JP4025898B2 - Method of changing composition in image surveillance system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composition changing method in an image monitoring system in a closed circuit television.
[0002]
[Prior art]
Image monitoring in a closed circuit television in which a place to be monitored is picked up by an image pickup means (hereinafter referred to as a TV camera), and the place is monitored by transmitting the image to a center via a telephone line. There is a method.
In this type of image monitoring system, it is common that the TV camera is pointed in the direction to be monitored and the TV camera is stationary. That is, frame data with a predetermined composition (data for one screen, also referred to as a screen) is sent to the center every predetermined time.
[0003]
When an image is monitored with a predetermined composition at the center, there is a case where it is desired to point the TV camera toward a specific subject displayed on the screen in the composition. For example, there is a case where something suspicious with movement appears near the subject.
[0004]
In such a case, conventionally, the rotation (swinging) angle of the TV camera is commanded from the center to the TV camera driving mechanism, the rotation angle of the TV camera is detected by the encoder, and the TV camera is directed toward a predetermined subject. It was. An encoder that detects the rotation angle of the TV camera is attached to a mechanism that moves the TV camera (that is, a mechanism that swings the neck of the TV camera).
However, the command angle for moving the TV camera (swinging the head) relies on the feeling while watching the monitor screen. In order to obtain the desired composition, it is common to send the command angle to obtain the desired composition screen from the center side to the TV camera side twice or three times while viewing the monitor screen. there were.
[0005]
Conventionally, since it has been essential to install a rotation angle detection means, for example, the encoder, on the TV camera side, the TV camera drive mechanism becomes large, and securing a place to install the TV camera system is a problem. It was.
[0006]
[Problems to be solved by the invention]
The present invention provides a composition changing method in an image monitoring system in which a TV camera system can be miniaturized by not installing an encoder on the TV camera side, and a monitor screen desired by the center can be obtained quickly. It is.
[0007]
[Means for Solving the Problems]
The present invention solves the problem of a composition changing method when an encoder is used in a closed circuit television system in which an image captured by a TV camera is appropriately transmitted to a center via a telephone line and monitored on the center side. The method is as follows.
[0008]
In a closed circuit television system in which an image captured by a TV camera is transmitted to a center via a telephone line and monitored on the center side,
(B) On the TV camera side, a step of subtracting the previous frame data from the current frame data, creating frame data from which data of a moving subject is removed, and recording the frame data in a memory;
When the monitoring is performed on the center side, the monitor selects a subject that does not have a predetermined movement to be imaged, and commands to that effect via the telephone line to the TV camera side;
The TV camera that has received the command uses the frame data obtained by removing the data of the moving subject recorded in the memory, and the subject without the predetermined movement is positioned at a predetermined part of the screen. And moving the TV camera to stand still,
Each time the step c) is performed, the previous frame data is subtracted from the current frame data, and frame data from which a moving subject is removed is created and recorded in a memory;
On the TV camera side, after the subject without the predetermined movement is located at a predetermined part of the screen, the frame data obtained by subtracting the immediately preceding frame data from the current frame data and removing the data of the moving subject is obtained. Creating and continuing to record in memory.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Normally, when the TV camera is stationary, the frame data obtained by subtracting the previous frame data from the current frame data and removing the moving subject data is created and recorded on the TV camera system side. The image is transmitted to the center via a telephone line.
Images and data are transmitted in both directions via a telephone line.
[0010]
To change the composition on the center side, the supervisor selects a subject that does not have a predetermined movement, which is a target for imaging, and instructs the TV camera side to that effect.
For example, if a target object with no predetermined movement is located in the right corner of the screen and you want a composition that positions this subject in the center of the screen, issue a command to move the TV camera to the right by an appropriate amount. Become.
[0011]
On the TV camera side, the TV camera is appropriately moved and stopped so that the subject without the predetermined movement is positioned at a predetermined part of the screen (here, the predetermined part is described as being in the center). . When the TV camera is first moved by an appropriate amount, the predetermined object that does not move probably does not come to the center of the screen and is not necessary.
[0012]
Next, at this stationary position, the TV camera side subtracts the previous frame data from the current frame data, and creates and records frame data from which the data of the moving subject is removed.
When the TV camera recognizes that the predetermined subject without motion is not yet located at the center of the screen, the above operation is repeated. In other words, the TV camera is moved to the target (shake the head) by feedback control.
[0013]
