A method for controlling color and color temperature in an environment comprising a lighting system

Abstract

A method for automatically controlling at least a color and / or a color temperature in an environment (10) comprising a lighting system (200) with controllable lighting devices (11-16), wherein the controllable lighting devices (11-16) comprise light sources (110-112; 120-122; 130-133; 140-142; 150-152; 160-163) forming a plurality of sets of primaries. The method comprises determining (300) a first color and / or a first color temperature of the light emitted by an active first set of primaries, determining (320) one or more second set of primaries, the one or more second set of primaries being configured to emit light having a second color and / or a second color temperature and being different from the first set of primaries, determining (340) a user activity in the environment (10), determining (350) an energy consumption of each of the one or more second set of primaries when emitting light, and selecting (360) a second set of primaries based on the determined energy consumption and user activity, the selected second set of primaries being determined to have a determined energy consumption being lower than the energy consumption of the first set of primaries, and switching (370) from the first set of primaries to the selected second set of primaries.

Description

[0001] A method for controlling color and color temperature in an environment comprising a lighting system

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a method for automatically controlling at least one of a color, a color temperature, a brightness, and a luminous flux in an environment comprising a lighting system with one or more controllable lighting devices. The method further relates to a corresponding system.

[0004] A set of primary colors generally consists of colorants or colored lights that can be mixed in varying amounts to produce a gamut of colors. Within digital color imaging, primaries are defined as colorimetric independent light sources, a linear combination of which can produce, in principle, any color.

[0005] As used herein, the term “primary”, when referring to a set of LEDs, is intended to refer to a LED of a group of LEDs.

[0006] As used herein, the term “set of primaries”, when referring to a set of LEDs, is intended to refer to a group of LEDs which together may be controlled to provide, in principle, any color and / or color temperature of light, but especially a dynamic transition from a primary color to white. Such a group of LEDs is typically a set of RGB LEDs, but may also be, for instance, a red LED, a green LED, a blue LED, or even a set of RGB LEDs, in combination with white (cold and warm white) LEDs. Also, various sets of primaries may consist of the same types of LEDs and differ only by one LED. For instance, desaturated red light could be achieved by three LEDs, RGB, or a by red LED and a warm / cold white LED(s), and in such a case these two sets share one type of LEDs, namely the red LED. The sets of primaries may also be the same, and the desired color is then achieved by combining them in different ways, since any color could be produced by three colorimetric independent LEDs. Also, any combination of LEDs that is greater than three could achieve the same color using different combinations of the LEDs.

[0007] As used herein, the term “ratio of primaries” when referring to a set of LEDs, is intended to refer to the ratio of the time during which light emitted by each primary or LED of a set of primaries or LEDs in order to provide a desired color. Effectively, the ratios are expressed by the PWM values that each primary or LED of the set of primaries are set to in order to provide a desired color. The PWM values may be expressed as percentages of use for each primary or LED in the set of primaries. For instance, the PWM value is 50 % if the PWM signal of a primary or LED has a duty cycle where the signal is on 50 % of the time and off 50 % of the time. Likewise, the PWM value is 60 % if the PWM signal of a primary or LED has a duty cycle where the signal is on 60 % of the time and off 40 % of the time.

[0008] It is noted that in case of three primaries or LEDs, that is for instance a set of RGB LEDs, to match a requested color there is only one way in which one ratio of RGB PWM values will result in desired color. However, if it is not important to exactly render the desired color, then the light control system may find and render the most energy efficient color in vicinity of requested color. This may be done, for instance by allowing a certain perceptual difference between the desired color and the color rendered in practice.

[0009] When a set of LEDs comprise more than three different primaries or LEDs, there is an infinite number of ways that any desired color can be rendered. To better understand this, assume that a given color is defined with three values, for instance denoted CIE XYZ.

[0010] When three primaries or LEDs are used, there is only one solution for the PWM values that satisfies the equation:

[0011] X Xr Xg Xb PWMr

[0012] Y Yr Yg Yb X PWMg Z. Zr Zg Zb -PWMb- where r is red, g is green, and b is blue. This is a standard solution for three equations with three unknown variables.

