Settings yielding different spectra and similar color

Abstract

Disclosed herein are methods for controlling light fixtures comprising unique color light sources with independently controllable luminous flux, comprising controlling a luminous flux of each of the light sources, wherein a spectral distribution of light emitted from the light sources upon being controlled according to settings within a plurality of setting is different between settings, and a color of light emitted from the light sources is similar or identical between settings. The methods may improve color rendering where a certain color of emitted light is required, e.g., where a certain prop or costume is better illuminated with one setting compared to another setting, drawing attention to certain objects in a scene, e.g., by choosing a setting which makes a certain object stand out, and/or providing an intriguing optical effect, e.g., by shifting between settings, which makes certain objects appear to change color while others appear to keep same color.

Claims

1. A method for controlling a light fixture, wherein the light fixture comprises a plurality of light sources including three or more light sources, wherein each of the light sources has a unique color, and wherein a luminous flux of each of the light sources is independently controllable, the method comprising: obtaining a plurality of settings, each of the settings being indicative of a luminous flux of each of the light sources; and controlling a luminous flux of each of the light sources according to one or more of the settings, wherein a spectral distribution of light emitted from the plurality of light sources upon being controlled according to one setting within the plurality of settings is different with respect to a spectral distribution of light emitted from the plurality of light sources upon being controlled according to another setting within the plurality of settings; wherein a color of light emitted from the plurality of light sources upon being controlled according to one setting within the plurality of settings is identical to a color of light emitted from the plurality of light sources upon being controlled according to another setting within the plurality of settings; and wherein each setting within the plurality of settings corresponds to a superposition of a plurality of basis settings, wherein each basis setting is indicative of a luminous flux of each light source within a different strict subset of light sources of the plurality of light sources.

2. The method of claim 1, wherein the plurality of light sources comprises four or more light sources; and wherein the four or more light sources comprise at least three light sources for which none of the three light sources has a color which can be provided as a linear combination of the two other light sources of the three light sources.

3. The method of claim 1, wherein the controlling of the luminous flux of each of the light sources comprises switching one or more times between controlling the luminous flux of each of the light sources according to different settings within the plurality of settings.

4. The method of claim 3, wherein the switching between controlling the luminous flux of each of the light sources according to the different settings is at a predetermined frequency that is greater than or equal a frequency selected from a group consisting of: 0.1 hertz (Hz), 1 Hz, and 10 Hz.

5. The method of claim 3, wherein the switching is carried out multiple times, back and forth between the same settings, and is at a predetermined period that is less than or equal to a period selected from a group consisting of: 10 seconds; 1 second; and 0.1 second.

6. The method of claim 1, wherein the controlling of the luminous flux of each of the light sources is according to at least a first setting and a second setting for which the difference in spectral distribution of light emitted from the plurality of light sources upon being controlled according to the first setting and the second setting is maximized for the color.

7. The method of claim 6, wherein a luminous flux of light emitted from the plurality of light sources upon being controlled according to the first setting is similar to a luminous flux of light emitted from the plurality of light sources upon being controlled according to the second setting.

8. The method of claim 7, wherein the controlling of the luminous flux of each of the light sources is according to at least: a third setting for which a spectral distribution of light emitted from the plurality of light sources upon being controlled according to the third setting is similar to a spectral distribution of light emitted from the plurality of light sources upon being controlled according to the first setting; and a fourth setting for which a spectral distribution of light emitted from the plurality of light sources upon being controlled according to the fourth setting is similar to a spectral distribution of light emitted from the plurality of light sources upon being controlled according to the second setting, wherein a luminous flux of light emitted from the plurality of light sources upon being controlled according to the third setting is identical or similar to a luminous flux of light emitted from the plurality of light sources upon being controlled according to the fourth setting; and wherein a luminous flux of light emitted from the plurality of light sources upon wherein a luminous flux of light emitted from the plurality of light sources upon being controlled according to one or more of the third setting and the fourth setting is different with respect to a luminous flux of light emitted from the plurality of light sources upon being controlled according to one or more of the first setting and the second setting.

