JP2001148849A - Video control system for multiple dwelling house - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically correct a high frequency attenuation frequency characteristic for a video signal fluctuated corresponding to a distance of a transmission line by detecting the distance of the transmission line on the basis of a level of a color burst signal included in the video signal. SOLUTION: The video control system for multiple dwelling house is provided with entrance units 1a, 1b, 1c with a camera that transmit a video signal captured by the camera, a video controller 2 having a video signal modulation section 11 that is connected respectively to the transmission line L1a, L1b, L1c with the camera and modulates the video signal, a living room monitor 3 having a video signal demodulation section 20 that demodulates the modulated video signal and a video display section 21 that displays the demodulated video signal, and the video controller 2 is provided with a detection section 10 that detects the distance of the transmission line from the entrance units 1a, 1b, 1c with the camera depending on the level of a color burst signal included in the video signal from the entrance units 1a, 1b, 1c with the camera and with a frequency characteristic correction section 12 that corrects the high frequency attenuation frequency characteristic fluctuated in the distance of the transmission line with the detection signal of distance from the detection section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video control apparatus for a multi-family house, and more particularly to a video control apparatus for transmitting a video signal in which the restriction on the distance of a transmission line is eliminated and noise is suppressed with an improvement in S / N ratio. The present invention relates to an image control device for an apartment house capable of displaying an image.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an image control apparatus for a multi-family house having a configuration shown in a block diagram of FIG.

[0003] The video control device for a multi-family house shown in FIG. 1 has a plurality of front doors 51a, 5a, 5b, 5c, which transmit video signals taken from a camera (not shown) as a video imaging function.
1b, 51c, and each of the camera-equipped entrance devices 51a, 51b, 5
A cable compensator 5 for manually correcting the frequency characteristic of the video signal, which fluctuates according to the distance of the transmission lines L51a, L51b, L51c (line length L51a <L51b <L51c) connected to 1c.
2a, 52b, 52c, and each cable compensator 52a, 5c
Video controller 53 having video signal modulator 60 for modulating the video signal whose frequency characteristic has been corrected via 2b and 52c
A video signal demodulation unit 70 for demodulating the video signal modulated via the video signal modulation unit 60 of the video controller 53; and a video display unit 71 for displaying the video signal demodulated via the video signal demodulation unit 70. And a living room monitor 54 having

[0004] In the video control apparatus for an apartment house constructed as described above, each of the camera-equipped entrance devices 51a, 51b, 51 is provided.
c from a camera (not shown) of the transmission line L51.
a, the video signal transmitted through L51b and L51c is converted to a video controller by the respective cable compensators 52a, 52b and 52c as the video signal whose frequency characteristic that fluctuates corresponding to the distance of the transmission path is corrected. 53 video signal modulators 6
Sent to 0.

[0005] The video signal modulator 60 of the video controller 53
The video signal whose frequency component has been corrected is modulated via each of the cable compensators 52a, 52b, and 52c and transmitted to the video signal demodulation unit 70 of the living room monitor 54.

The video signal demodulator 70 of the living room monitor 54
The video signal modulated via the video signal modulator 60 of the video controller 53 is demodulated and displayed on the video display 71.

[0007]

However, since the conventional video control device for a condominium is constructed as described above, it is taken in by the cameras (not shown) of the front doors 51a, 51b and 51c with cameras. In order to display the displayed video (video signal) on the video display unit 71 of the living room monitor 54, the video signal varies depending on the distance between the transmission lines L51a, L51b, and L51c via the cable compensators 52a, 52b, and 52c. In addition, there is a disadvantage that the frequency characteristics to be performed must be manually corrected, and there is a problem that the device is complicated, and a manufacturing cost is increased in configuring the device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and detects the distance of a transmission line based on the level of a color burst signal included in a video signal, and varies the distance according to the distance of the transmission line. It is an object of the present invention to provide an image control device for an apartment house in which a high-frequency attenuation frequency characteristic of a video signal to be automatically corrected.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, an image control apparatus for an apartment house according to the present invention transmits a video signal captured by a camera to a front door with a camera and transmits the video signal to the front door with a camera. A video controller having a video signal modulator connected to a road and modulating a video signal, a video signal demodulator for demodulating the modulated video signal, and a living room monitor having a video display for displaying the demodulated video signal in video. The video controller is configured to detect the distance of the transmission path from the camera-equipped entrance device based on the level of the color burst signal included in the video signal from the camera-equipped entrance device, and the distance from the detection unit. A frequency characteristic correction unit that corrects a high-frequency attenuation frequency characteristic that fluctuates according to the distance of the transmission path in accordance with the detection signal.