[0013] Now, if four or more primaries or LEDs are used, the equation system becomes three equations with four or more unknown variables. Therefore, there is no single solution, but rather an infinite number of solutions to the equation system. When four or more primaries or LEDs are used, a typical solution is to add an additional goal or requirement to the set of three equations. Such an additional goal or requirement could for instance be minimal power usage or optimal CRI. Then, an algorithm, such as for instance the well-known Simplex algorithm, can find the PWM values that best satisfy the three color equations and the additional goal or requirement.

[0014] By way of example, consider the case of a set of primaries with five primaries or LEDs, namely RBG, cool white and warm white. A first solution to the equations for a specific desired color in this case may then be to use all five primaries with ratios of 50%, 60%, 70%, 20% and 30%, respectively, to optimize CRI, and to use all five primaries with ratios of 40%, 70%, 10%, 20% and 50% to optimize energy usage. In a further example, one or more of the percentages may be set to zero, whereby only four of the five primaries or LEDs are used on practice, or in other words a subset of the set of primaries are used. In such an example, for a specific desired color, the five primaries may be used with ratios of 50%, 60%, 70%, 20% and 0%, respectively, to optimize CRI, and with ratios of 0%, 70%, 10%, 20% and 50%, respectively, to optimize energy usage.

[0015] BACKGROUND OF THE INVENTION

[0016] Pixelated lighting devices enable a huge number of light content patterns. However, users also appreciate both high quality lighting and lighting adapted to a specific user activity.

[0017] Known systems for controlling a lighting scene of an environment, such as the Philips Hue app, offers automatic adjustment of what LEDs from a subset of LEDs are selected for rendering a specific color. The key considerations in this connection are the quality of light output (e.g., CRI, spectrum) and energy consumption.

[0018] EP 2953428 Bl discloses techniques for manipulating both colored and tunable white lighting systems in order to enhance visual comfort and allow an observer's eyes to recover from exposure to colored light. A lighting system may gradually adjust the color, color temperature, and intensity of various multi-chip LED panels in order to provide pleasant and acceptable changes in light settings. Instead of abruptly switching from one light setting to another, a lighting system may fade to an intermediate transition setting and subsequently fade to the final light setting, allowing an observer's eyes time to adapt to the new light settings. In one example, switching from blue light to a neutral white light may involve a gradual fading from blue light to a cool white light, and then to a neutral white light, thus allowing the end user's eyes to adapt to the new light settings.

[0019] In general, methods and systems for controlling a lighting scene of an environment which offer more efficient dynamic transitions between different colors are desired.

[0020] For example, a dynamic transition from red to white, instead of being achieved by mixing R, G and B LEDs, could be more efficiently achieved by using red LED in combination with white (cold and warm white) LEDs, if a given lighting system comprises such LEDs, which is the case, for instance, for such known devices as the Hue color and white ambiance products. However, with the current prior art systems and methods this adaption disregards the user’s activity and thus either strive for the better quality or for energy efficiency, disregarding activity where quality could be reduced for the sake of energy saving in the former case, and disregarding activity where light quality might be more important than efficiency in the latter case.

[0021] It is therefore desired to provide methods and systems for controlling a lighting scene of an environment which optimize energy consumption of lighting devices by balancing between the rendering quality required for the specific user’s activity and energy consumption.

[0022] SUMMARY OF THE INVENTION

[0023] It is an object of the present invention to overcome this problem, and to provide a method for automatically controlling at least one of a color, a color temperature, a brightness, and a luminous flux in an environment comprising a lighting system, which method optimizes energy consumption of lighting devices by balancing between the rendering quality required for the specific user’s activity and the energy consumption of the lighting system.

[0024] According to a first aspect of the invention, this and other objects are achieved by means of a method for automatically controlling at least a color and / or a color temperature in an environment comprising a lighting system with one or more controllable lighting devices, where the one or more controllable lighting devices comprise a plurality of light sources adapted for, when active, emitting light, the plurality of light sources forming a plurality of sets of primaries, the method comprising determining, using a data processing device, one or more of a first color and a first color temperature of the light emitted by an active first set of primaries of the plurality of sets of primaries when operated at a first ratio of primaries, determining, using the data processing device, one or more second set of primaries of the plurality of sets of primaries, the one or more second set of primaries being configured to, when active and operated at a second ratio of primaries of a plurality of second ratios of primaries, emit light having a second color and / or a second color temperature, wherein the second color is the same as or within a predefined color threshold of the first color and the second color temperature is the same as or within a predefined color temperature threshold of the first color temperature, and wherein the plurality of second ratios of primaries is different from the first ratio of primaries, determining, using the data processing device, a user activity in the environment, determining, using the data processing device, an energy consumption of each of the one or more second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second color and / or the second color temperature, and selecting, using the data processing device, a second set of primaries of the one or more second set of primaries based on the determined energy consumption and on the determined user activity, the selected second set of primaries being determined to have a determined energy consumption being lower than the energy consumption of the first set of primaries, and switching, using the data processing device, from the first set of primaries to the selected second set of primaries.

