KR101444842B1 - Control method of monitoring camera and monitoring camera adopting the same - Google Patents

Abstract

A method according to the present invention is a method of controlling a surveillance camera that receives a reception signal from a communication object in setting horizontal periods of a vertical blank interval (VBI) of a video signal transmitted to a communication object, a) and (b). In step (a), a first threshold value is obtained in a main interval of each of the set horizontal periods, and it is determined whether the signal is valid-signal according to the voltage of the received signal. In step (b), a second threshold value lower than the first threshold value is obtained in the synchronization signal period of each of the set horizontal periods, and it is determined whether the signal is valid-signal according to the voltage of the received signal.

CCTV, security camera

Description

[0001] The present invention relates to a control method of a surveillance camera and a surveillance camera employing the surveillance camera,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a control method of a surveillance camera and a surveillance camera employing the surveillance camera, and more particularly to a surveillance camera using a coaxial cable, To a control method of a surveillance camera and a surveillance camera employing the same.

Surveillance system For example, in CCTV (Closed-Circuit TeleVision), video signals from a plurality of surveillance cameras are displayed on a recording device in a host device while being displayed through a communication object, for example, a host device.

The surveillance camera transmits the video signal to the communication object while communicating with the communication object through the coaxial cable. Here, communication signals are transmitted and received in a vertical blank interval (VBI) of a video signal transmitted to a communication object.

When the communication signal from the surveillance camera is transmitted to the communication object in the vertical blank section, the communication signal is transmitted together with the video signal, so that the communication signal is not delayed with respect to the video signal in the object of communication.

However, when the communication signal from the communication object is transmitted to the surveillance camera in the vertical blank section, the communication signal is delayed with respect to the video signal in the surveillance camera. Such a reception delay time in the surveillance camera includes a time at which the video signal is transmitted from the surveillance camera to the communication object, a reaction time at the communication object itself, and a time at which the communication signal is transmitted from the communication object to the surveillance camera.

In this case, a reception signal to be present only in a main section of a set horizontal period in the vertical blank section may exist in the synchronization signal section. Here, the synchronous signal section means a section in which a horizontal synchronous signal is generated.

Therefore, the potential of the effective signal existing in the synchronizing signal section becomes low due to the potential of the synchronizing signal section of any one set horizontal period being lower than the direct current potential of the main section, so that it can not be judged as an effective signal.

An object of the present invention is to provide a control method of a surveillance camera capable of overcoming a reception error due to a delay of a reception signal from a communication object and a surveillance camera employing the same.

A method of controlling a surveillance camera that receives a reception signal from a communication object in a set horizontal period of a vertical blank interval (VBI) of a video signal transmitted to a communication object, the method comprising: a) and (b).

In step (a), a first threshold value is obtained in a main section of each of the set horizontal periods, and it is determined whether the signal is valid-signal according to the voltage of the received signal.

In step (b), a second threshold value lower than the first threshold value is determined in the synchronization signal period of each of the set horizontal periods, and it is determined whether the signal is valid-signal according to the voltage of the received signal.

Further, the surveillance camera of the present invention includes a main control unit, a video-signal generating unit, and a communication interface. The surveillance camera includes a main control unit, a video-signal generating unit, and a communication interface. In the setting horizontal periods of a video signal transmitted to a communication object, And receives a reception signal from a communication object.

Here, the communication interface may determine a valid-signal according to the voltage of the received signal by obtaining a first threshold value in a main section of each of the set horizontal periods, Determines a second threshold value lower than the first threshold value and determines whether the signal is valid-signal according to the voltage of the received signal.

According to the control method of the surveillance camera of the present invention and the surveillance camera employing the surveillance camera, a second threshold value lower than the first threshold value in the main section is obtained in the synchronizing signal section of each set horizontal period, It is determined whether the signal is valid-signal.

Accordingly, the problem that the signal existing in the synchronization signal section due to the reception delay can not be judged as the valid signal can be overcome. That is, the reception error due to the delay of the reception signal from the communication object can be overcome.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a surveillance system to which surveillance cameras 1a, 1b, and 1c according to an embodiment of the present invention are applied.

