DE4233137C1 - Method and device for controlling a camera - Google Patents

Abstract

A method is described by which a camera (10) can be controlled easily via a computer (20) or a computer network (60). The movement of the camera can be angular, translational, or a combination of these. The particular improvement lies in the fact that the camera movement can be actuated by selecting points on the display screen of the computer, using a cursor (24, 92), which is depicted on the screen in addition to the image generated by the camera, positionable with a mouse (26).

Description

The invention relates to a method and a system for Control a camera, e.g. B. a video camera, according to the preamble of claim 1 and claim 6.

Devices for controlling cameras, in particular of video cameras that are capable of doing so continuously Images of a specific process on a monitor transferred, are taken in different in themselves Refinements known. In doing so - in particular for surveillance purposes - the cameras after one certain flow chart panned. For certain Applications - here are the monitoring examples of processes in workshops - are effects the observing person, e.g. B. an interruption the pan function, on the direction of the Camera necessary to get a suitable angle of view guarantee.

User-controlled camera controls are in turn various designs known. Here are particularly realizations with keys each for swiveling up, down, right and left, as well as combinations thereof (e.g. left and used simultaneously upwards). The camera then pivots in the specified direction until the button is released, or in an alternative Version in which the respective key only must be operated once until the corresponding Button or a stop button is pressed. The function the keys are occasionally replaced by a Joystick, e.g. B. in US-39 84 628, with which the  desired direction (by the direction of the deflection) and sometimes also the desired speed of movement - by the strength of the rash - is chosen. The direction of the panning process is done either by successively executed swiveling movements (e.g. top right and then up for a direction that is displaying the time 1:30 a clock or the compass direction NW) or by a corresponding position of the Joystick selected.

Versions are also known in which the monitor and the operator function coupled to a computer is. In this case, the camera image is preferably already in the camera - digitized and fed to the computer. The computer screen or part of the screen then serves simultaneously as a monitor for the camera. In this version can use the buttons specified above, by the computer software or operator-specified Keys of the computer keyboard.

Another known version using a Computers is tracking the camera through motion bars (Scrollbars) on the monitor be displayed and with the help of a positioning device, e.g. B. a so-called mouse or one touch-sensitive screen can be controlled can. With this control method there is also one Issuing commands only in one direction possible, mostly limited to the four cardinal directions and at most only one intermediate direction (corresponding e.g. to the compass direction NW) expanded.

All of these processes have the defect that a Data connection between the input station for the  Commands by the user and the actuating Camera control for the entire control process must be maintained (so-called online operation) or the transmission of a command to stop the Camera movement must be guaranteed without delay, to pan beyond the target avoid.

Furthermore, the known methods are liable for the defect indicates that entering the control command is complicated is and often only after several attempts to Success leads.

In US 51 07 336 is a camera control which is suitable for the moving images Camera relative to a selected image object by the Tracking method of image processing. This Camera tracking is for the cases where the User and therefore the object selection is not in in the immediate vicinity of the camera, because of the the strong coupling of image content and camera control caused computing requirements and the associated high transmission effort for the task at hand completely unsuitable.

The object of the invention is a method and a System for controlling a camera is available too with which an easier tracking of a Camera is possible.

The task is described with that in claim 1 Method and with that proposed in claim 6 System solved. The measures of claim 1 described methods cause first of all that  after entering the new target position (object selection) by the signal given with the signal means all Camera tracking data may be far computers installed by the camera are present and in an abstract way to one assigned to the camera Actuator system can be passed on. This Transmission is by no means time-critical, which means that a delay in transmission does not affect the new camera position.

The embodiment of the invention is advantageous Procedure in which the center of the image is the reference point represents.

The system of claim 6 is already in itself suitable to realize the basic idea of the invention. The means to determine the direction and amount, around which the camera should be tracked according to the invention capable of issuing a single Commands the desired control to the camera command.

The advantage of the invention is based on an application example are explained. When operating aircraft are in between two missions on the ground the air - especially in the event of special occurrences - Inspections necessary. An inspection process is particularly advantageous if it is with a swiveling video camera is performed, the Camera is installed at the location where the aircraft is  stands while assessing the state in one central maintenance operation, e.g. B. at the location of the headquarters the airline. The two places can be any distance apart. The object of the inspection is often a specific one Detail on the aircraft, e.g. B. the chassis. The operator in the main plant knows which objects he wants to inspect in what order.

