JPH08111846A - Image signal multiplex processing device for general-purpose analog VTR - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a simple image multiplexing processing device for a general-purpose analog VTR without deterioration in image quality. [Structure] Since an image signal is recorded by adding an input channel identification signal to a specific scanning line within a predetermined vertical blanking period, at the time of reproduction, it is possible to accurately identify each input channel based on this identification signal. It can be displayed on a display such as a CRT. In addition, since recording is performed without thinning out, deterioration of image quality does not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for multiplexing image signals from a plurality of signal sources with a general-purpose analog VTR for recording / reproducing.

[0002]

2. Description of the Related Art Conventionally, in order to record and play back images from a plurality of cameras on a single general-purpose analog VTR, images for one screen are thinned out and sampled, and divided into 4 or 9 divisions. It was formed on one screen.

[0003]

Therefore, since the recorded image data is thinned out, the more the images from many cameras are put in one screen, the larger the degree of thinning out becomes. Was causing it. There is also a method of compressing image data using a compression technique, but the compressed image data is for recording / reproducing to / from a computer peripheral device such as a hard disk, and is recorded by a general-purpose analog VTR unless a special device is used. / Couldn't play. According to the present invention, an image signal can be multiplexed and recorded / reproduced by a general-purpose analog VTR with a simple structure without using a special device, and at the same time, the image quality can be improved.

[0004]

According to the present invention, an input channel for converting an analog image signal into a digital image signal in order to record / reproduce analog image signals input from a plurality of cameras with one general purpose analog VTR. Several A / D conversion units 1 and frame memory units 1 for the number of input channels for storing digital image data from this A / D conversion unit 1.
And a multiplexing circuit unit for multiplexing the output from the frame memory unit 1 and superimposing the input channel identification signal at a predetermined position in the vertical blanking period, and the frame memory unit 1
And a memory control unit 1 for controlling the writing / reading of the data and for generating the timing of the multiplexing circuit unit, and a D / A for converting the multiplexed digital image signal from the multiplexing circuit unit into an analog image signal. The conversion unit 1, a general-purpose analog VTR for recording / reproducing the multiplexed analog image signal from the D / A conversion unit 1, and the general-purpose analog VTR
A / D conversion section 2 for converting the multiplexed analog image signal reproduced from the digital image data into digital image data, and separation for separating the multiplexed digital image data from the A / D conversion section 2 in accordance with the input channel. A circuit section, a frame memory section 2 for storing the digital image signals separated by the separation circuit section for each input channel, and a memory control section 2 for controlling writing / reading of the frame memory section 2; A channel identification unit for generating a selection signal for switching between the input channel identification signal and the image data, which is superposed at a predetermined position in the vertical blanking period, and the digital image data output from the frame memory unit 2 as an analog image signal. And the D / A conversion units 2 for the number of input channels to be converted into.

[0005]

According to the present invention, images from a plurality of cameras are time-division multiplexed on a frame-by-frame basis, and an input channel identification signal is provided on a predetermined scanning line in the vertical blanking period of each one-frame image. Therefore, the general analog VTR can be recorded as it is in a multiplexed state, and the image can be reproduced for each camera based on the identification signal.

[0006]

1 is a general-purpose analog VT for recording / reproducing image signals from three surveillance cameras according to an embodiment of the present invention.
FIG. 2 is a block diagram of the R image multiplexing processing apparatus, and FIG. 2 is a waveform diagram for explaining the operation of the general-purpose analog VTR image multiplexing processing apparatus. In FIG. 1, reference numerals 1, 5 and 9 are surveillance cameras, 2, 6 and 10 are A / D conversion units for converting analog composite image signals from the corresponding surveillance cameras 1, 5 and 9 into digital image data, 3, 7 and 11 are corresponding A / D converters 2, 6 and 1 respectively.
A RAM having a memory capacity for two screens of image data from a surveillance camera which stores digital image data from 0.
A double buffer frame memory unit 4 composed of (random access memory) separates a composite sync signal from an analog composite image signal from the surveillance camera 1, and outputs a horizontal sync signal, a vertical sync signal, a frame sync signal from the composite sync signal. A horizontal blanking signal, a vertical blanking signal, etc. are generated, and based on these signals, a write / read address signal for the double buffer frame memory unit 3 and R
The AM control timing signal is generated, the input channel identification signal data is generated, and a selection signal for switching between the identification signal data and the image data from the A / D converter 2 is generated at a predetermined vertical address. In addition, it is a memory control unit that supplies a synchronization system for the multiplexed image data.

