JP3515172B2 - TV camera device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television camera apparatus having a plurality of cameras mainly used for monitoring, crime prevention and the like. 2. Description of the Related Art Conventionally, in order to simplify installation work and the like, this type of television camera apparatus such as monitoring equipment and security equipment has been proposed.
For connection between each television camera and each power supply device, there is a one-cable system using one coaxial cable for each camera for power supply and signal transmission. The conventional one-cable television camera device will be described with reference to FIGS. 2 and 7 corresponding to an embodiment of the present invention. [0003] As shown in both figures, for example, a plurality of television cameras 1 of # 1 to #n arranged in various places of a monitoring area include:
Each power supply 3 is connected to each power supply 3 via one coaxial cable 2 for power supply and signal transmission for each camera, and this power supply 3 is used except for the case where the camera 1 is used as a reference for external synchronization.
An external synchronization superimposing unit 6 is provided together with the power supply unit 4 and the video output unit 5. FIG. 2 shows a case where the camera 1 of # 1 becomes a reference for external synchronization, and FIG. 7 shows a case where none of the cameras 1 becomes a reference for external synchronization. A vertical synchronizing signal of the external synchronizing unit 6 is superimposed on the DC power supply of the power feeding unit 4, and a signal formed by the superimposing is transmitted to the camera 1 via the cable 2. By this transmission, the camera 1 is supplied with a driving DC power supply, and forms an interlaced scanning video signal (composite video signal) of the captured image in the external synchronization vertical synchronization by the synchronization control based on the external synchronization vertical synchronization signal. . [0005] The video signal and the like are transmitted to the power supply device 3 via the cable 2, and the video signal is transmitted from a video output terminal 5 ′ such as a BNC terminal of the video output unit 5 via a connection cable 7 for each power supply device 3. For example, it is sent to the switcher 8 of the monitoring console. The switcher 8 automatically switches or splits the video signal of each camera 1 by video processing using a memory based on the automatic or manual switching and splitting operation of the monitor screen, and splits and synthesizes one or more monitors. The information is supplied to the monitor TV 9, and a monitoring screen or the like based on the shooting output of each camera 1 is displayed on the TV 9. At this time, since the vertical synchronization of each camera 1 matches, the synchronization of the screen when the video signals of each camera 1 are sequentially switched and displayed is prevented. In the above-mentioned conventional one-cable television camera apparatus, the vertical synchronization of each camera 1 matches, but the field of each camera 1 is not synchronized. For this reason, a field mismatch between the cameras 1 occurs. For example, when the video signal of each camera 1 is displayed on the monitor television 9 in a four-division composition by a screen division composition, one scan is performed between the cameras 1. There is a problem that a shift of about a line (line) occurs to make it hard to see. An object of the present invention is to synchronize vertical synchronization and field synchronization between television cameras. [0008] In order to achieve the above object, the present invention relates to a method of superposing a plurality of television cameras 1 and a power supply 3 of each television camera 1 by superimposing a power supply and a signal. Connected by one coaxial cable 2 for each camera for multiplex transmission, power is supplied from the power supply device 3 to the camera 1, and the video output of the camera 1 is output to the power supply device 3.
And a vertical synchronization separation circuit 6a to which an external synchronization composite synchronization signal C / SYNC is supplied in an external synchronization superimposing unit 6 of the power supply device 3.
, The vertical synchronization signal VD is separated and extracted, and the field identification signal generating circuit 6b separates and extracts the vertical synchronization signal VD.