1, the surveillance cameras 1a, 1b and 1c communicate with the host apparatus 2 as a communication object by means of the communication signals D _COM and generate a live-view video signal (S _VID ) to the host device 2. The video signal S _VID received from the host device 2 is displayed through a display device while being stored in a recording device, for example, a hard disk drive.

Here, each of the surveillance cameras 1a, 1b, 1c transmits the video signal S _VID to the host apparatus 2 while communicating with the host apparatus 2 via a coaxial cable. Accordingly, the communication signals D _COM are transmitted and received in the vertical blank interval (VBI) of the video signal S _VID transmitted to the host apparatus 2.

Fig. 2 shows the internal configuration of any one of the surveillance cameras 1a, 1b, or 1c in Fig.

1 and 2, a surveillance camera according to the present invention includes an optical system (OPS), a photoelectric conversion unit (OEC), a Correlation Double Sampler and Analog-to-Digital Converter (CDS-ADC) 101, a timing circuit 102, A dynamic random access memory (DRAM) 104, an electrically erasable and programmable read only memory (EEPROM) 105, a digital signal processor 107 as a main control unit, a video signal generator 108 ), And a communication interface 109.

An optical system (OPS) including a lens unit and a filter unit optically processes light from a subject.

A photoelectric conversion unit OEC of a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) converts light from the optical system OPS into an electrical analog signal. Here, the digital signal processor 107 as the main controller controls the timing circuit 102 to control the operations of the photoelectric conversion unit OEC and the analog-digital conversion unit 101.

A CDS-ADC (Correlation Double Sampler and Analog-to-Digital Converter) 101 as an analog-to-digital conversion section processes an analog video signal from a photoelectric conversion section OEC, removes high frequency noise, And then converts it into digital image data. The digital image data is input to the digital signal processor 107.

A digital signal processor 107 as a main control unit processes digital signals from the CDS-ADC element 501 to generate digital image data classified into luminance and chroma signals.

In the dynamic random access memory (DRAM) 104 for buffering, digital image data from the digital signal processor 107 is temporarily stored. An algorithm necessary for the operation of the digital signal processor 107 is stored in an EEPROM (Electrically Erasable and Programmable Read Only Memory) 105.

The video-signal generating unit 108 converts the digital image data from the digital signal processor 107 into a video signal S _VID which is an analog video signal.

The digital signal processor 107 as the main control unit transmits the transmission signal D _COMOUT 'to the host apparatus 2 as a communication object via the communication interface 109 and transmits the communication signal from the host apparatus 2 to the communication interface 109 ) while receiving a receive input signal (D _COMIN ') via a video-transmits the video signal _(VID S) from the signal generating unit 108 to the host apparatus 2.

The communication interface 109 transmits the video signal S _VID from the video-signal generation unit 108 to the host apparatus 2 as a communication object via a coaxial cable 110, The received signal D _COMIN is extracted from the communication signal D _COM in the cable 110 and input to the digital signal processor 107 so that the transmitted signal D _COMOUT ' Coaxial cable 110 to the communication signal D _COM .

That is, the digital signal processor 107 communicates with the host apparatus 2 via the communication interface 109 at the vertical blank interval VBI of the video signal S _VID transmitted to the host apparatus 2, And transmits the video signal (S _VID ) from the signal generating section 108 to the host apparatus 2 via the communication interface 109.

The received signal D _COMIN from the host apparatus 2 is input to the communication interface 109 by a polling method in the setting horizontal periods of the vertical blank interval VBI of the video signal S _VID .

Here, the communication interface 109 determines a first-threshold value in the main section of each of the set horizontal periods, determines whether the signal is valid-signal in accordance with the voltage of the received signal, A second threshold value lower than the first threshold value is obtained and it is determined whether the signal is valid-signal according to the voltage of the received signal.

Accordingly, the problem that the signal existing in the synchronization signal section due to the reception delay can not be judged as the valid signal can be overcome. That is, the reception error due to the delay of the reception signal from the communication object can be overcome.

Furthermore, when the reception delay is long, the valid signal may exist not only in the synchronous signal section but also in the burst signal section.

In this case, since the effective new signal existing in the burst signal interval due to the reception delay is mixed with the burst signal of the AC component, the judgment of whether the signal is valid-signal may be wrong.