Reference numerals 8 and 12 separate the composite sync signal from the analog composite image signals from the corresponding surveillance cameras 5 and 9, and from this composite sync signal, a horizontal sync signal, a vertical sync signal, a frame sync signal, and a horizontal blanking signal. And a vertical blanking signal and the like, and the corresponding double buffer frame memory unit 7 based on these signals.
When 11 and 11 are writing, a write address signal and a RAM control timing signal are generated, and when reading is 11, read address data and a RAM control timing signal generated by the memory control unit 4 are selected, and an input channel identification signal is selected. Data is generated, and the identification signal data and the A / D converter 6 are generated at a predetermined vertical address.
And 10 are memory control units for generating selection signals for switching respective image data, 13 is a multiplexing circuit unit for time-division-multiplexing the digital image data from the double-buffer frame memory units 3, 7, and 11 on a frame-by-frame basis.
Reference numeral 4 superimposes the digital composite synchronizing signal, the digital horizontal blanking signal and the digital vertical blanking signal from the memory control unit 4 on the digital image signal added with the input channel identification signal from the multiplexing circuit unit 13. And a D / A conversion unit for converting into an analog composite image signal.

Reference numeral 31 is a general purpose analog VTR for recording / reproducing the multiplexed analog composite image signal from the D / A converter 14, and 15 is a digital image of the multiplexed analog composite image signal reproduced from the general purpose analog VTR 31. A / D converter for converting data, 17 is a general-purpose analog VTR
The composite sync signal is separated from the multiplexed analog composite image signal reproduced from the, and the horizontal sync signal, vertical sync signal, frame sync signal, horizontal blanking signal, vertical blanking signal, etc. are generated from this composite sync signal. Also, based on these signals, the frame memory units 19 and 2 described later are provided.
A memory control unit for generating write / read address signals of 0 and 21 and a control timing signal, 18 is a vertical address of the memory control unit 17 and a predetermined vertical address from the digital image data from the A / D conversion unit 15. A channel identification unit that takes in the superimposed input channel identification signal data and generates a separation signal for each input channel, 16 is A based on the separation signal from the channel identification unit 18.
The frame memory units 19 and 20, which respectively correspond to the digital image data from the D / D conversion unit 15 for each input channel,
Separation circuit sections for separating into 21 and 21 and 22, 23, and 24 respectively correspond to digital image data from the frame memory sections 19, 20, and 21, which are composed of corresponding RAMs, digital digital sync signals from the memory control section 17, horizontal It is a D / A conversion unit that superimposes a blanking signal and a digital vertical blanking signal to convert into an analog composite image signal. FIG. 2A shows a part of the waveform of the vertical blanking period, which is a part where the input channel identification signal is superimposed,
From left, LSB, 2SB and MSB are shown. In this figure, the input channel 3 is shown. FIG. 2B shows a data selection signal for switching between the input channel identification signal and the image signal.

Next, the operation of such a general-purpose analog VTR image signal multiplexing processing apparatus will be described with reference to FIGS. 1 and 2. The analog composite image signal from the surveillance camera 1 is supplied to the A / D conversion unit 2 and the memory control unit 4. The analog composite image signal is converted into digital image data in the A / D conversion unit 2, and in the memory control unit 4,
Separate the composite sync signal from this analog composite image signal,
A horizontal synchronizing signal and a vertical synchronizing signal are separated from this composite synchronizing signal to generate a frame synchronizing signal, a horizontal blanking signal and a vertical blanking signal. At this time, in order to store a predetermined input channel identification signal, the vertical address is to be counted from before the scanning line where the actual image data exists. For example, 3 scan lines earlier. For this reason, a predetermined input channel identification signal data is generated, and at the same time, a data selection signal 1 is generated to switch the stored data between the address counted earlier and the address where the image data exists. The input channel identification signal is, for example, as shown in FIG. 2 (A), a 3-bit identification signal represented by data of three scanning lines, and LSB, 2SB, and MSB from the earliest input channel identification signal. To enable.