9. The method of claim 1, further comprising: quantifying a difference between spectral distributions of light emitted from the plurality of light sources according to two different settings by identifying a set of reference samples, identifying a reference light source, and selecting between employing a single reference sample or a plurality of reference samples; wherein, when the single reference sample is selected, the method further comprises: calculating two reflection spectra based on reflection from said reference sample of light emitted from the plurality of light sources according to the two different settings; calculating colors of the two reflection spectra; and quantifying the difference between spectral distribution of light emitted from the plurality of light sources according to the two different settings as the distance between the colors of the two reflection spectra, and wherein, when the plurality of reference samples is selected, the method further comprises: calculating for each reference sample within the plurality of reference samples, two reflection spectra based on reflection from said reference sample of light emitted from the plurality of light sources according to the two different settings, calculating colors of the provided reflection spectra, quantifying the difference between spectral distribution of light emitted from the plurality of light sources according to the two different settings as an average or weighted-average distance between the colors of the reflection spectra for the two reflection spectra for each reference sample.

10. The method of claim 9, wherein the identified set of reference samples comprises reference samples of the Color Quality Scale; wherein the identified reference light source is CIE Standard Illuminant D65; and wherein the average or weighted-average distance between the colors of the reflection spectra for the two reflection spectra is an average or weighted-average CIEDE2000 distance.

11. The method of claim 9, wherein the selection between employing the single reference sample or the plurality of reference samples is based upon whether a color of light emitted from the plurality of light sources upon being controlled according to the two different settings is not similar to a color of a reference sample when illuminated by the reference light source.

12. The method of claim 1, wherein each setting within the plurality of settings corresponds to a setting selected from a group consisting of: a basis setting, and the superposition of the plurality of basis settings.

13. The method of claim 12, wherein each setting in the plurality of settings is similar to a basis setting.

14. The method of claim 12, wherein at least a first setting within the plurality of settings is similar to a basis setting, and wherein the remaining settings are arranged so that a luminous flux of light emitted from the plurality of light sources upon being controlled according to the first setting is identical or similar to a luminous flux of light emitted from the plurality of light sources upon being controlled according to any one of the remaining settings.

15. The method of claim 14, wherein at least a second setting within the plurality of settings is similar to a basis setting, and wherein at least a third setting is similar to a basis setting, and wherein the second basis setting and the third basis setting are arranged so that a luminous flux of light emitted from the plurality of light sources upon being controlled according to the second setting is identical or similar to a luminous flux of light emitted from the plurality of light sources upon being controlled according to the third basis setting.

16. The method of claim 12, wherein the plurality of settings are arranged so that a luminous flux of light emitted from the plurality of light sources upon being controlled according to any setting is identical or similar to a reference luminous flux value.

17. The method of claim 12, wherein the plurality of settings are arranged so as to each differ from any one basis setting, and wherein the plurality of settings are arranged so that a luminous flux of light emitted from the plurality of light sources upon being controlled according to any setting is identical or similar to a reference luminous flux value.

18. A control device for controlling a plurality of light sources comprising three or more light sources, wherein each of the light sources within the plurality of light sources has a unique color; wherein a luminous flux of each of the light sources is independently controllable; wherein the control device is operable to control a luminous flux of each of the light sources according to one or more settings within a plurality of settings; wherein a spectral distribution of light emitted from the plurality of light sources upon being controlled according to one setting within the plurality of settings is different with respect to a spectral distribution of light emitted from the plurality of light sources upon being controlled according to another setting within the plurality of settings; wherein a color of light emitted from the plurality of light sources upon being controlled according to one setting within the plurality of settings is similar to a color of light emitted from the plurality of light sources upon being controlled according to another setting within the plurality of settings; and wherein each setting within the plurality of settings corresponds to a superposition of a plurality of basis settings, wherein each basis setting is indicative of the luminous flux of each light source within a different strict subset of light sources of the plurality of light sources.

19. A light fixture system comprising: the control device of claim 18; and a light fixture comprising a plurality of light sources including three or more light sources, wherein each of the light sources within the plurality of light sources has a unique color, and wherein a luminous flux of each of the light sources is independently controllable.

20. A light fixture system according to claim 19, further comprising: a storage unit operationally connected to the control device and comprising information corresponding to the plurality of settings.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Various embodiments will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the embodiments and are not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

(2) FIG. 1 shows a flow-chart of a method, in accordance with some embodiments of the disclosure.

(3) FIG. 2 illustrates a structural diagram of an illumination device, in accordance with some embodiments of the disclosure.