[0025] Thereby, a method for automatically controlling at least one of a color and a color temperature in an environment comprising a lighting system is provided. Such a method optimizes energy consumption of lighting devices by balancing between the rendering quality required for the specific user’s activity and the energy consumption of the lighting system.

[0026] Further, with such a method, the resulting impact on quality has little or no impact on the users performing said activity. In some cases, the resulting impact on quality may even not be perceived by the user at all.

[0027] It is noted that the first set of primaries and the second set of primaries may be the same set of primaries of may be different sets of primaries.

[0028] The method may further comprise determining, using a data processing device, one or more of a first brightness and a first luminous flux of the light emitted by the active first set of primaries of the plurality of sets of primaries when operated at the first ratio of primaries and, determining, using the data processing device, one or more second set of primaries of the plurality of sets of primaries, the one or more second set of primaries further being configured to, when active and operated at a second ratio of primaries of a plurality of second ratios of primaries, emit light having a second brightness and / or a second luminous flux, where the second brightness is the same as or within a predefined brightness threshold of the first brightness and the second luminous flux is the same as or within a predefined luminous flux threshold of the first luminous flux, and determining, using the data processing device and based on the determined user activity, an energy consumption of each of the one or more second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second brightness and / or the second luminous flux.

[0029] Thereby, a method for automatically controlling at least one of not only a color and a color temperature, but also a brightness and a luminous flux, in an environment comprising a lighting system is provided. Such a method further optimizes energy consumption of lighting devices by balancing between the rendering quality required for the specific user’s activity and the energy consumption of the lighting system.

[0030] The at least one user activity may be determined by the data processing device by at least one of detection by using a context / activity awareness system, receiving and processing user input, inferring directly from a mode of operation of the lighting system, and being assigned to a light scene.

[0031] Thereby, a simple and efficient determination of the user activity is enabled.

[0032] The at least one user activity may be determined by the data processing device by detection by using a context / activity awareness system, where the context / activity awareness system comprises one or more sensors.

[0033] Such a method makes it possible to emit the provision of a separate user activity detection system in favor of a simple sensor system.

[0034] The method may further comprise determining, using the data processing device and based on the determined user activity, a rendering quality of each of the one or more second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second color and / or the second color temperature, selecting, using the data processing device, a third set of primaries of the one or more second set of primaries based on the determined lowest acceptable rendering quality, the selected third set of primaries being determined to have the highest of the determined rendering qualities of the one or more second set of primaries, and switching, using the data processing device, from the first set of primaries to one or both of the selected second set of primaries and the selected third set of primaries.

[0035] Thereby, a method also enabling taking into account the rendering quality is provided for. With such a method, the resulting impact on quality has little or no impact on the users performing said activity. In some cases, the resulting impact on quality may even not be perceived by the user at all. Such a method further optimizes energy consumption of lighting devices.

[0036] The method may further comprise determining, using the data processing device, based on the determined user activity, a rendering quality of each of the one or more second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second brightness and / or the second luminous flux, the said step of determining being performed before the step of selecting. Thereby, a method also enabling taking into account the rendering quality, also in connection with controlling brightness and luminous flux, is provided for.

[0037] The rendering quality may be defined by at least one of a functional role and a decorative the role of the primaries of the two or more sets of primaries in a current lighting scene.

[0038] Thereby, a method also enabling taking into account the interaction between rendering quality and functionality is provided for.

[0039] In dependence of the user activity and / or the current lighting scene, the second set of primaries and the third set of primaries may be (i) the same set of primaries, or (ii) different sets of primaries.

[0040] The lighting system may be configured to be operated in a plurality of modes, and the method may further comprise determining, by means of the data processing device, an enabled mode of the plurality of modes, and determining, by means of the data processing device and based on the determined enabled mode, whether the step of selecting, using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the step of selecting, using the data processing device, a third set of primaries of the one or more second set of primaries, should be based primarily on the determined energy consumption or on the determined rendering quality.

