetermined rank. Second means for determining, if the rank information obtained by the reproduction processing does not include rank information equal to or higher than a predetermined rank, third means for rewinding one recording unit, and rank obtained by the reproduction processing. If the information includes rank information equal to or higher than a predetermined rank, the video tape is sent to a position where the next rank change position signal is recorded, and then a playback process for one recording unit is performed. Means for determining whether or not the rank information obtained by the reproduction process includes rank information higher than a predetermined rank. If no rank information is included, the same processing as the third means is performed. If the rank information obtained by the reproduction processing includes rank information equal to or higher than a predetermined rank, the same processing as the fourth means is performed. 5. The time-lapse digital V according to claim 1, further comprising: a fifth unit that performs processing.
TR. 3. The importance rank information recorded by the image data recording means indicates either a first rank having a high importance or a second rank having a low importance. A first means for performing a reproduction process for one recording unit; a second means for determining whether or not the rank information obtained by the reproduction process includes rank information of the first rank; If the rank information does not include the rank information of the first rank, third means for rewinding by one recording unit, and the rank information obtained by the reproduction processing include the rank information of the first rank. 4. The time lapse digital V according to claim 1, further comprising: a fourth means for sending the video tape until the next rank change position signal is recorded.
TR.