Is formed by the waveform shaping circuits 6c and 6d to which the vertical synchronizing signal VD and the field identification signal FI are supplied, for the superimposed transmission synchronized with the falling edge of the synchronization signal VD at the front edge of the field. Vertical synchronization signal v
d, the field identification signal fi is formed, and the vertical synchronization signal vd and the field identification signal fi are added and synthesized by the amplitude control circuit 6e to which the vertical synchronization signal vd and the field identification signal fi are supplied. pulse signal is superimposed on a DC power source, said coaxial cable 2 through a is transmitted to the camera 1, the signal separation unit 14 of the camera 1, each transmission input of the vertical sync separation circuit 14a by the external synchronizing pulse signal And the vertical synchronization signal vd is separated and extracted, and the field identification signal fi is superimposed and becomes a large amplitude by the field identification signal separation circuit 14b by the amplitude determination of the external synchronization pulse signal. only one field F _1, separated and extracted by reproducing the field identification signal fi at the timing of the pulse signal, Serial field identification signal separator circuit 14
and time delay approximately 1/2 field by b field identification signal fi delay circuit 14c of the the first central field F ₁ to form a phase-shifted field identification signal fi ', the timing control unit 15 of the camera 1 PL in
Based on the output of the voltage controlled oscillator 15a that L control, timing signal generation circuit 15b by the composite synchronizing signal C · SYNC of the video processing section 12, a vertical synchronizing signal vd internal vertical synchronizing signal corresponding to the int · vd and field identification signal f
internal identification signal int · fi corresponding to i is made form, before
The field identification signal fi ', the internal identification signal int
Fi is supplied to the detection circuit 15d via the AND gate 15c, and the vertical synchronization signal vd of the vertical synchronization separation circuit 14a and the output signal of the detection circuit 15d are supplied to the AND gate 15e, and the output of the detection circuit 15d Only when the signal goes high, the AND gate 15e turns on and the vertical synchronization signal vd is supplied to the phase comparator 15f.
The phase comparator 15f compares the phase of the output signal of the AND gate 15e with the internal vertical synchronization signal int · vd,
Forming a signal of phase difference between the two signals, the phase difference signal of the control voltage signal is smoothed is formed by the loop filter 15 g, the by the signal both synchronous signal vd, int · vd
There oscillation frequency of the voltage controlled oscillator 15a to match is PLL control, each signal by the PLL control is synchronized by the PLL control of the first field F _1, the camera 1 output from the timing signal generating circuit 15b A television camera device characterized in that vertical synchronization and field synchronization of a composite synchronization signal C / SYNC are established by a vertical synchronization signal vd of external synchronization and a field identification signal fi. In the case of the television camera apparatus of the present invention configured as described above, an external synchronization vertical synchronizing signal and field identification are transmitted from the external synchronization superimposing section of each power supply apparatus to each television camera via a coaxial cable. A signal is transmitted. Each television camera separates and extracts the transmitted vertical synchronizing signal and field identification signal by a signal separation unit, and the timing control unit performs vertical synchronization and field synchronization based on the external synchronization vertical synchronization signal and field identification signal. Take. Therefore, the vertical synchronization and the field synchronization of each television camera coincide with each other, and the disturbance of the screen due to the inconsistency of the fields when the video signal of each television camera is divided and synthesized on the screen and displayed on the monitor screen is prevented. . An embodiment will be described with reference to FIGS. 1 to 7. FIG. (1 embodiment) First, FIG. 1 to FIG.
This will be described with reference to FIG. FIG. 2 shows a case where the camera # 1 is used as a reference for external synchronization, and the vertical synchronization of this camera 1 and the vertical synchronization and field synchronization of another camera 1 are established based on a field. When the video signal is transmitted to the power supply 3 via the cable 2, the synchronization separation circuit 10 for external synchronization of the power supply 3 is used as shown in FIG.
The composite synchronization signal C / SYNC shown in (a) is separated and extracted. The composite synchronization signal C / SYNC is transmitted to the power supply device 3 of each of the cameras 1 after # 2 via the connection cable 11 for external synchronization. The difference between the power supply device 3 of the camera 1 after # 2 and the conventional device is that the external synchronization superimposition unit 6 causes the composite synchronization signal C · SY of the connection cable 11 to be different.
The point is that a vertical synchronization signal and a field identification signal for external synchronization are formed from the NC and transmitted to the respective cameras 1 via the cable 2. That is, the external synchronizing superimposing section 6 is configured as shown in FIG.
