Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T15/00—3D [Three Dimensional] image rendering
  • G06T15/04—Texture mapping

Definitions

• the invention relates to a method for generating and / or updating
• Textures of background object models in a three-dimensional scene model of a surveillance scene with background objects and a control device and a video surveillance system for performing the method and a computer program.
• Video surveillance systems are used for camera-based control of relevant areas and usually include a plurality of surveillance cameras, which are set up in the relevant areas for recording surveillance scenes.
• the surveillance scenes can be designed, for example, as parking lots, intersections, streets, squares, but also as areas in buildings, factories, hospitals or the like.
• the image data streams recorded by the surveillance cameras are merged into a monitoring center where they are either automated or evaluated by monitoring personnel.
• German patent application DE 10001252 A1 proposes a monitoring system which enables a more efficient working with a monitoring system through an object-oriented presentation. To do this, signals from the cameras used for each selected view are decomposed into objects and then passed to a display, adding artificial objects and deleting other objects.
• the invention creates a possibility that surveillance scenes at least partially in a virtual reality or a partially virtual reality in
• Form of a three-dimensional scene model can be displayed, with a particularly realistic representation of the surveillance scene can be achieved by generating and / or updating textures of background object models in the three-dimensional scene model.
• the method allows the mapping of a particular real
• the surveillance scene can be streets, intersections, squares or areas in buildings, factories, prisons, hospitals, etc.
• the behind grand objects are preferably defined as static and / or quasi-static objects, which do not change or change only slowly and which are mapped to the background object models.
• Typical static objects are buildings, trees, panels, etc.
• the quasi-static objects include, for example, shadows, parked cars or the like.
• the static objects have a retention period in the
• the quasi-static objects Monitoring scene of preferably more than several months, the quasi-static objects, however, preferably more than one or more days.
• the three-dimensional scene model includes the background object models, each of which is formed as a three-dimensional model.
• the three-dimensional scene model is "walkable", so that a user can move between the background object models in the three-dimensional scene model and / or change the view by adjusting the viewing direction or viewing angle / or an overlapping hierarchy (Z hierarchy) of
• the background object models and optionally the rest of the background have textures, with textures preferably being in the form of color, hatchings, patterns, and / or features of the surface of the background objects.
• a background image of the surveillance scene is formed from one or more camera images of the surveillance scene, wherein it is preferably provided that foreground objects or other interfering objects are masked out or suppressed.
• the background image can be formed in its thickness, ie in terms of the columns and rows of pixels, identical to the camera images.
• the background image is a section of one or more camera images. It is also possible that the background image has an arbitrary edge contour course, so that, for example, a background image represents exactly one background object.
• the background image is projected onto the scene model.
• the background image is imaged in such a way that a pixel of a background object coincides with a corresponding model point of the background object model.
• the projection can also be done pixelwise in - A -
• mapping rule Take place in the form of a mapping rule, wherein preferably only the pixels are displayed, to which a corresponding model point is available.
• the textures of the background object models are each stored with an orientation information, so that the textures in turn can be distributed on the background object models in the representation of the scene model on a monitor or the like, in the same manner as to the projection and projection.
• the method allows to provide a three-dimensional scene model with realistic textures, wherein the textures can be updated at regular or irregular intervals.
• the background image is through
• temporal filtering thus for example by averaging, moving averaging, or by elimination of foreground objects formed. It is also possible to form the median of several camera images or to cut out known objects. In principle, all known methods for creating the background image can be used.
• the projection of the background image onto the scene model takes place using the parameters of a camera model from the surveillance camera, from the perspective of which the background image is created.
• the parameters of the camera model it is possible to perform the projection of a point in the coordinate system of the surveillance scene into the coordinate system of the camera image and vice versa.
• the camera model it is also possible to use a look-up table which provides a corresponding point in the monitoring scene's coordinate system for each pixel in the camera image of the surveillance camera.
• an assignment rule between the surveillance scene and the camera image it is possible to project the background image resulting from the camera image in the correct position and / or perspective corrected onto the scene model so that misallocations are minimized.
• the background image is optionally corrected in addition to distortions, which are unintentionally caused by aberrations in the surveillance camera system, e.g. as optical aberrations may have arisen, on the other hand, but also wanted distortions, which are introduced for example by the use of 360 ° - or fish eye cameras.
• a mutual occlusion of background object models is checked with the aid of a depth buffer, wherein pixels which are to be assigned to a background object model concealed in the region of the corresponding model point are discarded.
