BACKGROUND PLAYBACK SETUP

Description

[0001] The invention relates to a background display device for a virtual image recording studio, which is designed to display a representation of a virtual background behind or above a real subject for recording by means of an associated camera.

[0002] Such background reproduction devices can be provided in particular for reproducing a landscape or an environment in an image recording studio in which a recording is to be made using an assigned camera and which forms a virtual background for a scene to be recorded. The image recording studio can be, for example, a film studio for recording moving image sequences or a photo studio in which individual images or still images are recorded. In general, such a recording can comprise local storage of image data or transmission to a remote location (e.g. broadcast, streaming). In the virtual image recording studio, a virtual background or an environment can thus be created in which an actor can move during a moving image recording or which can form a background for a still image recording.

[0003] For example, in moving image recordings, a background playback device can be used to play back a representation of a virtual background in order to record a scene directly in the intended environment. In particular, this can make acting easier because any events taking place in the virtual background can be perceived by an actor and the actor can react to these events. Unlike, for example, when using a green screen, where the environment is not visible to the actor, the actor can thus adapt their acting to any background events and a director, a camera operator or other people involved in a shoot can gain an overall impression of the scene and assess it during filming.In addition, the entire scene or a corresponding section of a film can be viewed and reviewed immediately after recording, without having to overlay the background intended for the scene.

[0004] For still image photography, such a background playback device can be used, for example, to capture photographs in virtually any environment in a photo studio, thus providing a controllable environment, while maintaining a complete view of the resulting image. The background and the real subject, or a person being photographed, can thus be optimally coordinated and interact with each other. Furthermore, the captured photo can be viewed immediately to make any necessary adjustments.

[0005] To display the representation of the virtual background, background display devices can, in particular, form or comprise an electronic display with an active pixel matrix and, for example, comprise an active lighting device with a plurality of light sources and / or active pixel elements. For example, to display a representation of a virtual background in a virtual image recording studio, an LED wall can be used, the LEDs of which can be controlled individually and / or in groups of adjacent LEDs or in arrays of LEDs. LEDs of such an LED wall can, for example, be provided as LEDs (Light Emitting Diodes) or as OLEDs (Organic Light Emitting Diodes). Furthermore, the LEDs can be part of a liquid crystal display.Such background playback devices may, for example, extend over a width of at least 5 m and a height of at least 2 m in order to be able to record several actors in front of a common (virtual) background.

[0006] Furthermore, background display devices can comprise a plurality of panels on which the pixel elements are arranged and which together form the LED wall. While the panels, for which the term panel is also commonly used, are essentially two-dimensional and the pixel elements arranged on a panel can extend in a flat arrangement, a suitable arrangement of a plurality of panels can, for example, result in the background display device being curved and / or arched in sections. This allows the background display device to be arranged, for example, both behind and above the real subject in the virtual image recording studio in order to also enable the direct recording of a representation of a virtual sky or a virtual ceiling of a room in the image recording studio.As an alternative to an LED wall, a virtual background can also be created using light points generated by reflection or transmission from a light source wall, such as a screen for rear projection. Active light generation can be achieved by a projector, with the light sources on the screen only being indirectly generated.

[0007] A background display device for use in this way is described, for example, in US 2020 / 145644 A1. WO 2021 / 216645, the article "Comparative Evaluation of the Imaging Performance of Multi-Primary Color LCDs With RGBCW and RGBCY Pixel Units by Simulation" from the Journal of Display Technology, Vol. 10, No. 9, September 1, 2014, and the article "4.5 Multi-primary LCD for TV Applications" from the Proceedings of the 2007 SID International Symposium of the Society for Information Display, Vol. XXXVIII, May 20, 2007, describe the use of multi-primary displays in televisions, which use light sources of other colors in addition to RGB light sources.

[0008] In particular, such a background display device can make it possible to visually display a virtual background by appropriately controlling the pixel elements and / or to adapt it by changing the control during a recording. The virtual background referred to in the present context can, in particular, represent a background motif whose representation can be directly recorded by an associated camera as a seemingly real environment of a (foreground) scene. A background display device thus offers a way to vividly and easily adaptably display a virtual background for a scene to be recorded, thereby facilitating, in particular, acting or gestures.

[0009] In order to be able to reproduce different representations of a virtual background on such a background display device, one generally strives to design the background display device to reproduce the largest possible color space. To this end, for example, different light sources that emit light in a respective wavelength range can be mixed with one another at the pixel elements in order to determine a color of a respective pixel element. For example, mixing red, green, and blue light sources can make it possible to reproduce a large RGB (red-green-blue) color space on the background display device, so that a respective pixel of the representation of the virtual background can be reproduced in particular by mixing respective red, green, and blue light sources of a pixel element on the background display device.

[0010] To maximize the color space that can be reproduced on the background display device, it may also be provided to use spectrally narrowband light sources on the background display device, which can emit colors that lie far out in the visible spectrum in particular. This means that even these far out colors can, in principle, be accessible for reproduction on the background display device, and by appropriately mixing the individual light sources, all colors between the outer colors can be reproduced.

[0011] In connection with such background reproduction devices designed to reproduce a large color space, however, the problem arises that the light spectrum emitted by the background reproduction device may differ from the spectrum of natural light and, for example, be discontinuous. However, the light emitted by the background reproduction device is reflected by real subjects, in particular actors, recorded by the camera in front of or below the representation of the virtual background, whereby these real subjects may have wavelength-dependent reflection properties. Because the light from the background reproduction device differs spectrally from natural light, the light reflected by the real subject may, for example, appear in a different color than a reflection of natural light and may be imaged accordingly by the camera.As a result, such background display devices with a wide color space can usually only achieve inadequate color reproduction quality, which can result in complex post-processing of the recorded camera footage, particularly in the area of ​​the real subjects depicted. However, such correction is usually hardly possible, especially in situations where the real subject is additionally illuminated, for example, by spotlights in the virtual image recording studio, which in turn may have a different emission spectrum and, for example, an emission spectrum optimized for good color reproduction.

[0012] It is therefore an object of the invention to provide a background display device which enables a representation of a virtual background to be displayed in a large color space and which has an improved color reproduction quality compared to conventional background display devices.

[0013] This object is achieved by a background playback device having the features of claim 1.

[0014] The background display device comprises at least one panel with a plurality of pixel elements in an at least two-dimensional arrangement, wherein each of the plurality of pixel elements has a respective light source unit comprising a first light source for generating a first emission spectrum, a second light source for generating a second emission spectrum, and a third light source for generating a third emission spectrum. Furthermore, the background display device comprises a control device configured to individually control the light sources of the light source units and to generate a respective light source unit emission spectrum by mixing the respective first emission spectra, second emission spectra, and third emission spectra.Furthermore, the at least one panel has a plurality of correction light sources and the control device is designed to adapt the respective light source unit emission spectrum by controlling the correction light sources to a corrected emission spectrum which approximates a predetermined or predeterminable emission spectrum.

[0015] In particular, the representation of the virtual background can be composed of a plurality of pieces of image information, wherein each piece of image information can, in particular, comprise a color value and a brightness that is reproduced at a respective pixel element. Since each pixel element comprises a light source unit having three light sources for generating respective emission spectra, image information associated with the pixel element can be set at the pixel element by means of the control device by appropriately adjusting the intensities and / or brightnesses of the individual light sources, so that the image information can be reproduced at and from the pixel element on the background display device or on the at least one panel.In particular, the first emission spectrum, the second emission spectrum, and the third emission spectrum can differ from one another, so that a specific color value can be set by appropriately mixing the emission spectra. For example, the light sources of the light source units can be configured to emit a respective narrowband emission spectrum, wherein two of the three light sources of a light source unit can be configured, in particular, to emit light with colors located far outside the visible spectrum in order to be able to reproduce the largest possible color space using the background display device.

[0016] By having each of the pixel elements such a respective light source unit, a large color space can be reproduced on the background display device, in particular, at a resolution determined primarily by the arrangement of the pixel elements. In principle, any desired color can be set at each pixel element by appropriately mixing the emission spectra of the three light sources, whereby the settable color space can be determined, in particular, by the spectrally outermost emission spectra of the first emission spectrum, the second emission spectrum, and the third emission spectrum.

