JP2003244647A - Image recording apparatus for monitoring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording apparatus for monitoring capable of recording an image signal from a monitor camera at an optimum compression rate matching the capacity of a recording medium and a recording time. <P>SOLUTION: After an analog/digital converter section 1 digitizes an image signal S1 outputted from a monitor camera, a JPEG compression section 2 compresses a still picture in compliance with the JPEG system and records the signal at an initially set recording interval on a hard disk 3. A data count section 4 counts the amount of data compressed by a JPEG compression section 2 and a maximum data quantity calculation processing section 5b of an MPU 5 captures the count by e.g. 1 minute. The maximum data quantity calculation processing section 5b calculates a maximum data quantity capable of being recorded by each prescribed time on the basis of the residual capacity of the recording medium received from the hard disk 3 and the recording time required for monitoring. A compression rate control processing section 5c as a compression rate control means calculates the compression rate so that the data quantity after the compression is a maximum data quantity or below to control the compression rate of the JPEG compression section 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveillance image recording apparatus for recording an image signal from a surveillance camera.

[0002]

2. Description of the Related Art Since an image recording apparatus for recording image information from a surveillance camera needs to record for a long time, generally, JPEG is used after digitizing an image from the surveillance camera at every predetermined time.
(Joint Photographic Experts Group) is doing intermittent recording to compress and record. In the image recording by such a digital method, the recording time changes depending on the data amount of the compressed image. Therefore, if the compression rate is set high, the image quality of the reproduced image is deteriorated without using up the capacity of the recording medium, and if the compression rate is set low, a time zone in which recording cannot be performed occurs. There is.

Japanese Unexamined Patent Publication No. Hei 7-162850 discloses a method of adjusting the compression rate for each scene change frame so that the output bit rate is constant, as a method of adjusting the compression rate of moving image data. However, in this method, since the output is performed at a constant bit rate regardless of the data amount of the image, the image quality is deteriorated in the image having a large data amount. In addition, it is difficult to deal with emergency recording such as image recording of a surveillance camera, which switches from intermittent recording to continuous recording in response to an emergency signal from a sensor that detects an emergency.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and monitoring image recording for recording an image signal from a monitoring camera at an optimum compression rate according to the capacity and recording time of a recording medium. The purpose is to provide a device.

[0005]

In a surveillance image recording apparatus for compressing an image signal from a surveillance camera by a compression means and recording it on a recording medium, a data amount calculation means for calculating the data amount of the compressed image, Recording data amount calculation means for calculating the maximum amount of data that can be recorded at predetermined time intervals from the remaining amount of data recorded and the total capacity of the recording medium and the recording time required for monitoring, and the maximum amount of data after compression The compression rate control means for controlling the compression rate of the compression means is provided so as to be equal to or less than the amount so that the image signal from the surveillance camera can be recorded on the recording medium for a predetermined time.

The compression means is JPEG (Joint Photogra
Phic Experts Group) is used for still image compression, and recording on the recording medium is intermittent recording to record still images at specified time intervals, and the recording interval is controlled along with the maximum data amount based on the remaining capacity and the recording time required for monitoring. To

The compression means is a JPEG (Joint Photog
raphic Experts Group) still image compression and MPEG
Video compression by (Moving Picture Experts Group) and JPEG by output from sensor that detects an emergency
An intermittent continuous switching means for switching and recording the output from the MPEG and the output from the MPEG is provided to enable continuous recording by the sensor output.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to Examples. FIG. 1 is a block diagram of essential parts of one embodiment of a monitoring image recording apparatus according to the present invention. The image signal S1 output from the surveillance camera is transferred to the A / D converter 1
After being digitized by, the still image is compressed by JPEG in the JPEG compression unit 2 as a compression means. The compressed image data is stored in the hard disk 3 as a recording medium.
First, the recording interval control processing unit 5a of the MPU 5 initializes and records at the recording interval. The data amount compressed by the JPEG compression unit 2 is counted by the data counting unit 4 as a data amount calculating means, and is taken into the maximum data amount calculation processing unit 5b of the MPU 5 every one minute, for example. The maximum data amount calculation processing unit 5b calculates the maximum amount of data that can be recorded at predetermined time intervals from the remaining capacity of the recording medium taken from the hard disk 3 and the recording time required for monitoring. The compression rate control processing unit 5c as the compression rate control unit calculates the compression rate such that the data amount after compression is equal to or less than the maximum data amount, and controls the compression rate of the JPEG compression unit 2.