Based on these signals, write / read address data of the double buffer frame memory unit 3 and a control timing signal for controlling a RAM (random access memory) forming the frame memory are generated. The double-buffer frame memory unit 3 has a capacity for two screens of the surveillance camera 1, and one of the frames is alternately written for writing and the other is read only for each frame based on the signal generated by dividing the frame synchronization signal by two. It operates as a frame memory. This is done so that the data is always readable for multiplexing. In this way, the double buffer frame memory unit 3 receives the input channel identification signal at the vertical address predetermined by the data selection signal 1 and the remaining vertical address from the A / D conversion unit 2. The digital image data is stored and the image data to which the input channel identification signal is added is formed.

Further, in order to multiplex in the multiplexing circuit unit 13, the double buffer frame memory units 3, 7 and 1
Since it is necessary to read 1 with the same synchronization signal, the double buffer frame memory units 7 and 11 use the read address data generated from the memory control unit 4 and the RAM.
A control timing signal is used. Further, in order to sequentially and time-division-multiplex the digital image data from the three double-buffer frame memory units 3, 7, and 11, the frame synchronization signal is divided by 3, and the result is decoded. To generate a multiplexing switching signal.

The analog composite image signal from the surveillance camera 5 is supplied to the A / D converter 6 and the memory controller 8. A /
The D converter 8 converts the analog composite image signal into digital image data, and the memory controller 8 separates the composite sync signal from the analog composite image signal and outputs the horizontal sync signal and the vertical sync signal from the composite sync signal. And a frame synchronization signal, a horizontal blanking signal and a vertical blanking signal are generated. At this time, in order to store the predetermined input channel identification signal, the vertical address is to be counted from before the scan line where the actual image data exists. For example, 3 scan lines earlier. For this reason, a predetermined input channel identification signal data is generated, and at the same time, a data selection signal 2 is generated to switch the stored data between the address counted earlier and the address where the image data exists.

Based on these signals, write address data of the double buffer frame memory unit 7 and a control timing signal for controlling the RAM constituting the frame memory are generated. The double-buffer frame memory unit 7 has a capacity for two screens of the surveillance camera 5, and one of them is written exclusively for each frame and the other is read-only alternately based on a signal generated by dividing the frame synchronization signal by two. It operates as a frame memory. This is done so that the data can always be read for multiplexing. However, when the reading is started by the multiplexing switching signal, the writing / reading is not switched until the reading of one frame is completed.
In this way, the double buffer frame memory unit 7 receives the input channel identification signal at a vertical address predetermined by the data selection signal and the digital signal from the A / D converter 2 at the remaining vertical addresses. The image data is stored, and the image data to which the input channel identification signal is added is formed.

Similarly, the image signal from the surveillance camera 9 is also converted into digital image data by the A / D converter 10.
Under the control of the memory control unit 12, the double buffer frame memory unit 11 is formed as image data to which an input channel identification signal is added.

As described above, the image data from each surveillance camera is stored in the double buffer frame memory units 3, 7, and 11 with the input channel identification signal added. Double buffer frame memory section 3, 7 and 1
The image data to which the memory address data generated by the memory control unit 4 and the input channel identification signal read by the RAM control timing signal are added to the multiplexing circuit unit 13 and monitored by the multiplexing switching signal. The signals are cyclically switched in synchronization with the frame synchronization signal of the camera 1 and time division multiplexed. The multiplexed digital image signal from the multiplexing circuit unit 13 to which the input channel identification signal is added and the digital composite synchronizing signal, the digital horizontal blanking signal and the digital vertical blanking signal from the memory control unit 4 are D / A converted. Input to section 14,
It is converted into an analog composite image signal which can be recorded in the general purpose analog VTR, and recorded in the general purpose analog VTR 31.

