JP2001339686A - Image data processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce storage capacity, while the image data with the high importance is stored in order to become high resolution. SOLUTION: The video signal outputted from camera 1 is quantized in a quantization means 22 and stored in a first storage area region 31. From the first storage area 31, the image data stored before the fixed period is read out and supplied to a means for reducing an amount of information 23, and the amount of data is reduced, when a controller 21 receives a timing signal that is outputted from a timer 24 every fixed period. The image data reduced the amount of data is stored in a second storage area. Further, the controller erases from the first storage area 31 the data corresponding to the image data read out from the first storage area 31, and the image data stored after that time is kept to be stored in the first storage area 31. The old data which passed more than the fixed period within the image data stored in the second storage area may be also erased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video data recording device, and more particularly to a video data recording device for reducing the amount of video data to be recorded in a monitoring system.

[0002]

2. Description of the Related Art Today, security systems using surveillance cameras are installed in banks, companies, schools, shops, homes, and the like. In the security system, an observer monitors images from a surveillance camera on a monitor screen as necessary, and stores the images on a storage medium such as a video tape or a hard disk. The video data stored in the storage medium is played back when necessary to check the state of the monitoring area.

When storing video data from such a surveillance camera in a storage medium, the storage capacity of the storage medium is limited, so that the data amount is reduced and stored. There is a time lapse method which is a recording method. In the time lapse method, FIG.
As shown in FIG.
.., For example, without storing even frames, only odd frames 1, 3, 5,. In this way, by not storing video signals at predetermined intervals,
By reducing the data amount, the time to be recorded can be extended equivalently. This interval can be set variably,
Thereby, the time to be recorded can be variably set. However, in the time lapse method, since the recording interval is intermittent, when an important one is included in the instantaneous video signal, it may not be possible to record the important one. May be overlooked.

[0004] One method of compressing and storing video data is to reduce the amount of data by not storing all pixel data in one frame. In this method, as shown in FIG. 2B, when one frame is composed of 720 × 480 pixels, for example, by storing every other horizontal and vertical direction of one frame, 1 pixel
Therefore, the data amount as a whole can be reduced to 1/4. However, in this case, since the video is recorded at a reduced resolution, the image quality during reproduction deteriorates. This makes it impossible to confirm the details at the time of reproduction when the details in the video include necessary information.

[0005] Furthermore, there is a method of reducing the amount of data by compressing the video data by the MPEG method or the like. However, this method also stores the image at a reduced resolution, so that the reproduction is performed in the same manner as described above. Sometimes it is impossible to see the required details. The present invention has been made in view of such problems of the conventional example, and an object of the present invention is to store video data of high importance in a video data storage device that records video data in a security system or the like. An object of the present invention is to store information in a storage medium so that details can be clearly displayed, that is, display can be performed at a high resolution, and the storage capacity of the storage medium can be relatively reduced.

[0006]

In order to achieve the above object, in a video data recording apparatus for recording video data according to the present invention, a first storage means for storing video data from a video data source; Information amount reducing means for reducing the data amount of data, second storage means for storing video data with reduced data amount, and control means for controlling the operation of the video data storage device, at an arbitrary timing,
From among the video data stored in the first storage means, data stored before an arbitrary predetermined period of the timing is read and supplied to the information amount reduction means, and the data amount is reduced to obtain the second data.
Control means for storing the image data in the storage means and for controlling the erasing of the video data read out from the first storage means. The first storage means and the second storage means may be the same storage medium or separate storage media.

[0007]

FIG. 1 shows an embodiment of a video data storage device according to the present invention. In FIG.
A camera such as a D camera, 2 is an information processing unit for processing a video signal from the camera 1, 3 is a recording medium, and 4 is a monitor.
The information processing unit 2 includes a controller 21, a quantization unit 22,
Information amount reducing means 23, timer 24, inverse quantization means 25,
Display driving means 26 is provided. The storage medium 3 includes a hard disk, a CD-R, a magneto-optical storage disk, and the like, and includes a first storage area 31 and a second storage area 32.
Contains.

In the information processing section 2, all operations are performed under the control of the controller 21. The video signal from the camera 1 is quantized by the quantization means 22 and compressed by the information amount reduction means 23 at a relatively low information reduction rate (including no reduction), and the signal is converted into pixel data in the first storage area. 31 is stored. Note that, as the camera 1, L
When a camera such as an AN camera having a quantization unit on the camera side is used, it is apparent that it is not necessary to incorporate the quantization unit into the information processing unit 2. On the other hand, as described above in connection with the conventional example, the information amount reducing means 22 operates to reduce the data amount by any method such as a time lapse method and a video compression method and a combination thereof. . The information reduction rate in the information amount reduction unit 22 is adjustable, and the video data from the quantization unit 22 has the information reduced at a relatively low rate and is read from the first storage area 31 as described above. In video data, information is reduced at a relatively high rate. The video signal whose data amount has been reduced is supplied to and stored in the second storage area 32.

