JPH04320183A - Remote monitor camera control system - Google Patents

Abstract

PURPOSE:To improve the operability of a remote monitor system by solving a problem of a position deviation between a monitor screen and a site camera in real time by presetting a backward quantity of a camera with respect to combinations of conditional quantities. CONSTITUTION:An attitude revision command section 10 of a camera 1 implements a movement and stop command of the camera 1 while a video image of a monitor section 8 is observed. The content of the command is processed into a signal by an attitude revision command signal section 11 and the signal is sent to a channel selection side communication section 4 through a communication network 5 by means of a receiver side communication equipment 6. The received signal is converted into an electric signal by an attitude revision command control section 12 and the signal is sent to an attitude revision section 9, which controls the attitude of the camera 1. In this case, the movement of the camera has an overshoot and some retraction is required. Thus, the retract amount of the camera depending on a communication speed of a communication line, a compression coding time of a video image and a moving speed of the camera is preset with respect to the combinations of conditions and the result is integrated in the electric signal to apply automatic reverse retract control to the camera. Thus, the deviation of the position of the monitor and the camera is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to attitude control of a camera in a system for video monitoring of a remote location via a communication line.

0002

[Prior Art] Conventionally, in video surveillance systems,
The imaging location of this camera has been changed by rotating the camera stand with a motor. The main method is to monitor the video while on the same campus, etc.
It was controlling the camera's attitude. When implementing something similar to this via a communication line, there was a problem of video delay. For traditional telephone networks, 9600b/s
In the case of ISDN, 64k modem is used.
b/s is used. Therefore, 320×200pe
Sending a monochrome image of 8 bits/pel on a screen with a resolution of 53 seconds and 8 seconds, respectively, is required. In order to shorten this transmission time, video compression encoding is performed, but time is also required for this processing. Therefore, if the camera position is moving at a constant speed, Figure 6
As shown in the figure, the screen position seen on the receiving side and the camera position at that point are different positions, and even if you control the stop by looking at the screen, the camera stop position will be at a different position. turn into.

[0003] Conventionally, therefore, when controlling the position of a camera via a communication line, a method has been adopted in which the amount of movement of the camera is instructed in advance and the position of the camera is controlled by that amount. For this reason, it was not possible to appropriately control the position of the camera while viewing the monitoring screen.

0004

[Problems to be Solved by the Invention] With the development of the information society, the demand for video communication is increasing. In particular, as communication lines become faster, there are high expectations for systems that allow real-time viewing of on-site images, such as surveillance systems.

[0005] An object of the present invention is to reduce encoding delay,
The objective is to improve the operability of a remote monitoring system by solving the problem that communication delays cause a discrepancy between the image displayed on the monitor screen and the camera position at the site.

[0006]

[Means for Solving the Problems] According to the present invention, when a camera that takes an image of an object via a communication line receives a stop instruction while moving, the camera moves backward by a predetermined amount and issues a stop instruction. The main feature is that the camera is stopped near the screen. For this reason, conventional technology has the advantage of controlling the amount of camera retraction, which is determined by the communication speed of the communication line, the video compression encoding time, and the moving speed of the camera, by setting it in advance for each combination of these conditional quantities. It is different from

