HRP20080188A2 - Positioning remote controlled devices with fixed camera - Google Patents

Abstract

The system for tracking moving objects in the field of view of the camera using the remotely controlled devices shown in Figure 1 consists of a camera (1) connected to a computer (2). The computer (2) has one or more screens (3) to which the image of the space captured by the camera (1) is transmitted. The operator (O) monitors one or more remotely controlled devices (5) with a moving object (7) by following its movement on the screen (3) with the mouse cursor. The computer (2) by means of the program, via the interface (4) converts the movement path of the moving object (7) on the screen (3) into the movement of remotely controlled devices (5) that follow the moving object (7) in real space. The system is applied indoors when recording television or theater performances to follow performers with lights or video cameras. The system is also used in open spaces for video surveillance of larger spaces such as stadiums, town squares and security systems for placing multiple cameras in one point.

Description

The field of technology

This invention relates to a system for tracking moving objects in the camera's field of view using remotely controlled devices. Moving objects are tracked by remotely controlled devices by the camera recording the field of view, the image of which is transferred to the computer screen. The current positions of moving objects on the computer screen are tracked with a cursor. Using a dedicated program, the computer converts the cursor movements into the movements of remote-controlled devices that are controlled via the interface. The system is applicable for recording television shows and theater performances for monitoring performers with lights or video cameras, for video surveillance of larger spaces such as stadiums, city squares, and for security systems for placing multiple cameras at one point.

Technical problem

One of the basic prerequisites for television recording is uniform and continuous lighting of the person or object being recorded. If a person or an object moves within the space, then the entire space is uniformly illuminated or light tracking devices are used.

Therefore, it is necessary to solve the system and define an algorithm that allows one operator to simultaneously manage a large number of devices for tracking a person or object, without that person or object having to wear radio transmitters or some other devices. The control effect must not be limited by the distance between the moving object and the operator. Laser positioning should not be used in the new control system.

State of the art

Devices for tracking the launched objects can be manual or automatic. The use of manual devices requires one operator who works with only one device.

Automatic positioning of remotely controlled devices in space is done by moving them along the tilt and pan as a function of the height at which they are placed.

One type of automatic system requires that the tracking object has a radio device on it.

Positioning, in this case, is performed through the exchange of information between the radio device on the tracking object and the radio device inside the space.

Another type of automatic systems uses a laser for positioning.

Over time, systems based on laser beams, radio and ultrasound transceivers were used.

To use the laser beam system, the operator must be within a given area defined by the viewing angle of the stage and its height. He must have the entire stage in his field of vision. He must have a sight on his device with which he tracks a person or an object. The advantage of this system is that the monitored object does not have to carry any transmitter for its positioning, because it is done manually by the operator. One of the limitations of the system is that it requires a field of view at a certain angle. The angle must not be too steep because it obstructs the operator's field of vision. The angle must also not be too slight, because a small movement of the operator causes large changes in position on the stage. One of the manufacturers defines placing the device at an angle of 25 to 75 degrees.

The use of a system with ultrasonic transceivers requires that the monitored person or object wears a belt with an ultrasonic transmitter and batteries, and at the same time, ultrasonic receivers must be placed inside the space. Another limitation is the distance between the two receivers as well as the distance between the receiver and the transmitter.

The essence of invention

The essence of this invention is a new system for tracking moving objects using a camera that records moving objects and whose image is transferred to a computer screen. Through the interface, the computer converts the trajectory of the moving object on the screen into the motion of remote-controlled devices that follow the object in real space.

The system consists of a fixed camera, a computer that contains a program for calculating the required position, an interface to remotely controlled devices and remotely controlled devices.

The video camera is placed above the space in which the monitored person or object is moving. The image from the camera is displayed on the computer screen and thus shows the floor plan of the space to the operator. By pressing the control button, the operator activates the tracking program and follows a person or object on the screen with the mouse cursor. The operator follows the movement of a person or object in space by moving the cursor on the screen, which gives new coordinates for calculation. The program calculates new control parameters and sends them through the interface to remote controlled devices, which results in their movement to a new position. The interface is connected by a communication network to each of the remotely controlled devices. In the case of lighting fixtures, they are DMX network or ArtNetTM network.