[0041] The plurality of modes may comprise one or more of an illumination mode, an ambiance mode, an out-of-home mimicking mode, an on-screen entertainment mode and a music synchronization mode, and where, if the determined enabled mode is any one of an ambiance mode, an out-of-home mimicking mode, and a music synchronization mode, the step of selecting, using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the step of selecting, using the data processing device, a third set of primaries of the one or more second set of primaries, are determined to be based primarily on the determined energy consumption, and where, if the determined enabled mode is any one of an illumination mode and an on-screen entertainment mode, the step of selecting, using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the step of selecting, using the data processing device, a third set of primaries of the one or more second set of primaries, are determined to be based primarily on the determined rendering quality.

[0042] Thereby, a method also enabling taking into account that of energy consumption and rendering quality which is the most important for a given mode of operation is provided for. Such a method even further optimizes energy consumption of lighting devices. It is noted that while in some cases the decision may be to focus all lighting devices on either energy consumption or rendering quality, the decision may in other cases be to focus some lighting devices on energy consumption and others on rendering quality. For example, for reading as a user activity, the functional light (for instance from a reading lamp) should focus on quality, while the decorative light (for instance from a pendant) may focus on energy saving. In another example, for a user activity being a relaxing evening with family / friends all lighting devices should probably be focused on rendering quality.

[0043] The method may further comprise receiving an input indicative of a user switching the mode in which the lighting system operates, and where the step of determining, by means of the data processing device and based on the determined enabled mode, whether the step of selecting, using the data processing device, a second ratio of primaries of the one or more second ratio of primaries, and / or the step of selecting, using the data processing device, a third ratio of primaries of the one or more second ratio of primaries, should be based primarily on the determined energy consumption or on the determined rendering quality is further based on the input indicative of a user switching the mode in which the lighting system operates.

[0044] The method may further comprise receiving an input indicative of a user switching the system between a state in which the lighting system always optimizes for quality, state in which the lighting system always optimizes for energy efficiency, and state in which the lighting system automatically switches between optimizing for quality and optimizing for energy efficiency based on the detected user activity and / or the determined mode in which the lighting system operates.

[0045] The method may further comprise determining, using the data processing device, a pre-set lower threshold of the rendering quality, and the step of selecting, using the data processing device, a third set of primaries of the one or more second set of primaries may further be based on the determined pre-set lower threshold of the rendering quality, such that the selected third set of primaries being determined to have a determined rendering quality being above the pre-set lower threshold of the rendering quality.

[0046] Thereby, a method also enabling avoiding that the rendering quality drops below a general threshold and thus ensuring a minimum rendering quality, is provided for.

[0047] The method may further comprise providing a lighting control system configured to control the lighting system and thus the plurality of lighting devices, where the lighting control system is configured to enable or disable controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux.

[0048] The method may further comprise providing a lighting control system configured to control the lighting system and thus the plurality of lighting devices, where the lighting control system is configured to control a level of optimization of controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux.

[0049] Such a method provides for simple, efficient, and precise control of the lighting system.

[0050] The method may further comprise providing a lighting control system configured to control the lighting system and thus the plurality of lighting devices, where the lighting control system is configured to one or more of visualizing a current level of optimization of controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux, and showing a pre-view of the result of switching, using the data processing device, from the first set of primaries to one or both of the selected second set of primaries and the selected third set of primaries.

[0051] Such a method provides for keeping users updated an enabling users to take action based on the pre-view.

[0052] The method may further comprise determining a target threshold for the quality of the light having a second color and / or a second color temperature, the target threshold being determined based at least on the determined user activity, and the step of selecting, using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the step of selecting, using the data processing device, a third set of primaries of the one or more second set of primaries is further based on the determined target threshold.

[0053] Thereby, it is ensured that the overall quality of the emitted light after switching to a second and / or third set of primaries remains over a minimum acceptable value.

[0054] The invention also relates to a lighting control system comprising a data processing device, a memory unit, and a display, where the memory unit comprises computer executable code stored thereon, the computer executable code being configured to, when executed on the data processing device, cause the data processing device to perform a method according to the present invention. The data processing device may be any computing device such as a personal computer or laptop, a tablet, a smartphone, a camera, or a server in communication with such a computing device via a network interface.