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0008] Considering the transmission side of the monitoring system, when a certain screen is captured, it is compressed and encoded and transmitted. This process is repeated and the screens are sent one after another, but generally a single encoder is installed, and until the compression encoding of one screen is completed, processing of the next screen cannot be started. . Of course, the communication system is compatible with communication lines, and unless the transmission of a certain screen is completed, the transmission of the next screen cannot be started. Note that these circumstances are the same on the receiving side. Here, in a system where compression encoding and communication are performed in series, a time chart as shown in FIG. 3 is obtained. Now, if we focus on the nth screen, the display start time (n+1)Tc+nTt
Display end time (n+2)Tc+(n+1)
Tt Screen input time (n-1)Tc+(
n-1) Tt Tc: encoding time
Tt: Communication time If you issue a stop signal while looking at the nth screen, the time is (n+1+α)(Tc+Tt)-Tt
(0<α<1) If the screen being input at that time is the m-th screen, then (m-1) (Tc+Tt)<(n+
1+α)(Tc+Tt)-Tt<m(Tc+Tt) Therefore, 1+α-Tt/(Tc+Tt)<m-n<2+α-
Tt/(Tc+Tt)m=n+1 or n+2
becomes. When the video compression encoding method is implemented on an LSI, Tc/
Since Tt→0, m→n+1, and the screen that has already been input to the sending side when the stop signal is input is the screen that is one step ahead of the screen that is currently being viewed. In a system where compression encoding and communication are performed in parallel, when Tc<Tt, a time chart as shown in FIG. 4 is obtained. Now, if we focus on the nth screen, the display start time is nTt+2T
c Display end time (n+1)Tt+2T
c Screen input time (n-1)TtIf you issue a stop signal while looking at the nth screen, the time is (n+α)Tt+2Tc (0<α<1) m If it is (m−
1) Tt<(n+α)Tt+2Tc<mTt Therefore,
α+2Tc/Tt<m-n<1+α+2Tc/Tt
m=n+1 or n+2
Or it becomes n+3. When the video compression encoding method is implemented in LSI, Tc/Tt→0, so m→n+
1, and the screen that has already been input to the transmitting side when the stop signal is input is the screen that is one step ahead of the screen that is currently being viewed. In a system where compression encoding and communication are performed in parallel,
When Tc>Tt, a time chart as shown in FIG. 5 is obtained. Now, focusing on the nth screen, display start time (n+1)Tc+Ttdisplay end time (n+2)Tc+Ttscreen input time (n-1)TcIf you issue a stop signal while looking at the nth screen, then The time is (n+1+α)Tc+Tt (0<α<1)
If the screen being input at that time is the mth screen, (m
-1) Tc<(n+1+α)Tc+Tt<mTc Therefore, 1+α+Tt/Tc<m-n<2+α+Tt/T
c m=n+2 or n+
It becomes 3.

[0009] In this case, a compression encoding method is used that is slower than the communication speed of ISDN, which is a high-speed public network, and is not a system that originally requires quick response. It is okay to go back about 2, 3 or 2.5 steps from the point where you are.

FIG. 1 is a diagram illustrating a system configuration for implementing the present invention, in which 1 is a camera that images an object, 2 is a photoelectric converter that converts the image into an electrical signal, and 3 is a compressor that compresses this electrical signal. 4 is a communication unit on the transmitting side that controls communication; 5 is a communication network used for remote monitoring; 6 is a communication unit on the receiving side; 7 is a decompression unit for decompressing the previously compressed and encoded signal. 8 is a monitor unit for viewing images; 9 is an attitude change unit for the camera 1; 10 is an attitude change instruction unit for the camera 1; 11 is an attitude for converting the instruction from the attitude change instruction unit 10 of the camera 1 into an electrical signal. A change instruction signal unit 12 is an attitude change instruction control unit that provides a change signal to the attitude change unit 9.

That is, an image captured by the camera 1 is converted into an electrical signal by a photoelectric conversion section 2, and this signal is compressed and encoded by an encoding section 3 and sent to a communication section 4 on the transmitting side. In the communication unit 4 on the transmitting side, via the communication network 5,
The compression-encoded signal is transmitted to the communication unit 6 on the other party's receiving side. The signal received by the communication section 6 on the receiving side is compressed and expanded by the decoding section 7, and can be viewed as a video on the monitor section 8. During normal monitoring, images are continuously viewed by repeating this sequence. In such a system, in order to control the position of the camera 1, it is necessary to give an electrical signal equivalent to the amount to be changed to the attitude changing unit 9 of the camera 1. On the receiving side equipped with the monitor section 8, while viewing the image on the monitor section 8, an instruction to start moving the camera 1 or an instruction to stop the camera 1 is issued using the posture change instruction section 10 of the camera 1. The content instructed by the attitude change instruction unit 10 is converted into a signal by the attitude change instruction signal unit 11 that sends a corresponding signal, and is sent to the communication unit 6 on the receiving side, and the camera 1 is sent via the communication network 5. The information is transmitted to the equipped communication unit 4 on the transmitting side. The attitude change instruction signal received by the communication unit 4 on the transmitting side is sent to the attitude change instruction control unit 12, which sends an equivalent electrical signal to the attitude change unit 9. The attitude changing unit 9 is supposed to control the attitude of the camera 1 according to the electric signal. In the case of such a system, as explained earlier, the camera may go too far, so it is necessary to move back a little. Figure 2
The following describes the output signal of the attitude change instruction control unit 12.