SYNC is supplied to the vertical sync separation circuit 6a and the field identification signal generation circuit 6b. FIG. 1 shows the camera 1 of # 2 and its power supply device 3, and the cameras 1 and their power supply devices 3 after # 3 have the same configuration as FIG. Then, the synchronization separation circuit 6a separates and extracts the vertical synchronization signal VD of FIG. 3B, and the generation circuit 6b forms the field identification signal FI of FIG. 3C having a period twice as long as the vertical synchronization signal VD. I do. Further, the vertical synchronizing signal VD and the field identification signal FI are supplied to the waveform shaping circuits 6c and 6d, where the waveforms are shaped and synchronized with the falling edge of the synchronizing signal VD at the leading edge of the field, as shown in FIGS. ), The vertical synchronizing signal vd and the field identification signal fi for superimposed transmission of the same positive polarity pulse waveform.
Is formed. At this time, the first field (odd field) is F ₁ , and the second field (even field) is F ₂
Then, the vertical synchronizing signal vd is formed in each field in synchronization with the fall of the vertical synchronizing signal VD in FIG. 4A as shown in FIG. 4B, and the field identification signal fi depends on the presence or absence of this signal. In order to enable the field identification, as shown in FIG. 9D, it is formed for each first field F ₁ in synchronization with the rise of the field identification signal FI in FIG. Further, the vertical synchronizing signal vd and the field identification signal fi are supplied to an amplitude control circuit 6e formed by a variable gain amplifier, an adder or a multiplier, and the control circuit 6e controls the gain of the field identification signal fi. The vertical synchronizing signal vd and the field identification signal fi are added and synthesized. [0019] The additive synthesis, a positive polarity pulse signal becomes small (low level) when the large second field becomes (high level) F ₂ when the amplitude (level) of the first field F ₁ is It is formed as a pulse signal for external synchronization. Then, the external synchronization pulse signal of the positive polarity is superimposed on the DC power supply of the power supply unit 4 and transmitted to the camera 1 via the cable 2. [0020] At this time, since the composite video signal of the imaging field of the video processing unit 12 of the camera 1 is transmitted to the video output unit 5 of the power supply device 3 through the cable 2, the amplitude control circuit 6 e external synchronization pulse The signal is actually superimposed on the composite video signal of the DC power supply and the imaging output. In consideration of the fact that the polarity of the synchronizing signal of the composite video signal is negative, the vertical synchronizing signal vd and the field identification signal fi are formed to have a positive polarity in order to facilitate signal separation and the like. Camera 1
Transmitted to The reason why the field identification signal fi is not a code signal or the like but is a pulse signal is that the vertical synchronization signal v
This is because this is the simplest means for adding field information to the external synchronization signal without affecting the phase information of d, the circuit configuration is extremely simple, and signal separation is easy. The signal of the cable 2 becomes as shown in FIG. 5 (a) by superimposing a positive polarity external synchronization pulse signal of the amplitude control circuit 6e on the composite video signal of the camera 1. [0024] FIG solid line A is the first field field F ₁ of the external synchronizing pulse signal identification signal fi is present, Jissen'i the second field F ₂ that there is no field identification signal fi external synchronization of the (a) A pulse signal C indicates a vertical synchronizing signal portion of the composite video signal of the camera 1. FIG. 5B is an enlarged view of the vertical synchronizing signal portion c of the first and second fields F ₁ and F ₂ in FIG. 5A. Then, FIGS. 5 (a) and 5 (b)
As is clear from FIG. 7, when synchronization is achieved, the externally synchronized pulse signal is superimposed on the vertical blanking period of the composite video signal, and does not affect the video output of the camera 1. Next, the camera 1 after # 2, in which the pulse signal of the external synchronization of the amplitude control circuit 6e is transmitted via the cable 2, is different from the conventional camera, as shown in FIG. Signal separation unit 1 together with power supply circuit unit 13
Fourth, a timing control unit 15 is provided. Then, the DC power transmitted from the power supply unit 4 via the cable 2 is supplied from the power supply circuit unit 13 to each unit of the camera 1, the camera 1 operates, and the composite video signal of the captured image is converted into a video processing unit. 12 is output to the cable 2. The amplitude control circuit 6 via the cable 2
The external synchronization pulse signal e is supplied to the vertical synchronization separation circuit 14a and the field identification signal separation circuit 14b of the signal separation unit 14. The sync separation circuit 14a is shown in FIG.