Descriptions of drawings

Figure 1 schematically shows a system for tracking one person in the field of view of the camera using two remotely controlled devices.

Picture. 2 shows the calibration of the device and the placement of the device at the required point.

Description of the realization of the invention

The basic design of the system is shown in Figure 1. The system consists of a camera 1 that is placed above the space being recorded and that is connected to a computer 2. Camera 1 can be a stationary or mobile remotely controlled camera. The computer 2 has one or more screens 3 to which the image of the space recorded by the camera 1 is transmitted. The computer 2 is connected to the interface 4 to which one or more remotely controlled devices 5 are networked. The computer 2 contains a program by which the movement of the cursor on the screens 3 , through the interface 4, converts it into the motion of remotely controlled devices 5.

In the field of view 6 of the camera 1, there are one or more moving objects 7 that are the subject of monitoring using remote controlled devices 5.

The process of tracking moving objects 7 using remote-controlled devices 5 is performed by one or more operators O who monitor the movements of moving objects 7 on screens 3. In this case, one operator O with one or more remote-controlled devices 5 monitors only one moving object 7 by its movement on the screen 3 followed by the mouse cursor. The computer 2, using the program a through the interface 4, converts the trajectory of the moving object 7 on the screen 3 into the motion of the remotely controlled devices 5 that follow the object 7 in real space.

The basis of the computer program 2 which through the interface 4 converts the trajectory of the moving object 7 on the screen 3 into the motion of remotely controlled devices 5 that follow the object 7 in real space and their calibration is the mathematical method described below. Since it is a mathematical method, it is not the subject of the invention, but serves as a confirmation of the feasibility of the invention.

Before actual use, each of the remote controlled devices 5 must be calibrated.

We start the calibration shown in Figure 2 by turning on the device 5 and placing it in a vertical position. With many manufacturers, this position is also the starting position, so it is only necessary to turn it on, while it itself is placed in a vertical position.

As the camera 1 displays the image on the screen 3 of the computer 2, in the case of the lighting fixture as a remotely controlled device, the light circuit of the lighting fixture is visible on it. By placing the cursor in the center of that circle and pressing the control key, we indicate the initial position of the device. Let's mark that position as TH.

Let screen 3 of computer 2 have a resolution of 1280x1024. If we place the origin of the coordinate system (0,0) in the lower left corner, point TH has coordinates xH, YH. The upper right corner of the screen has coordinates 1279,1023. These coordinates are expressed in pixels.

In the next step, it is necessary to move the device 5 along the tilt channel to the position that is visible on the screen 3. It is necessary to place the cursor again in the center of the light circle and mark its position by pressing the control button. With this procedure, we defined the point Ti, which has coordinates x1, y1.

The distance between these points defines the radius of the circle R in Fig. 2, expressed in pixels.

[image]

Each of the equipment manufacturers defines the total range of movement per tilt in degrees. Let's assume that this shift is 267 degrees. So, for the range of control values from 0 to 255, the displacement of the device 5 per tilt is from 0 to 267 degrees. If we divide these two data, we get the shift of the tilt channel of the device 5 in degrees when the control value increases by one. Let's denote this shift as:

[image]

By moving device 5 from point TH to point T1, we increased the control value of the tilt channel by the amount of 12. That is, from the value 128 to the value 140. Let's denote this shift as:

[image]

Let's mark the angle β made by device 5, the angle β is:

[image]

Fig. 2 shows that the radius of the circle and the height of the device 5 form a right angle. It follows that the height at which device 5 is located is expressed in pixels:

[image]

By determining the height of the device 5, we completed the calibration of the device.

Note 1:

With this calibration, it was assumed that it is possible to move only by tilt and place device 5 from point TH to point T1. When this is not possible, then it is necessary to make a shift by tilt and pan to place the device 5 from point TH to point T1. These two parameters are labeled DMXTilt.Home and DMXPan.Home

In this case, we calculate ΔDMX according to the following formula:

[image]

Placement of device 5 in the set point.

Calculation of tilt

When operator O moves the cursor on screen 3 to a new position, it is first necessary to calculate the shift by tilt position. Mark the new position with the point Tz, i.e. its coordinates xz, yz. The distance between this point and point TH defines the radius of the circle RZ in Fig. 2, expressed in pixels.

