JP2002300568A - Monitor camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitor camera system which can get the appropriate image quality in a reproduced video, covering each camera, and facilitates computation of the video recording time to the data storage means of limited storage capacity. SOLUTION: This monitoring camera system possesses cameras 1A and 1B, a controller 3, a data storage means 4, and a monitor 5. The controller 3 is equipped with a control circuit, which includes a plural-camera-channel receiving function, an image data conversion function, a data compression function which forms compressed image data, by compressing the digital image data and also whose compressibility is changeable by each camera channel, a storage output function, a data expansion function which obtains image data, by extending the compressed image reproduced data and outputted from a storage means, a video signal conversion function, and a monitor output function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surveillance camera system having a function of receiving a plurality of camera channels.

[0002]

2. Description of the Related Art In a conventional surveillance camera system of this type, the compression ratio of video data is configured to apply a common value to all camera channels.

[0003]

For this reason, when a different image is input for each camera, the amount of data differs for each camera channel, and the amount of data is extremely increased or decreased. Cannot calculate the video storage time that can be stored in a finite data storage device.
Therefore, it is unclear how long recording can be performed on the data storage device. Therefore, the actual video data capacity is manually checked and the reproduction video state and the compression ratio are set by trial and error, thereby estimating the recording time.

Also, if a high compression rate is applied to a video with a small amount of video data, the image quality of the reproduced video will be degraded. The amount of data becomes very large, and data with a higher image quality than necessary is stored, which causes a disadvantage that the recording time is extremely reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a surveillance camera system capable of obtaining an appropriate image quality of reproduced video over each camera channel and easily calculating a video recording time for data storage means having a finite storage capacity. I do.

[0006]

A surveillance camera system according to the first aspect of the present invention comprises: a camera; a plurality of camera channel reception functions capable of receiving video signals from a plurality of cameras; and converting the received video signals into digital image data. An image data conversion function, a data compression function of compressing digital image data to form compressed image data, a compression ratio variable for each camera channel, and a storage output function of outputting compressed image data to data storage means, A data decompression function for decompressing compressed image data reproduced and output from the data storage means to obtain digital image data, a video signal conversion function for converting digital image data into a video signal,
And a controller including a monitor output function for outputting a video signal to a monitor described later; data storage means for storing and reproducing compressed image data output from the storage output function; and displaying video data output from the monitor output function. And a monitor that performs the operation.

In the present invention and each of the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

<About Cameras> The number of cameras used may be one or more. In addition, power may be supplied to the camera by superimposing the captured video signal on a single coaxial cable connected between the camera and the controller, or separately from the video signal. May be supplied. Further, the camera may be of either color or monochrome type.

<Regarding the Controller> The controller is a central part of the surveillance camera system, and is connected to a camera, data storage means and a monitor which will be described later.
Send and receive required data. Also, the controller
It includes at least a camera channel reception function, an image data conversion function, a data compression function, a storage output function, a data expansion function, a video signal conversion function, and a monitor output function.

The camera channel receiving function is a function capable of receiving video signals from a plurality of camera channels. This function only needs to have the ability to connect a plurality of cameras regardless of the number of cameras actually connected.

The image data conversion function is a function of converting a received video signal into digital image data by A / D conversion in the camera channel reception function.

The data compression function is a function of compressing digital image data to form compressed image data.
At the time of the compression, the compression ratio is variable for each camera channel. Note that the compression ratio may be automatically set according to the digital image data, or may be set by a user operation. Of course, both setting functions are provided, and it is allowed to make them selectable. The method of compressing digital image data is not particularly limited, but when an image is stored as a still image for each frame, the JPEG method can be adopted. Then, the compression ratio can be selected for each camera channel on the monitor screen. Note that the number of cut frames (number of frames / second) can be set in the same manner.

The storage output function is a function of sending compressed image data to a data storage means described later in order to record the compressed image data.

The data decompression function is a function for decompressing the compressed image data reproduced by the data storage means and returning it to the original digital image data.

The video signal conversion function is a function of D / A converting digital image data and returning it to a video signal.

The monitor output function is a function of transmitting a video signal to a monitor for imaging.

<Regarding the Data Storage Unit> The data storage unit is a unit for storing image data. In order to reproducibly store video signals received from a plurality of camera channels, a unit having a large storage capacity is generally used. Can be
For example, a hard disk storage device, a DVD storage device, and a long-time VTR can be used.

The data storage means may be housed in a case independent of the controller, or may be housed in the case of the controller.

<Monitor> A monitor is a means for converting a video signal into an image. The monitor may display image data currently captured by a camera, or may display a video signal obtained by reproducing from a data storage means. It may be displayed. Of course, any of the above video signals can be arbitrarily selected and displayed. In addition, the monitor can display images of a single or multiple camera channels.

<Operation of the Present Invention> In the present invention, since an appropriate compression ratio is set for each of a plurality of camera channels, an appropriate image quality of a reproduced video can be obtained for each of the camera channels. Further, the calculation of the video storage time in the data storage means having a finite storage capacity becomes easy. Therefore, convenience is improved.

According to a second aspect of the present invention, a surveillance camera system comprises:
2. The surveillance camera system according to claim 1, wherein the data compression function includes: a compression ratio varying unit that varies a compression ratio for each camera channel; an image data amount detection unit that detects a digital image data amount for each camera channel; And an adjusting means for setting the compression ratio by operating the compression ratio variable means so that the storage data amount for each of them becomes substantially constant.