[0017] While the light source units thus enable precise adjustment of the reproduced color of the pixel element, the light source unit's emission spectrum generated for a specific color may differ from the emission spectrum of natural light due to the mixing of only three emission spectra, and in particular three narrowband emission spectra, and may, for example, be discontinuous. However, in order to achieve the highest possible color reproduction quality using the background reproduction device, a plurality of correction light sources are also arranged on the panel, which can also be controlled by the control device.

[0018] These correction light sources make it possible, as a result of control by the control device and in particular by mixing emission spectra of the correction light sources, which can also be referred to as correction light emission spectra, with the light source unit emission spectra, to adapt the light source unit emission spectra in such a way that the corrected emission spectrum ultimately emitted by a light source unit approximates the predetermined or predeterminable emission spectrum.In particular, by additionally emitting light from the correction light sources, the corrected emission spectrum can be stabilized relative to the light source unit's emission spectrum and thus approximated to an emission spectrum of natural light, in that the emission spectra of the correction light sources can, to a certain extent, bridge gaps in a light source unit's emission spectrum between the respective emission spectra of the individual light sources. For this purpose, the correction light sources can be designed, in particular, to emit light with an emission spectrum that differs from the first emission spectrum, the second emission spectrum, and the third emission spectrum.

[0019] In particular, such a correction of the light source unit's emission spectrum can make it possible to image real subjects arranged in front of or below the representation of the virtual background or the background reproduction device in an environment resembling natural light using the associated camera, for which purpose an emission spectrum of natural light can be provided as the predetermined or predeterminable emission spectrum. The resulting impression of a scene recorded in the virtual image recording studio can thus be brought even closer to the impression of a recording in a real background corresponding to the virtual background, for example, a landscape in natural light.In addition, such a corrected emission spectrum can be approximated to the illumination emission spectrum of any other lighting devices in the virtual image recording studio, for example, a spotlight, which can be designed for the highest possible reproduction quality, so that the illumination emission spectrum of the lighting device can form the specified or specifiable emission spectrum. Any transitions in an image of the real subject generated by the camera due to the spectral reflection properties of the real subject, which can lead to a different color impression in the image during a transition from illumination by a spotlight to illumination by the background reproduction device, can thus be avoided.Accordingly, the effort required for subsequent processing of the image generated by the camera to compensate for such effects can be minimized by adjusting the light source unit emission spectrum to a corrected emission spectrum and increasing the color rendering quality of the background rendering device.

[0020] In principle, it can be provided that the control device is designed to approximate the corrected emission spectrum to a predetermined emission spectrum, for which purpose such a predetermined emission spectrum can be stored, for example, in a memory of the background display device. For example, an emission spectrum of natural white light can form the predetermined emission spectrum, so that the control device can be designed to approximate the corrected emission spectrum to the emission spectrum of natural light. However, different predetermined emission spectra can also be stored, for example emission spectra of natural light with different color temperatures, wherein the control device can be designed to approximate the corrected emission spectrum to a natural emission spectrum whose color temperature corresponds to the color temperature of the respective light source unit emission spectrum.Furthermore, for example, an illumination emission spectrum of a lighting device can be stored as a predetermined emission spectrum in a memory, so that the corrected emission spectrum can be approximated to such a predetermined illumination emission spectrum.

[0021] Alternatively, the emission spectrum to which the corrected emission spectrum is to be approximated can also be predefined, for which purpose a user can, for example, enter any emission spectra into an input device and transmit them to the control device. Furthermore, it can be provided that the emission spectrum can be predefined by further devices, in particular a lighting device or a measuring device for measuring an illumination emission spectrum of a lighting device, in that the respective emission spectrum or information thereabout can be transmitted to the control device by the corresponding device. The background reproduction device can, in particular, have a signal input in order to be able to receive corresponding information.

[0022] Further embodiments can be found in the dependent claims, the description and the drawings.

[0023] In some embodiments, the background display device can be designed as an LED wall, and the pixel elements can be designed as light-emitting diode units. The light sources and / or the correction light sources can also be designed as light-emitting diodes. Furthermore, the light source units can be designed, in particular, as light-emitting diode units.

[0024] The light-emitting diodes of such an LED wall can, for example, be designed as LEDs (light-emitting diodes) or as organic light-emitting diodes or OLEDs (organic light-emitting diodes). Furthermore, in an LED wall, it can generally be provided that the individual pixel elements, which together generate the representation of the virtual background, are formed by individual light-emitting diodes. However, the individual pixel elements can also be formed by respective light-emitting diode units, wherein each light-emitting diode unit can comprise several, in particular three, light-emitting diodes as light sources. For example, an light-emitting diode unit can also comprise three, four or more light-emitting diodes, wherein the multiple light-emitting diodes of a light-emitting diode unit can, in particular, have different emission spectra and can optionally be equipped with a color mixer.Furthermore, in such an LED unit, it can be provided that the individual LEDs of the LED unit can be selectively controlled in order to generate a desired color of the pixel element formed by the LED unit. In particular, a LED unit can comprise a red-emitting LED, a green-emitting LED, and a blue-emitting LED.

[0025] Furthermore, in some embodiments, the correction light sources can be embodied as light-emitting diodes. The correction light sources can also be embodied, in particular, to emit light with a narrowband correction light emission spectrum, wherein a broadened and / or steady corrected emission spectrum of the light source unit can be generated by appropriately mixing the light sources of a light source unit and, in particular, a plurality of correction light sources. In particular, correction light sources embodied as light-emitting diodes can be embodied to emit light with a color that differs from the light emitted by the light sources in order to be able to correct the light source unit's emission spectrum.

[0026] In some embodiments, it may further be provided that the pixel elements can be individually controlled to generate the representation of the virtual background. In particular, by controlling the pixel elements, a respective color and / or brightness of the pixel element can be adjusted in order to be able to adjust a section or point of the representation of the virtual background represented by the respective pixel element to the intended color and / or brightness.

[0027] In some embodiments, the background display device can extend in a vertical and / or horizontal orientation. For example, it can be provided that the background display device extends in a vertical orientation flat behind the real subject in order to display the representation of the virtual background behind the real subject. Alternatively or additionally, however, it can also be provided that the background display device extends at least partially in a horizontal orientation, so that the representation of the virtual background can also be displayed above the real subject, for example. In addition, the background display device can be designed to surround and cover the real subject in order to enable the most complete possible reproduction of the virtual background over a large angular range.In a section where the background display device transitions from a vertical to a horizontal orientation, the background display device can also be arched and / or curved. In particular, when the background display device is composed of multiple panels, the panels can be combined to form different, for example, arch-like geometries to create a desired environment for a recording in the virtual image recording studio.

[0028] In some embodiments, the background rendering device can be curved. The background rendering device can thus be arranged, for example, to surround an actor in the virtual image recording studio, so that the representation of the virtual background can be imaged by the associated camera, particularly with as many camera orientations or recording angles as possible, for example, when the camera images the actor from different directions. In particular, the background rendering device can be designed to surround the real subject, and in particular an actor, in such a way that the representation of the virtual background and the real subject can be imaged together over a recording angle range of at least 180 degrees.In particular, the background reproduction device can be arranged in the virtual image recording studio in a vertical orientation in a circular arc extending around the real subject.

[0029] Furthermore, in some embodiments, the background rendering device can extend over a width of at least 5 m and a height of at least 2 m. In particular, the background rendering device can thereby be sufficiently large to record multiple actors against a common (virtual) background. Furthermore, such a sufficient size of the background rendering device can, for example, enable various real objects, such as furniture and / or seating, to be positioned in the virtual image recording studio and, for example, to record a film scene incorporating these real objects and / or with moving actors against the representation of the virtual background.In particular, the representation of the virtual background and / or the background reproduction device can extend beyond a section imaged by the camera during a typical recording in the virtual image recording studio, in particular a recording of a scene played by actors, so that the representation of the virtual background can extend, for example, in the image generated by the camera to all edges of the image and is not limited to an interior section of the image.

