WO2007104367A1

WO2007104367A1 - Video monitoring system

Info

Publication number: WO2007104367A1
Application number: PCT/EP2006/066686
Authority: WO
Inventors: Gerald Schreiber; Christoph Steinbrück
Original assignee: Siemens Aktiengesellschaft
Priority date: 2006-03-16
Filing date: 2006-09-25
Publication date: 2007-09-20
Also published as: DE102006012239A1

Abstract

Video monitoring system comprising: a number of video cameras (1, 2, 3) whose video images can be displayed on a display device (11) in order to monitor an object (4) located in a monitoring area (5), with each video camera being arranged in a fixed position, but with its alignment with respect to the object (4) controllable by a connected video camera monitoring device (15); a user controller (8) which is connected to the video camera monitoring device (15) and is used to select a first video camera manually by means of an operator action when an object (4) is in motion, and with this being used to follow the motion, and with the video camera monitoring device (15) selecting at least one second video camera, and controlling its alignment such that it or they tracks or track the motion of the object (4), and with the video image from the first video camera and the video image from the at least one second video camera being displayed at the same time on the display device (11).

Description

description

Video-surveillance system

Technical area

The invention relates to a video surveillance system with a number of video cameras whose video images can be displayed on a display device to monitor a located in an observation room object, each video camera is fixed in position, the orientation but is controlled by a connected video camera control device. The video camera controller is connected to a user controller. By means of the user control can manually a

Video camera to be selected, which appears suitable for monitoring the object.

State of the art

Video surveillance systems are used, for example, in railway stations or airports to increase security and to reduce vandalism. Even with major sporting events, such. in a stadium, video cameras are used to detect possible crimes and

To be able to recognize panic situations in advance and to be able to better manage visitor flows. The evaluation of the monitor images takes place in a control room by one or more operators. Systems are known in which the orientation of the individual video cameras can be preset manually by means of an operating device by the operator. In the video observation of an object in motion, so far has been moved so that the operator tracks the movement of the object until the object threatens to disappear from the picture. At this point, the operator switches to a suitable second camera. In order not to lose sight of the object, this switching must be carried out quickly. However, this requires on the part of the operator always knowledge of local conditions of the observation room, as well as the location and the detection range of the individual video cameras. Only in this way can she select a camera that is best suited for tracking the object. In addition, with the second camera, the target object must be targeted as quickly as possible in order to focus on it. Due to stress can be such a manual

Handover lost valuable time. It may happen that when switching important image information can not be recorded in the desired quality or not at all. This is unsatisfactory in the case of legal prosecution or in the attempted foiling of an offense.

Systems are also known that can identify and (for example with a mark) track objects in video images through image processing algorithms. Also known are systems that can use this information to guide other cameras (AW Senior, A. Hampapur, M. Lu (IBM TJ Watson Research Center): Acquiring Multi-Scale Images by Pan-Tilt-Zoom Control and Automatic Multi-Scale. Camera Calibration). The image processing algorithms used in such systems are very expensive and require powerful computing units and are therefore rarely in use. The present invention is based on the fact that a User manually introduces a guide camera and aims to allow the use of additional cameras to observe the selected object with simpler means.

Presentation of the invention

It is an object of the present invention to provide a video surveillance system so that the risk of losing image information when switching between video cameras is minimized.

The invention is based on the assumption that video monitoring of an object in motion can take place in a particularly favorable manner if the object is tracked by a manually operated first video camera (guiding camera) and if at least one further second video camera (tracking camera) is automatically assigned to this movement. which also visualizes the environment of the object in real time. In addition to the video image of the manually operated guidance camera, video images of one or more tracking cameras, which are already focused and focused on the object, are displayed to the operator at the same time. The auto-managed tracking cameras also make the object real-time images, but from a different perspective. The operator can now use this enhanced visual representation to quickly select a video camera other than a guide camera as the object moves out of the image. Once he has chosen and focused on a new guidance camera through a manual operator action, a new set of pre-aligned and focused tracking cameras will automatically follow. The operator no longer has to make a complicated choice. Due to this lower load the danger decreases, important Lose footage. At the same time, the operator gains a better overview of the observation area with otherwise potentially hidden details due to the different perspectives offered. This is a decisive advantage in the investigation of crimes. When monitoring a stadium, an approaching deviant visitor behavior can be detected very quickly and, if necessary, suitable countermeasures can be taken early.

