Method for creating projections on surfaces of real world objects

Description

1 / 10 METHOD FOR CREATING PROJECTIONS OF REAL-WORLD OBJECTS ON SURFACES TECHNICAL FIELD

[001] The invention relates to a method for creating undistorted projections on the surfaces of real objects in the case of artistic lighting of architectural buildings, structures and similar objects, as well as in the case of luminous marking in industrial installations and on civil objects. TECHNICAL BACKGROUND OF THE INVENTION

[002] Document DE 102005034990 A1 describes a method for projecting an image onto the surfaces of real objects. The method involves using a plurality of projectors to project a plurality of digital images onto a projection surface (surfaces), with the projectors being tuned to different image planes, where the image elements – pixels – are projected onto areas of the projection surface(s) simultaneously from different projectors. With this display method, all areas of the projection surfaces that can be illuminated by the projectors are automatically adjusted by an autofocus mechanism to optimal sharpness after calibration to correct geometry and color and to determine the sharpness values ​​and appropriate transformation when manipulating the intensities to be corrected. In this case, calibration is a long and complex process, and the image on the surface is ultimately not completely realistic.

[003] Document RU 2433487 (published November 10, 2011, Patent Bulletin No. 31) describes a method for projecting an image of three-dimensional objects onto the surface of real objects by means of laser measurement and / or firing and / or scanning of the real objects onto whose surface the image will be projected, calculating the position of projectors, light sources and viewers. Petition 870250095161, dated 10 / 17 / 2025, page 8 / 42 2 / 10 in relation to real objects. In this method, 3D models of real and virtual objects are created and textured, and a virtual scene is constructed, including virtual light sources, virtual projectors, and 3D models of real objects whose location is identical to the location of the real objects, light sources, and projectors, and 3D models of virtual objects. The programming of the virtual scene visualization is performed based on the observer's location in real time, the programming of the display of the image obtained on the surface of the real object models in real time, the programming of the resulting scene visualization based on the location of the projectors in real time, the programming of the interactive part, and the scenario of the models' behavior. Then, the projectors are arranged in the real environment identically to the virtual scene, and the images obtained are displayed by means of the real projectors on the surface of the real objects.In some cases, due to inaccuracies in the initial measurements or in the calibration of the projectors, it is necessary to adjust (reset) the projectors in the real environment. After positioning the projectors in the real environment, the projected image is further corrected to account for the projector positioning by editing the 3D models of the real objects. If difficulties arise in overlaying the final video image onto the real objects due to inaccuracies in the initial measurements or in the calibration of the projectors, the projectors are adjusted in the real environment by adjusting the projected image with a 3D model editing tool.

[004] The complexity of the above method is caused by the duration of the adjustment and determination of the projectors' position, due to the fact that their position is determined by a virtual 3D model of objects, and the transfer of the projectors' location points from the virtual model to the real object requires numerous iterations in search of the ideal location and, sometimes, adjustment of the projected image, taking into account the positioning of the projectors, editing Petition 870250095161, dated 10 / 17 / 2025, page 9 / 42 3 / 10 3D models of real objects. Digital projectors (see document RU 2433487: figures 3-5) do not allow the projection of an image, avoiding locations where lighting is undesirable (windows, galleries, openings, etc.). The design of video projectors does not imply their use in open spaces, except for the adoption of additional measures to protect them from the effects of weather conditions; they are most often installed inside a building or under an awning, which significantly limits the choice of locations for their installation.

[005] The state of the art describes ways of projecting images onto the surface of real objects, which use so-called Gobo projectors, street projectors in the form of a small LED device that projects the image of a gobo slide onto any surface, preferably flat, such as an asphalt pavement, a building wall, a shopping mall floor, etc. The projector's gobo slide is usually a thin, heat-resistant dichroic glass disc with a laser-etched image, which is installed in front of the light source (Goes Before Optics - GOBO).