(4) FIG. 3 illustrates a structural diagram of a moving head light fixture, in accordance with some embodiments of the disclosure.

(5) FIG. 4 shows a CIE 1931 color space 400 with coordinates of four light sources, in accordance with some embodiments of the disclosure.

(6) FIG. 5 shows a graph 500 with possible selected preferences for weighting to achieve two or more settings, in accordance with some embodiments of the disclosure.

(7) FIGS. 6-7 show an illustration of an embodiment in the context of illumination of a scene, in accordance with some embodiments of the disclosure.

DETAILED DESCRIPTION

(8) FIG. 1 shows a flow-chart of a method 100 for controlling a light fixture, wherein the light fixture comprises: a plurality of light sources comprising three or more light sources, wherein each of the light sources within the plurality of light sources has a unique color, wherein a luminous flux of each of the light sources is independently controllable, and wherein the method comprises: obtaining 102 a plurality of settings where each setting within the plurality of settings is indicative of a luminous flux of each of the light sources within the plurality of light sources, and controlling 104 a luminous flux of each of the light sources within the plurality of light sources according to one or more settings within the plurality of settings, which in the present figure is “setting 1,” wherein: a spectral distribution of light emitted from the plurality of light sources upon being controlled according to one setting (such as “setting 1”) within the plurality of setting is different with respect to a spectral distribution of light emitted from the plurality of light sources upon being controlled according to another setting (such as “setting 2”) within the plurality of settings, and a color of light emitted from the plurality of light sources upon being controlled according to one setting (such as “setting 1”) within the plurality of settings is similar or identical to a color of light emitted from the plurality of light sources upon being controlled according to another setting (such as “setting 2”) within the plurality of settings.

(9) The flow-chart furthermore shows additional, subsequent steps of: controlling 106 a luminous flux of each of the light sources within the plurality of light sources according to another setting, which in the present figure is “setting 2” which is different from “setting 1,” within the plurality of settings, and subsequently controlling 108 a luminous flux of each of the light sources within the plurality of light sources according to another setting, which in the present figure is “setting 1” which is different from “setting 1,” within the plurality of settings,

(10) The flow-chart thus depicts controlling a luminous flux of each of the light sources within the plurality of light sources according to a first setting and/or a second setting, which comprises switching multiple times between controlling the luminous flux of each of the light sources within the plurality of light sources according to different settings within the plurality of settings.

(11) FIG. 2 illustrates a structural diagram of an illumination device 200 (wherein “illumination device” and “light fixture” may be understood interchangeably throughout the present application). The illumination device comprises a cooling module 201 comprising a plurality of LEDs 103 (which may in various embodiments be other light sources), a light collector 241, an optical gate 242 and an optical projecting and zoom system 243. The cooling module is arranged in the bottom part of a lamp housing 248 of the illumination device and the other components are arranged inside the lamp housing 248. The lamp housing 248 can be provided with a number of openings 250. The light collector 241 is adapted to collect light from the LEDs 103 and to convert the collected light into a plurality of light beams 245 (dotted lines) propagating along an optical axis 247 (dash-dotted line). The light collector can be embodied as any optical means capable of collecting at least a part of the light emitted by the LEDs and convert the collected light to a light beams. In the illustrated embodiment the light collector comprises a number of lenslets each collecting light from one of the LEDs and converting the light into a corresponding light beam. However it is noticed that the light collector also can be embodied a single optical lens, a Fresnel lens, a number of TIR lenses (total reflection lenses), a number of light rods or combinations thereof. It is understood that light beams propagating along the optical axis contain rays of light propagating at an angle, e.g. an angle less than 45 degrees to the optical axis. The light collector may be configured to fill the optical gate 242 with light from the LEDs 103 so that the area, i.e. the aperture, of the gate 242 is illuminated with a uniform intensity or optimized for max output. The gate 242 is arranged along the optical axis 247. The optical projecting system 243 may be configured to collect at least a part of the light beams transmitted through the gate 242 and to image the optical gate at a distance along the optical axis. For example, the optical projecting system 243 may be configured to image the gate 242 onto some object such as a screen, e.g. a screen on a concert stage. A certain image, e.g. some opaque pattern provided on a transparent window, an open pattern in a non-transparent material, or imaging object such as GOBOs known in the field of entertainment lighting, may be contained within the gate 242 so that that the illuminated image can be imaged by the optical projecting system. Accordingly, the illumination device 200 may be used for entertainment lighting. In the illustrated embodiment the light is directed along the optical axis 247 by the light collector 241 and passes through a number of light effects before exiting the illumination device through a front lens 243a. The light effects can for instance be any light effects known in the art of intelligent/entertainments lighting for instance, a CMY subtractive color mixing system 251, color filters 253, gobos 255, animation effects 257, iris effects 259, a focus lens group 243c, zoom lens group 243b, prism effect 261, framing effects (not shown), or any other light effects known in the art. The mentioned light effects only serves to illustrate the principles of an illuminating device for entertainment lighting and the person skilled in the art of entertainment lighting will be able to construct other variations with additional are less light effects. Further it is noticed that the order and positions of the light effects can be changed.