At long range, use a Computer network advantageous (claim 7).

The idea of the invention can already be realized, if only an angle is tracked (e.g. only the azimuth). The The most advantageous version is with a tracking of two angles (claim 8), the orthogonal stand to each other and the height and direction represent (claim 9).

Of different ways, the means to To realize moving the camera are commercially available, digitally controllable stepper motors in particular advantageous because this solution is not very technical Effort required (claim 10). In case of need autonomous stabilization can also Instead of the stepper motors, an independent one from Computer preferably digitally controlled Actuator system are used, for. Legs Gyro-stabilized platform.  

The camera control can also be used for other applications advantageous for two-dimensional translational Movements are used (claims 11 and 12).

It is particularly advantageous to control the camera for the execution of swiveling movements as well also build for translatory movements. In In this case, the means for entering the command on the monitor and to determine the control-relevant Parameters of the camera ultimately executing Actuators can be realized twice.

The aforementioned, as well as the claimed and in the described in the following exemplary embodiments, Components, devices to be used according to the invention and means or process steps are subject in their realization, the design, the Selection and the technical conceptions or the Procedural conditions no special exceptions, so that in the respective application known selection criteria without restriction Can find application.

In particular, all implementations are not there bound that they are in as a program or software package implemented a freely programmable computer were or can be, rather it is the individual Application left whether an electrical Circuit, a special computer or a program on a freely programmable digital data processing system is used.

More details, features and advantages of the The object of the invention result from the the following description of the associated drawing,  in the - an example - a device according to the invention and the method according to the invention is shown are.

The drawing shows:

Fig. 1 shows an apparatus, are connected to each other in the two computers over a computer network as a block diagram;

Fig. 2 shows an inventive device with a single computer as a block diagram;

Fig. 3 shows a flow diagram of the method according to the invention;

Fig. 4 shows an inventive device for translational control in a block diagram and

Fig. 5 shows an apparatus according to the invention with two pointers on the screen illustrated.

With the device designated 100 as a whole in FIG. 1, images of the objects to be displayed are taken with the camera 10 and output on a data output 16 of the camera 10 . In the exemplary embodiment, this data is applied to an input interface 52 of the further computer 50 . The output signal from camera 10 is an RGB (red, green, blue) video signal. This further computer 50 feeds the data to a computer network 60 , from where it is fed to the computer 20 and displayed on its monitor 22 . In the exemplary embodiment, the aforementioned process is carried out at a frame repetition frequency of 30 Hz, so that a continuous sequence of images is produced on the monitor 22 of the computer 20 .

In addition, a pointer (cursor) 24 is shown on the monitor 22 of the computer 20 in the form of an arrow, which can be positioned over the entire screen regardless of the content of the image data. In the exemplary embodiment, a so-called computer mouse serves as the positioning device 26 . The pointer 24 can be moved by moving the mouse. If the left mouse button (signaling means 28 ) is actuated twice within a period of 300 milliseconds (signaling means 28 ), in the exemplary embodiment it is achieved that the current position of the pointer 24 is to represent the new image center 82 of the camera 10 and the camera 10 is pivoted so far until this goal is reached.

In the exemplary embodiment, the center of the image ( 80 ) is the standard reference point of the method, but it can also be placed anywhere else on the screen as desired.

In the computer 20 , a means 74 for determining the angles, which is implemented with a computer program, is controlled, which determines the pivoting angle of the camera 10 . The calculation is carried out taking into account a zoom position of the camera 10 which is possible in the exemplary embodiment and commanded in a known manner with a key input and an enlargement of the image section on the monitor (pseudo zoom), which is also controlled by keys (functions enlarge and reduce image). The calculation of the angle is thus in the exemplary embodiment using the formula

where A is the half aperture of the camera 10 , Z is the current zoom magnification of the camera 10 and P is the current image section magnification on the monitor 22 .

These two angles are in turn routed via the computer network 60 to the further computer 50 , and from there stepper motors 34 and 36 of an actuator system 30 for pivoting the camera 10 are each acted upon by a number of clock cycles proportional to the commanded angles.