[0055] The invention also relates to a computer program product comprising computer executable code configured to, when executed on a data processing device, cause the data processing device to perform the steps of a method according to the present invention.

[0056] The computer program may be implemented on any computing device such as personal computer or laptop, tablet, smartphone, camera or on a server in communication with such a computing device via a network interface.

[0057] It is noted that the invention relates to all possible combinations of features recited in the claims.

[0058] BRIEF DESCRIPTION OF THE DRAWINGS

[0059] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

[0060] Fig 1 shows schematically an environment comprising a lighting system with a plurality of lighting devices as well as a lighting control system in wireless communication with the lighting system of the environment.

[0061] Fig. 2 shows schematically an environment comprising a lighting system with a plurality of lighting devices, further illustrating light sources of the respective lighting devices.

[0062] Fig. 3 illustrates schematically steps of a method according to the invention.

[0063] Fig. 4 illustrates schematically possible additional steps of the method according to Fig. 3.

[0064] Fig. 5 illustrates schematically further possible additional steps of the method according to Fig. 3.

[0065] As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout. DETAILED DESCRIPTION

[0066] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0067] Fig 1 shows schematically an environment 10 comprising a lighting system 200 with a plurality of lighting devices 11-16. In the embodiment shown, the environment 10 is a room 20. Fig 1 further shows schematically a lighting control system 100 in wireless communication with the lighting system 200 of the environment 10.

[0068] The environment 10, may comprise fittings and fixtures such as furniture, e.g., in the form of a couch or a television. The environment 10 may also comprise a fitting in the form of, for example, a doorway, or a bookcase, or a painting or mirror. The environment 10 comprises lighting system 200. The lighting system 200 comprises a number of lighting devices 11, 12, 13, 14, 15, 16. The lighting devices may be any suitable type of lighting devices, such as for example a ceiling mounted pendant luminaire 13, ceiling recessed spotlights 14 and 15, wall mounted lights 11 and 12, and a standing lamp 16. Each lighting device 11-16 may be switched on or off as usual, and one or more of the lighting devices 11- 16 may be “intelligent” or programmable in that they offer different luminance (dimming) and may also provide a range of hues (warm white to cold white) or colors to provide a lighting atmosphere or lighting scene.

[0069] The lighting control system 100 generally comprises a data processing device 1, a memory unit 21, and a display 2. The lighting control system 100 is in communication, wired or wireless, with the lighting system 200 and thus with the plurality of lighting devices 11-16. The lighting control system 100 is used to control the lighting system 200 and thus the plurality of lighting devices 11-16. The memory unit 21 therefore comprises computer executable code stored thereon, which computer executable code is configured to, when executed on the data processing device, cause the data processing device to perform a method according to any embodiment of the invention and as described below with reference to Figs. 3 to 5.

[0070] Furthermore, and referring also to Fig. 2, a context / activity awareness system 22 may be provided to enable determining or detecting a user activity. The context / activity awareness system 22 comprises one or more sensors 23, 24. Referring to Fig. 2, the context / activity awareness system 22 forms part of the lighting system 200. Alternatively, or additionally, the context / activity awareness system 22 may form part of the lighting control system 100.

[0071] Referring still to Fig. 2, each lighting device of the plurality of lighting devices 11-16 comprises one or more light sources 110-112; 120-122; 130-133; 140-142; 150-152 and 160-163. The light sources 110-112; 120-122; 130-133; 140-142; 150-152 and 160-163 may be any type of controllable light sources, that is light sources being controllable by the lighting control system 100. Typically, the light sources are LEDs, and each lighting device 11-16 comprises, as illustrated on Fig. 2, a plurality of light sources, and more particularly at least one set or group of light sources which together are controllable to provide, in principle, any color and / or color temperature of light, such as a dynamic or non-dynamic transition from at least one primary color to white. Such a group of LEDs is typically a set of RGB LEDs, but may also be, for instance, a red LED, a green LED, and / or a blue LED, or even a set of RGB LEDs, in combination with white (cold and warm white) LEDs. The LEDs of a particular color, i.e., red, green, or blue, may be configured to emit light of slightly different frequencies. For instance, the blue LED could be a regular blue LED emitting light with a peak frequency of 470 nm or a royal blue LED emitting light with a peak frequency of 450 nm. A set or group of light sources 110-112; 120-122; 130-133; 140-142; 150-152 and 160- 163 which together are controllable to provide, in principle, any color and / or color temperature of light, but especially a dynamic transition from at least one primary color to white, is herein denoted a “set of primaries”.