(12) FIG. 3 illustrates a structural diagram of a moving head light fixture 302 comprising a head 200 rotatable connected to a yoke 363 where the yoke is rotatable connected to a base 365. The head is substantially identical to the illumination device shown in FIG. 2 and substantial identical features are labeled with the same reference numbers as in FIG. 2 and will not be described further. The moving head light fixture comprises pan rotating means for rotating the yoke in relation to the base, for instance by rotating a pan shaft 367 connected to the yoke and arranged in a bearing (not shown) in the base). A pan motor 369 is connected to the shaft 367 through a pan belt 371 and is configured to rotate the shaft and yoke in relation to the base through the pan belt. The moving head light fixture comprises tilt rotating means for rotating the head in relation to the yoke, for instance by rotating a tilt shaft 373 connected to the head and arranged in a bearing (not shown) in the yoke). A tilt motor 375 is connected to the tilt shaft 373 through a tilt belt 377 and is configured to rotate the shaft and head in relation to the yoke through the tilt belt. The skilled person will realize that the pan and tilt rotation means can be constructed in many different ways using mechanical components such as motors, shafts, gears, cables, chains, transmission systems, bearings etc. Alternatively it is noticed that it also is possible to arrange the pan motor in the base and/or arrange the tilt motor in the head. A space 379 between the yoke and the bottom part of the head is limited as the moving head light fixture is designed to be as small as possible. As known in the prior art the moving head light fixture receives electrical power 381 from an external power supply (not shown). The electrical power is received by an internal power supply 383 which adapts and distributes electrical power through internal power lines (not shown) to the subsystems of the moving head. The internal power system can be constructed in many different ways for instance by connecting all subsystems to the same power line. The skilled person will however realize that some of the subsystems in the moving head need different kind of power and that a ground line also can be used. The light source will for instance in most applications need a different kind of power than step motors and driver circuits. The light fixture comprises also a controller 385 (where “controller” throughout the present text is used interchangeably with “control device”) which controls the components (other subsystems) in the light fixture based on an input signal 387 indicative light effect parameters, position parameters and other parameters related to the moving head lighting fixture. The controller receives the input signal from a light controller (not shown) as known in the art of intelligent and entertainment lighting for instance by using a standard protocol like DMX, ArtNET, RDM etc. Typically the light effect parameter is indicative of at least one light effect parameter related to the different light effects in the light system. The controller 385 is adapted to send commands and instructions to the different subsystems of the moving head through internal communication lines (not shown). The internal communication system can be based on a various type of communications networks/systems. The moving head can also comprise user input means enabling a user to interact directly with the moving head instead of using a light controller to communicate with the moving head. The user input means 389 can for instance be bottoms, joysticks, touch pads, keyboard, mouse etc. The user input means can also be supported by a display 391 enabling the user to interact with the moving head through a menu system shown on the display using the user input means. The display device and user input means can in some embodiments also be integrated as a touch screen.

(13) FIG. 4 shows a CIE 1931 color space 400 with coordinates of four light sources, wherein each of the light sources within the four light sources has a unique color, wherein a luminous flux of each of the light sources is independently controllable. The four unique colors are red (as indicated by pentagon 402), green (as indicated by triangle 404), blue (as indicated by circle 406) and white (as indicated by diamond 408), where the white light source may have a substantially continuous spectrum. Coordinates of a desired color are indicated with star 410. The four light sources comprises two sets of light sources for which a convex hull encompasses the coordinates of the desired color. The gamut of all color points that a light fixture with a plurality of independently controllable, differently colored light sources can generate is encompassed by the convex hull of all the color points of these light sources. The desired color point can be generated by a combinations of all combinations of, e.g., three light sources which encompasses the target point. For example, the desired color can be produced as a combination of the red, green and blue light sources, as indicated by the larger triangle with dotted sides. As another example, the desired color can be produced as a combination of the white, green and blue light sources, as indicated by the smaller triangle with dashed sides. While the desired color can thus be produced in two different ways, the resulting spectra will not be identical (for example, in the first instance, the spectrum may comprise red, green and blue peaks while in the second instance the spectrum may be substantially continuous and have blue and green peaks).