Therefore, the communication interface 109 obtains the first threshold value in the state where the burst signal is removed in the burst signal period of each of the set horizontal periods, and determines whether the signal is valid-signal according to the voltage of the received signal .

Accordingly, the reception error due to the delay of the reception signal from the communication object can be more completely overcome.

The related contents will be described in detail with reference to Figs.

FIG. 3 shows the internal configuration of the communication interface 109 of FIG. In Fig. 3, the same reference numerals as those in Figs. 1 and 2 denote objects having the same function.

1 to 3, the communication interface 109 includes a bidirectional signal processing unit 301, a transmission interface 302, a reception interface 303, and a synchronization signal detection unit 304. [ Here, the output terminal of the transmission interface 302, the input terminal of the reception interface 303, and the input terminal of the synchronization signal detection unit 304 are connected to a coaxial cable 110 through a BNC (Bayonet Neil- Respectively.

The synchronous signal detecting unit 304 detects the vertical synchronous signals V _SYNC and the horizontal synchronous signals H _SYNC from the video signal S _VID from the video signal generator 108 and outputs the detected vertical synchronous signals V _SYNC and H _SYNC to the bidirectional signal processor 301. [ And the reception interface 303, as shown in FIG.

The bidirectional signal processing unit 301 modulates the transmission signal D _COMOUT 'from the digital signal processor 107 as a main control unit in accordance with a setting protocol. The bidirectional signal processor 301 transmits the modulated transmission signal D _COMOUT 'to the host through the transmission interface 302 and the coaxial cable 110 in the vertical blank interval of the video signal S _VID To the DVR (2).

The bidirectional signal processor 301 receives the reception signal D (D) input from the host device (DVR) 2 through the coaxial cable 110 and the reception interface 303 in the vertical blank interval of the video signal S _{VID COMIN} ) according to the setting protocol. Further, the bidirectional signal processing unit 301 _{inputs the} demodulated received signal D _COMIN 'to the digital signal processor 107 as a main control unit.

Here, the reception interface 303 determines a first-threshold value in the main section of each of the set horizontal periods, determines whether the signal is valid-signal in accordance with the voltage of the received signal, A second threshold value lower than the first threshold value is obtained and it is determined whether the signal is valid-signal according to the voltage of the received signal. The effective reception signal D _COMIN according to the determination result is input to the bidirectional signal processing unit 301.

Accordingly, the problem that the signal existing in the synchronization signal section due to the reception delay can not be judged as the signal can be overcome. That is, the reception error due to the delay of the reception signal from the communication object can be overcome.

Furthermore, when the reception delay is long, the valid signal may exist not only in the synchronous signal section but also in the burst signal section.

In this case, since the effective new signal existing in the burst signal interval due to the reception delay is mixed with the burst signal of the AC component, the judgment of whether the signal is valid-signal may be wrong.

Accordingly, the reception interface 303 obtains the first threshold value in the state where the burst signal is removed in the burst signal period of each of the set horizontal periods, and determines whether the signal is valid-signal according to the voltage of the received signal .

Accordingly, the reception error due to the delay of the reception signal from the communication object can be more completely overcome.

The related contents will be described in detail with reference to Figs.

FIG. 4 shows the structure of the video signal (S _VID ) output from the video-signal generator 108 of FIG. In FIG. 4, reference symbol V _SYNC denotes vertical synchronization signals, S _IM denotes video signals, BS denotes burst signals, and H _SYNC denotes horizontal synchronization signals. 5 shows a received signal (D _{COMIN in} Fig. 3) from the communication object (2 in Fig. 1) at the set horizontal periods (e.g., t11 to t14) of the vertical blank interval (VBI) . In Fig. 4, the same reference numerals as those in Fig. 5 denote objects having the same function.

In Fig. 5, Tde indicates a reception delay time. The reception delay time Tde in the surveillance camera includes a time at which the video signal is transmitted from the surveillance camera to the communication object, a reaction time at the communication object itself, and a time at which the communication signal is transmitted from the communication object to the surveillance camera do.

5, reference numeral Vth denotes a threshold for judging whether the signal is valid-signal, Vps denotes a peak value of the received signal, Vpb denotes a peak value of a burst signal BS, and Vsy denotes a peak value of a burst signal And the amplitude of the generated horizontal synchronizing signal.