As shown in (5), the vertical synchronizing signal vd is reproduced every transmission input of the external synchronization positive pulse signal, and the vertical synchronizing signal vd is separated and extracted. The discrimination signal separating circuit 14b determines the amplitude of the externally synchronized positive polarity pulse signal, and superimposes the field discrimination signal fi on the first field F _1.
Only at the timing of the positive pulse signal,
The field identification signal fi shown in (b) is reproduced and separated and extracted. Further, in order to prevent the hunting operation of the PLL control of the timing control section 15, the field identification signal fi of the identification signal separating circuit 14b is delayed by a delay circuit 14c for approximately 1/2 field time τ, and the first field F A field identification signal fi ′ of FIG. 6C shifted to the center of ₁ is formed. On the other hand, the timing control section 15 performs PLL control on the voltage-controlled oscillator 15a. Based on the output of the oscillator 15a, the timing signal generating circuit 15b controls the composite synchronizing signal C / SYNC of the video processing section 12 and various timings of the camera 1. Generate a signal. [0033] The timing signal is a vertical synchronization signal vd
In internal identification signal int · fi corresponding to the internal vertical synchronizing signal int · vd and field identification signal fi corresponds to
And they are formed based on the composite synchronization signals C and SYNC , respectively. At this time, the synchronization signal int · vd is a positive pulse signal of FIG. 6D generated in synchronization with the leading edge of each field of the composite synchronization signal C · SYNC similarly to the vertical synchronization signal vd. The identification signal int · fi is shown in FIG.
As in the case of the identification signal FI of FIG. 4C, the level is inverted for each field and becomes high in the first field.
It is a synchronous signal of the positive polarity of (e). Then, the field identification signal fi ', in
t · fi is detected by the detection circuit 15d via the AND gate 15c
When the odd and even fields of the external synchronization field coincide with the camera 1 and the two identification signals fi ′ and int · fi go high at the same time, the output signal of the detection circuit 15 d goes high. Further, the vertical synchronization signal vd of the synchronization separation circuit 14a and the output signal of the detection circuit 15d are connected to the AND gate 1
The AND gate 15e is turned on only when the output signal of the detection circuit 15e is at a high level, and the vertical synchronization signal vd is supplied to the phase comparator 15f. The phase comparator 15f compares the phase of the output signal of the AND gate 15e with the internal vertical synchronizing signal int.vd to form a signal having a phase difference between the two signals. This signal is smoothed by a loop filter (low-pass filter) 15g to form a control voltage signal, and the oscillator 1 uses this signal so that the two synchronization signals vd, int · vd match.
The oscillation frequency of 5a is PLL controlled. The synchronized signals in FIG. 6 by the PLL control is the same, the PLL control of the first field _{F 1,} vertical sync and field sync of the composite synchronizing signal C · SYNC of the camera 1 is output from the timing generating circuit 15b It is established by an externally synchronized vertical signal vd and a field identification signal fi. Therefore, the vertical synchronization and the field of each camera 1 after # 2 coincide with the vertical synchronization and the field of the camera 1 of # 1. In addition, when the video signal of each camera 1 is displayed by the screen division synthesis such as the four-division synthesis, the deviation of the scanning line between the cameras 1 is prevented. It should be noted that the field synchronization signal fi 'obtained by delaying the field identification signal fi by .tau.
Since the LL control is performed, so-called out-of-synchronization does not occur even if the field identification signal fi fluctuates, and the operation is stable.
1 and 2 indicate a resistor, and C indicates a capacitor. (Other Embodiment) Next, another embodiment will be described with reference to FIG. FIG. 7 shows a case where the synchronization of each camera 1 is controlled using an external synchronization signal generator 16 separate from each camera 1 as a reference for the synchronization of each camera 1. The difference from FIG. The power supply 3 is also shown in FIG.
Each of the cameras 1 is connected from the external synchronization signal generator 16 via a connection cable 17 for each one or the power supply 3.