That is, on the TV camera side, every time the TV camera is moved and stopped until the subject without the predetermined movement is located at a predetermined part of the screen, the immediately preceding frame data is subtracted from the current frame data, and there is movement. Create and record frame data with the subject removed.
[0014]
After the subject without the predetermined motion is positioned at a predetermined portion of the screen, the previous frame data is subtracted from the current frame data, and frame data from which the data of the subject with motion is removed is continuously created and recorded.
After this, if you want to change the composition, you can change the position of the subject with no movement on the screen as the imaging target, and change the position of the target with no movement on the screen. That's good.
[0015]
【Example】
In closed circuit television, it is a common practice to transmit the difference between the current frame data and the previous frame data. This difference data occurs when there is a movement in the subject. Therefore, on the TV camera side, the frame data obtained by subtracting the previous frame data from the current frame data and removing the moving subject data is created and recorded (that is, stored in the memory). Easy with technology.
[0016]
On the center side, the supervisor selects a subject that does not have a predetermined movement as a target for imaging, and instructs the TV camera side to that effect. The subject can be selected by the supervisor, but is performed in the following cases, for example.
When a human (or animal) that has not been shown on the screen appears before, or when a human (animal or object) appears to behave suspiciously (moving), it is fixed near the person or suspicious person who appears. An object should be selected as the goal to point the TV camera at.
From the center side, a signal for moving the TV camera in a predetermined direction is sent via a telephone line so that the fixed object comes to the center of the screen, for example.
[0017]
The TV camera system has a TV camera drive mechanism, and moves the TV camera left and right or up and down with an electric motor, for example (shakes the head). An encoder is not necessary for executing the composition changing method according to the present invention.
On the TV camera side, the TV camera is appropriately moved and stopped so that the subject (fixed object) having no predetermined movement is positioned at a predetermined part of the screen.
[0018]
Next, on the TV camera side, the previous frame data is subtracted from the current frame data, and frame data is created and recorded by removing the data of the moving subject. However, at this stage, since the screen of the composition requested by the center side is probably not yet obtained, the TV camera side (TV camera system) continues to perform the same operation.
[0019]
That is, every time the TV camera is moved and stopped until the subject without the predetermined movement is located at a predetermined portion of the screen, the TV camera subtracts the immediately preceding frame data from the current frame data, and moves the subject. Create and record frame data from which
That is, the TV camera is directed in a direction in which a desired composition can be obtained by feedback control with reference to the frame data from which the moving subject is removed.
[0020]
On the TV camera side, after the subject without the predetermined movement is positioned at a predetermined part of the screen, the previous frame data is subtracted from the current frame data, and the frame data is created by removing the data of the moving subject. And keep recording.
[0021]
The above-described operation on the TV camera side can be represented schematically as shown in FIG.
[0022]
【The invention's effect】
Since the present invention is a method for changing the composition in the image monitoring system as described above, the following effects can be obtained.
Since the TV camera side no longer requires an encoder, the TV camera system can be made compact and it is easy to secure the installation location.
Conventionally, the TV camera is moved to obtain a predetermined composition while transmitting an image for adjusting the TV camera drive amount to the center side and viewing the monitor screen. Since it is no longer necessary to perform feedback control for driving and transmit images to the center side, the composition can be changed quickly.
[Brief description of the drawings]
FIG. 1 is a block diagram showing movement on the TV camera side

Claims (1)

In closed-circuit television system the image captured by the TV camera and transmitted by the telephone line to the center to monitor center side,
(B) On the TV camera side, a step of subtracting the previous frame data from the current frame data, creating frame data from which data of a moving subject is removed, and recording the frame data in a memory;
When you are Oite the monitor Russia center side, without the subject of predetermined motion which is a target of imaging with observer selects the steps of commanding through the fact, the telephone line to the TV camera,
The TV camera receiving the command uses the frame data obtained by removing the data of the moving subject recorded in the memory, and the subject without the predetermined movement is positioned at a predetermined part of the screen. And moving the TV camera to stand still ,
Each time the step c) is executed, the previous frame data is subtracted from the current frame data, and the frame data from which the moving subject is removed is created and recorded in the memory;
On the TV camera side, after the subject without the predetermined movement is located at a predetermined part of the screen, the frame data obtained by subtracting the immediately preceding frame data from the current frame data and removing the data of the moving subject is obtained. And a step of changing the composition in the image monitoring system , comprising the step of continuing to create and record in a memory .

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