In a preferred embodiment, the

Video camera control device in the selection of at least one other video camera, a three-dimensional model of the observation room, which is kept in a memory of the video camera control device. The 3-D model contains the coordinates of the locations of each video camera. The orientation information (spatial and optical) of the Fuhrungskamera is also on the part of the video camera control device, so that the location information of the object from the Anvisierung the Fuhrungskamera and computational linkage of the above information can be determined. If the position of the object is fixed, the selection of additional cameras can be done automatically and quickly. A complex image processing (image processing) is not required for the selection.

With regard to the accuracy of the computationally determined object position, it is favorable if, in addition to the desired orientation information, the actual orientation of the guidance camera is taken into account. Advantageously, this alignment information is measured locally on the camera and transmitted to the video control device. The measurement is performed by transducers attached to each actuator of each video camera. The orientation information is provided by the tilt angle, the tilt angle, and the positioning of the vision system's optical system (aperture, focus, and zoom).

In a particularly preferred embodiment of the invention, the operating device of the video surveillance system on a joystick, a so-called. Joystick on. The joystick makes it easy to sight and manually follow a guide camera.

Advantageously, the joystick hereby assigned a switching device by means of which the joystick can be used alternately either for spatial orientation of the Fuhrungskamera or for alignment of the optical system of the Fuhrungskamera.

Of particular advantage here is the coupling of the joystick with a trained in the control device force generating device. Thereby, a force counteracting the manual actuation force can be generated, which enables the user to tactually perceive positioning limits.

To signal a limit range of an actuating movement to the user as early as possible, it is favorable if the counterforce increases with manual deflection.

Has proven to be particularly favorable when the

Relationship between the generated counterforce and the manual deflection of the joystick is non-linear. The too Overcome counterforce is increasingly greater, the closer the user comes to the limit.

It has proved to be useful if the video image of the guide camera and the video image of tracking cameras are each displayed on separate monitors.

For archiving the image material are particularly suitable video servers, as they are already used in the monitoring of public buildings.

Brief description of the drawings

To further explain the invention, reference is made in the following part of the description to the drawings, from which further advantageous embodiments, details and further developments of the invention can be found. Show it:

Figure 1 is an exemplary embodiment of the inventive

Video surveillance system in a simplified block diagram;

Figure 2 is a flow chart for an automatic

Object tracking based on camera position data and a 3D model of the surveillance room;

Figure 3 is a diagram illustrating the counter force operation of the joystick;

Figure 4 is a schematic representation of a video camera, in a position before being aligned with a Target object, where the target object is located on a tribune of a stadium.

Exemplary embodiment of the invention

In the figure 1 an embodiment of the invention is shown as it is for the observation of visitors to a sporting event, e.g. a football stadium can be used. Reference numeral 13 denotes the video surveillance system throughout. The video surveillance system 13 essentially consists of several video cameras in operation, of which only the video cameras 1, 2, 3 can be seen in FIG. 1 for the sake of clarity, a video camera control device 15 and an operating and display device 9, 11th Observed is the target object 4 which is located in an observation room 5 and is freely movable there. The observation space 5 is sketched in FIG. 1 as a delimited spatial area by a dashed line.