2 is supplied with a composite synchronizing signal C / SYNC similar to the output signal of the synchronizing separation circuit 10 in FIG. In this case, vertical synchronization and frame synchronization of each camera including the camera 1 of # 1 are externally synchronized, and the same effect as that of the first embodiment can be obtained. The configuration of each part of the camera 1 and the power supply device 3 is not limited to the configuration of the above-described two embodiments, but includes the vertical synchronization signal vd, the signal shape of the field identification signal fi,
The polarity and the like are not limited to the two embodiments. Of course, the present invention can also be applied to a case where an audio signal and the like are transmitted together with a video signal from the camera 1 to the power supply device 3 via the cable 2. Further, in the above two embodiments, the case of the basic configuration in which one power supply device 3 is provided for each camera 1 has been described. However, the number of cameras 1 is large, and one power supply device is provided for each of a plurality of cameras. It is needless to say that the present invention can be applied to a configuration or the like. The present invention can be applied to a one-cable television camera device for various uses. Since the present invention is configured as described above, the following effects can be obtained. The plurality of television cameras 1 and the power supply 3 of each television camera 1 are
The power supply and the power supply device 3 are connected by one coaxial cable 2 for each camera for superimposing and multiplexing and transmitting a power supply and a signal.
From the power supply device 3 to the outside, and a power supply device 3 supplies power to the camera 1 from the power supply device 3. The vertical synchronization signal VD is separated and extracted by the vertical synchronization separation circuit 6a supplied with SYNC, and the field identification signal generation circuit 6
b to form a field identification signal FI having a period twice as long as the vertical synchronization signal VD, and the waveform shaping circuits 6c and 6d to which the vertical synchronization signal VD and the field identification signal FI are supplied fall of the synchronization signal VD at the leading edge of the field. Vertical synchronizing signal vd for superimposed transmission synchronized with
Forming a said vertical sync signal vd, and a vertical synchronizing signal vd and the field identification signal fi by adding synthesized by the field identification signal fi amplitude control circuit 6e supplied, the DC power supply external sync pulse signal added synthesized It is superimposed on,
Transmitted to the camera 1 via the coaxial cable 2,
In the signal separation unit 14 of the camera 1, a vertical synchronization separation circuit 14a reproduces a vertical synchronization signal vd for each transmission input of the external synchronization pulse signal, separates and extracts the vertical synchronization signal vd, and a field identification signal separation circuit. 14
by the amplitude determination of b the external synchronizing pulse signal of only the first field F ₁ that superimposes a field identification signal fi becomes large amplitude, separated by reproducing the field identification signal fi at the timing of the pulse signal extraction The field identification signal fi of the field identification signal separation circuit 14b
The time-delayed almost half the field by the delay circuit 14c, the first field F ₁ of forming a field identification signal fi 'that phase in the center, the voltage control of the PLL control in the timing control unit 15 of the camera 1 Oscillator 1
5a, an internal vertical synchronizing signal int.vd corresponding to the composite synchronizing signal C.SYNC and the vertical synchronizing signal vd of the video processing unit 12 by the timing signal generating circuit 15b.
And an internal identification signal i corresponding to the field identification signal fi
nt · fi is made form, the field identification signal f
i ′, the internal identification signal int · fi is AND gate 1
5c is supplied to a detection circuit 15d through the vertical synchronization signal vd of the vertical synchronization separation circuit 14a and the detection circuit 15d.
Only when the output signal of signal d is supplied to the AND gate 15e and the output signal of the detection circuit 15d goes high, the AND gate 15e is turned on and the vertical synchronization signal vd is supplied to the phase comparator 15f. A phase comparator 15f compares the phase of the output signal of the AND gate 15e with the internal vertical synchronizing signal int · vd to form a signal having a phase difference between the two signals, and the phase difference signal is smoothed by a loop filter 15g. control voltage signal is formed, the <br/> both synchronization signals vd by the signal, the oscillation frequency of the voltage controlled oscillator 15a as int · vd match is PLL controlled, synchronized signals by the PLL control is the same , First field F ₁
, The vertical synchronization and the field synchronization of the composite synchronization signal C / SYNC of the camera 1 output from the timing signal generation circuit 15b are externally synchronized.
d, since it is established by the field identification signal fi, not only the vertical synchronization of each camera 1 but also the field can be matched, and the video signal of each camera 1 is divided into a screen and displayed on a monitor screen, etc. Is prevented from being disturbed due to the field mismatch, and the performance is remarkably improved. Further, a PLL is applied using the vertical synchronization signal as a reference signal.