[0030] In some embodiments, the background rendering device can further be configured to illuminate the real subject. In particular, this background rendering device can serve to illuminate the real subject in addition to other lighting in the virtual image recording studio. For example, this can ensure that the real subject casts an expected shadow if the virtual background contains lighting sources, such as a street lamp, by basing the illumination of the real subject on the rendered representation of the street lamp in the virtual background on the expected illumination of a real street lamp.However, the background rendering device can also be configured to emit light in sections to illuminate a scene, effectively acting as a spotlight, while the background rendering device can reproduce the representation of the virtual background in other sections. Particularly with regard to such illumination of the real subject, an increased color rendering quality of the background rendering device achievable through the correction light sources can expand its possible applications.

[0031] In some embodiments, the virtual background can represent a three-dimensional scene. For example, the virtual background can be a landscape or a room in which a scene to be recorded in the virtual image recording studio takes place. In particular, the representation of the virtual background displayed on the background display device and / or a portion of the representation of the virtual background displayed on the at least one panel can correspond to a projection of the three-dimensional scene or a portion of the three-dimensional scene onto the two-dimensional arrangement of pixel elements.

[0032] In some embodiments, the background playback device can be configured to vary the representation of the virtual background over time during recording. In particular, events occurring in the virtual background during a camera recording can be directly reproduced by the background playback device, so that an actor, unlike, for example, in a green screen recording, can react to these events and coordinate the acting accordingly. The background playback device can therefore be configured, in particular, to play back a film sequence during camera recording, which can be recorded directly by the camera. Subsequent overlaying of the camera recording with a provided background is thus no longer necessary.

[0033] In some embodiments, the control device can be configured to adapt the light source unit's emission spectrum such that a maximum of the corrected emission spectrum corresponds to a maximum of the light source unit's emission spectrum. Alternatively or additionally, in some embodiments, the control device can be configured such that a wavelength associated with a maximum of the corrected emission spectrum corresponds to a wavelength associated with a maximum of the light source unit's emission spectrum.

[0034] In particular, the control device can be configured to adapt the light source unit's emission spectrum such that the corrected emission spectrum approximates an emission spectrum of natural light with the color temperature defined by the light source unit's emission spectrum. For this purpose, in particular, a wavelength at which the corrected emission spectrum reaches a maximum can correspond to a wavelength at which the light source unit's emission spectrum reaches a maximum.Consequently, the control device can be configured to adapt the light source unit's emission spectrum such that the predetermined color and / or the color associated with the light source unit's emission spectrum continues to be reproduced at the respective pixel element. However, the corrected emission spectrum emitted by the pixel element can approximate a spectrum emitted by a pixel represented by the pixel element in a real background corresponding to the virtual background, in which real background natural light is ultimately reflected by the pixel. This can make it possible, in particular, to reproduce a representation of basically any virtual background, for example a landscape, by means of the background reproduction device, in that colors from a large color space can be reproduced at the background reproduction device.In addition, the light emitted by the background rendering device or the pixel elements can be reflected by a real subject in the image recording studio in the same way as would be expected from natural light and thus from a real background corresponding to the virtual background, for example, from a real landscape. Overall, this can achieve a natural impression of a scene captured in the virtual image recording studio as well as high color reproduction quality, thereby reducing any necessary post-processing.

[0035] Since the control device can also be configured to adapt the light source unit's emission spectrum such that a maximum of the corrected emission spectrum corresponds to a maximum of the light source unit's emission spectrum, in particular, the brightness of the light emitted by the pixel element can also be unchanged or at least slightly changed by adapting the light source unit's emission spectrum. In particular, the image information reproduced at the pixel element can thus remain substantially unchanged by adapting the light source unit's emission spectrum, so that the reproduced representation of the virtual background can remain substantially unchanged for an observer by adapting the light source unit's emission spectrum.

[0036] In some embodiments, the first light source can be configured to emit red light, the second light source can be configured to emit green light, and the third light source can be configured to emit blue light. The light source units can thus, in particular, form respective red-green-blue (RGB) units, wherein, by additively mixing these three primary colors, a large (RGB) color space can be mapped and reproduced on the background display device or the at least one panel. In particular, such RGB units can also be provided in existing background display devices, so that such background display devices can be retrofitted, for example, by attaching correction light sources and correspondingly adapting the control devices to improve the color reproduction quality within the meaning of the present disclosure.A complete redesign of background display devices or their panels to achieve improved color reproduction quality is therefore not necessarily required.

[0037] In some embodiments, the first emission spectrum, the second emission spectrum, and the third emission spectrum may form narrowband emission spectra around a respective emission maximum.

[0038] For example, these emission maxima, at least the emission maxima of two of the three emission spectra, can be located far out in the visible light spectrum in order to be able to reproduce the largest possible color space using the light source units. In particular, the emission spectra can be generated by respective light-emitting diodes, as which the light sources can be designed and which can be suitable for emitting narrow-band emission spectra. In particular, the first emission spectrum, the second emission spectrum, and the third emission spectrum can emit approximately monochromatic light. The first emission spectrum, the second emission spectrum, and the third emission spectrum can therefore differ from an emission spectrum of natural light, in particular with regard to the color generated by the first light source, the second light source, and the third light sources.

[0039] In some embodiments, the control device can be configured to approximate the light source unit's emission spectra to a blackbody spectrum by controlling the correction light sources. In particular, the control device can thus be configured to combine the respective emission spectra of the light sources to a certain extent by mixing the first emission spectrum, the second emission spectrum, and the third emission spectrum of the light sources of a light source unit with the emission spectra of the correction light sources, thereby bridging gaps in the light source unit's emission spectrum in order to approximate the corrected emission spectrum of the light source unit to a continuous blackbody spectrum of natural light.In particular, the control device can therefore be designed to stabilize the light source unit emission spectrum by controlling the correction light sources in order, for example, to compensate for jumps between the individual maxima of the first emission spectrum, the second emission spectrum and the third emission spectrum in the light source unit emission spectrum.

[0040] Since the color space that can be generated by the background display device can, in some embodiments, extend beyond a color space that can be generated by blackbody radiation, such an approximation to a blackbody spectrum and / or the emission spectrum of natural light can thus be achieved in particular by stabilizing or broadening the light source unit emission spectrum and / or generating a more continuous corrected emission spectrum. In addition, it can be provided that the control device is designed to underlie the light source unit emission spectrum by controlling the correction light sources, a blackbody spectrum that is as close as possible to the color generated by the light source unit, so that this blackbody spectrum reflects the reflection of the light generated by the background display device ora pixel element can at least influence the light emitted by the real subject and approximate a reflection in natural lighting conditions.

[0041] In some embodiments, the control device can further be configured to approximate the light source unit emission spectra to a blackbody spectrum by controlling the correction light sources, the maximum of which corresponds to a maximum of the respective light source unit emission spectrum. Furthermore, the control device can be configured to approximate the light source unit emission spectra to a blackbody spectrum by controlling the correction light sources, the maximum of which lies at a wavelength at which the light source unit emission spectrum also reaches its maximum. In particular, if the color generated by the light source unit corresponds to a color that can be generated by blackbody radiation, the control device can thus be configured to adapt the light source unit emission spectrum to the corresponding blackbody spectrum, but without changing the color and / or brightness emitted by the pixel element.The representation of the virtual background can thus be reproduced in a substantially unchanged manner, although the color rendering quality can be improved by such an adaptation of the light source unit emission spectrum.

[0042] In some embodiments, the control device may be configured to adjust intensities and / or brightnesses of the respective first light source, second light source, and third light source to generate a light source unit emission spectrum.

[0043] In particular, the respective intensity and / or brightness of the light sources can determine a contribution of the associated first emission spectrum, second emission spectrum, and third emission spectrum to the light source unit's emission spectrum, thereby generating a color emitted by the respective pixel element in the color space defined by the light source units. In this respect, the control device can be designed, in particular, to individually define and / or adjust a respective intensity and / or brightness for the first light source, the second light source, and the third light source of a light source unit.

[0044] In some embodiments, the first control device can further be configured to adjust the light source unit's emission spectrum by adjusting an intensity and / or brightness of the correction light sources. In particular, by adjusting an intensity and / or brightness of the correction light sources, a respective contribution of an emission spectrum of a correction light source to the corrected emission spectrum of the light source unit can ultimately be determined.