The video cameras 1, 2, 3 are so-called pan-tilt-zoom cameras (pan-tilt-zoom cameras), that is to say they are stationary with respect to the coordinates X, Y, Z on a mast 20, but pivotable with respect to the alignment of their optical axes 14 on the object 4 to be observed. Within predefined limits, therefore, the viewing direction of each of these video cameras 1, 2, 3 can be aligned. The pivoting movement is predetermined by in Fig. 1 is not shown closer and known per se positioning drives an adjusting device. As drives, for example, stepper motors or electric motors can be used in a position control loop. The optical adjustment (focus and zoom) is also by a corresponding electrical positioning specified. Each positioning drive is coupled to a transmitter to metrologically detect the position. This actual size is reported back to the video camera selection and control device 6 of the video camera control device 15 as an electrical signal via the bus connections 141, 142 143. The illustrated for the optical adjustment can also relate to the value of the aperture, in other known embodiments, the aperture is fixed to a known value or manually adjustable mechanically.

In this case, the current aperture value of the video camera control device 15 must be known as a configuration parameter. In a plurality of the known embodiments, the values for focus are determined either manually or automatically by the camera and adjusted (so-called autofocus mode). The automatic setting is done, for example, by contrast measurements in the image determined by the image recorder not shown individually. This relieves the operator of such setting operations. The determined setting values are available to the video camera control device 15 as described above.

The operation of the video surveillance system 13 is carried out by means of a user control 8 by an operator. The user control 8 is connected to the video camera selection and control device 6 via a signal-conducting connection 146. The user control 8 has a camera control dome, a so-called joystick 9 and a switching device 10. By means of the joystick 9, a selected video camera can manually with respect to their

Orientation and focusing aligned or the movement of the object 4 nachgefuhrt. The control device 10, among other things, allows the assignment of the joystick 9 to certain positioning drives (spatial orientation, focus and zoom) of a video camera. The switching device 10 consists of several switches and cubicles, which are arranged in the immediate vicinity of the joystick 9. Through this adjacent arrangement of joystick 9 and

Switching device 10, the position of the hand of the operator can be maintained during operation, which facilitates handling.

The image material supplied by the video cameras 1, 2, 3 passes via the signal-conducting connection 145 to a display device 11. The display is effected by means of the monitors 12.

The video camera control device 15 consists essentially of a video camera selection and control device 6 and a computing device 7, which are connected via the 144. The computing device 7 is a conventional personal computer (PC). The PC 7 has a memory device 100. The video camera control device 15 generates for controlling the video cameras 1,2,3 control signals by which each of the video cameras 1,2,3 can be focused in their spatial orientation and in terms of their optical system on the object to be observed 4. The memory device 100 contains so-called 3D data, which images the observation space 5 as a three-dimensional model. This includes the coordinates of the installation location of each video camera 1,2,3.

As in the procedure below, using a

Flowchart explained in more detail, selects the operator via the user control 8, one of the video cameras 1,2,3 as a guide camera, which hereinafter also referred to as a lead camera referred to as. The selection of the guide camera is freely selectable. The operator positions this lead camera by means of the joystick 9. The joystick 9 is, as already mentioned universally applicable: Depending on the specification of the switching device 10, the joystick 9 can be used either for spatial orientation of the guide camera or for adjusting the optical system of the guide camera. The assignment depends on a switch position of the switching device 10. In accordance with one aspect of the present invention, the joystick 9 is configured to counteract manual design with increasing joystick force feedback. This joystick counterforce is generated by actuators in the user control 8.

Since the control information for the video cameras 1, 2, 3 are usually transmitted as vector information relative to the current setting with a control value that is often unactuated in advance due to the functional principle or certain values are automatically determined by the camera depending on the operating mode used (autofocus ), the actual orientation or the actual control value for the optical properties (aperture, focus, zoom) is detected metrologically and transmitted via the signal-conducting connection 141, 142, 143 back to the video camera control device 15. As a result of this readback of actual values of a guide camera (pivot angle 16, tilt angle 17, aperture, focus and zoom) directed onto the object 4, the respective object position of the object 4 to be observed can be calculated on the basis of the three-dimensional model by means of the computing device 7. If this object position is known, a tracking camera, in the following also as a slave, can be used on the basis of the 3-D model Camera, to be selected. This selection of a slave camera is based on the 3D data stored in the memory 100: from each eligible video camera, the viewing area is described in the form of a cone, in the top of the video camera and in the center of the

