JPH09261585A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide continuous monitor images by alternately performing access in time division manner while designating recording and reproducing addresses, and simultaneously performing recording and reproducing on real time. SOLUTION: A write mode is instructed from an instruction input part 6, image signal pixel data are fetched into a compression processing part 1, and the compression processing part 1 compresses this information quantity through a compression circuit. On the other hand, the number of addresses per block in the storage area of a memory part 3 is previously set and corresponding to the data amount of the source image and the kind of compression processing to be utilized, the number of addresses is set to a setting part based on maximum information quantity after compression. When the reading mode and the desired time of reading are instructed from the instruction part 6, writing is continued and reading is started at the same time so that the continuous monitor images can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus using a random access recording medium, and more particularly to a method for reproducing an already recorded image while recording the image or the like. .

[0002]

2. Description of the Related Art Conventionally, a VTR (Video Tape Recorder) has been in widespread use as a device for recording television programs and images from cameras. The VTR is used, for example, for recording / reproducing applications such as television programs, or for reproducing video tapes (package software) such as movies.

By the way, the VTR has industrial applications in addition to the above-mentioned home applications, and is used, for example, for recording / reproduction of a video surveillance system. In the surveillance system, for example, NTSC (National Telev
A video signal conforming to the Iion System Committee) is transmitted and continuously recorded in the VTR. The watcher watches the current video on the monitor display and also plays back the video during the time when he / she was away from his / her seat to watch the video as appropriate.

However, since the VTR is a serial access type recording, recording cannot be performed at the same time while the video is reproduced. Therefore, during the playback time, continuous monitoring video recording will be interrupted, and part of the recording will be lost, so past images cannot be played back while recording in real time. It was a system performance problem.

Further, in order to obtain continuous monitoring video recording, a method of dividing the video signal into two and recording the video signals by using two VTRs can be considered, but there is a problem of cost increase.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to access a recording address and a reproducing address alternately in a time division manner by designating a recording address and a reproducing address, and to perform recording and reproducing in real time. It is an object of the present invention to provide an image recording device that can be simultaneously used.

[0007]

In order to achieve the above object, a compression processing unit for reducing input data to within a required amount of information, and an input buffer connected to the next stage of the compression processing unit for temporarily storing data. Section, a memory section for recording data by designating a required recording address and reproducing data by designating a required reproducing address, an output buffer section for temporarily storing the reproduced data, and the output buffer. A decompression processing unit connected to the next stage of the unit to restore the original data, an instruction input unit for inputting a recording mode and a reproduction mode or an operation instruction, a clock unit for measuring a recording time, and a recording corresponding to the recording time. By configuring the storage unit that stores the address in association with each other and the control unit that controls each unit, and by reducing the amount of information in the compression processing unit to one half or less of the data transfer rate of the memory unit, Run the writing and reading to the memory unit, and to perform recording and reproduction of data in real time.

Further, an address conversion unit for converting the time when the designated data is recorded into the corresponding address where the data is recorded is provided.

Further, a setting section is provided and the number of addresses is set in the setting section.

[0010]

With the above-described configuration, the amount of information per unit time of input data, for example, the data of image A, in the compression processing unit can be calculated by writing or reading per unit time of the memory unit. The amount of information (transfer speed) is reduced to less than half. Therefore, in the memory unit, it is possible to write to the designated address via the input buffer unit in the first half of each unit time, and then in the latter half of the unit time, another address of the memory unit is designated to B can be read out to the decompression processing unit via the output buffer unit, and the decompression processing unit restores and outputs the image B data supplied for each unit time, thereby recording the image A and recording other images. Read B. In summary, writing and reading are alternately performed with respect to the memory unit in time division for each unit time, so that image data is written in real time while other image data is reproduced.

Further, since it is constructed as described above, for example,
When an instruction is given to reproduce the recording 10 minutes before, the address conversion unit converts it to the writing address at the time corresponding to the time 10 minutes before, and instructs it.