Another embodiment with only one computer 20 , which is connected both to the camera 10 and to the monitor 22 and the positioning device 26 , is designated as a whole by 200 in FIG. 2.

In an alternative embodiment of the device according to the invention, it is not the angle calculated according to the form specified above that is transmitted to the control device of the camera 10 , but rather a period of time in which the camera 10 is to be moved in the selected direction at a predetermined speed. This time period is proportional to the tracking angle at constant speed. In this alternative exemplary embodiment, however, the angle by which the camera is to be tracked is broken down into a sequence of time intervals in which the camera 10 , starting at a low speed and gradually increasing to the maximum speed which the pivoting device of the camera permits, is then moved to stop the movement process from the smallest speed range for the purpose of ending the movement process and again gradually taking lower speeds. The angle by which the camera is to be tracked is accordingly broken down into a sum of time intervals which enables the camera to accelerate smoothly into the swivel device. The device, which represents the means 74 for determining the information, also contains correction information for compensating for the non-linearities of the acceleration and deceleration process. These correction data have been determined experimentally.

In a further exemplary embodiment, designated in its entirety by 300 in FIG. 4, the camera 10 is not pivoted, but is moved in translation on a rail 84 . The rail 84 itself is in turn attached to a pair of rails 86 in such a way that the rail 84 and thus the camera 10 can be moved perpendicular to the first-mentioned direction of movement.

This exemplary embodiment is particularly suitable for applications in which the distance of the camera 10 from an observation plane (reference plane) is known. The location determined by the positioning and subsequent fixation of the pointer 24 by the positioning device 26 and the signaling means 28 , to which the camera 10 is to be moved, corresponds to the value of the angle function tangent to the angle determined as in the aforementioned exemplary embodiment multiplied by the distance of the reference plane from the camera.

A further exemplary embodiment, in which the possibilities of the two aforementioned designs are combined, has both the means 90 for the translatory movement which represent the combination of the rails 84 and 86 , and also the pivoting device. A second pointer 92 is shown on the monitor 22 of the computer 20 in addition to the pointer 24 and the image of the camera 10 , which differs as a symbol from the pointer 24 ( FIG. 5). In this exemplary embodiment, the second pointer 92 is moved with the same computer mouse as the pointer 24 , but the right button of the computer mouse, with which both the means 26 for positioning the pointer 24 and the means 94 for positioning the second pointer 92 are realized, held down to move the second pointer. In this exemplary embodiment, the means 96 for emitting a second control signal are implemented by pressing the right button of the computer mouse twice in a period of up to 300 milliseconds. The translatory movement process is thus commanded with the same means as the swivel process. The device according to the invention described in this exemplary embodiment is particularly suitable for monitoring workshops from above, the two translational directions representing and covering the ceiling of the workshop and the camera translating the objects in the hall to any observation point and then pivoting them can grasp the object. The reference level is a level in which the working points of the machines are located in the hall or else the floor of the hall itself. The reference level can be selected from the computer 20 by entering a key (eg entering a number). A further implementation of this exemplary embodiment is possible and useful in the case of the aforementioned use for checking the condition of an aircraft by a maintenance manager, the maintenance manager having to check individual objects away from the scene (e.g. the landing gear). In this example, however, this should be viewed from different angles. For this purpose, the two translational directions of movement of the camera 10 are selected such that a vertical observation wall is set up in front of the aircraft, on which the camera 10 can be moved. A middle section plane through the aircraft parallel to the observation wall is chosen as the reference plane. Control errors of the camera 10 , which result from the fact that the object to be observed is not exactly on the reference plane, do not play a role in this embodiment, because exactly the object to be observed (e.g. the undercarriage) to the center of the image during the pivoting process Camera 10 can be brought. This version is particularly advantageous in the application example mentioned, because the selected object in the preselected viewing direction can be compared with a reference image that is available to the maintenance manager as an archive image, so that any damage and necessary repair work can be determined with great accuracy.

The basic principle of the method according to the invention is shown in FIG. 3 as a flow chart.