2 to 5, the unit frames t1 to t525 of the video signal S _VID output from the video-signal generating unit 108 are divided into odd-numbered fields t1 to t263 and odd-numbered fields t1 to t263 according to the interlace display scheme And is divided into an even field (t263 to t525). In addition, each of the odd field (t1 to t263) and the even field (t263 to t525) is divided into a vertical blank interval (VBI) and an active period.

As described above, the received signal D _COMIN from the communication object (2 in FIG. 1) is _{polled by} the setting horizontal periods (for example, t11 to t14) of the vertical blank interval VBI . Here, a pulse having a width W _L less than the reference width indicates low logic data "0 ", and a pulse W _H having a width larger than the reference width indicates high logic data" 1 ".

For reference, in the conventional surveillance camera, the threshold value Vth for judging whether the signal is valid-signal is fixed.

FIG. 6 shows the operation of the receive interface 303 of FIG. 3 for the receive signal of FIG. In Fig. 6, the same reference numerals as those in Fig. 5 denote objects having the same function.

3 and 5, the receiving interface 303 obtains a first threshold value Vth1 in a main interval of each of the set horizontal periods (for example, t12 to t15) Signal and determines a second threshold value Vth2 lower than the first threshold value Vth1 in the synchronization signal period of each of the set horizontal periods to determine whether the signal is valid-signal according to the voltage of the received signal. The effective reception signal D _COMIN according to the determination result is input to the bidirectional signal processing unit 301.

Each of the first threshold value Vth1 and the second threshold value Vth2 is limited to be smaller than the peak value Vps of the received signal and larger than the peak value Vpb of the burst signal BS. This can be expressed by the following equations (1) and (2).

Vpb < Vth1 < Vps

Vpb < Vth2 < Vps

Here, if the amplitude value of the burst signal BS is Vwb, the first threshold value Vth1 is obtained by the following equation (3).

If the minimum value of the horizontal synchronizing signal is Vls, the second threshold value Vth2 is obtained by the following equation (4).

As described above, a received signal that should exist only in a main period of a set horizontal period (for example, t12 to t15) may exist in a synchronous signal period due to a signal delay. Here, the synchronizing signal section means a section in which a horizontal synchronizing signal having a constant amplitude (Vsy) is generated.

Therefore, the potential of the effective signal existing in the synchronizing signal section is lowered because the potential of the synchronizing signal section of one set horizontal period is lower than the direct current potential of the main section.

However, since the validity signal is judged by the second threshold value Vth2 lower than the first threshold value Vth1 in the synchronizing signal section, the problem that the valid signal existing in the synchronizing signal section can not be judged as the valid signal can be overcome . That is, the reception error due to the delay of the reception signal from the communication object can be overcome.

Furthermore, when the reception delay is long, an effective signal may exist not only in the synchronization signal section but also in a burst signal section (for example, t12 to t13).

In this case, since the effective new signal existing in the burst signal period (for example, t12 to t13) due to the reception delay is mixed with the burst signal BS of the AC component, It can be wrong.

Therefore, the receiving interface 303 can set the first threshold value in the state where the burst signal BS is removed at a burst signal interval (for example, t12 to t13) of each of the set horizontal periods And determines whether the signal is valid-signal according to the voltage of the received signal.

Accordingly, the reception error due to the delay of the reception signal from the communication object can be more completely overcome.

FIG. 7 shows the internal configuration of the receive interface 303 of FIG. 3 for performing the operation of FIG. 3, 6 and 7, the internal configuration of the reception interface 303 of FIG. 3 for performing the operation of FIG. 6 will be described below.

The receiving interface 303 includes a clamp circuit 71, a burst removing unit 72, an amplifying unit 73, a peak detecting unit 76, a threshold value generating unit 75 and a comparing unit 74 .

A clamp circuit 71 converts a reception signal inputted through a coaxial cable 110 from a communication object into a positive signal. The received signals in Figs. 5 and 6 are outputted from the clamp circuit 71. Fig.

The burst eliminator 72 removes the burst signal BS from the positive received signal from the clamp circuit 71. [ 5 and 6, it can be seen that the burst signal BS is removed in the burst period of t12 to t13. Thus, it is possible to prevent the effective new signal existing in the burst signal period (t12 to t13) due to the reception delay from being mixed with the burst signal of the AC component.