The timer 24 measures time and sends a periodic timing signal to the controller 21 at a predetermined period (for example, every 12 hours, every 24 hours) or at a predetermined time (for example, every day at 3:00). Supply. In response,
The controller 2 performs control for reducing the amount of information as described in detail below. The operation for reducing the amount of information is performed not only when the timing signal is output from the timer 24 but also when the remaining storage capacity of the storage medium 3 is reduced to half or when the operator determines that it is necessary. You can also do so.

In the video data storage device of the present invention having such a configuration, the video signal from the camera 1 is transmitted to the display driving means 26 and the quantization means 22 of the information processing section 2.
Supplied to The video signal supplied to the display driving means 26 is displayed on the monitor 4. The video signal supplied to the quantization supply unit 22 is quantized by the quantization unit 22 under the control of the controller 21, and the information amount is reduced at a relatively low rate by the information amount reduction unit 23. 3 in the first storage area 31.

In such a state, when the timing signal is output from the timer 24, the controller 21 reads the video data from the first storage area 31 of the storage medium 3 out of the video data stored in the first storage area 31. All the video data stored at least a predetermined period before the timing signal is supplied is read out and supplied to the information amount reducing means 23. As a result, the data amount is reduced, and the video data having the reduced data amount is stored in the second storage area 32 under the control of the controller 21.
To be stored. At this time, the video data may be stored in the second storage area and displayed on the monitor 4 via the inverse quantization means 25 and the display driving means 26 at the same time.

When the timing signal is output, the controller 21 stores the data corresponding to the video data read from the first storage area 31 in the first storage area 3.
Erase from 1. At this time, the video data stored after the predetermined period is left without being erased in the first storage area 31. Therefore, the video data stored during the predetermined period is stored in the first storage area 31. Will remain stored. That is, even if the first storage area 31 stores the video data from the quantization means 22 in the first storage area without any compression (no compression) in the information amount reducing means 23,
It is sufficient to store the video data corresponding to twice the predetermined period, so that it is sufficient to have at least the storage capacity. Also,
By performing the processing at a high compression rate, the storage capacity of the first storage area can be reduced to twice or less.

[0013] Of the video data stored in the second storage area, old data that has passed a predetermined period or more may be deleted as necessary. Note that, as described above, the timing for compressing the information amount is not limited to the timing signal from the timer 24 only. The video data stored in the first and second storage areas is read as needed,
The image is displayed on the monitor 4 via the inverse quantization means 25 and the display driving means 26.

In the above embodiment, the first and second storage areas are set in the storage medium 3 so that the video data whose data amount is not reduced and the video data whose data amount is reduced can be stored respectively. However, it is also possible to provide these storage areas on separate storage media. For example,
The video data from the quantization means via the information amount reducing means may be stored on the hard disk, and the video data from the hard disk via the information amount reducing means may be stored on a separately provided video tape, CD-R, or the like. . In addition, the number of times the information amount is reduced by the information amount reduction unit 23 is not limited to once, and may be a plurality of times. For example, when a low-compression, high-quality image stored in the first storage area is set for one day, an image stored in the second storage area is converted to a high-compression, low-quality image for one week, and the high-compression image is stored for one week. Thus, a time-lapse video may be obtained by combining a plurality of information reduction techniques over a plurality of times so as to be one month worth of video.

[0015] Considering the state of utilization of video in a security system or the like, more recently captured information often includes information to be referred to, that is, a new video signal signal is more likely to be necessary information. . In the present invention, as described above, new video data with high importance can be stored without reducing the data amount, and old video data with relatively low importance can be stored with reduced data amount. Therefore, even if the storage capacity is limited, it can be effectively used, and relatively important video data can be reliably held.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a video data storage device of the present invention.

FIG. 2 is an explanatory diagram for explaining a time lapse method for reducing a data amount and one data compression method.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/915 H04N 5/92 H 5/765 5/91 K 7/18 L G11B 27/02 K F term (Ref.) BA26 BB07 CA02 DC03 5D110 AA13 AA16 AA17 AA27 AA29 BC05 CA04 CA13 CB06 CC02 CL03

Claims (4)

[Claims] 1. A video data recording apparatus for recording video data, a first storage means for storing video data from a video data source, an information amount reducing means for reducing a data amount of the video data, and a data amount reduced. A second storage unit for storing the obtained video data, and a control unit for controlling an operation of the video data storage device, wherein the video data stored in the first storage unit at an arbitrary timing. Reading the data stored before the predetermined period and supplying it to the information amount reducing means, reducing the data amount and storing it in the second storage means, and
A video data recording apparatus, comprising: a control unit that controls so as to erase the video data read from the first storage unit. 2. The video data storage device according to claim 1, wherein the first storage means and the second storage means are storage areas of the same storage medium. 3. The video data storage device according to claim 1, wherein the first storage means and the second storage means are separate storage media. 4. The video data storage device according to claim 1, wherein the information amount reducing unit further stores the video data stored in the first storage unit and the video data information stored in the second storage unit. A video data storage device comprising means for reducing at a reduction rate lower than the amount reduction rate.