[image]

From this radius comes the angle required to place the device 5 from the initial position to the position of the radius RZ.

[image]

The required tilt value is obtained from this angle.

[image]

DMX Tilt.Home is the tilt value at point TH.

Calculation of pana

Let's set a new coordinate system with the origin in TH as shown in Figure 2. In Figure 2 we see that the points T1 and TZ are located in the first quadrant of this coordinate system. Let's define the angle a as the angle between the y coordinate and the line through the points TH and T1. Angle 8 is the angle between the y-coordinate and the line through the points TH and TZ. Angle (p is the angle between the line through points TH and T1 and the line through points TH and TZ.

In the case when the angle 8 is greater than the angle a the angle (p is equal to:

[image]

Each of the equipment manufacturers defines the total range of movement per pan in degrees. Let's assume that this shift is 540 degrees. So, for the range of control values from 0 to 255, the displacement of the device 5 per tilt is from 0 to 540 degrees. If we divide these two data, we get the shift of the pan channel of device 5 in degrees when the control value increases by one. Let's denote this shift as:

[image]

For point T1 we know that the control value of the pan channel is equal to DMXPan.Home. From the angle 9, we calculate how much shift of the control value of the pan channel should be made to place the device 5 in the point TZ.

[image]

With this procedure, the control sizes of the tilt and pan devices and the placement of the device 5 at the point TZ are defined.

Note 2:

When defining the control program, positive and negative directions for pan shift should be adopted. In this calculation, a positive direction is assumed when moving to the right.

Application of the invention

The described system according to the invention has multiple application possibilities. Some of these application possibilities are mentioned in the description of the technical field. In all cases of application, the following components of the system are represented: camera 1, computer 2, screens 3 and interface 4. Remote controlled devices 5 change depending on the purpose of the system and can be lighting devices, video cameras or other video surveillance devices.

The system is used in closed spaces during the recording of television or theater performances to follow the performers with lights or video cameras.

The system is also used in open spaces during video surveillance of larger spaces such as stadiums, city squares, and in security systems for placing multiple cameras at one point.

In addition to tracking moving objects with remote-controlled devices, the system can also be used to manage the parameters of the remote-controlled devices themselves, such as the intensity of the light flux in light devices or iris and focus in recording devices.

In all cases of application, the quality of tracking moving objects does not depend on the distance of the computer, that is, the operator from the place where the tracking object is located, because the image transmission from the camera to the operator can be done via network or wireless transmission.

Claims (4)

1. A system for tracking moving objects in the field of view of the camera using remote-controlled devices, characterized by the fact that it consists of a camera (1) that can be stationary or mobile remotely controlled, which is placed above the area being recorded and which is connected to a computer (2) which has one or more screens (3) to which the image of the space recorded by the camera (1) is transmitted and which is connected to the interface (4) to which one or more remotely controlled devices 5 are networked. 2. A procedure for tracking moving objects in the field of view of the camera using remote-controlled devices, indicated by the fact that one or more operators (O) use a mouse cursor to follow on the screen (3) the path of movement of the selected moving object (7) which the computer (2) uses the program and through the interface (4) converts into motion one or more remotely controlled devices (5) that follow the selected moving object (7) in the field of view (6) of the camera (1) that records the moving objects (7). 3. A system for tracking moving objects in the field of view of the camera using remote-controlled devices according to patent claim 1, characterized by the fact that it is applied in closed spaces during the recording of television or theater performances for tracking performers with light devices or devices for recording and transmitting images, in the open areas during the video surveillance of larger areas such as stadiums, city squares and in security systems for placing multiple cameras in one point and for managing the parameters of remotely controlled devices such as the intensity of the light flux in light devices or the iris and focus in recording devices. 4. The procedure for tracking moving objects in the field of view of the camera using remote-controlled devices according to patent claim 2, characterized by the fact that it is applied in closed spaces during the recording of television or theater performances for tracking performers with light devices or devices for recording and transmitting images, in the open spaces during the video surveillance of larger spaces such as stadiums, city squares, and for security systems, the deployment of multiple cameras at one point and for managing the parameters of remote-controlled devices, such as the intensity of the light flux in light devices or the iris and focus in recording devices.