[0072] It will be appreciated that Figs. 1 and 2 are only an example in order to aid understanding and provide context, and that embodiments are applicable across many different environments 10 or rooms 20 having a plurality of lighting devices 11-16.

[0073] Turning now to Figs. 3 to 5, embodiments of a method according to the invention will be described. The method according to the invention is generally a method for automatically controlling at least one of a color, a color temperature, a brightness, and a luminous flux in an environment 10 comprising a lighting system 200 as described above.

[0074] Generally, the method according to the invention is performed by the lighting control device 100, and more particularly using the data processing device 1 of the lighting control device 100.

[0075] Referring first to Fig. 3, in a first step 300 of the method according to the invention, one or more of a first color and a first color temperature of the light emitted by an active first set of primaries of the plurality of sets of primaries when operated at a first ratio of primaries is determined.

[0076] In a step 320, at least one second set of primaries of the plurality of sets of primaries is determined. The at least one second set of primaries are configured to, when active and operated at a second ratio of primaries of a plurality of second ratios of primaries, emit light having a second color and / or a second color temperature. The at least one second ratio of primaries is different from the first ratio of primaries. The second color is the same as or within a predefined color threshold of the first color. The second color temperature is the same as or within a predefined color temperature threshold of the first color temperature.

[0077] The predefined color threshold and the predefined color temperature threshold, respectively may exist for any color model that is used to specify the desired color, and for for any color temperature model that is used to specify the desired color temperature, respectively. For instance, feasible color models may be CIE xyz, CIE L*u*v*, RGB, HSV, CT and so forth. In any event the color threshold such be defined such that the generated color does not deviate too much from the original color, and similarly for the color temperature threshold. For the color threshold, in color science deviation between colors is usually referred to as the distance between colors and is quantified as "delta E". Irrespective of how delta E is calculated there is a threshold. As an example, Lab color space is most commonly used to calculate distance between colors. However, the distance between colors may also be calculated by using RGB space as delta E = sqrt(deltaR*deltaR + deltaG*deltaG + deltaB*deltaB). As another example, delta E may be calculated using CIE Lab, in which case a feasible example of the color threshold may be equal to 1, which is very often referred as "just noticeable difference". However, a higher or lower color threshold may be set depending on the application.

[0078] In a step 340, a user activity in the environment 10 is determined.

[0079] In a step 350, an energy consumption of each of the at least one second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second color and / or the second color temperature is determined.

[0080] Based on the determined energy consumption and the determined user activity, a second set of primaries of the at least one second set of primaries is selected in a step 360. The selected second set of primaries is determined to have a determined energy consumption being lower than the energy consumption of the first set of primaries. The selected second set of primaries may even be determined to have a determined energy consumption being the lowest determined energy consumption.

[0081] Finally, in a step 370, a switching from the first set of primaries to the selected second set of primaries is performed. That is, in case the first set of primaries and the second set of primaries are different sets of primaries, the first set of primaries is switched off or deactivated, and the selected second set of primaries is switched on or activated. Alternatively, in case the first set of primaries and the second set of primaries are the same set of primaries, the first set of primaries is switched from emitting light at the first ratio of primaries to emitting light at the second ratio of primaries.

[0082] Referring still to Fig. 3, the method may further comprise the following optional steps. In a step 310, one or more of a first brightness and a first luminous flux of the light emitted by the active first set of primaries of the plurality of sets of primaries when operated at the first ratio of primaries is determined. In a step 330 at least one second set of primaries of the plurality of sets of primaries is determined. The at least one second set of primaries is further being configured to, when active and operated at a second ratio of primaries of a plurality of second ratios of primaries, emit light having a second brightness and / or a second luminous flux. The second brightness is the same as or within a predefined brightness threshold of the first brightness. The second luminous flux is the same as or within a predefined luminous flux threshold of the first luminous flux.

[0083] By way of example, the predefined brightness threshold may be set such that a first brightness and a second brightness are within 5 cd / m2, 10 cd / m2or no more than 15 cd / m2of one another. By way of example, the predefined luminous flux threshold may be set such that a first luminous flux and a second luminous flux are within 5 Im, 10 Im or no more than 15 Im of one another.