Floor surface the targeted object 4 is located. Between the top and the center of the bottom surface, a location vector 18 to the object 4 is calculated. Is the view cone or the location vector 18 an obstacle against (that is, the object 4 is partially or completely in one

Shadow area), this video camera can not be used as a slave camera. If, on the other hand, the view of the object 4 is unhindered, then this video camera is eligible for selection as a slave camera. In this way, the suitability for each operational video camera is checked successively.

FIG. 2 shows a flowchart with reference to which the automatic object tracking according to the invention is explained in more detail by program steps:

First, it is assumed in the process description that an operator has manually selected a first camera as a lead camera and has directed this by means of the joystick 9 to the object 4 to be observed. In case of movement of the object 4, the operator traces the master camera of movement of the object 4.

In a first program step (1), positioning data (alignment information) are determined by the lead camera. This determination is made by reading back the respective actual values from the periphery, that is to say swivel angle 16, tilt angle 17 and aperture, focus and zoom. These positioning data are transmitted via the bidirectional Bus 141, 142, 143 transmitted to the video camera evaluation and control device 15 and subsequently via the bus 144 to the computing device 7.

In the subsequent second program step (2), the targeted object position is calculated by the computing device 7. For this purpose, the positioning data of the guide camera determined in program step (1) are used together with 3D data which are stored in the memory 100 of the computing device 7. In conjunction with the 3D data, a verification can be performed so that the object position can be displayed accurately. The result of this calculation is a location vector 18, which points from the guidance camera to the instantaneous object position.

Subsequently, in program step (3), at least one further video camera is selected as the tracking camera from the number of installed video cameras. This selection is likewise carried out by the computing device 7 on the basis of the object position determined in the second program step (2) and the coordinates of the respective installation location of a video camera. The result is at the end of program step

(3) Determine which video cameras are suitable as a tracking camera (s) (slave cameras).

In a subsequent fourth program step

(4) the computing device 7 calculates positioning information that is suitable for aligning the tracking camera (s) selected in program step (3) so that they point to the object position (calculated in program step (2)) and to the object 4 are focused. This actuating information is transmitted via the signal-conducting connection 144 to the video camera selection and control device 6 from there via the connection 141 or 142 or 143 to the selected or selected Nachfuhrkamera (s).

In program step (5), the automatic alignment of the tracking cameras takes place. As can be seen from the flowchart of FIG. 2, this program loop is closed by a jump back to program step (1).

As shown in the flow chart of Figure 2, is in

Program step (6) offered to the operator to change the association between Nachfuhrkamera and Fuhrungskamera: He decides on the basis of the monitor images displayed on the display device 11, whether for further monitoring of the object 4 is not a displayed monitor image of a

Nachfuhrkamera proves to be cheaper as a new guide camera. If this is the case, he selects in the program step (7) by appropriate input to the user control 8 this video camera as a new guide camera and the process shown starts again.

FIG. 3 shows in a diagram the force curve of the joystick counter force F (force feedback strength) as a function of a camera angle (tilt angle or tilt angle). The counterforce is generated in the user control 8 by suitable actuators. The size of the counterforce can be specified by the user control 8. As can be seen from FIG. 3, no counterforce is at all effective at a specific interval around the zero point of the camera angle. After this interval, the counterforce to be overcome by the operator progressively increases with the camera angle (camera angle). As a result, the near end of a parking range (for example, the pivoting action of a Video camera) by the operator's hand. That is, the operator is not only the visual control, but also a tactile perceptible information available. When the joystick 9 is used to tilt and tilt the guidance camera, motorized feedback allows the operator to detect the approaching end of the camera movement early, that is, even before the camera has reached a mechanical stop. This makes it possible for him to select another camera as a new guide camera in good time. The same applies to the use of the joystick 9 when focusing and / or when zooming the guide camera. This is particularly advantageous if one considers that a digital transmission of the video data, especially in the case of high compression (MPEG-4), there is a significant delay between image acquisition on the camera and the visual display. Due to this delay, an operator concentrating exclusively on the visual presentation when setting focus and zoom may notice too late the end of an optical adjustment possibility. The tactile signaling of the "Force Feedback" makes the guidance camera more efficient to handle. The operation is significantly improved.