[006] Patent document RU 2667346 (published September 18, 2018, Patent Bulletin No. 26) describes a method for projecting an image onto the surfaces of real objects, which involves determining a projection area and an approximate location of a gobo projector and calibrating the projector with a calibration gobo slide so that the gobo slide with reference points is inserted and projected, after which a projection size and focus are adjusted. After defining the aperture angle and focus, the distance from the gobo projector to the extreme points of the projection is measured, the projection of the calibration gobo is photographed from the installation location of the gobo projector and / or from the projection viewpoint, the projection distortion is calculated, and a primary model is created in a graphic editor based on the photograph of the calibration gobo projection, removing all information from the model image. Petition 870250095161, dated 10 / 17 / 2025, page 10 / 42 4 / 10 graphics, except those present in the projection area. Next, the projection area is distorted to ensure the possibility of linking the image to the reference points of the calibration gobo projection. If necessary, the primary model is divided into a main model of the projected image and a mask model for cutting off the luminous flux from areas where light should not fall. Then, the main model is superimposed on the image for projection and, if necessary, the luminous flux cut-off zones are marked on the mask model. The main model with the image and the mask model with the luminous flux cut-off zones are distorted according to the geometry and original dimensions of the calibration gobo. Then, a gobo slide is created from the main model with the image and the unilluminated zones for cutting off the luminous flux.The slide in the gobo is installed in the gobo projector, the gobo projector is directed and adjusted according to the previously made settings, the gobo with the image and the gobo mask are adjusted in relation to the axis of the luminous flux, and the focus of the projected image is adjusted by moving and tilting the lenses.

[007] The above method for creating the slide in gobo is quite laborious, requiring a great deal of manual work to adjust the projectors, perform the necessary measurements and calculations, first create the primary model and then the main model and the clipping mask model, create and use the calibration gobo and, in some cases, a repeated set of work to determine the new location of the projectors and their adjustment. SUMMARY OF THE INVENTION

[008] The objective of the claimed method is to ensure its manufacturability by reducing the labor intensity of the process of creating undistorted projections on the surface of real objects. Petition 870250095161, dated 10 / 17 / 2025, page 11 / 42 5 / 10

[009] The technical result of the claimed invention is to reduce the labor intensity of the method for creating undistorted projections on the surface of real objects by: creating a three-dimensional digital model (3D model) of the object and its spatial environment with the given real coordinates without creating an additional virtual model of the object; post-field processing of projection scenarios taking into account the location of objects in the spatial environment that impede the passage of projection rays from a projector(s) light stream to the object; determining the ideal projector(s) installation location by modeling and comparing projection variants without additional adjustments to the installation location of the projection sources; and creating a main image model and, if necessary, a mask model, a final gobo slide.

[010] The technical result is achieved by the claimed method, which includes: performing preliminary geodetic measurements of a real object and its spatial environment to create a vertical control network in which each point of the scanning object is linked to a coordinate system; performing a photographic survey of the real object onto which a projection will be made and its spatial environment to subsequently determine the installation location of the projectors, taking into account the location of objects that impede the projection; and creating a three-dimensional digital model (3D model) of the projection object in a given coordinate system, performing the necessary calculations based on it to obtain a distortion-free image and determine the ideal installation locations of the projectors. A model of the “source (projector)-screen” system is created based on the coordinates obtained in the process of working with the 3D model.

[011] Depending on the composition of the object on which the projection will be made, photogrammetry or laser scanning is used to collect the Petition 870250095161, dated 10 / 17 / 2025, page 12 / 42 6 / 10 The necessary amount of information about the object and its spatial environment. The information about the projected object is linked to the coordinate system provided by software such as ContextCapture or Metashape for photogrammetry or Trimble Business Center for laser scanning. The three-dimensional digital model (3D model) is created in the specified coordinate system to determine the coordinates of the projector and the projection plane in the adopted coordinate system, without the need to create an additional virtual model.The construction of a 3D model of a real object using photogrammetry technology, where a raster model is created based on pixels from photographic images, or laser scanning technology, where the model is created based on point clouds obtained through a laser beam reflected from the object's surface, is carried out using software such as ContextCapture, Metashape, and Trimble Business Center, depending on the equipment used, for example, digital cameras, quadcopters, and laser scanners, while involving identifications obtained based on geodetic measurements.