Further, because of the above-mentioned configuration, the number of addresses set in the setting section is referred to, and the write or read data is accessed for the number of consecutive addresses from the designated address.

[0013]

EXAMPLE An image recording apparatus according to the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an image recording apparatus according to the present invention. Reference numeral 1 is a compression processing unit that reduces the amount of input data to within a required amount of information.
G (Joint Photographic coding Experts Group) standard or MPEG (Moving Picture coding Experts Gr)
oup) It is based on the standards. An input buffer unit 2 is connected to the next stage of the compression processing unit 1 and temporarily stores compressed data, and is composed of a FIFO (First In First Out) memory having a required capacity, for example, 1 kbyte.

Reference numeral 3 denotes a memory unit for recording data by designating a recording address and reading data by designating a reading address, which has a large capacity, a high transfer rate, and a random access type. , For example, 4G
HDD (hard disk) device, MO (Magneto-Optical) device, DVD (Disital Video Disk) device, or RAM (Random Access Memory) if high speed is important, etc. To do.

Reference numeral 4 denotes an output buffer unit for temporarily storing the reproduced data, which is composed of the same FIFO memory as the input buffer unit 2, for example, a FIFO memory. Reference numeral 5 denotes a decompression processing unit which is connected to the next stage of the output buffer unit 4 and restores the original data, and which is installed as a pair with the compression processing unit 1.
Similar to the compression processing unit 1, it conforms to the JPEG standard or the MPEG standard, for example. Reference numeral 6 is an instruction input unit for instructing a recording mode and a reproduction mode, or a recording start time of an image desired to be reproduced, and 7 is an address conversion unit for converting the recording start time into a corresponding address. 8 is
A clock unit that measures the recording time. A storage unit 9 stores the recording start time and the corresponding address in association with each other. Reference numeral 10 is a control unit that controls the above-mentioned units.

The writing / reading operation of the image recording apparatus according to the present invention will be described with reference to FIGS. FIG. 2 is a timing chart of writing and reading to and from the memory of the image recording apparatus according to the present invention. The "writing mode" is instructed from the instruction input unit 6, and the compression processing unit 1 is provided with, for example, an image signal from a camera, for example, 360 pixels horizontally and 240 pixels vertically, which corresponds to the image quality level of VHS (Video Home System). Capture data. In this case, the amount of information is about 8 MBPS per second (megabytes per second), and the compression processing unit 1 configures this information amount with an MPEG-2 compliant compression circuit so that, for example, a maximum of 1 kbyte per 1 ms. Compress to the amount of information.

On the other hand, when the memory unit 3 is composed of, for example, an HDD (hard disk) device having a maximum transfer speed of 20 MBPS, the transfer speed becomes a maximum of 10 MBPS as a result of compression by the MPEG-2. HD speed
It can be less than half of the D device. The FIFO memory of the input buffer unit 2 sequentially stores a maximum amount of 1 kbyte of information output by the compression processing unit 1 every 1 millisecond,
The data is read in the stored order in accordance with the transfer speed of the memory unit 3, and is sequentially written to the designated address of the memory unit 3, for example, the address next to the previously stored address or the like.

In practice, a setting unit (not shown) is provided, and the number of addresses per block of the storage area of the memory unit 3 is preset in the setting unit. For example, 1 k (1000) addresses or the like are assigned as one block of the storage area. For the number of addresses per block, the required number of addresses is determined based on the maximum amount of information after compression according to the data amount of the original input image and the type of compression processing to be used. The number of addresses such as 1k is set in the setting section.
The next 1 millisecond (unit time) of compressed data is sequentially written to the required number of addresses after the next address. In this way, the operation of sequentially writing the compressed data from the required address of the memory unit 3 onwards is performed.