The analog composite image signal reproduced from the general-purpose analog VTR is the A / D converter 15 and the memory controller 17.
Is supplied to. The analog composite image signal is converted into digital image data in the A / D conversion unit 15, and the composite sync signal is separated from the analog composite image signal in the memory control unit 17, and the horizontal sync signal and the vertical sync signal are separated from the composite sync signal. The sync signal is separated and a frame sync signal, a horizontal blanking signal and a vertical blanking signal are generated. At this time, unlike the memory control unit 4 and the like, the vertical address starts counting from the scanning line where the image data actually exists. This is to prevent the input identification signal from being displayed on a display unit such as a CRT. Based on these signals, write address data for the frame memory units 19, 20 and 21 and a control timing signal for controlling the RAM constituting the frame memory are generated. Further, the data selection signal 4 for distinguishing the input identification signal from the image data is generated.

The digital image data from the A / D conversion unit 15 is supplied to the channel identification unit 18, where the input channel identification signal data is extracted by the data selection signal 4 and is decoded to be separated for each input channel. Generate a signal. By this separation signal, the digital image data from the A / D conversion unit 15 supplied to the separation circuit unit 16 is converted into the frame memory unit 19, 20, or 2
It is stored in any one of 1 under the control of the memory control unit 17. Frame memory units 19, 20, and 21
The digital image data from is read out under the control of the memory control unit 17, and the corresponding D / A conversion unit 2
2, 23, and 24, and an analog composite image signal that can be displayed on a display such as a CRT by being superimposed on the digital composite synchronizing signal, the digital horizontal blanking signal, and the digital vertical blanking signal from the memory control unit 17. Is converted to.

As described above, since an image signal is recorded by adding an input channel identification signal to a specific scanning line within a predetermined vertical blanking period, this identification signal is used as a basis during reproduction. It can be accurately displayed on the display unit such as a CRT for each input channel. In addition, since recording is performed without thinning out, deterioration of image quality does not occur.

[0019]

According to the present invention, an input channel identification signal is added to a specific scanning line within a predetermined vertical blanking period to continuously form a time division multiplexed analog composite image signal. Therefore, a plurality of video signal inputs can be continuously recorded / reproduced by a single general-purpose analog VTR without wasting the tape and without degrading the image quality. In addition, addition of input channel identification data does not require a special circuit because it only writes predetermined number data to a predetermined address,
It is easily feasible.

[Brief description of drawings]

FIG. 1 is a block diagram of an image multiplexing processing apparatus for a general-purpose analog VTR showing an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the general-purpose analog VTR multiplexing processing device of FIG.

[Explanation of symbols]

 1, 5, 9 Surveillance cameras 2, 6, 10, 15 A / D conversion unit 3, 7, 11 Double buffer frame memory unit 4, 8, 12, 17 Memory control unit 13 Multiplexing circuit unit 14, 22, 23, 24 D / A conversion unit 16 Separation circuit unit 18 Channel identification unit 19, 20, 21 Frame memory unit 31 General-purpose analog VTR

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 5/91 K

Claims (1)

[Claims] 1. An A / D converter for converting input analog image signals into digital image signals for recording / reproducing analog image signals input from a plurality of cameras with one general-purpose analog VTR. 1 and the frame memory unit 1 for the number of input channels for storing the digital image data from the A / D conversion unit 1 and the output from the frame memory unit 1 are multiplexed to determine a predetermined vertical blanking period. A multiplexing circuit section for superimposing an input channel identification signal on a position; a memory control section 1 for controlling writing / reading of the frame memory section 1; and a timing for the multiplexing circuit section; and the multiplexing circuit. D / A converter 1 for converting the multiplexed digital image signal from the D / A converter to an analog image signal, and the multiplexed analog image signal from the D / A converter 1. A general-purpose analog VTR for recording / reproducing video, an A / D conversion section 2 for converting a multiplexed analog image signal reproduced from the general-purpose analog VTR into digital image data, and a multiplexed analog signal from the A / D conversion section 2. Separation circuit section for separating the digital image data corresponding to the input channel, frame memory sections 2 for the number of input channels for storing the digital image signals separated by the separation circuit section for each input channel, and this frame memory section A memory control unit 2 for controlling writing / reading of 2; a channel identification unit for generating a selection signal for switching between an input channel identification signal and image data superimposed at a predetermined position in a vertical blanking period; D / A conversion units 2 for the number of input channels for converting the digital image data output from the memory unit 2 into analog image signals Video multiplexed processing apparatus for a general-purpose analog VTR, characterized in that it comprises a.