[0010] In such an image control device for an apartment house, the detection unit of the image control device also detects the level of the color burst signal contained in the image signal transmitted from the entrance device with the camera and transmitted through the transmission path. Then, the distance of the transmission path is detected. The frequency characteristic correction unit of the video controller automatically corrects the high-frequency attenuation frequency characteristic of the video signal that fluctuates according to the distance of the transmission path based on the detection signal of the distance from the detection unit, and The frequency component of the modulated wave of the video signal modulator is controlled to a level at which the level of the color burst signal does not attenuate so that the output waveform (demodulated wave) from the signal demodulator can be normally reproduced. As a result, the restriction on the distance of the transmission path for transmitting the video signal is eliminated, and a good video in which noise is suppressed with the improvement of the S / N ratio can be displayed on the video display unit of the living room monitor.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred embodiment of the present invention;

FIG. 1 is a block diagram showing the configuration of an embodiment of an image control apparatus for a multi-family house according to the present invention. As an image pickup function, a plurality of image signals taken from a camera (not shown) are transmitted. Entrance machine with camera 1a, 1b, 1c
And the distance of the transmission lines L1a, L1b, L1c (line length L1a <L1b <L1c) connected to each of the camera-equipped entrance machines 1a, 1b, 1c, by the level of the color burst signal included in the transmitted video signal ( (Hereinafter referred to as amplitude level), a video signal modulator 11 for modulating video signals transmitted through the transmission lines L1a, L1b, and L1c, and a distance detection signal from the detector 10. , Each transmission line L1a, L1b, L1c
Of the video signal whose amplitude level is attenuated almost in inverse proportion to the square root of the frequency due to the skin effect of the transmission path, the dielectric volume of the insulating material, and the like.
By automatically correcting the high-frequency attenuation frequency characteristic (see the graph of FIG. 2A), the video signal
A video controller 2 having a frequency characteristic correction unit 12 for controlling the frequency component of the modulated wave to a predetermined threshold level (see the graph of FIG. 2B) at which the attenuation of the amplitude level of the color burst signal does not occur; Video signal demodulation unit 2 for demodulating a video signal modulated via video signal modulation unit 11 of controller 2
0, and a living room monitor 3 having a video display unit 21 for displaying a video signal demodulated via the video signal demodulation unit 20.

The color burst signal contained in the video signal is, for example, 3.
8 to 12 cycles of the 85 MHz color subcarrier are inserted, and the peak value of the color burst signal is the same as the amplitude of the horizontal synchronization signal (not shown).

The operation of the video control apparatus for a condominium thus constructed will be described below with reference to the block diagram of FIG. 1 and the graphs of FIGS. 2 (a) and 2 (b).

The color burst signals contained in the video signals captured by the cameras (not shown) of the camera-equipped entrance machines 1a, 1b, 1c are transmitted through transmission lines L1a, L1b, L
The amplitude level is almost inversely proportional to the square root of the frequency due to the skin effect of 1c, the dielectric volume of the insulating material, and the like, and the amplitude level is attenuated in accordance with the distance of the transmission line (see the graph of FIG. 2A).