[012] The 3D digital model, taking into account the use of ground control points and coordinates from camera photography centers (GPS), is an exact digital copy of the real object, which allows any necessary measurements of the object to be taken without repeated trips to the location of the real object.

[013] For each image projection scenario in different projector placement locations, virtual image projection is performed, lighting calculation is performed, the distortion of the projected image is fixed to form a future undistorted projection on the surface of the real object, computational processing of the results obtained is performed and, as a result, a view of the final image is created for its subsequent transfer to the gobo slide. Petition 870250095161, dated 10 / 17 / 2025, page 13 / 42 7 / 10

[014] The distorted image of the future projection is created in the three-dimensional digital model in a post-field manner. As a result, an image of the projection is obtained and, if necessary, a luminous flux cut-off zone is formed for the subsequent production of the gobo slide and the Gobo mask based, for example, on borosilicate dichroic glass.

[015] Directly on the real object, only the projector is mounted according to the coordinates of the projector installation location on the 3D model, the prepared slide and, if necessary, the gobo mask are installed on it, and then the device is adjusted.

[016] The use of this method significantly reduces the labor intensity of the process of creating distortion-free projections on the surfaces of real objects, since all operations in the virtual projector setup, such as determining the projection location, modeling the luminous flux depending on the projector's power and optics, determining the presence of obstacles in its path, possible changes in the projector's location, correcting distortions, determining the necessary parameters, and processing all the information, are performed post-field, without additional trips to the location of the real object. When working with the 3D model post-field, there is no need to apply calibration gobos; all editing is done in the process of working with the program. The observer is not confined to a specific location to view the projection and their freedom of movement is not restricted.

[017] The method allows for the virtual projection of a light stream with the display of a light point on a projection surface (location) in the 3D model of the real object from the chosen (optimal) projector location according to the results of the illumination calculation only, without additional trips to the location of the real object, as well as processing the fixed distortions of the light point on the projection surface with the help of a software product for Petition 870250095161, dated 10 / 17 / 2025, page 14 / 42 8 / 10 Transferring distortion parameters to the future projection image (reverse distortion of the original image), create the slide, for example, from borosilicate dichroic glass according to the virtual distortion parameters of the original image to install it in the projector and mount the projector exactly according to the coordinates of the virtual projector on the 3D model of the real object.

[018] One of the variant applications of the claimed method is its use for light demarcation for both still images and moving images after moving loads and moving mechanisms (active demarcation), when the image projection is carried out with the aid of projectors installed on the moving mechanisms, at an unchanged distance from the projector to the projection surface. DETAILED DESCRIPTION OF THE INVENTION

[019] The method is performed as follows. With the aid of geodetic equipment, a vertical control network is created, in which each scan point of an object is linked to a coordinate system and serves to link a future 3D digital model to the real object. A raster model of the real object is created based on pixels from photographic images or with the aid of laser scanning technology, when the model is created based on point clouds obtained with the aid of a laser beam reflected from the surface of the object.

[020] Software such as ContextCapture, Metashape, and Trimble Business Center are used to: build the 3D model of the object, which is an exact digital copy of a real object and allows any necessary measurements of the object to be made virtually, in a real coordinate system without additional site visits; build a digital model of the spatial environment; edit reality models and digital terrain models consisting of hundreds of millions of triangles or point clouds; import, retouch, and export the models of Petition 870250095161, dated 10 / 17 / 2025, page 15 / 42 9 / 10 reality in various formats; and move the data to the best formats for processing.

[021] For each viewing scenario, a virtual projection of the image is performed, a lighting calculation is made, the distortion of the projected image is recorded, computational processing of the results obtained is carried out, and a preview of the final image is created for its subsequent transfer to a gobo blade. The distorted image of the future projection is created in the three-dimensional digital model in a post-field manner. As a result, the main image of the projection is obtained and, if necessary, a luminous flux cutoff zone is formed for the subsequent production of the blade and a gobo mask based, for example, on borosilicate dichroic glass.