• the depth buffer is based on a known Z-hierarchy from the rendering.
• the textures are formed on the basis of a plurality of camera images, which originate from a common surveillance camera with a common viewing angle or from different surveillance cameras with different viewing angles onto the surveillance scene.
• the camera images are projected from different angles in the manner described on the scene model in the correct position.
• pixels of different background images which belong to a common texture point or a common texture of a background object model, are merged in each case.
• the Merging can be done, for example, by averaging.
• a color balance of the pixels to be merged takes place.
• Surveillance area formed monitoring scenes - texture information from other sources, such as aerial photographs taken.
• Another object of the invention relates to a video surveillance system which is connected to one or a plurality of surveillance cameras and / or connectable and which has a control device, characterized in that the control device circuitry and / or program technology for performing the method just described and / or it has been defined in the preceding claims is formed.
• the video surveillance system is designed so that the described method preferably runs in the background at periodic intervals and thus keeps the textures up to date.
• a particular advantage of the video surveillance system is the fact that for the creation or
• a final object of the invention relates to a computer program with program code means for carrying out all the steps of the described method when the program is executed on a computer and / or a video surveillance system.
• FIG. 1 is a flow chart illustrating a first embodiment of the method according to the invention
• Figure 2 is a block diagram of a video surveillance system for performing the
• FIG. 1 shows, in a schematic flowchart, the sequence of a method for generating and / or updating textures of background object models in a three-dimensional scene model as an exemplary embodiment of the invention.
• Surveillance cameras are 10 ( Figure 2), used. These video images 1 are converted in a first method step 2 into a background image with background pixels. The transfer is accomplished by methods known in image processing, such as averaging or median formation of multiple video frames 1, clipping known objects, long-term observation, or the like.
• a background image is generated, which has as active pixels only background pixels from the one or more video images 1 and optionally disabled pixels, which are set to the positions of the video image 1, where a disturber object or foreground object is shown.
• the background image generated in this way is projected onto a scene model.
• the scene model is designed as a three-dimensional scene model and has a multiplicity of background object models, for example representative of buildings, furniture, streets or other stationary objects.
• Surveillance cameras that have supplied the background image underlying video image 1, which projects pixels of the background image in the image coordinate system to the respective corresponding point of the three-dimensional scene model.
• the distortion distortions such as distortions or the like are corrected.
• a pixel-by-pixel check for occlusion from the camera's view takes place with the aid of a depth buffer.
• a pixel of the background image which was projected by the method step 3 on a background object model, by another background object model and / or a real, e.g. dynamic object in the current camera view is obscured.
• the test assesses the inspected pixel as hidden, it is discarded and no longer used. Otherwise, the pixel, ie the projected video pixel or background pixel, is used for creating and / or updating the textures.
• the textures 6 are created and output on the basis of the transferred background pixels.
• several pixels of different background images which are arranged overlapping at least in sections after the projection and thus relate to the same regions of the same background object models, are merged into a common background pixel.
• a common background pixel e.g. also a color match done.
• any remaining gaps in the scene model may be filled by static textures, e.g. taken from aerial photographs.
• FIG. 2 shows a video surveillance system 100 which is designed to carry out the method described in FIG.
• the video surveillance system is connected to a plurality of security cameras 10 wirelessly or wired signal technology and is designed for example as a computer system.
• the Surveillance cameras 10 are directed to relevant areas which show surveillance scenes in the form of squares, intersections or the like.
• the image data streams of the surveillance cameras 10 are transferred to a background module 20, which is designed to carry out the first method step 2 in FIG.
• the background image (s) generated are forwarded to a projection module 30, which is designed to carry out the second method step 3.
• the projected background images are passed to a masking module 40, which is implemented for carrying out the third method step 4.
• the textures 6 are created or updated on the basis of the checked background images and forwarded to a texture memory 60.
• a display unit 70 Based on the stored data and the three-dimensional scene model is displayed on a display unit 70, such. a virtual representation of a monitor

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• Engineering & Computer Science (AREA)
• Computer Graphics (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Closed-Circuit Television Systems (AREA)
• Processing Or Creating Images (AREA)
• Image Analysis (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2007
  • 2007-10-11 DE DE102007048857A patent/DE102007048857A1/de not_active Withdrawn
• 2008
  • 2008-09-11 US US12/682,069 patent/US20100239122A1/en not_active Abandoned
  • 2008-09-11 CN CN2008801109019A patent/CN101999139A/zh active Pending
  • 2008-09-11 WO PCT/EP2008/062093 patent/WO2009049973A2/de active Application Filing
  • 2008-09-11 EP EP08804058A patent/EP2201524A2/de active Pending

Non-Patent Citations (4)

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