[0012] A is the simplest control method; when the attitude change instruction control unit 12 receives a movement start signal, it issues a signal to move in the forward direction, and when it receives a stop instruction signal midway through, it moves in the opposite direction. The control is stopped by issuing a signal. The time period for this movement in the opposite direction is determined in advance based on the conditions of actual use, and the movement is made to stop near the desired stop position.

[0013] b is a case where the encoding processing time is very short compared to the communication time. Posture change instruction control unit 1
When the 2 receives a movement start signal, it issues a signal to move in the forward direction, and when it receives a stop instruction signal on the way, it further drives to the next video input position, and when it reaches that position, the 2
It issues a signal to move in the opposite direction by an amount corresponding to the step and stops the control.

[0014] c is a case where the encoding processing time is longer than the communication time. When the attitude change instruction control unit 12 receives a movement start signal, it issues a signal to move in the forward direction, and when it receives a stop instruction signal on the way, it immediately issues a signal to move in the opposite direction by an amount equivalent to two and a half steps. This method stops the control by issuing a signal.

[0015]

Effects of the Invention As explained above, according to the present invention, in a monitoring system where the camera position and the monitored image are time-discrepant, when a stop instruction is given based on the monitored image, the automatic Since the camera is moved back slightly in the opposite direction, operability on the monitoring side is improved.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention.

FIG. 2 is a waveform diagram showing an output signal of the attitude change instruction control section of FIG. 1;

FIG. 3 is a time chart in a system in which compression encoding and communication are performed in series to explain the present invention.

FIG. 4 is a time chart for explaining the present invention when Tc<Tt in a system in which compression encoding and communication are performed in parallel.

FIG. 5 is a time chart for explaining the present invention when Tc>Tt in a system in which compression encoding and communication are performed in parallel.

FIG. 6 is an explanatory diagram showing the relationship between the position on the monitor screen and the actual camera position when the camera is moving at a constant speed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Camera, 2...Photoelectric conversion unit, 3...Encoding unit, 4...Communication unit on the transmitting side, 5...Communication network, 6...Communication unit on the receiving side, 7...Decoding unit, 8...Monitor unit, 9... Attitude change section, 10... Attitude change instruction section, 11... Attitude change instruction signal section, 12... Attitude change instruction control section.

Claims (3)

[Claims] 1. A camera that images an object, means for converting the image captured by the camera into an electrical signal, means for encoding the converted signal, and means for changing the attitude of the camera at a constant speed. a remote monitoring and transmitting device comprising means for transmitting the amount of change to the attitude changing means as an electrical signal; and means for communicating the encoded video signal and the camera attitude change signal; means for communicating the encoded video signal and the camera attitude change signal with a remote monitoring transmitter; means for decoding the encoded video signal; and displaying the decoded electrical signal. In a remote monitoring system comprising a remote monitoring receiving device comprising means for instructing the camera to change its posture, means for instructing the camera to change its posture, and means for converting the instruction into a camera posture change signal, the camera posture change instructing means: When a stop instruction is given after a movement instruction, the camera is caused to move backward by a certain amount after stopping, by means of transmitting the amount of change received by the camera attitude change signal as an electric signal, and by the camera attitude change means. Features a remote monitoring camera control system. 2. An electric circuit that encodes an electric signal of an image captured by a camera and an electric circuit that decodes the code, and upon receiving a stop instruction signal of the camera, moves the camera to the next image input position. 2. The remote monitoring camera control system according to claim 1, wherein the remote monitoring camera control system is moved forward to a position and then retreated to a position two positions before the previous image input position. 3. A device comprising means for encoding an electrical signal of an image captured by a camera using software, means for decoding the code using software, and a communication means having an ISDN interface, and transmitting a stop instruction signal of the camera. 2. The remote monitoring camera control system according to claim 1, wherein upon receiving the camera, the camera is immediately stopped and then retreated by a distance corresponding to 2.5 times the video input position interval.