[0045] In some embodiments, at least one respective correction light source can be assigned to each of the light source units. In particular, in such embodiments, the control device can be configured to individually adapt the light source unit emission spectrum of each light source unit by controlling the respective correction light source in order to approximate the light source unit emission spectrum to a predetermined or predeterminable emission spectrum. In particular, the emission spectrum emitted by the pixel element can therefore be individually adapted at each pixel element by controlling the correction light sources in order to be able to emit an emission spectrum from each pixel element that approximates the predetermined or predeterminable emission spectrum.

[0046] Furthermore, in some embodiments, each of the light source units may be assigned a plurality of correction light sources, wherein each of the plurality of correction light sources may be configured to generate a respective correction light emission spectrum. In particular, the plurality of correction light sources may be configured to generate respective correction light emission spectra that differ from one another.

[0047] By assigning a plurality of correction light sources to a respective light source unit in this way, the possibilities for influencing the light source unit's emission spectrum can be expanded. For example, it can be provided that each of the plurality of light source units is assigned at least one correction light source with an emission spectrum whose maximum is reached at a wavelength that lies between the wavelength of the maximum of the first emission spectrum and the wavelength of the maximum of the second emission spectrum. Furthermore, each light source unit can be assigned at least one correction light source that has an emission spectrum with a maximum at a wavelength between respective wavelengths at which the second emission spectrum and the third emission spectrum reach their respective maximum.By such an arrangement of correction light sources on the light source units, the light source unit emission spectrum can be influenced by appropriately controlling the correction light sources, in particular both between the first emission spectrum and the second emission spectrum or their maxima and between the second emission spectrum and the third emission spectrum or their maxima, in order to enable an approximation to the predetermined or predeterminable emission spectrum and in particular the emission spectrum of natural light and / or to stabilize the light source unit emission spectrum.

[0048] In some embodiments, the control device can be configured to determine setting instructions for controlling the correction light sources depending on the control of the light source units. For example, the control device can be configured to determine respective setting instructions for controlling the correction light sources depending on a color to be generated at a respective pixel element, which can ultimately be generated by controlling the light source units and mixing their emission spectra, in order to approximate the light source unit emission spectrum generated by the light source unit, for example, to an emission spectrum of natural light at the set color.

[0049] In some embodiments, the control device can be connected to a memory and configured to look up the setting instructions in a lookup table stored in the memory depending on the control of the light source units. For example, such a lookup table can contain information about how the correction light sources are to be controlled depending on a color value or color temperature set on the light source unit or the pixel element. Such controls can be determined, in particular, by prior calibration of the light source units and / or the correction light sources.In particular, the control of the correction light sources can be carried out quickly by such access to a lookup table in that the setting instructions for the correction light sources can be determined and retrieved directly by the image information transmitted to the control device for a respective pixel element, which can include the color and / or brightness to be reproduced at the respective pixel element for reproducing the representation of the virtual background.

[0050] In some embodiments, the control device may further be configured to determine the light source unit emission spectra as a function of the control of the respective light sources and / or the corrected emission spectrum as a function of the control of the correction light sources.

[0051] For example, the control device can be configured to determine the light source unit emission spectra as a function of the respective set intensities and / or brightnesses of the first light source, the second light source, and the third light source. In particular, the respective first emission spectra, second emission spectra, and third emission spectra can be stored in a memory connected to the control device, so that the control device can determine the contributions of their emission spectra to the light source unit emission spectrum for respective settings or controls of the individual light sources and can determine the light source unit emission spectrum by combining the individual contributions.Likewise, the control device can be configured to access the emission spectra of the correction light sources by reading a memory and to determine the correction light emission spectra as a function of the control of the correction light sources, in particular a set intensity and / or brightness. In particular, the control device can be configured to calculate the emission spectra of the light sources and / or the correction light sources.

[0052] In some embodiments, the control device may be connected to a memory in which the first emission spectrum, the second emission spectrum and the third emission spectrum and / or emission spectra of the correction light sources are stored.

[0053] For example, the respective emission spectra can be stored in the memory as histograms. Alternatively or additionally, parameters and / or calculation instructions for determining curves describing the respective emission spectrum can also be stored in the memory. In particular, one of these parameters can be a brightness and / or intensity of the respective light source or correction light source, in order to enable the respective emission spectrum to be determined depending on such a setting or control of the light source or correction light source.The control device can thus be provided with information by means of the memory which enables the determination of the light source unit emission spectrum as a mixture of the emission spectra of the light sources and / or the determination of the corrected emission spectrum with additional mixing of the emission spectra of the correction light sources to form the light source unit emission spectrum.

[0054] In some embodiments, the control device can be configured to determine the corrected emission spectrum by superimposing the emission spectra of the light sources and the correction light sources. In particular, the control device can access respective emission spectra stored in the aforementioned memory, in particular a semiconductor memory, in order to determine a contribution of a respective emission spectrum, for example based on a brightness and / or intensity of the respective light source and / or correction light source. By superimposing the individual emission spectra or contributions determined in this way, the corrected emission spectrum emitted during a specific control of the correction light sources and / or the light sources can then ultimately be determined by means of the control device.

[0055] In some embodiments, the control device can be configured to determine the setting instructions using an approximation method. In particular, the control device can be configured to compare a specific corrected emission spectrum, for example by superimposing the emission spectra of the light sources of the light source unit and the correction light sources, with the predefined or predeterminable emission spectrum and in particular the emission spectrum of natural light at a specific color, in order to increasingly approximate the (determined and / or calculated) corrected emission spectrum to the emission spectrum of natural light by adapting the control of the correction light sources. The setting instructions for controlling the correction light sources can therefore be determined in particular by those setting instructions in which the corrected emission spectrum comes closest to the predefined or predeterminable emission spectrum.In particular, the predetermined or predeterminable emission spectrum can also be stored in a memory or can be written to a memory which the control device can access. In turn, the predetermined or predeterminable emission spectrum can be stored in the memory, for example as a histogram, wherein it can also be provided that parameters of curves which describe the predetermined or predeterminable emission spectrum are stored in such a memory. One of these parameters can in particular be a specific color value which can, for example, correspond to a color reproduced by the pixel elements by controlling the first light source, second light source and third light source. However, different predetermined or predeterminable emission spectra for different color values ​​can also be stored in the memory.

[0056] In some embodiments, the control device can be configured to compare a corrected emission spectrum to be expected for respective setting instructions with the predefined or predefinable emission spectrum and to determine a deviation between the expected corrected emission spectrum and the predefined or predefinable emission spectrum. Furthermore, the control device can be configured to determine the setting instructions by minimizing the deviation. For example, the control device can be configured to determine a mean square deviation between the expected corrected emission spectrum and the predefined or predefinable emission spectrum in order to determine the setting instructions for the correction light sources by minimizing the mean square deviation. The control device can also be configured to determine the setting instructions using a chi-square test.In particular, as already mentioned, the control device can be connected to a memory in which information on the emission spectra of the light sources and / or the correction light sources as well as on the predetermined or predeterminable emission spectrum, in particular on respective emission spectra of natural light at different color values, can be stored.

[0057] In some embodiments, the background display device may have a signal input for receiving information about an illumination emission spectrum generated by a lighting device of the virtual image recording studio, in particular a spotlight. The control device may be configured to approximate the corrected emission spectrum to the illumination emission spectrum. The illumination emission spectrum may thus form the predetermined or predeterminable emission spectrum, so that the control device may be configured to match the emission spectrum of the background display device to the illumination of the virtual image recording studio.By approximating the corrected emission spectrum to the illumination emission spectrum in this way, it is possible to avoid, in particular, any color differences in an image produced by the camera of the real subject illuminated by both the background display device and the illumination device due to its spectral reflection properties.

[0058] The signal input can, for example, be configured to receive information and / or metadata from the lighting device, based on which the illumination emission spectrum can be determined or which represents the illumination emission spectrum. In particular, these can be parameters of settings of a headlight, for example, a color setting of the emitted light or a brightness setting. Furthermore, it can be provided that the signal input can be connected to a measuring device configured to determine the illumination emission spectrum.

