JP2002290965A - Frame switch type digital monitoring and recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frame switch type digital monitoring and recording device, with which the number of recording frames of each of connected cameras can be increased. SOLUTION: This device is provided with a plurality of cameras 3-6, data switching circuit 112 for switching and selecting video signal data from the cameras 3-6 on the basis of a camera select signal from a camera select signal synchronizing circuit 113, recording part 115 for recording the video signal data, memories 130-133 for storing the video signal data corresponding to the cameras 3-6, memory 134 for reproducing for storing the video signal data outputted from the recording part 115, and memory control part 135 for respectively writing the video signal data on the memories 130-136 while the cameras 3-6 are not selected in the case of recording, performing reading accelerated rather than the time of memory writing when any one of cameras 3-6 is selected, storing the video signal data outputted from the recording part 115 on the memory 134 for reproducing in the case of reproducing and varying the reading speed corresponding to the amount of data per frame recorded in the recording part 115.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame switch type digital monitoring and recording apparatus for recording and reproducing a plurality of input video signals.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional frame switch type digital monitoring and recording apparatus. In FIG.
3 to 6 are cameras. 10 is a control unit, 11 is an operation unit, 12 is a data switching circuit, 13 is a camera selection signal synchronization circuit, 14 is a frame synchronization signal generation circuit, 15 is a recording unit, 16 to 19 are A / D conversion units, 20 Is a D / A converter. 21 is a display output terminal, 22 is an operation signal,
23 is a camera selection signal, 24 is a recording / playback switching signal, 25
Reference numerals 28 are camera input terminals connected to the cameras 3 to 6, respectively. FIG. 4 shows each signal when four cameras are continuously recorded.
A frame synchronization signal output from the synchronization signal generation circuit 14,
(B) shows a camera selection signal 23 (number information corresponding to the input terminals 25 to 28 is referred to as cameras 1 to 4, respectively).
(C) to (F) are video signal data output from the A / D converters 16 to 19, (G) is video signal data to be recorded in the recording unit 15, and (H) is output from the recording unit 15 during reproduction. 3 shows video signal data to be output.

Next, a frame switch recording operation in the frame switch type digital monitoring and recording apparatus will be described. As shown in FIGS. 4C to 4F, each camera 3
The video signals continuously transmitted from 〜 to ６ are continuously converted into digital signal video signal data by the A / D converters 16 to 19 in frame units. When a recording button (not shown) is pressed, the control unit 10 is notified of the start of recording via the operation signal 22. The control unit 10 outputs a camera selection signal 23 corresponding to the number information of the camera input terminals 25 to 28, and the camera selection signal synchronization circuit 13 outputs the signal from the frame synchronization signal generation circuit 14 in FIG.
Synchronization with the frame synchronization signal shown in FIG.

When the data switching circuit 12 receives the camera selection signal 23 of FIG. 4B synchronized with the frame synchronization signal, the data switching circuit 12 is connected to the camera input terminals 25 to 28 corresponding to the camera selection signal. The video signal data output from the / D conversion units 16 to 19 are switched and selected, and
Output to The recording unit 15 enters a recording state according to the recording / playback switching signal 24 received from the control unit, and records the video signal data output from the data switching unit 12.
As described above, the video signal data obtained by digitally converting the video signals of the camera input terminals 25 to 28 are sequentially recorded in units of one frame in a state where the video signals are synchronized with the frame synchronization signal by the camera selection signal 23 specified by the control unit 10. The frame switch recording operation is performed by switching the output to the unit and sequentially recording by the recording unit 15. For example, video signal data output from the camera input terminal 25 via the A / D conversion unit 16 includes 1-5 and 1-9 surrounded by a thick line in FIG.
Is recorded in the recording unit 15. Therefore, as shown in FIG. 4 (G), the output data of the A / D converters 16 to 19 are recorded on the recording unit 15 at intervals of once every four frames.

Next, a reproducing operation in the frame switch type digital monitoring and recording apparatus will be described. For example, when an operator (not shown) presses a play button (not shown) of the operation unit, the control unit 10 can be controlled via the operation signal 22.
To start playback. The control unit 10 outputs a recording / playback switching signal 24 to the recording unit 15 to select recorded predetermined video data (details of the method are omitted). For example, when the camera 1 is selected, FIG.
Data as shown in (H) is output. The selected data is converted to an analog signal through the A / D converter 20, and is output from the display output terminal 21 to the monitor 2, where a reproduced video is displayed. Therefore, in the case of four cameras, the reproduced video is updated once every four frames.