(14) A color of a light source may be described by tristimulus levels X, Y, Z, according to CIE 1931 color matching functions where Y is the luminous flux, and a scalar control value d which is a value in the range [0; 1] where 1 means that a light source is fully on and 0 for fully off. A resulting color R.sub.abc of a superposition of three light sources denoted “a,” “b,” “c” (with RGB color levels of light source “a” being X.sub.a, Y.sub.a, Z.sub.a, and luminous flux da and anologosly for light sources “b” and “c”) may be given as a matrix product (with matrices being indicated with two lines above a symbol and vectors indicated with one arrow above a symbol):

(15) ${\stackrel{.fwdarw.}{R}}_{abc}=\left[\begin{array}{ccc}{X}_a& X_b& X_c\\ Y_a& Y_b& Y_c\\ Z_a& Z_b& Z_c\end{array}\right].\left[\begin{array}{c}{d}_a\\ d_b\\ d_c\end{array}\right]={\stackrel{\_}{\stackrel{\_}{C}}}_{abc}.Math.{\stackrel{.fwdarw.}{d}}_{abc}$

(16) By inverting the 3×3 matrix {tilde over (C)}.sub.abc a solution {right arrow over (d)}.sub.abc for the luminous flux settings of a set of three light sources “a,” “b” and “c” for the resulting color {right arrow over (R)}.sub.abc may be provided as:
{right arrow over (d)}.sub.abc={tilde over (C)}.sub.abc.sup.−1.Math.{right arrow over (R)}.sub.abc

(17) Note that it might be necessary to scale the resulting vector {right arrow over (d)}.sub.abc so that for i=a, b, c, max(d.sub.i)=1, where it is understood that luminous flux is normalized so as to be controllable from 0 to (maximum) 1. The coordinates in a color space (x, y) may be provided from these coordinates.

(18) Thus, a method for identifying a plurality of settings may comprise (a) find all M triangles that contains desired color point (x, y), (b) identify settings for the light sources of each triangle (e.g., by inverting a matrix and scaling as outlined above) and (c) weight the M solutions according to a selected preference.

(19) FIG. 5 shows a graph 500 with possible selected preferences for weighting to achieve two or more settings. In the example of FIG. 5, there are two possible solutions (such as triangles, cf., e.g., the situation of FIG. 4. The figure shows on the x-axis a variable a with values between 0 and 1 (both endpoints 0 and 1 included) and indicative of a contribution from each solution, such as the combination varying from being made up of exclusively one solution at α=0, gradually increasing the contribution from the other solution until the combination is made op exclusively of the other solution at α=1 (such as the weighting in the combination D of the first solution S1 and the second solution S2 being D=(1−α)S1+αS2)). The solution must be scaled such that all elements of D are in the range [0; 1]. The curve of the graph indicates the maximum luminous flux of the respective combinations of the two solutions. The top point of the curve, where the two sections meet in the top point 530, is the point of maximum lumen output, could in general be chosen according to a objective to maximize lumen output. However, according to some embodiments, alternative weightings may be applied with an objective to provide multiple settings with similar or identical colors and different spectra. The more light we allow to loose, the higher the spectral difference we can achieve. It is conceivable and encompassed though, that in some embodiments, one setting corresponds to the weighting for which maximum lumen output may be achieved.

(20) According to some embodiments, the two settings (combinations of solutions) are chosen so that the difference in spectral distribution of light emitted from the plurality of light sources upon being controlled according to the first setting and the second setting is as large as possible and the luminous flux for each combination is as large as possible, such as the combinations being represented by the circle 521 and the star 522.