[0059] In particular, the signal input can further be configured to continuously receive information about the illumination emission spectrum during a recording and to provide it to the control device. The control device can be configured to always control the correction light sources such that the corrected emission spectrum approximates the current illumination emission spectrum. This can, in particular, make it possible to react to a possible change in illumination during a recording and to control the correction light sources accordingly.

[0060] In some embodiments, the light source units and / or the light sources can be arranged in a regular grid, wherein the correction light sources can be arranged between several of the light source units and / or the light sources of the regular grid. Alternatively, it can also be provided that the correction light sources are arranged instead of a respective light source of the regular grid.

[0061] In particular, such an insertion of the correction light sources into the regular grid can make it possible to integrate the correction light sources into existing background display devices. For example, in a background display device, a respective light source unit can be assigned an area on the at least one panel that is not completely occupied by the first light source, the second light source, and the third light source, so that sufficient free space can still exist in an area assigned to the light source unit for attaching one or more correction light sources. Such background display devices can thus be retrofitted with such correction light sources, for example, without the need for fundamental restructuring, in order to achieve an improvement in color reproduction quality by adapting the control device accordingly.For this purpose, the correction light sources can, for example, also be designed to be smaller than the light sources. However, it can also be provided to arrange the correction light sources instead of a respective light source in the regular grid, so that, for example, after the corrective light sources have been attached, the respective light source units can be displaced compared to a conventional arrangement.

[0062] In some embodiments, the background display device can comprise a plurality of panels, wherein each of the plurality of panels can be rectangular and in particular square. Furthermore, each of the plurality of panels and in particular also the at least one panel can be borderless. The plurality of panels can also be arranged in an at least two-dimensional matrix. In particular, the background display device can thus be composed of a plurality of panels, each of which has a plurality of pixel elements. Because these panels can be borderless, it can be achieved in particular that the representation of the virtual background can be displayed without interruption, even at a transition between different panels.

[0063] The invention further relates to a background rendering system comprising a background rendering device of the type disclosed herein and comprising an illumination device, in particular a spotlight, which is configured to generate an illumination emission spectrum for illuminating the real subject in the virtual image recording studio. The background rendering device further comprises a signal input for receiving information about the illumination emission spectrum, and the control device is configured to approximate the corrected emission spectrum to the illumination emission spectrum.

[0064] With such a background rendering system, the emission spectrum generated by the background rendering device can thus be approximated to the illumination emission spectrum, so that reflections from the real subject, which can be illuminated by both the illumination device and the background rendering device, always occur in the same way. This prevents any color shifts in an image generated by a camera depending on whether the real subject is illuminated by the illumination device or the background rendering device.

[0065] In some embodiments, the signal input can be connected to a measuring device for measuring the illumination emission spectrum. Alternatively or additionally, in some embodiments, the signal input can be connected to the illumination device, and the illumination device can be configured to transmit the information about the illumination emission spectrum to the signal input. In particular, the control device can be configured to always approximate the corrected emission spectrum to a current illumination emission spectrum in order to be able to react to changing illumination during a recording.

[0066] The invention further relates to a method for recording a real subject against a virtual background in a virtual image recording studio. In this method, a representation of the virtual background is displayed on a background display device of the type disclosed herein, the real subject is placed in front of the background display device, and the real subject is recorded by a camera in front of the virtual background display. In particular, the light source unit's emission spectrum can be adjusted in the method to a corrected emission spectrum that approximates a predetermined or predeterminable emission spectrum, in particular an emission spectrum of natural light or an illumination emission spectrum of an illumination device of the virtual image recording studio.

[0067] In particular, the background reproduction device can have a width of at least 5 m and a height of at least 2 m, so that, for example, one or more actors, in particular also moving actors, can be imaged in front of the representation of the virtual background by means of an associated camera, without an image window of the camera, which determines the area imaged by the camera, extending beyond the background reproduction device. The background reproduction device can thus have a size that enables the image of the real subject, in particular one or more actors, in a virtual environment represented by the virtual background, for example a landscape or a room.

[0068] The invention is explained below purely by way of example using an embodiment with reference to the drawings.

[0069] They show: Fig. 1 is a schematic representation of a recording system for an image recording studio with a background reproduction device for reproducing a representation of a virtual background and with a camera, Fig. 2 is a schematic representation of a camera provided for recording in the image recording studio, Figs. 3A and 3B are respective schematic representations of a light source unit of the background reproduction device to illustrate its control during a reproduction of the representation of the virtual background, and Fig. 4 is a further schematic representation of a recording system for an image recording studio with a background reproduction system which comprises a background reproduction device for reproducing a representation of a virtual background and a lighting device.

[0070] Fig. 1 schematically shows a virtual image recording studio 13 in which a scene, in particular in the form of a moving image recording and / or a photograph, can be recorded using an associated camera 23. The camera 23 can, for example, be designed as a moving image camera in order to be able to take moving image recordings that can be saved as a sequence of images generated by the camera 23. For this purpose, the camera 23 has a lens 59, which can in particular be designed as an interchangeable lens that can be optionally connected to a housing of the camera 23. This means that a respective lens 59 that is optimally adapted to the environment in the image recording studio 13 can always be used in order to be able to create the best possible recordings.In the housing of the camera 23, in particular, an image sensor 1 with a plurality of light-sensitive sensor elements can be arranged, onto which light penetrating through an aperture of an aperture can be directed by means of a lens system or at least one lens to produce an image (see also . Fig. 2 ).

[0071] Furthermore, a background reproduction system 11 with a background reproduction device 15 is arranged in the image recording studio 13, which, together with the camera 23, forms a recording system 10. The background reproduction device 15 comprises an active illumination device 31, which is designed in particular as an LED wall 33, in order to reproduce a representation 19 of a virtual background 21 for recording by the camera 23. For this purpose, the illumination device 31 or the LED wall 33 has a plurality of actively luminous pixel elements 35, which are arranged next to one another in a two-dimensional arrangement and in a regular grid 55.

[0072] For example, the pixel elements 35 in such a background display device 15 can be designed as individually controllable light sources, but in particular as individually controllable light source units 45, wherein each of such a light source unit 45 can comprise several, in particular three, light sources 44a, 44b and 44c (cf. also Fig. 3A and 3B). Such a light source unit 45 can also comprise a color mixer in order to be able to adjust a respective color and / or brightness emitted by the pixel element 35 by individually controlling the light sources 44a, 44b, and 44c of the light source unit 45, as will be explained in more detail below. In particular, the light sources 44a, 44b, and 44c can be designed as LEDs or as organic light-emitting diodes (OLEDs). In principle, background display devices can also be used to display a representation of a virtual background in the image recording studio 13, which generate the representation by means of rear projection.

[0073] Furthermore, the background display device 15 comprises a plurality of panels 41, which can also be referred to as panels. A respective plurality of actively illuminated pixel elements 35 are arranged on each panel 41 of the plurality of panels 41, so that a section of the representation 19 of the virtual background 21 can be displayed on each of the panels 41. The panels 41 are in particular rectangular and / or square and borderless, so that the representation 19 of the virtual background 21 can be displayed without visible interruptions, even at the transitions between panels 41. The panels 41 are further arranged in a two-dimensional matrix to form the background display device 15. In this respect, the active illumination device 31 in the embodiment shown comprises a plurality of panels 41.

[0074] The representation 19 of the virtual background 21 here reflects, by way of example, a three-dimensional scene 43 with objects 91, 92, 93, and 94, three trees, and a path, which can be generated by appropriately controlling the pixel elements 35, in particular by appropriately adjusting their respective color and brightness. The three-dimensional scene 43 is projected onto the essentially two-dimensional arrangement of the pixel elements 35 of the illumination device 31, wherein, in particular, the objects 91, 92, and 93 appear at different distances from the illumination device 31 or the background display device 11 in order to simulate the three-dimensionality of a real background corresponding to the virtual background 21.

[0075] In particular, background reproduction device 15 is used to create a background for a recording of a real subject 17, for example an actor, in front of which a recording can be made or a film scene can be played. This means that in principle any landscapes, rooms or environments can be created in the image recording studio 13, in front of or in which a scene, for example for a cinema film, is to be shot. To make this possible, the background reproduction device 15 can in particular have a width of at least 5 meters and a height of at least 2 meters. Furthermore, it is possible to represent movements in the virtual background 21, for example a passing car, by a time-varying control of the pixel elements 35, to which movements the actor 17 can react in a simpler and improved manner compared to an act in front of a green screen. The virtual background 21 orThe representation 19 thereof can thus be directly imaged by the camera 23 during a recording in the virtual image recording studio, so that a virtual background 21 does not have to be subsequently added to the image generated by the camera 23, as in a green screen recording.