[0006]

In the conventional frame switch type digital surveillance and recording apparatus as described above, the video signal data of the camera input from the plurality of camera input terminals 25 to 28 is frame synchronized by the data switching circuit 12. The selection is sequentially switched based on the camera selection signal 23 synchronized with the signal, and when selected, the video signal data is sequentially recorded in the recording unit 15 in units of one frame. If the interval between the selection and the next selection becomes long, the number of recording frames in each camera will decrease. As a result,
There have been problems such as that a required video signal is not recorded or that the number of recorded frames is small, so that a smooth reproduced image cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a frame switch type digital surveillance recording apparatus capable of increasing the number of recording frames of each connected camera. And

[0008]

In a frame switch type digital surveillance recording apparatus according to the present invention, a plurality of cameras, a camera selection signal output means for outputting a camera selection signal for selecting the camera, and a camera selection signal A frame switch unit for switching and selecting video signal data from the camera based on the camera, and a recording unit for recording the video signal data output from the frame switch unit. A memory provided before the switch means for storing the video signal data corresponding to the camera, a reproduction memory for storing the video signal data output from the recording section, and the frame switch means at the time of recording; While the camera is not selected,
Each of the video signal data is written to the memory, and when the camera is selected, the video signal data is read out at a higher speed than at the time of writing to the memory, and at the time of reproduction, the video signal data output from the recording unit is reproduced. And a memory control unit that varies the readout speed in accordance with the amount of data per frame recorded in the recording unit and stored in the recording unit.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram of a frame switch type digital monitoring and recording apparatus according to the present invention, and FIG. 2 is an explanatory diagram of each signal. In FIG. 1, reference numeral 100 denotes a frame switch type digital monitoring and recording apparatus, 2 denotes a monitor, and 3 to 6 denote cameras.
Reference numeral 110 denotes a control unit, 111 denotes an operation unit, and 113 denotes a camera selection signal synchronizing circuit which is a camera selection signal generating unit that outputs a camera selection signal synchronized with the frame synchronizing signal from the frame synchronizing signal generating circuit 114. , 112
A / A to which a camera input terminal corresponding to the camera selection signal 123 from the camera selection signal synchronization circuit 113 is connected.
This is a data switching circuit that is a frame switching unit that switches and selects video signal data output from the D conversion units 116 to 119 and outputs the video signal data.

Reference numeral 115 denotes a recording unit that records the video signal data output from the data switching circuit 112, and 120 denotes a D / A conversion unit that converts a digital video signal from the memory 134 into an analog video signal. Reference numeral 121 denotes a display output terminal, 122 denotes an operation signal, 124 denotes a recording / playback switching signal, 1
Reference numerals 25 to 128 denote camera input terminals which are connected to the cameras 3 to 6, respectively. 130 to 133 are cameras 2 to 6;
, A memory for reproduction, 134 a memory control unit for controlling the memories 130 to 133 and the memory 134 for reproduction, and 136 a memory control signal.

FIG. 2 shows each signal in the case of continuous recording by the four cameras 3 to 6 according to the present invention. FIG. 2A shows the output of the synchronizing signal generating circuit 114. (B) shows a camera selection signal 123 (number information corresponding to the input terminals 125 to 128 is referred to as cameras 1 to 4 respectively), and (C) to (F) show A / D converters 116 to 119. Output video data,
(G) to (J) show operations of the memories 130 to 133,
(K) is data recorded in the recording unit 15, (L) is video signal data output from the recording unit 115 during reproduction,
(M) shows the output of the memory 134.

Next, a frame switch recording operation in the frame switch type digital monitoring and recording apparatus will be described. As shown in FIGS. 2C to 2F, the video signals continuously transmitted from the cameras 3 to 6 are converted into digital video signals by the A / D converters 116 to 119 in frame units. The converted video signal data is input to the memories 130 to 133. When a recording button (not shown) is pressed, the control unit 110 is notified of the start of recording via the operation signal 122. The control unit 110 includes camera input terminals 125 to 1
The camera selection signal 123 corresponding to the number information of No. 28 is output, and the camera selection signal
As shown in (B), since the synchronization with the frame synchronization signal output from the frame synchronization signal generation circuit 114 is established, a camera selection instruction is issued in frame units.

Next, the write operation of the memories 130 to 133 will be described. The memory control unit 135 is selected by the camera selection signal 123 output from the control unit 110, and stores the memories 130 to 13 corresponding to the cameras not called.
3, the memory control signal 136 is output, and an instruction to write video signal data in frame units is issued. Therefore,
As shown in each memory operation of FIGS. 2G to 2J, the video signal data of each camera is stored in the corresponding memory 130 to 133.
Are stored until several frames are selected by the camera selection signal 123.

For example, if the A / D
The video signal data output via the conversion unit 116 is selected and read by 1-4 and 1-8 surrounded by a thick line in FIG. 1-5,
Writing is performed in 1-6 and 1-7. The other video signals also indicate that video signal data for three frames is written in the memories 130 to 133 in the same manner. The number of frames to be stored is set in advance according to the number of connected cameras and the switching interval of each camera.

The memory control unit 135 includes the control unit 110
When a specific camera is designated by the camera selection signal 123 shown in FIG. 2B output from the memory 130, the memories 130-1 storing video signal data of the designated camera are stored.
A memory control signal 136 is output to any one of 33, and an instruction to read video signal data as shown in the memory operation of FIGS. It is assumed that the reading instruction by the memory control signal can complete the reading of all data written in the memory within one frame period in which the camera is specified by the camera selection signal.