(21) According to alternative embodiments, the two settings (combinations of solutions) are chosen so that the difference in spectral distribution of light emitted from the plurality of light sources upon being controlled according to the first setting and the second setting is as large as possible and wherein a luminous flux of light emitted from the plurality of light sources upon being controlled according to the first setting is identical or similar to a luminous flux of light emitted from the plurality of light sources upon being controlled according to the second setting, such as the combinations being represented by the heart 527 and the star 522.

(22) Note that each of the above solutions involving the circle 521, star 522 and heart 527 correspond to a basis setting wherein each basis setting is indicative of a luminous flux of each light source within a strict subset of light sources (with each strict subset being one of the triangles, with the remaining light source not contributing) within the plurality of light sources.

(23) However, it is also conceivable and encompassed that a solution is a superposition of a plurality of basis settings. For example in case of controlling a luminous flux of each of the light sources within the plurality of light sources according to at least a fifth setting, cf., pentagon 525, and a sixth setting, cf., hexagon 526, for which the difference in spectral distribution of light emitted from the plurality of light sources upon being controlled according to the first setting and the second setting is as large as possible for a given luminous flux θ.sub.56, a third setting, cf., triangle 523, for which spectral distribution of light emitted from the plurality of light sources upon being controlled according to the third setting is similar or identical to a spectral distribution of light emitted from the plurality of light sources upon being controlled according to the fifth setting, and a fourth setting, cf., diamond 524, for which spectral distribution of light emitted from the plurality of light sources upon being controlled according to the fourth setting is similar or identical to a spectral distribution of light emitted from the plurality of light sources upon being controlled according to the sixth setting, and wherein a luminous flux θ.sub.34 of light emitted from the plurality of light sources upon being controlled according to the third setting is identical or similar to a luminous flux θ.sub.34 of light emitted from the plurality of light sources upon being controlled according to the fourth setting, and wherein a luminous flux θ.sub.34 of light emitted from the plurality of light sources upon being controlled according to the third setting and/or the fourth setting is different with respect to a luminous flux θ.sub.56 of light emitted from the plurality of light sources upon being controlled according to the fifth setting and/or the sixth setting.

(24) FIGS. 6-7 show an illustration of an embodiment in the context of illumination of a scene.

(25) FIG. 6 shows a moving head 602 emitting light 634 according to a first setting, which light illuminates a scene 600, comprising a background 633, a first object being a heart 631 and a second object being a star 632. The light 634 according to the first setting has a first spectral distribution as indicated by spectrum 635, which makes both the first object being a heart 631 and the second object being a star 632 clearly visible to an observer, such as a person in an audience in a theatre.

(26) FIG. 7 shows the same moving head 602 as in FIG. 6 emitting light 734 according to a second setting, which light illuminates the same scene 600 as in FIG. 6, comprising the same background 633, the same first object being a heart 631 and the same second object being a star 632. The light 734 according to the first setting has a second spectral distribution as indicated by spectrum 735, which makes only the first object being a heart 631 clearly visible to an observer, whereas the second object being a star 632 is not clearly visible to an observer, such as pale (as indicated by the dotted line forming the star 632 in FIG. 6), such as a person in an audience in a theatre. This could for example be utilized to make the star appear to be blinking by repeatedly switching abruptly between the first and second settings and/or to be sparkling by repeatedly changing gradually between the first and second settings. The light 734 emitted according to the second setting has the same color as the light 634 emitted according to the first setting. Thus, in case the background is formed by a white material, there might be little or no difference as observed by an observer between illumination of the background 633 according to the first or the second setting, e.g., in case the luminous flux according to the first and second setting were identical.

(27) There is presented a method 100 for controlling a light fixture 200 comprising unique color light sources with independently controllable luminous flux, wherein the method comprises controlling 104 a luminous flux of each of the light sources, wherein a spectral distribution of light emitted from the plurality of light sources upon being controlled according to settings within a plurality of setting is different between settings, and a color of light emitted from the plurality of light sources is similar or identical between settings. The methods and systems disclosed herein may be advantageous for improved color rendering in case a certain color of emitted light is required, e.g., where a certain prop or costume is better illuminated with one setting compared to another setting, drawing attention to certain objects in a scene, e.g., by choosing a setting which makes a certain object stand out, and/or providing an intriguing optical effect, e.g., by shifting between settings, which makes certain objects appear to change color while others appear to keep same color.

(28) Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms “comprising” or “comprises” do not exclude other possible elements or steps. Also, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.