[0076] The background rendering device 15 extends essentially vertically here, so that the actor 17 can move in front of the virtual background 21. However, in order to be able to display the virtual background 21 more extensively, the background rendering device 15 can also extend around the actor 17 or above him, wherein the background rendering device 15 can in particular have a horizontal orientation above the actor 17. In order to be able to surround the actor 17 or to create a transition from the shown vertical orientation to a horizontal orientation, the background rendering device 15 or the lighting device 31 or the LED wall 33 can also be arched or curved, at least in sections.

[0077] In addition to displaying the virtual background 21, the background rendering device 15 can also serve to illuminate the real subject 17. As a result, the background rendering device 15 can, for example, support a lighting device 105, in particular a spotlight 107, which generates light with an illumination emission spectrum A to illuminate the real subject 17. Furthermore, by illuminating the real subject 17 by means of the background rendering device 15, the interaction of the real subject 17 or the actor 17 with light sources present in the virtual background 21, for example lanterns or lamps, can be improved by the real subject 17 casting a shadow that corresponds to the lighting conditions visible in an image generated by the camera 23.

[0078] In order to generate the representation 19 of the virtual background 21 and to control the pixel elements 35 for reproducing the representation, the background rendering device 15 has a control device 37 connected to a memory 39. In particular, a model of the virtual background 21 can be stored in the memory 39, so that the control device can generate the virtual background 21 based on the model. Furthermore, the control device 37 can be configured to project the virtual background 21 onto the background rendering device 15, and in particular the two-dimensional arrangement of the pixel elements 35.

[0079] A possible version of the assigned camera is shown in Fig. 2 shown schematically. The camera 23 has a camera body 53 to which a lens 59 is attached. The lens 59 can in particular be designed as an interchangeable lens, so that differently designed lenses 59 can be optionally connected to the camera body 53 and a lens 59 optimal for a particular recording can always be selected. The lens 59 has three lens rings 81, by means of which respective parameters of the lens 59 can be adjusted. For example, a focus distance, a focal length, a zoom factor and / or an aperture, in particular an opening of an iris diaphragm, can be set or adapted by rotating a respective one of the lens rings 81. The camera 23 can in particular be designed as a motion picture camera or moving image camera in order to be able to sequentially generate a sequence of images 73, which can for example be played back as a film.

[0080] To adjust the lens rings 81, a lens ring drive unit 85 is connected to the camera body 53 via a support rod 87, which has a respective lens servo motor 83 for each of the lens rings 81. These lens servo motors 83 can rotate the lens rings 81, thereby making adjustments to the lens 59. In particular, the lens ring drive unit 85 can be remotely controlled, so that the aforementioned lens parameters can be set or changed remotely.

[0081] A further display device 49 is arranged on the camera body 53, via which information about the settings of the camera 23 can be displayed to a user. The display device 49 can in particular be a display. In addition, the camera 23 has an input device 51 arranged on the camera body 53, via which the user can make settings of the camera 23. In particular, an exposure time of the camera 23 can be set on the input device 51, wherein a control device 25 connected to the input device 51 can be designed to control the camera 23 according to the entered exposure time. In particular, the display device 49 and the input device 51 can be formed by a touchscreen, via which information can be displayed to the user and user inputs can be received.

[0082] In order to create an image of the light entering through the lens 59, the camera 23 further comprises an image sensor 1 arranged within the camera body 53. This image sensor 1 can, for example, be based on CMOS technology or CCD technology and have a plurality of light-sensitive sensor elements that can be arranged in several rows and columns. The camera 23 further comprises a readout circuit 97 which is designed to read out the signals from the respective sensor elements, process them, digitize them and output them to or via a signal output 99. For this purpose, the readout circuit 97 can in particular comprise amplifiers, multiplexers, analog-to-digital converters, buffer memories and / or microcontrollers. Ultimately, an image data set B can thus be generated by the camera 23, which image data set B can be used for the image orcorresponds to an image of a field of view of the camera 23, and the image data set B can be output via the signal output 99. In order to check the field of view of the camera 23 and to be able to align the camera 23 to a respective image section, a viewfinder 79 is also arranged on the camera body 53, through which a cameraman can see.

[0083] Furthermore, the background display device 15 has an interface 103, and the camera 23 has an interface 101, via which, in particular, information I can be transmitted from the camera 23 to the background display device 15. In particular, the control device 37 of the background display device 15 can be configured to control the active illumination device 31 depending on information I received from the camera 23.

[0084] As already mentioned, each of the plurality of pixel elements 35 in the shown embodiment of the background display device 15 comprises a respective light source unit 45, wherein such a light source unit 45 is shown schematically in Fig. 3A is illustrated.

[0085] The light source unit 45 has a first light source 44a, a second light source 44b, and a third light source 44c. The first light source 44a is configured to generate a first emission spectrum E1, the second light source 44b is configured to generate a second emission spectrum E2, and the third light source 44c is configured to generate a third emission spectrum E3, wherein the emission spectra E1, E2, and E3 differ from one another. Fig. 3A the emission spectra E1, E2 and E3 are shown as examples, wherein the dependence of a brightness H or intensity of the light generated by the respective light source 44a, 44b or 44c on an emitted wavelength L is shown.

[0086] As from Fig. 3A As can be seen, the light sources 44a, 44b, and 44c are particularly designed to generate narrow-band emission spectra E1, E2, and E3. In particular, the light sources 44a, 44b, and 44c can be respective light-emitting diodes. Furthermore, the first light source 44a can be designed to emit red light, while the second light source 44b can be designed to emit green light. The third light source 44c can be designed, in particular, to emit blue light. In this respect, the light source unit 45 can be designed, in particular, as a so-called red-green-blue (RGB) unit.

[0087] Since the light source unit 45 has the three light sources 44a, 44b and 44c with mutually differing emission spectra E1, E2 and E3, the control device 37 can be designed to generate a light source unit emission spectrum S by mixing M the emission spectra E1, E2 and E3. For this purpose, the light sources 44a, 44b and 44c can be individually controlled, in particular by means of the control device 37, in order to set a respective brightness H and / or intensity of the light sources 44a, 44b and 44c and thereby determine a respective contribution of the first emission spectrum E1, the second emission spectrum E2 and the third emission spectrum E3 to the light source unit emission spectrum S.

[0088] In particular, the first light source 44a and the third light source 44c can further be configured to generate light in a respective end range of the visible light spectrum. For example, the first light source 44a can be configured to emit red light in an end range of the visible light, and the third light source 44c can be configured to emit blue light in an end range of the visible light. In particular, the wavelengths L at which the emission spectra E1 and E2 reach their respective maximum can lie in such an end range. Such emission of light in end ranges of the visible light can, in particular, make it possible to emit light in a large (RGB) color space by means of the light source unit 45.In particular, a large color space can thus be available at each pixel element 35 of the background display device 15, and almost any color that exists in the representation 19 of the virtual background 21 at a pixel assigned to the respective pixel element 35 can be displayed.

[0089] However, as can be seen from the lower part of the Fig. 3A As can be seen, the light source unit emission spectrum S composed of the narrowband emission spectra E1, E2 and E3 differs from an emission spectrum N of natural light, which in particular is continuous, whereas the light source unit emission spectrum S composed of the emission spectra E1, E2 and E3 has gaps and / or dips between the respective emission spectra E1, E2 and E3 and abrupt transitions between the respective portions of the emission spectra E1, E2 and E3 of the light sources 44a, 44b and 44c. In particular, the emission spectrum N of natural light, on the other hand, can be described by a blackbody spectrum P.