And make it possible to match the field synchronization,
High-precision vertical synchronization and field synchronization can be matched.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a detailed block diagram of a part of an embodiment of a television camera device of the present invention. FIG. 2 is a block diagram of the overall configuration of one embodiment of the present invention. 3 (a) to 3 (e) are first timing charts for explaining the operation of the external synchronizing superposition unit in FIG. 4 (a) to 4 (d) are second timing charts for explaining the operation of the external synchronizing superposition unit in FIG. FIGS. 5A and 5B are signal waveform diagrams of the coaxial cable of FIG. 6 (a) to 6 (e) are timing charts for explaining the operation of the signal separation unit and the timing control unit in FIG. FIG. 7 is a block diagram of another embodiment of the present invention. [Description of Signs] 1 TV camera 2 Coaxial cable 3 Power supply device 6 External synchronization superposition unit 14 Signal separation unit 15 Timing control unit

Claims (1)

(57) [Claims 1] A single coaxial cable for each camera that multiplexes and transmits a plurality of television cameras 1 and a power supply device 3 of each television camera 1 by superimposing a power supply and a signal. A television camera device connected to each other by a cable 2 to supply power to the camera 1 from the power supply device 3 and externally output a video output of the camera 1 from the power supply device 3; In the section 6, the vertical synchronizing signal VD is separated and extracted by the vertical synchronizing separation circuit 6a to which the composite synchronizing signal C • SYNC of the external synchronizing is supplied. Field identification signal FI
The vertical synchronizing signal VD and the field identification signal FI are supplied, and the waveform shaping circuits 6c and 6d to which the vertical synchronization signal VD and the field identification signal FI are supplied. The amplitude control circuit 6e to which the vertical synchronization signal vd and the field identification signal fi are supplied is added and synthesized with the vertical synchronization signal vd and the field identification signal fi. And transmitted to the camera 1 via the coaxial cable 2. In the signal separation unit 14 of the camera 1, a vertical synchronization separation circuit 14a outputs a vertical synchronization signal vd for each transmission input of the external synchronization pulse signal. And the vertical synchronization signal vd is separated and extracted, and the external synchronization signal of the field identification signal separation circuit 14b is reproduced. The amplitude discrimination of the scan signal, only the first field F ₁ that superimposes a field identification signal fi becomes large amplitude, separated and extracted by reproducing the field identification signal fi at the timing of the pulse signal, the field identification signal approximately 1/2 field time delays, to form a field identification signal fi 'that phase shift in the center of the first field F _1, the timing control of the camera 1 by the field identification signal fi delay circuit 14c of the separation circuit 14b based on the output of the voltage controlled oscillator 15a to the PLL control in the section 15, timing signal composite synchronizing signal C · sYNC generation circuit 15b the image processing unit 12, the internal vertical synchronizing signal int · vd and field identification corresponding to the vertical synchronizing signal vd internal identification signal int · fi that corresponds to a signal fi is made form, the field identification Another signal fi ', the internal identification signal in
t · fi is detected by the detection circuit 15d via the AND gate 15c
The vertical synchronization signal vd of the vertical synchronization separation circuit 14a and the output signal of the detection circuit 15d are supplied to an AND gate 15e, and only when the output signal of the detection circuit 15d becomes high level, 15e is turned on, the vertical synchronization signal vd is supplied to the phase comparator 15f, and the phase comparator 15f compares the phase of the output signal of the AND gate 15e with the internal vertical synchronization signal int · vd,
Forming a signal of phase difference between the two signals, the phase difference signal of the control voltage signal is smoothed is formed by the loop filter 15 g, the two synchronization signals vd, the voltage as int · vd matches with the signal control the oscillation frequency of the oscillator 15a is PLL controlled, synchronized signals by the PLL control is the first field F
_By the PLL control of ₁ , the timing signal generation circuit 15b
A vertical synchronization and a field synchronization of a composite synchronization signal C / SYNC of the camera 1 outputted from the camera 1 are established by an external synchronization vertical synchronization signal vd and a field identification signal fi.