[022] The projector installation location is modeled in the 3D model, creating a virtual visualization of the luminous flux projection from the projector, depending on the projector's power and its optics installed on surfaces fundamentally suited for this in the spatial environment of the projection object for a given projection location. As the ideal option is determined (no obstacles in the path of the luminous flux, compliance with the requirement of the minimum possible angle of inclination of the luminous flux for comfortable image perception by viewers, the closest location (within reasonable limits) of the projector to the projection location), the projector installation location is fixed, linking it to the coordinates of the 3D model.To perform lighting calculations, track beam paths and calculate their interactions with objects along the paths, as well as solve geometric optics problems, software such as the ZEMAX and DIALUX packages are used. These packages allow for modeling and analyzing various optical systems, creating a model of the source (projector) - screen system based on the coordinates obtained during the creation of the 3D model. A uniform grid of... Petition 870250095161, dated 10 / 17 / 2025, page 16 / 42 A 10 / 10 grid is created on the screen, the size of which corresponds to the size of the image. Based on the calculation results, two text files are created: one with the coordinates of the uniform grid in the gobo mask in the virtual projection, and another with the coordinates of the distorted grid.

[023] Directly on the actual object, only the projector installation is carried out according to the coordinates of the projector installation location in the 3D model, after which the prepared slide and, if necessary, the gobo mask are installed on it, and the projectors are then adjusted. Petition 870250095161, dated 10 / 17 / 2025, page 17 / 42

Claims

1 / 3 CLAIMS 1. A digital method for creating a projection image on the surface of a real object, characterized in that it comprises: filming or laser scanning the real object; based on the filming or laser scanning data, creating a 3D model of the real object; modeling projection scenarios taking into account the spatial environment of the real object; determining and calculating the projection image; calculating the position of at least one projector; transferring the projection image to a gobo slide; mounting at least one projector on site; installing the gobo slide with the projection image on each of the at least one projector; and projecting the projection image onto the surface of the real object; wherein the projection scenarios are modeled according to the selected coordinates of each of the at least one projector in the 3D model of the real object;whereby, when performing a virtual projection of the projection image in each of the projection scenarios, a lighting calculation is performed and distortions of the projection image are recorded; wherein the projection image is transferred to the gobo slide as a distorted image that is formed, taking into account a minimum angle of inclination of a light flow, by software processing of the recorded distortions of the projection image in each of the projection scenarios in different placement locations of each of the at least one projector in the 3D model of the real object; and Petition 870250095161, of 10 / 17 / 2025, p. 18 / 42 2 / 3 wherein each of the at least one projectors is mounted in place according to the selected coordinates of each of the at least one projectors in the 3D model of the real object.

2. Method, according to claim 3, characterized in that it further comprises performing preliminary geodetic measurements of the real object and the spatial environment of the real object to create a vertical control network in which each point of the real object is linked to a coordinate system.

3. Method, according to claim 3, characterized in that it further comprises performing filming or laser scanning of the spatial environment of the real object to determine a mounting location for each of at least one projector, taking into account the location of environmental objects that impede the projection of the projection image.

4. Method, according to claim 3, characterized in that the 3D model of the real object is additionally created based on preliminary geodetic measurement data of the real object and the spatial environment of the real object and laser shooting or scanning data of the spatial environment of the real object.

5. Method, according to claim 3, characterized in that the illumination calculation includes: modeling the light flux depending on the power of each of at least one projector and the optics included in each of at least one projector, and determining obstacles in the path of the light flux.

6. Method according to claim 3, characterized in that it further comprises the use of a gobo mask on each of at least one projector to form a light flux cutoff zone. Petition 870250095161, dated 10 / 17 / 2025, page 19 / 42 3 / 3 7. Method according to claim 3, characterized in that each of the at least one projector is installed in movable mechanisms, at an unaltered distance from each of the at least one projector to the surface. Petition 870250095161, dated 10 / 17 / 2025, p. 20 / 42