The amplifying unit 73 amplifies the received signal from the burst removing unit 72 with a constant amplification degree. Of course, the amplifying unit 73 may be omitted in some cases.

The peak detector 76 detects the peak value (Vps) of the received signal from the burst eliminator 72.

The threshold value generation unit 75 generates a threshold value Vps of the reception signal from the peak detection unit 76 and the vertical synchronization signals V _SYNC and H _SYNC from the synchronization signal detection unit 304, , The first threshold value Vth1 or the second threshold value Vth2 is calculated and output.

Here, the above equations (1) to (4) are used.

In the use of Equations 1 to 4, the peak value Vpb of the burst signal BS, the amplitude Vsy of the horizontal synchronizing signal, the amplitude value Vwb of the burst signal BS, And the minimum value Vls of the horizontal synchronizing signal are set in advance.

The comparison section 74 compares the effective value of the received signal from the amplification section 73 with the first threshold value Vth1 or the second threshold value Vth2 variable from the threshold value generation section 75, And outputs the valid reception signal D _COMIN according to the determination result to the bidirectional signal processing unit 301.

As described above, according to the control method of the surveillance camera and the surveillance camera adopting the surveillance camera according to the present invention, in the synchronization signal period of each of the set horizontal periods, the second threshold value lower than the first threshold value in the main section And whether the signal is valid-signal is determined according to the voltage of the received signal.

Accordingly, the problem that the signal existing in the synchronization signal section due to the reception delay can not be judged as the valid signal can be overcome. That is, the reception error due to the delay of the reception signal from the communication object can be overcome.

Further, in case that the reception delay becomes longer, the first threshold value is obtained in the state where the burst signal is removed in the burst signal period of each of the set horizontal periods, and the first threshold value is valid according to the voltage of the received signal. - Determine whether the signal is a signal.

Accordingly, the reception error due to the delay of the reception signal from the communication object can be more completely overcome.

And can be used for overcoming reception errors in a general communication system.

1 is a block diagram illustrating a surveillance system to which surveillance cameras according to an embodiment of the present invention are applied.

FIG. 2 is a block diagram showing an internal configuration of a surveillance camera of FIG. 1;

3 is a block diagram showing the internal configuration of the communication interface of FIG.

FIG. 4 is a waveform diagram showing a structure of a video signal output from the video-signal generator of FIG. 2. FIG.

FIG. 5 is a waveform diagram showing that a received signal from the communication object is loaded in the set horizontal periods (for example, t11 to t14) of the vertical blank interval (VBI) of FIG.

FIG. 6 is a waveform diagram illustrating the operation of the receive interface of FIG. 3 for the receive signal of FIG. 5;

FIG. 7 is a block diagram illustrating an internal configuration of the reception interface of FIG. 3 for performing the operation of FIG.

Description of the Related Art

1a, 1b, 1c ... surveillance cameras, 2 ... host device,

OPS ... Optical system, OEC ... Photoelectric conversion unit,

101 ... analog-digital converter, 102 ... timing circuit,

104 ... Dynamic RAM, 105 ... EEPROM,

107 ... digital signal processor, 108 ... video-signal generator,

109 ... communication interface, 110 ... coaxial cable,

VBI ... vertical blank section, 301 ... bidirectional signal processing section,

302 ... transmission interface, 303 ... reception interface,

304 ... synchronous signal detecting section,

305 ... BNC (Bayonet Neil-Concelman) connector,

71 ... clamp circuit, 72 ... burst eliminator,

73 ... amplifying section, 74 ... comparing section,

75 ... threshold value generator, 76 ... peak detector.