The present invention defines a configuration in which the compression ratio of digital image data is automatically set for each camera channel. In detecting the amount of digital image data, an average value over a certain period of time can be obtained.

Thus, in the present invention, since the compression ratio of digital image data is automatically set for each camera channel, a great saving in setting the compression ratio is achieved.
In addition, an appropriate image quality can be obtained for the reproduced video, and an inappropriate setting is not performed, so that an appropriate video storage time can be obtained.

According to a third aspect of the present invention, a surveillance camera system comprises:
The surveillance camera system according to claim 1 or 2,
The data compression function is characterized in that the data compression ratio can be arbitrarily changed for each camera channel.

The present invention defines a configuration in which the compression ratio once set manually or automatically can be changed according to circumstances.

Thus, in the present invention, the above configuration enables the compression ratio to be changed to a desired compression ratio each time for various reasons. In particular, even when the compression ratio is automatically set, it is possible to set the compression ratio according to the user's feeling and the purpose of the image instead of the standard and uniformly set compression ratio. it can.

[0027]

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

FIG. 1 is a system block diagram showing one embodiment of the surveillance camera system of the present invention.

FIG. 2 is a system block diagram showing the internal structure of the controller.

In each figure, 1A and 1B are cameras, 2 and
2 is a coaxial cable, 3 is a controller, 4 is data storage means, and 5 is a monitor.

The cameras 1A and 1B are two color video cameras, each connected to one camera channel of the controller 3 by one coaxial cable 2.

The coaxial cables 2, 2 are connected to the cameras 1A, 1B
And the controller 3 are connected to each other to supply power from the controller 3 and transmit video signals transmitted from the cameras 1A and 1B to the controller 3.

As shown in FIG. 2, the controller 3 has a control circuit 3a, a camera interface 3b and a monitor interface 3c. The control circuit 3a
Multiple camera channel reception function, image data conversion function,
It has a data compression function, a storage output function, a decompression function, a video signal conversion function, and a monitor output function. The camera interface 3b includes the cameras 1A and 1B and the control circuit 3.
a and is connected to the multiple camera channel reception function inside the control circuit 3a. Similarly, the monitor interface 3c is interposed between the monitor 5 and the control circuit 3a, and is connected to a monitor output function inside the control circuit 3a. The data compression function of the control circuit 3a is configured to perform automatic setting and manual change setting. The manual change setting is configured to be operated while viewing the display of the menu screen of the monitor 5.

The data storage means 4 comprises a hard disk type storage device, and is connected to the storage output function of the control circuit 3a.

[0035]

According to each of the first to third aspects of the present invention, a camera, a controller, a data storage means and a monitor are provided, and the controller has a data compression function of varying a compression ratio for each of a plurality of camera channels. By doing
Since an appropriate compression ratio can be set for each camera channel, an appropriate image quality of the reproduced video can be obtained for each camera channel, and the calculation of the video storage time in the data storage means having a finite storage capacity is facilitated, which is convenient. Can be provided.

According to the second aspect of the present invention, the data compression function varies the compression ratio for each camera channel, and the image data amount detection unit detects the amount of digital image data for each camera channel. Adjusting means for setting the compression ratio by operating the compression ratio variable means so that the storage data amount for each camera channel becomes substantially constant, so that the compression ratio of digital image data is automatically set for each camera channel. Monitoring system that can save the labor of setting the compression ratio, achieves the appropriate image quality of the reproduced video, and prevents improper settings from being performed. Can be provided.

According to the third aspect of the present invention, in addition, the data compression function can arbitrarily change the data compression ratio for each camera channel, so that the compression ratio can be set according to the user's feeling and the purpose of the image. A possible surveillance camera system can be provided.

[Brief description of the drawings]

FIG. 1 is a system block diagram showing an embodiment of a surveillance camera system of the present invention.

FIG. 2 is a system block diagram showing an internal configuration of the controller.

[Explanation of symbols]

 1A ... Camera 1B ... Camera 2 ... Coaxial cable 3 ... Controller 4 ... Data storage means 5 ... Monitor

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme coat II (Reference) H04N 7/24 H04N 7/13 Z F Term (Reference) 5C053 GB28 LA01 5C054 AA01 CC02 EG01 GB01 HA18 5C059 KK22 SS06 SS11 TA60 TB00 TC15 TD11 UA02 UA05 UA34 5C084 AA13 BB31 DD11 GG43 GG52 GG78 HH10 HH12 HH13

Claims (3)

[Claims] A camera; a plurality of camera channel receiving functions for receiving video signals from a plurality of cameras; an image data conversion function for converting received video signals into digital image data; A data compression function that forms image data and has a variable compression ratio for each camera channel, a storage output function that outputs compressed image data to a data storage unit, and a compressed image data that is reproduced and output from the data storage unit. A controller including a data decompression function for obtaining digital image data, a video signal conversion function for converting digital image data into a video signal, and a monitor output function for outputting a video signal to a monitor described below; output from the storage output function Data storage means for storing and reproducing compressed image data; from a monitor output function Surveillance camera system characterized in that it comprises a; a monitor for displaying the force video data. 2. A data compression function comprising: a compression ratio variable unit for varying a compression ratio for each camera channel; an image data amount detection unit for detecting a digital image data amount for each camera channel; and a storage data amount for each camera channel. 2. The surveillance camera system according to claim 1, further comprising adjusting means for setting a compression ratio by operating a compression ratio variable means so that the compression ratio becomes substantially constant. 3. The surveillance camera system according to claim 1, wherein the data compression function is capable of arbitrarily changing a data compression ratio for each camera channel.