The detection unit 10 of the video controller 2 controls each transmission line L
1a, L1b, and L1c, based on the amplitude level of the color burst signal included in the video signal transmitted, detecting the distance of the transmission path from the camera-equipped entrance device, and converting the detected distance detection signal to a frequency. It is sent to the characteristic correction unit 12. The frequency characteristic correction unit 12 adjusts the frequency component of the modulated wave of the video signal modulated via the video signal modulation unit 11 based on the distance information forming the input detection signal to the variation in the distance of the transmission path. A predetermined threshold value at which the amplitude level of the color burst signal is not attenuated so that the output waveform (demodulated wave) from the video signal demodulation unit 20 of the living room monitor 3 is normally reproduced by automatically correcting the frequency component thus obtained. The level is controlled (see the graph of FIG. 2B). Video signal modulator 11
Modulates the video signal whose high-frequency attenuation frequency characteristic that fluctuates according to the distance of the transmission path is corrected, and sends the modulated video signal to the video signal demodulation unit 20 of the living room monitor 3.

The video signal demodulation section 20 of the living room monitor 3 demodulates the video signal modulated via the video signal modulation section 11 of the video controller 2 and causes the video display section 21 to display the video.

[0018]

As is apparent from the above description, according to the image control apparatus for a housing complex of the present invention, the level of the color burst signal included in the image signal captured by the camera of the camera-equipped entrance machine is determined. Then, the distance of the transmission path from the camera-equipped entrance device to the video controller that modulates the video signal is detected, and the high-frequency attenuation frequency characteristic of the video signal that fluctuates according to the distance of the transmission path is automatically corrected. be able to. This eliminates the trouble of manually correcting the high-frequency attenuation frequency characteristic of the video signal as in the conventional example, and eliminates the need for a cable compensator assigned to each transmission line, thereby reducing the manufacturing cost in configuring the device. Can be reduced, and restrictions such as an increase in the distance of a transmission line, which are difficult to improve the S / N ratio, are eliminated, and a good image with suppressed noise can be displayed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an image control device for a multi-family house according to the present invention.

FIG. 2A is a diagram showing a relationship between a level of a color burst signal included in a video signal transmitted through a transmission path and a frequency of the transmission path in an embodiment of the video control apparatus for an apartment house according to the present invention. Graph diagram. (B) is a graph showing the relationship between the level of the color burst signal included in the video signal whose high-frequency attenuation frequency characteristic has been corrected and the frequency of the transmission path.

FIG. 3 is a block diagram showing a configuration of a conventional video control device for a condominium.

[Explanation of symbols]

 1a, 1b, 1c... Entrance device with camera 2... Image controller 3... Living room monitor 10... Detector 11. ······ Frequency characteristic correction unit 20 ····· Video signal demodulation unit 21 ····· Video display unit L1a, L1b, L1c

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C054 DA08 EA01 EA03 ED12 ED15 EE01 EG08 EJ05 FB04 HA22 5C057 AA01 AA03 BA02 CB07 CC01 DA11 DB02 DC02 DC09 EA17 EB05 EC01 EC02 EC12 EF01 GC02 GE02 EC05 EC02 EC05 EC05 EF04 GA05 GA16 KA13 KC03 KD02 KD06 KP02 5K046 AA01 BA00 BB03 DD11 EE00 EE01 EE12 EE42

Claims (1)

[Claims] A camera-equipped entrance device (1a, 1b, 1c) for transmitting a video signal captured from a camera, and the video-emission signal connected to the camera-equipped entrance device via transmission lines (L1a, L1b, L1c). A video controller (2) having a video signal modulator (11) for modulating, a video signal demodulator (20) for demodulating the modulated video signal, and a video display (21) for displaying the demodulated video signal in video. And the living room monitor (3), wherein the video controller controls the distance of the transmission path from the camera-equipped entrance device based on the level of a color burst signal included in the video signal from the camera-equipped entrance device. And a frequency characteristic correction unit (12) that corrects a high-frequency attenuation frequency characteristic that fluctuates according to the distance of the transmission line based on a distance detection signal from the detection unit. To Characteristic video control device for apartment houses.