As already shown above, the selection of a

Fuhrungskamera always by a manual switching action of the operator. It may be that during the observation of a scenario several times between guide camera and Nachfuhrkamera is changed. The selection of a suitable Nachfuhrkamera is always automatic, the selection of a Fuhrungskamera, however, always manually. In the present application, in which a plurality of video cameras is present and these are operated by multiple operators, it may be advantageous to regulate the authorization of the individual operators in the form of a priority system. The prioritization system grants hierarchical tiered permissions to the operators and also takes into account the distance of each video camera to the current location of the target object 4.

FIG. 4 shows, in a schematic representation, a video surveillance camera 1 which is aimed at a viewer 4 who is located on a tribune 19 of a stadium. The grandstand 19 is shown in Figure 4 by the Cartesian coordinates 0,0, 0; 100.0, 0; 100,20,100 and 0, 20,100 models. The video-surveillance camera 1 is fixedly arranged on a mast 20 and rotatably mounted about a ball joint 21. Their Aufstellkoordinaten, that is, the coordinates of the ball joint 21 are -50, 100, -50. In order to align its optical axis 14 (dashed line in Figure 4) on the visitor 4, the camera 1 is pivoted about the pivot angle 16 and inclined by the tilt angle 17. Thus, the location vector 18 (solid line in FIG. 4) of the camera 1 points to the target person 4 on the platform 19. The location vector 18 thus contains spatial direction information (the spatial orientation of the video camera 1) as well as a

Distance information (the length of the location vector 18, ie the distance between the video camera 1 and the viewer 4). When the optical system of the video camera 1 (focus and zoom) is focused on the object 4, this optical adjustment corresponds to the spatial distance between the video camera 1 and the object 4. When this video camera 1 is aligned and focused on the visitor 4, the position data is transmitted from the periphery back to the video camera controller 15, that is, to the calculator 7. As already mentioned, in the memory device 100 of the

7 both the spatial coordinates of the video cameras (in Figure 4, the video camera 1 with the Cartesian coordinates -50, 100, -50 and 3D data, in this case the Schragflache 22 of the tribune 19 data-technically mapped .. The calculation of the location coordinates (65, 10 , 75) of the target object 4 (visitor 4 in the tribune 19) results from the intersection of the location vector 18 (optical axis 14 of the video surveillance camera 1) with the oblique surface 22 of the platform 19. From this location information with the aid of the 3D model If the viewing range of an eligible video camera is not affected by the Visitor 4, it will be considered as a tracking camera (slave camera) when the selection of the tracking cameras is completed The calculation of the control information for these slave cameras takes place so that they are aligned with the visitor 4 and focus on him can be ssiert. Each video image of a selected Nachfuhrkamera is placed in the control room on a monitor 12 for display. Is it in the sports stadium under the

Spectators for tumult or panic situations, for example, are suspected of preparing to throw fireworks, so they can be seen quickly and from different perspectives. As a result, any necessary countermeasures can be taken early on. If an offense is observed, relevant evidence can be recorded in a short amount of time and temporarily activated in a video server. Compilation of the reference numbers used