As a concrete example, first, the maximum data amount calculation processing section of the MPU 5 calculates the maximum data amount so that a predetermined recording time can be obtained. For example, if the recording capacity of the hard disk 3 is 60 GB and recording is performed for 24 hours, the maximum amount of data per minute is 60 GB / 24 hours / 60 minutes = about 42 MB. Therefore, in the compression rate control processing unit 5c, the
The amount of data per minute should be 42MB or less.
The PEG compression unit 2 is controlled. Similarly, the maximum data amount is calculated every one minute from the remaining capacity of the recording medium and the recording time required for monitoring. For example, hard disk 3 after 8 hours
If the remaining capacity of 50 GB is 50 GB, the maximum data amount per minute is 50 GB / (24-8) hours / 60 minutes = about 52 MB. Therefore, in the compression rate control processing unit 5c, the
The amount of data per minute should be 52MB or less.
The PEG compression unit 2 is controlled. As a result, the compression rate can be lowered according to the remaining capacity of the hard disk 3,
It is possible to record a monitoring image for a predetermined time with better image quality.

In addition, in a situation where it is desirable for monitoring recording to shorten the recording interval instead of improving the image quality of the image to be recorded, the recording interval control processing unit 5a of the MPU 5
It is also possible to set a shorter recording interval on the hard disk 3 within the range of the maximum data amount.

FIG. 2 is a block diagram of the essential parts of another embodiment of the monitoring image recording apparatus according to the present invention. The same functional parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, as the compression means, in addition to the JPEG compression unit 2 for compressing a still image, an MPEG compression unit 22 for compressing a moving image and a changeover switch 26 for switching these outputs and sending them to the hard disk are provided. In addition, a sensor signal S2 from a sensor that detects an emergency such as a fire or intrusion of a suspicious object that is detected by an infrared sensor is input to the MPU 5.
Then, the emergency recording processing unit 25d causes the changeover switch 2
6, the still image from the JPEG compression unit 2 is intermittently recorded on the hard disk 3 during normal operation, and the MPE
The moving image from the G compression unit 22 is continuously recorded. In this embodiment, the intermittent continuous switching means is composed of the changeover switch 26 and the emergency recording processing section 25d. Even if there is a period for recording such a moving image, it is possible to perform a predetermined time monitoring recording by the control function of the compression rate or recording interval every minute.

[0012]

As described above, in the surveillance image recording apparatus for compressing the image signal from the surveillance camera by the compression means and recording it on the recording medium, the data amount calculation for calculating the data amount of the compressed image is calculated. Means, a recording data amount calculating means for calculating the maximum data amount that can be recorded at a predetermined time from the remaining capacity calculated from the recorded data amount and the total capacity of the recording medium, and the recording time required for monitoring, and the compressed data amount. The compression rate control means for controlling the compression rate of the compression means is provided so that the value becomes less than the maximum data amount, and the compression rate is controlled according to the data amount, so that the image signal from the surveillance camera is recorded with the best image quality. It becomes possible to record on the medium for a predetermined time.

[Brief description of drawings]

FIG. 1 is a block diagram of an essential part of an embodiment of a surveillance image recording apparatus according to the present invention.

FIG. 2 is a block diagram of a main part of another embodiment of the monitoring image recording apparatus according to the present invention.

[Explanation of symbols]

1 A / D converter 2 JPEG compression section 3 hard disk 4 Data counter 5 MPU 5a Recording interval control processing unit 5b Maximum data amount calculation processing unit 5c Compression rate control processing unit 22 MPEG compression unit 25d Emergency recording processing unit 26 Changeover switch S1 image signal S2 sensor signal

Claims (3)

[Claims] 1. In a surveillance image recording apparatus for compressing an image signal from a surveillance camera by a compression means and recording it on a recording medium, a data amount calculation means for calculating a data amount of an image after compression, and a recorded data amount. And a recording data amount calculation means for calculating the maximum amount of data that can be recorded at predetermined time intervals from the remaining capacity calculated from the total capacity of the recording medium and the recording time required for monitoring, and the amount of data after compression is less than the maximum data amount. Compression rate control means for controlling the compression rate of the compression means is provided,
An image recording apparatus for surveillance, characterized in that an image signal from a surveillance camera can be recorded on a recording medium for a predetermined time. 2. The compression means is a JPEG (Joint Photog)
Still image compression by raphic Experts Group), recording on the recording medium is intermittent recording to record still images at specified time intervals, and the recording interval is controlled along with the maximum data amount based on the remaining capacity and the recording time required for monitoring. The monitoring image recording apparatus according to claim 1, wherein: 3. The compression means is JPEG (Joint Phot).
Image compression and MPEG by ographic Experts Group)
Video compression by (Moving Picture Experts Group) and JPEG by output from sensor that detects an emergency
2. The monitoring image recording apparatus according to claim 1, further comprising an intermittent continuous switching means for switching and recording the output from the MPEG and the output from the MPEG to enable continuous recording by the sensor output.