For example, when the reading of the memory 130 is instructed, assuming that the video signal data 1-8 shown in FIG. 2C is to be read, during this frame period 1-5, between the previous reading 1-4 and It is necessary to complete the reading of the write data 1-6 and 1-7. Thus, the memories 130 to 13
3 performs a read operation once every four frames, and the read speed is required to be at least three times the write speed.

As described above, when the recording of n cameras is continuously performed in units of one frame, paying attention to a certain camera, video signal data for (n-1) frames is accumulated in the corresponding memory. Will be. Therefore, in this case, in order to read out all the data within one frame period in which the camera selection is performed, (n-
1) It is necessary to perform the read operation at twice or more speed.

The data switching circuit 112 switches and outputs data from any of the memories 130 to 133 in response to the camera selection signal 123, and the recording unit 115 records the video signal data.

With the above operation, the video signal data of each camera recorded in the recording unit 115 is recorded with several frames of video signal data temporally compressed with respect to the time axis of one frame. It will be. In FIG. 2 (K),
This indicates that video signal data for three frames is recorded on the time axis for one frame. For example, when reading and recording the memory 130, if the video signal data 1-8 shown in FIG. 2C is to be read, 1-5, 1-5, 1 -6,
The write data 1-7 is stored.
This is shown in the frame corresponding to -8.

Next, a reproducing operation in the frame switch type digital monitoring and recording apparatus will be described. The control unit 110 outputs a recording / reproduction switching signal 124 to the recording unit 115 to select recorded predetermined video data (details of the method are omitted). For example, when the input terminal 125 (the number information is camera 1) is selected, the data as shown in FIG.
4 and the memory 134 sequentially writes data from the recording unit.

The memory 134 performs a read operation in response to a memory control signal 137 from a memory control unit 135. The readout instruction is based on the amount of data recorded on the time axis for one frame, and when data of n frames compressed temporally is recorded in one frame, one frame is read. At a speed obtained by dividing n by n. FIG. 2 (M) shows a case where the data shown in FIG. 2 (L) is read at a speed obtained by dividing one frame by three. In order to continuously output the video signal data in frame units as shown in FIG. 2 (M), the memory 134 stores any one frame from the video signal data output from the recording unit 15. Is performed twice consecutively. In this case, three frames of video are updated every four frames.

The D / A converter 120 sequentially converts the video signal data received from the memory 134 into an analog video, and outputs the analog video from a video output terminal to 121, and the monitor 2 displays the video.

[0023]

As described above, according to the present invention, a plurality of cameras, a camera selection signal output means for outputting a camera selection signal for selecting the camera, and a camera output signal from the camera based on the camera selection signal. In a frame switch type digital monitoring and recording apparatus, comprising: a frame switch for switching and selecting video signal data; and a recording unit for recording the video signal data output from the frame switch, provided at a stage preceding the frame switch. And
A memory for storing the video signal data corresponding to the camera, a reproduction memory for storing the video signal data output from the recording unit, and the camera is selected by the frame switch unit during recording. While the video signal data is written to the memory while the camera is selected, when the camera is selected, the video signal data is read at a higher speed than at the time of writing to the memory. A memory control unit for accumulating data in the memory for reproduction and varying the readout speed in accordance with the amount of data per frame recorded in the recording unit, so that the camera is not selected for recording. The video at that time can be recorded, and the number of recording frames can be increased.

[Brief description of the drawings]

FIG. 1 is a block diagram of a frame switch type digital monitoring and recording apparatus showing an embodiment of the present invention.

FIG. 2 is a signal diagram of a frame switch type digital monitoring and recording apparatus according to an embodiment of the present invention.

FIG. 3 is a block diagram of a conventional frame switch type digital monitoring and recording apparatus.

FIG. 4 is a signal diagram of a conventional frame switch type digital monitoring and recording apparatus.

[Description of References] 3, 4, 5, 6 cameras, 110 control unit, 112 data switching unit, 113 camera selection signal synchronization circuit, 114,
Frame synchronization signal generation circuit, 115 recording unit, 116 to
119 A / D converter, 120 D / A converter, 121
Display output terminal, 122 operation signal, 123 camera selection signal, 124 recording / playback switching signal, 125 to 128
Camera input terminal, 130 to 134 memory, 135 memory control unit, 136 memory control signal, 137 memory control signal.

Claims (1)

[Claims] A plurality of cameras; a camera selection signal output unit for outputting a camera selection signal for selecting the cameras;
A frame switch type digital monitoring record comprising: frame switch means for switching and selecting video signal data from the camera based on the camera selection signal; and a recording unit for recording the video signal data output from the frame switch means. In the apparatus, a memory provided before the frame switch means and accumulating the video signal data corresponding to the camera; a reproduction memory for accumulating the video signal data output from the recording unit; Writing the video signal data into the memory while the camera is not selected by the frame switch means, and reading out the memory at a higher speed than when writing the memory when the camera is selected; At the time of reproduction, the video signal data output from the recording unit is stored in the memory for reproduction. Product and, in response to said data amount per frame is recorded in the recording unit, frame-switched digital surveillance recording apparatus characterized by comprising a memory controller for varying the reading speed.