Claims (13)

1. Method for controlling a camera ( 10 ), with the steps

• - That an image generated by the camera ( 10 ) is sent to a first computer ( 50 ),
• - That the image is sent from the first computer ( 50 ) to a further computer ( 20 ) via a first data connection,
• - That the image is displayed on a screen ( 22 ) of the further computer ( 20 ),
• - That the old position of the camera ( 10 ) is assigned to a point (reference point) on the screen ( 22 ) of the further computer ( 50 ),
• - That on the screen ( 22 ) of the further computer ( 20 ) in addition to the image shown, a pointer ( 24 ) that can be positioned with a positioning device ( 26 ) is shown,
• - that in response to a signal that can be triggered by a triggering device, a new position of the camera ( 10 ) is calculated as a function of the distance between the position of the pointer ( 24 ) and said point (reference point) assigned to the old position of the camera ( 10 ),
• - That the new position of the camera ( 10 ) is sent from the further computer ( 20 ) to the first computer ( 50 ) via a second data connection,
• - That the new position of the camera ( 10 ) in the first computer ( 50 ) is converted into control information,
• - That the control information is transmitted to the camera ( 10 ) and
• - That the camera ( 10 ) is moved into the new position.

2. The method according to claim 1, characterized in that said point associated with the old position of the camera ( 10 ) (reference point) is the center of the image. 3. The method according to claim 1 or 2, characterized in that the first computer ( 50 ) in the camera ( 10 ) is integrated. 4. The method according to any one of claims 1 to 3, characterized in that the first and the second data connection between the first computer ( 50 ) and the further computer ( 20 ) uses the same connecting line. 5. The method according to any one of claims 1 to 4, characterized in that at least one, the first computer ( 50 ) with the further computer ( 20 ) connecting data connection is realized as a computer network ( 60 ). 6. System for controlling a camera ( 10 )

• - With a first computer ( 50 ) connected to the camera ( 10 )
• with a second computer ( 20 ) with a screen ( 22 ) for displaying the images taken by the camera,
• with means for displaying a pointer ( 24 ) on the screen ( 22 ) in addition to the image shown in each case,
• - With means for positioning ( 26 ) the pointer ( 24 ) and for generating a signal to end the positioning process ( 28 ),
• with a data connection between the first computer ( 50 ) and the second computer ( 20 ) for transmitting the images recorded by the camera ( 10 ) to the second computer ( 20 ),
• - With a data connection from the second computer ( 20 ) to the first computer ( 50 ) for transmitting a new position of the camera ( 10 ), and
• - With means ( 74 ) with which the information necessary for controlling the camera ( 10 ) corresponding to the distance of the pointer ( 24 ) from a point associated with the old position of the camera ( 10 ) (reference point) on the screen ( 22 ) is furthermore Computers ( 20 ) can be calculated.

7. System according to claim 6, characterized in that the connection of the computer ( 20, 50 ) with a computer network ( 60 ) is realized. 8. System according to claim 6 or 7, characterized in that the camera ( 10 ) has means ( 30 ) for tracking in two angular directions. 9. System according to claim 8, characterized in that the camera control ( 30, 90 ) tracks the camera ( 10 ) independently at an elevation angle (elevation 70 ) and an azimuth angle ( 72 ). 10. System according to one of claims 6 to 9, characterized in that a camera control ( 30, 90 ) is provided which has stepper motors ( 34, 36 ), the stepper motors ( 34, 36 ) being controlled by the first computer ( 50 ) will. 11. System according to claim 6 or 7, characterized in that the camera ( 10 ) is connected to means ( 90 ) for tracking in at least one translational direction. 12. System according to claim 11, characterized in that the camera ( 10 ) is connected to means ( 90 ) which moves it in two, largely perpendicular to each other translational directions. 13. System according to any one of claims 6 to 12, characterized by

• Means with which the camera can be moved both in its direction and in its translational position,
• Means for displaying a second pointer ( 92 ) on the screen ( 22 ) in addition to the pointer ( 24 ) and in addition to the respectively displayed image,
• - Means for positioning the second pointer ( 92 ) and for generating a second signal ( 94 ) for ending the positioning process of the second pointer ( 92 ) and
• - Further means ( 94 ) for determining a second control signal, with which the information necessary for controlling the camera ( 10 ) according to the distance of the second pointer ( 92 ) from a point (reference point) assigned to the old position of the camera ( 10 ) on the Screen ( 22 ) of the further computer ( 20 ) can be calculated.