[0090] However, this difference between the light source unit emission spectrum S and the emission spectrum N of natural light can lead to the light emitted by the light unit 45 from a real subject 17 located in front of or below the background reproduction device 15 being emitted differently, depending on any spectral reflection properties of the real subject 17, than would be the case under natural lighting conditions in a real background corresponding to the virtual background 21, for example a landscape. In particular, this can also lead to the colors of the real subject 17, such as an actor's clothing, appearing differently in the image generated by the camera 23 than when natural light is reflected from the real subject 17. The correspondingly poor color reproduction quality of such a background reproduction device 15 ora light element unit 45 may therefore require post-processing, possibly carried out in sections, in the image generated by the camera 23 in order to correct such an unnatural impression of the images generated in the virtual image recording studio 13. Furthermore, for certain recordings, it may be provided that the real subject 17 in the virtual image recording studio 13 is illuminated not only by the background reproduction device 15 but also by spotlights, which, however, may have an emission spectrum optimized for the illumination with high color reproduction quality, which may, in particular, be modeled on natural light. In such mixed light situations, the light reflection from the real subject 17 may, in particular, even vary in sections depending on whether the respective section is primarily illuminated by the background reproduction device 15 or the spotlight.However, such partial effects in the image produced by the camera 23 often cannot be corrected with reasonable effort during post-processing and / or post-production.

[0091] To address this problem, the Fig. 3B The illustrated light source unit 45 is assigned, by way of example, two correction light sources 46, wherein the correction light sources 46 are designed to emit a respective correction light emission spectrum K1 and K2, respectively. In the illustrated embodiment, the correction light emission spectra K1 and K2 differ both from each other and from the emission spectra E1, E2, and E3 of the light sources 44a, 44b, and 44c.

[0092] The additional arrangement of correction light sources 46 enables the control device 37, by controlling these correction light sources 46, to adapt the light element unit emission spectrum S to a corrected emission spectrum S1, which approximates a predetermined or predeterminable emission spectrum N and in particular the emission spectrum N of natural light and / or the blackbody spectrum P. In particular, the correction light emission spectrum K1 can emit light with wavelengths L between the second emission spectrum E2 and the third emission spectrum E3, while the second correction light emission spectrum K2 can be arranged, with regard to the emitted wavelengths L, between the first emission spectrum E1 and the second emission spectrum E2 of the light sources 44a and 44b.

[0093] The correction light sources 46 can also be designed, in particular, as light-emitting diodes and emit correspondingly narrow-band correction light emission spectra K1 and K2. However, the corrected emission spectrum S1 can be at least stabilized compared to the light element unit emission spectrum S by controlling the correction light sources 46, wherein, in particular, an intensity and / or brightness H of the correction light sources 46 can again be adjusted, and thus approximated to the emission spectrum N of natural light. In particular, the strong increase in the emission spectrum N of natural light at short wavelengths L and the slow decline towards long wavelengths L can be simulated in the corrected emission spectrum S1 by appropriately controlling the correction light sources 46.

[0094] In addition, the control device 37 is designed to control the correction light sources 46 such that a wavelength L of a maximum T of the corrected emission spectrum S1 corresponds to a wavelength L of a maximum T of the light element unit emission spectrum S. The control unit 37 can thus be designed to approximate the corrected emission spectrum S1 to the emission spectrum N of natural light, but without noticeably changing the color set on the light source unit 45. In particular, this also allows the large color space that can be generated by the light source unit 45 to be retained, although by stabilizing the light element unit emission spectrum S to approximate the emission spectrum N of natural light, the color rendering quality of the background reproduction device can be increased.

[0095] Furthermore, the control device 37 can also be designed to control the correction light sources 46 such that the maximum T of the corrected emission spectrum S1 corresponds to the maximum T of the light element unit emission spectrum S. The brightness H of the light element unit emission spectrum S can thus also remain substantially unchanged by the adaptation, so that the representation 19 can be reproduced substantially unchanged on the background display device 15 despite the adaptation of the light element unit emission spectra S.

[0096] To enable appropriate control of the correction light sources 46, setting instructions E for controlling the correction light sources 46 depending on the control of the light sources 44a, 44b, and 44c can be stored in a lookup table in the memory 39. For example, a respective setting instruction E for controlling the correction light sources 46 can be stored in such a lookup table for a specific color or color value set on the light element unit 45 in order to approximate the light element unit's emission spectrum S to the emission spectrum N of natural light by appropriately controlling the correction light sources 46.

[0097] However, parameters and / or calculation instructions can also be stored in the memory 39, wherein the control device 37 can be configured to calculate the light source unit emission spectrum S and / or the corrected emission spectrum S1 based on the calculation instructions and / or parameters. Furthermore, for example, the emission spectra E1, E2, E3 and / or the correction light emission spectra K1 and K2 can be stored in the memory 39, wherein the control device 37 can be configured to determine the light element unit emission spectrum S and / or the corrected emission spectrum S1 depending on the respective control of the light sources 44a, 44b and 44c and / or the correction light sources 46.

[0098] In addition, the control device 37 can be configured, for example, to determine the corrected emission spectrum S1 using an approximation method, in particular by determining respective expected corrected emission spectra S1 for specific activations of the correction light sources 46 and determining a deviation from the emission spectrum N of natural light. The respective required adjustment instructions E for the correction light sources 46 can then be determined as those adjustment instructions E for which the deviation between the corrected emission spectrum S1 and the emission spectrum N of natural light is minimized.

[0099] In particular, it can be provided that at least one respective correction light source 46 is assigned to each pixel element 35 and / or each light source unit 45 of the background display device 15. Furthermore, it can be provided that one or each light source unit 45 is assigned, in particular, a plurality of correction light sources 46, in particular two or more than two correction light sources, in order, for example, to further enhance the stabilization of the corrected emission spectrum S1 and its approximation to the emission spectrum N of natural light. However, it can also be provided that only some pixel elements 35 or light source units 45 are assigned one or more correction light sources 46.

[0100] Furthermore, Fig. 3B It can be seen that the correction light sources 46 can be inserted into the regular grid 55 formed by the pixel elements 35. In this respect, existing background display devices 15 can, for example, be retrofitted by attaching such correction light sources 46 and correspondingly adapting a control device 37 in order to achieve improved color reproduction quality. To facilitate such insertion, the correction light sources 46 are designed, in particular, to be smaller than the light sources 44a, 44b, and 44c. A complete restructuring of the background display device 15 and / or the panels 41 is therefore not necessarily required.

[0101] As an alternative to an approximation of the corrected emission spectrum S1 to a, in particular given, emission spectrum N of natural light, it is possible to Fig. 4 In the embodiment shown, it is provided that the control device 37 is designed to approximate the corrected emission spectrum S1 to the illumination emission spectrum A generated by the illumination device 105. For this purpose, the background reproduction device 15 has a signal input 111 connected to the illumination device 105, so that the background reproduction device 15 forms a background reproduction system 109 with the illumination device 105. The signal input 111 is designed to receive information I about the illumination emission spectrum A from the illumination device 105 and to transmit it to the control device 37, wherein the information I can, for example, comprise metadata describing the illumination emission spectrum A.Based on this information I, which may also include the illumination emission spectrum A itself, for example as a histogram, the control device 37 can then determine the control of the correction light sources 46 in order to approximate the corrected emission spectrum S1 to the illumination emission spectrum A that can be predetermined by the illumination device 105.

[0102] In particular, by such an approximation of the corrected emission spectrum S1 to the illumination emission spectrum A, it can be achieved that the light of the background display device 15 and the illumination device 105 used to illuminate the real subject 17 in the virtual image recording studio 13 has approximately identical spectral properties. Spectral shifts of the light reflected by the real subject 17, depending on whether the real subject 17 is illuminated by the background display device 15 or the illumination device 105, can thus be avoided.

[0103] The control device 37 can also be designed to approximate or track the corrected emission spectrum S1 to an illumination emission spectrum A that changes during a recording, for which purpose corresponding information I about the illumination emission spectrum A can be provided during the recording. Furthermore, in the embodiment shown, the signal input 111 is connected to a measuring device 115, for example a spectrometer, which is designed to determine the illumination emission spectrum A and to transmit corresponding information I to the signal input 111, so that the control device 37 can also make the required adjustment based on this information I or solely on this information I.