Claims (14)

delete A method of controlling a surveillance camera receiving a reception signal from a communication object in horizontal periods of a vertical blank interval (VBI) of a video signal transmitted to a communication object, (a) determining a first threshold value in a main period of each of the set horizontal periods and determining whether the signal is valid-signal according to the voltage of the received signal; (b) determining a second threshold value lower than the first threshold value in the synchronization signal period of each of the set horizontal periods, and determining whether the signal is valid-signal according to the voltage of the received signal; And (c) determining the first threshold value in a state where a burst signal is removed in a burst signal period of each of the set horizontal periods, and determining whether the signal is valid-signal according to the voltage of the received signal A method of controlling a surveillance camera, A method of controlling a surveillance camera receiving a reception signal from a communication object in horizontal periods of a vertical blank interval (VBI) of a video signal transmitted to a communication object, (a) determining a first threshold value in a main period of each of the set horizontal periods and determining whether the signal is valid-signal according to the voltage of the received signal; And (b) determining a second threshold value lower than the first threshold value in the synchronization signal period of each of the set horizontal periods, and determining whether the signal is valid-signal according to the voltage of the received signal, Wherein the first threshold value and the second threshold value, respectively, Wherein the peak value of the received signal is smaller than the peak value of the burst signal. Claim 4 has been abandoned due to the setting registration fee. The method of claim 3, Wherein the first threshold value is Vth1, the peak value of the reception signal is Vps, the peak value of the burst signal is Vpb, the amplitude of the horizontal synchronization signal generated in the synchronization signal interval is Vsy, Assuming that the amplitude value of the signal is Vwb,

Wherein the first threshold value is obtained by the following equation. Claim 5 has been abandoned due to the setting registration fee. 5. The method of claim 4, If the second threshold value is Vth2 and the minimum value of the horizontal synchronizing signal is Vls,

Wherein the second threshold value is obtained by the following equation. delete A receiving unit for receiving a received signal from the communication object in horizontal periods of a vertical blank interval (VBI) of a video signal transmitted to a communication object, the receiving unit including a main control unit, a video-signal generating unit, A surveillance camera comprising: Wherein the communication interface comprises: Determining a first threshold value in a main interval of each of the set horizontal periods to determine whether the signal is valid-signal according to the voltage of the received signal, A second threshold value lower than the first threshold value is determined in a synchronization signal period of each of the set horizontal periods to determine whether the signal is valid-signal according to the voltage of the received signal, Wherein the first threshold value is obtained in a burst signal period of each of the set horizontal periods and the burst signal is removed, and the validity-signal is determined according to the voltage of the received signal. delete Claim 9 has been abandoned due to the setting registration fee. 8. The method of claim 7, The video- Converts the digital video data from the main control unit into a video signal which is an analog video signal, inputs the video signal into the communication interface, Wherein, And transmits the video signal from the video-signal generating unit to the communication target via the communication interface while communicating with the communication target through the communication interface in the vertical blank interval of the video signal transmitted to the communication target. delete Claim 11 has been abandoned due to the set registration fee. 10. The method of claim 9, In the communication interface, a video signal from the video-signal generator is transmitted to the communication object via a coaxial cable, Wherein the communication interface includes a bidirectional signal processing unit, a transmission interface, a reception interface, and a synchronization signal detection unit, Wherein an output terminal of the transmission interface, an input terminal of the reception interface, and an input terminal of the synchronization signal detection unit are commonly connected to the coaxial cable. Claim 12 is abandoned in setting registration fee. 12. The apparatus according to claim 11, And a vertical synchronizing signal and a horizontal synchronizing signal from the video signal from the video signal generating unit are detected and input to the bidirectional signal processor and the receiving interface. Claim 13 has been abandoned due to the set registration fee. 13. The apparatus of claim 12, wherein the bi- Transmitting a transmission signal from the main control unit to the communication destination through the transmission interface and the coaxial cable at a vertical blank interval of the video signal, And inputs a received signal input from the communication object through the coaxial cable and the receiving interface in the vertical blank interval of the video signal to the main control unit. Claim 14 has been abandoned due to the setting registration fee. 14. The method of claim 13, A clamp circuit for converting a reception signal received through the coaxial cable from the communication object into a positive signal; A burst canceling unit for removing the burst signal from a positive received signal from the clamp circuit; An amplifying unit for amplifying a received signal from the burst removing unit; A peak detector for detecting a peak value of a received signal from the burst deactivation; A threshold value generation unit for calculating and outputting the first threshold value or the second threshold value according to a peak value of a reception signal from the peak detection unit and vertical synchronization signals and horizontal synchronization signals from the synchronization signal detection unit; And Wherein the control unit determines whether the received signal from the amplifying unit is an effective signal in accordance with the first threshold value or the second threshold value from the threshold value generating unit and generates an effective reception signal according to the determination result, The surveillance camera comprising:

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