1 first video camera

2 second video camera 3 third video camera

4 target object

5 observation room

6 video camera selection and control device

7 computing device 8 user control

9 joystick

10 switching device

11 display device

12 monitor 13 video surveillance system

14 optical axis

15 video camera control device

16 swivel angle

17 tilt angle 18 position vector

19 Tribune (Schragflache) 20 Camera mast

21 ball joint

22 oblique surface 100 memory

141 Connection between 6 and 1

142 Connection between 6 and 2

143 Connection between 6 and 3

144 Connection between 6 and 7 145 Connection between 6 and 11

146 connection between 6 and 8

F counterforce (Force Feedback)

(1) to (7) process steps in the flowchart

Claims

claims

A video surveillance system comprising:

- A number of video cameras (1,2,3), the video images on a display device (11) can be displayed to monitor a in an observation room (5) located object (4), each video camera is arranged stationary, with respect to the alignment on the object (4) but by a connected video camera control device (15) is controllable;

- A user control (8) connected to the video camera control device (15), by means of which in the case of an object in motion (4) by a user action a first

Manually selected video camera and the movement is tracked,

- wherein the video camera control device (15) selects at least one second video camera and controls for them the orientation so that they also track or track the movement of the object (4), and

- Wherein the video image of the first video camera and the video image of the at least one second video camera on the display device (11) are displayed simultaneously.

2. Video-Uberwachungssystem according to claim 1, characterized in that the video camera control device (15) in the selection of the at least one second video camera, a three-dimensional model of the observation room (5) used in a Memory (100) of the video camera controller (15) is kept ready.

3. Video surveillance system according to claim 2, characterized in that in the selection of the at least one second video camera, an external direction information is taken into account, which is measured by transmitters on the first video camera and via a signal-conducting connection (141, 142, 143) to the video camera control device (15). is transmitted back.

A video surveillance system according to claim 3, characterized by alignment information including the swivel angle (16), the tilt angle (17) and information representing the aperture, focus and zoom of the first video camera.

5. Video surveillance system according to one of claims 1 to 4, characterized in that the user control (8) has a joystick (9) to the first

Video camera manually to track the movement of the object (4).

6. Video-Uberwachungssystem according to claim 5, characterized in that the joystick (9) has a

Switching device (10) is assigned, by which the function of the joystick (9) can be predetermined.

7. Video surveillance system according to claim 6, characterized in that by means of the switching device (10) of the joystick (9) between a first function, for spatial alignment of the optical axis (14) of the first video camera, and a second function, the Alignment of focus and zoom of the first video camera, is switchable.

A video surveillance system according to claim 5, characterized in that the joystick (9) is coupled to a force generating means which generates a counteracting force counteracting the manual actuating force.

9. Video-Uberwachungssystem according to claim 8, characterized in that the counterforce increases with increasing manual deflection of the joystick (9).

10. Video-Uberwachungssystem according to claim 9, characterized in that the course of the reaction force in

Dependence of the deflection is nonlinear.

11. Video surveillance system according to one of claims 1 to 10, characterized in that the video image of the first video camera and the video image or the

Video images of at least one second video camera are displayed simultaneously on a separate monitor (12).

12. Video surveillance system according to at least one of the preceding claims, characterized in that the video image of the first and the at least one second video camera are recorded on a video server.

13. Video surveillance system according to claim 12, characterized in that the recording is performed automatically on the video memory and is automatically deleted after a predetermined time interval.

14. Video-Uberwachungssystem according to claim 13, characterized in that the recording of video images is dependent on a manual switching operation.

15. Video surveillance system according to one of the preceding claims, characterized in that the at least one second video camera is controlled by the video camera control device (15) so that the adjustment of focus and zoom coincide with the first video camera.

16. Video surveillance system according to at least one of the preceding claims, characterized in that the selection of the proposed at least one second video camera for automatically tracking the movement of the first video camera must be confirmed by the user.

17. The video surveillance system according to claim 1, characterized in that the video cameras used can be movably mounted and are variable in their position by an adjusting device, wherein the current position is transmitted to the video camera control device via a signal-conducting connection (141, 142, 433). 15) and is included in the calculation accordingly.