[0104] In principle, the illumination device 105 can also be designed to generate light with the highest possible color rendering index and, in this respect, an illumination emission spectrum A that approximates the emission spectrum N of natural light, so that, in order to simulate the illumination emission spectrum A, in particular the measures explained above for simulating the emission spectrum N of natural light, in particular a stabilization of the light source unit emission spectrum S, can be carried out. Bezugszeichenliste

[0105] 1Image sensor 10Recording system 11Background playback system 13Image recording studio 15Background playback device 17Real subject, actor 19Representation 21Virtual background 23Camera 25Control device 31Lighting device 33LED wall 35Pixel element 37Control device 39Storage 41Panel 43Three-dimensional scene 44aFirst light source 44aSecond light source 44aThird light source 45Light source unit 46Correction light source 49Playback device 51Input device 53Camera body 55Grid 59Camera lens,Interchangeable lens 79 Viewfinder 81 Lens ring 83 Lens servo motor 85 Lens ring drive unit 87 Support rod 91 First object 92 Second object 93 Third object 94 Fourth object 97 Readout circuit 99 Signal output 101 Interface 103 Interface 105 Illumination device 107 Spotlight 109 Background reproduction system 111 Signal input 113 Background reproduction system 115 Measuring device A Illumination emission spectrum B Image data set E1 First emission spectrum E2 Second emission spectrum E3 Third emission spectrum H Brightness I Information L Wavelength K1, K2 Correction light emission spectrum MMixing NE Natural light emission spectrum P Blackbody spectrum S Light source unit emission spectrum S1 Corrected emission spectrum T Maximum,

Claims

1. A background display device (15) for a virtual image recording studio (13) that is configured to display, behind or above a real subject (17), a representation (19) of a virtual background (21) for a recording by an associated camera (23), wherein the background display device (15) has at least one panel (41) having a plurality of picture elements (35) in an at least two-dimensional arrangement, wherein each of the plurality of picture elements (35) has a respective light source unit (45) which comprises a first light source (44a) for generating a first emission spectrum (E1), a second light source (44b) for generating a second emission spectrum (E2), and a third light source (44c) for generating a third emission spectrum (E3), wherein the background display device (15) has a control device (37) which is configured to individually control the light sources (44a, 44b, 44c) of the light source units (45) and to generate a respective light source unit emission spectrum (S) by mixing (M) the respective first emission spectra (E1), second emission spectra (E2), and third emission spectra (E3), characterized in that the panel (41) furthermore has a plurality of correction light sources (46), wherein the control device (37) is configured to adapt the respective light source unit emission spectrum (S) to a corrected emission spectrum (S1), which is approximated to a predefined or predefinable emission spectrum (N), by controlling the correction light sources (46).

2. A background display device (15) according to claim 1, wherein the background display device (15) is configured as an LED wall (33), wherein the picture elements (35) are configured as light-emitting diode units and the light sources (44a, 44b, 44c) and / or the correction light sources (46) are configured as light-emitting diodes; and / or wherein the background display device (15) is arched; and / or wherein the background display device (15) comprises a plurality of panels (41), wherein each of the plurality of panels (41) is formed as rectangular and without margins, and wherein the plurality of panels (41) are arranged in an at least two-dimensional matrix; and / or wherein the background display device (15) extends over a width of at least 5 m and a height of at least 2 m; and / or wherein the virtual background represents a three-dimensional scene (43).

3. A background display device (15) according to one of the preceding claims, wherein the control device (37) is configured to adapt the light source unit emission spectrum (S) such that a maximum (T) of the corrected emission spectrum (S1) corresponds to a maximum (T) of the light source unit emission spectrum (S) and / or such that a wavelength (L) associated with a maximum (T) of the corrected emission spectrum (S1) corresponds to a wavelength (L) associated with a maximum (T) of the light source unit emission spectrum (S).

4. A background display device (15) according to any one of the preceding claims, wherein the first light source (44a) is configured to emit red light, wherein the second light source (44b) is configured to emit green light, and wherein the third light source (44c) is configured to emit blue light; and / or wherein the first emission spectrum (E1), the second emission spectrum (E2), and the third emission spectrum (E3) form narrow-band emission spectra around a respective emission maximum; and / or wherein each of the light source units (45) is associated with at least one respective correction light source (46).

5. A background display device (15) according to any one of the preceding claims, wherein the control device (37) is configured to approximate the light source unit emission spectra (S) to a blackbody spectrum (P) by controlling the correction light sources (46).

6. A background display device (15) according to any one of the preceding claims, wherein the control device (37) is configured to adapt intensities and / or brightnesses (H) of the respective first light source (44a), second light source (44b), and third light source (44c) in order to generate a light source unit emission spectrum (S); and / or wherein the first control device (37) is configured to adapt the light source unit emission spectra by adapting an intensity and / or a brightness (H) of the correction light sources (46).

7. A background display device (15) according to any one of the preceding claims, wherein the control device (37) is configured to determine setting instructions (E) for the control of the correction light sources (46) in dependence on the control of the light source units (45).

8. A background display device (15) according to claim 7, wherein the control device (37) is connected to a memory (39) and is configured to look up the setting instructions (E) in a look-up table stored in the memory (39) in dependence on the control of the light source units (45); and / or wherein the control device (37) is configured to determine the light source unit emission spectra (S) in dependence on the control of the respective light sources (44a, 44b, 44c) and / or to determine the corrected emission spectrum (S1) in dependence on the control of the correction light sources (46); and / or wherein the control device (37) is connected to a memory (39) in which the first emission spectrum (E1), the second emission spectrum (E2), and the third emission spectrum (E3) and / or at least one emission spectrum (K1, K2) of the correction light sources (46) are / is stored.

9. A background display device (15) according to claim 7 or 8, wherein the control device (37) is configured to determine the corrected emission spectrum (S1) by superposing the emission spectra (E1, E2, E3) of the light sources (44a, 44b, 44c) and the correction light sources (46).

10. A background display device (15) according to any one of the claims 7 to 9, wherein the control device (37) is configured to determine the setting instructions (E) by an approximation method; wherein the control device (37) is preferably configured to compare a corrected emission spectrum (S1) to be expected in the case of respective setting instructions (E) with the predefined or predefinable emission spectrum (N) and to determine a deviation between the corrected emission spectrum (S1) to be expected and the predefined or predefinable emission spectrum (N), and wherein the control device (37) is configured to determine the setting instructions (E) by minimizing the deviation.

11. A background display device (15) according to any one of the preceding claims, wherein the background display device (15) has a signal input (111) for receiving information (I) about an illumination emission spectrum (A) generated by an illumination apparatus (105) of the virtual image recording studio (13), in particular a spotlight (107), wherein the control device (37) is configured to approximate the corrected emission spectrum (S1) to the illumination emission spectrum (A).

12. A background display device (15) according to any one of the preceding claims, wherein the light source units (45) and / or the light sources (44a, 44b, 44c) are arranged in a regular grid (55), wherein the correction light sources (46) are arranged between a plurality of the light source units (45) and / or light sources (44a, 44b, 44c) of the regular grid, or wherein the correction light sources (46) are arranged in place of a respective light source (44a, 44b, 44c) of the regular grid (55).

13. A background display system (113) comprising a background display device (15) according to any one of the preceding claims and an illumination apparatus (105), in particular a spotlight (107), which is configured to generate an illumination emission spectrum (A) for illuminating the real subject (17) in the virtual image recording studio (13), wherein the background display device (15) has a signal input (111) for receiving information (I) about the illumination emission spectrum (A), and wherein the control device (37) is configured to approximate the corrected emission spectrum (S1) to the illumination emission spectrum (A).

14. A background display system according to claim 13, wherein the signal input (111) is connected to a measurement device (115) for measuring the illumination emission spectrum (A); or wherein the signal input (111) is connected to the illumination apparatus (105) and the illumination apparatus (105) is configured to transmit the information (I) about the illumination emission spectrum (A) to the signal input (111).

15. A method of recording a real subject (17) in front of a virtual background in a virtual image recording studio (13), comprising the steps: - displaying a representation (19) of the virtual background (21) at a background display device (15) according to any one of the claims 1 to 12; - placing the real subject (17) in front of the background display device (15); and - recording the real subject (17) in front of the representation (19) of the virtual background (21) by a camera (23).