Next, the case where the "reading mode", the desired time of reading, and the like are designated from the instruction input unit 6 will be described. The time << A >> in FIG. 2 corresponds to the designated time. FIG.
As can be seen, the writing continues and at the same time the reading is started. As shown in FIG. 2, in the time division method,
For example, in the first half of the unit time, the storage areas corresponding to the number of addresses of one block set in the setting unit are continuously read and output from the addresses corresponding to the instructed time converted by the address conversion unit 7. The data is sequentially written in the FIFO memory of the buffer unit 4. The decompression processing unit 5 receives the compressed data from the FIFO memory, decompresses the data with the same compression algorithm, for example, MPEG-2, and outputs it.

FIG. 3 is a diagram showing an image of a memory map of the memory section of the image recording apparatus according to the present invention. Both writing and reading are performed in units of one block of storage area indicated by the number of addresses per unit time as described above.
For the reading, the compressed data stored in, for example, three addresses a, b, c are continuously read in the first unit time, and the next three unit addresses are read from the next three addresses. . In the writing, for example, the first unit time is continuously written to three addresses h, i, j, etc., and the next unit time is continuously written to the next three addresses. In the above example, the number of addresses is 1k and the storage area is one block. If the memory unit 3 is required to have a higher transfer rate, one of the methods is to configure the memory so that memory access (writing or reading) is performed in parallel, for example, 4 bytes at a time. The transfer rate may be increased four times as compared with the case of accessing in units of 1 byte.

[0021]

As described above, according to the present invention, a recording address and a reproducing address can be designated and alternately accessed in a time division manner.
Also, an image recording apparatus is provided which enables simultaneous recording and reproduction in real time. Therefore, when the present invention is used in the surveillance system, it is possible to reproduce the past image while recording the surveillance image of the camera in real time. Therefore, continuous monitoring images can be obtained even during reproduction, which is advantageous in terms of reliability of the monitoring system.

[Brief description of drawings]

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

FIG. 2 is a timing chart of writing and reading to and from a memory of the image recording apparatus according to the present invention.

FIG. 3 is a diagram showing an image of a memory map of a memory unit of the image recording apparatus according to the present invention.

[Explanation of symbols]

 1 compression processing unit 2 input buffer unit 3 memory unit 4 output buffer unit 5 decompression processing unit 6 instruction input unit 7 address conversion unit 8 clock unit 9 storage unit 10 control unit

Claims (7)

[Claims] 1. A compression processing unit that reduces input data to within a required amount of information, an input buffer unit that is connected to the next stage of the compression processing unit and temporarily stores data, and data that specifies a required recording address. And a memory unit for reproducing data by designating a required reproduction address, an output buffer unit for temporarily storing the reproduced data, and a connection to the next stage of the output buffer unit to restore the original data. A decompression processing unit, an instruction input unit for inputting a recording mode and a reproduction mode or an operation instruction, a clock unit for measuring a recording time, a storage unit for storing the recording time in association with a corresponding recording address, and each unit. And a control unit that controls the data transfer rate of the memory unit, and reduces the amount of information in the compression processing unit to one half or less of the data transfer rate of the memory unit, thereby writing and reading data to and from the memory unit. And an image recording apparatus which is characterized in that so as to record and reproduce data in real time. 2. The image recording apparatus according to claim 1, further comprising an address conversion unit for converting an instructed recording time into a corresponding address in which data is recorded at the time. 3. The image recording apparatus according to claim 1, wherein a setting section is provided and the number of addresses is set in the setting section. 4. The compression processing unit and the decompression processing unit are JP
The image recording apparatus according to claim 1, which is based on the EG standard or the MPEG standard. 5. The image recording apparatus according to claim 1, wherein the input buffer section and the output buffer section are constituted by a FIFO memory. 6. The hard disk device,
The image recording apparatus according to claim 1, wherein the image recording apparatus is composed of an MO apparatus or a DVD apparatus. 7. The image recording apparatus according to claim 1, wherein the memory unit is a RAM.