[0084] When the method comprises steps 310 and 330, step 350 involves determining the energy consumption of each of the at least one second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second brightness and / or the second luminous flux.

[0085] The at least one user activity may be determined by detection by using a context / activity awareness system 22, by the lighting control system 100 receiving and processing user input, by being inferring directly from a mode of operation of the lighting system 200, by being assigned to a light scene or by a combination thereof.

[0086] For instance, the at least one user activity may be determined by the data processing device 1 of the lighting control system 100 by detection by using a context / activity awareness system 22 comprising one or more sensors 23, 24. In such a case the method, and especially step 340 thereof, involves receiving, at the lighting control system 100, sensor data from the sensors 23, 24, and processing the sensor input using the data processing device 1 to determine a user activity.

[0087] Referring now to Fig. 4, further optional steps 400-440, which may be added to a method according to the invention and described above in relation to Fig. 3, are described. The method may further comprise the following optional steps. In a step 400, a rendering quality of each of the at least one second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second color and / or the second color temperature is determined based on the determined user activity. In a step 430 a third set of primaries of the at least one second set of primaries is selected based on the determined lowest acceptable rendering quality. The selected third set of primaries is determined to have the highest of the determined rendering qualities of the at least one second set of primaries.

[0088] When the method comprises steps 400 and 430, the step 440 of switching involves switching from the first set of primaries to one or both of the selected second set of primaries and the selected third set of primaries. That is, in case the first set of primaries, the second set of primaries and the third set of primaries are different sets of primaries, the first set of primaries is switched off or deactivated, and both the selected second set of primaries and the selected third set of primaries is switched on or activated. Alternatively, when the first set of primaries and the second set of primaries are the same set of primaries, the first set of primaries may be switched from emitting light at the first ratio of primaries to emitting light at the second ratio of primaries, while the third set of primaries are switched on. Likewise, when the first set of primaries and the third set of primaries are the same set of primaries, the first set of primaries may be switched from emitting light at the first ratio of primaries to emitting light at a second ratio of primaries corresponding to the highest of the determined rendering qualities, while the second set of primaries are switched on.

[0089] Referring still to Fig. 4, the method may further comprise the following optional step. In a step 410, a rendering quality of each of the one or more second set of primaries when operated at a second ratio of primaries of a plurality of second ratios of primaries and emitting light having the second brightness and / or the second luminous flux is determined based on the determined user activity. Where present, step 410 may be performed before step 430. The method may further involve defining the rendering quality determined in step 400 and / or step 410 by at least one of a functional role and a decorative the role of the primaries of the two or more sets of primaries in a current lighting scene.

[0090] Referring still to Fig. 4, the method may further comprise the optional step 420 of determining a lower threshold of the rendering quality. The determined lower threshold of the rendering quality may then be used when selecting a third set of primaries in step 430. More particularly, step 430 the involves selecting a third set of primaries of the at least one second set of primaries based on the pre-set lower threshold of the rendering quality determined in step 420, such that the selected third set of primaries are determined to have a determined rendering quality being above the pre-set lower threshold of the rendering quality.

[0091] The second set of primaries and the third set of primaries may be either the same set of primaries, or different sets of primaries, for instance in dependence of the user activity and / or the current lighting scene.

[0092] Referring now to Fig. 5, the lighting system 200 may be configured to be operated in a plurality of modes. In such a case, the method may further comprise the following optional steps. In a step 500, an enabled mode of the plurality of modes is determined. In a step 510 it is determined, based on the determined enabled mode, whether the step of selecting 360 a second set of primaries of the at least one second set of primaries, or the step 430 of selecting a third set of primaries of the at least one second set of primaries, should be based primarily on the determined energy consumption or on the determined rendering quality. Steps 500 and 510 may be performed before step 360 or step 430.

[0093] The plurality of modes in which the lighting system 200 may be configured to be operated may comprise one or more of an illumination mode, an ambiance mode, an out- of-home mimicking mode, an on-screen entertainment mode and a music synchronization mode. If the enabled mode determined in step 500 is any one of an ambiance mode, an out- of-home mimicking mode, and a music synchronization mode, it is in step 510 determined that step 360 or step 430 are to be based primarily on the determined energy consumption. If, on the other hand, the enabled mode determined in step 500 is any one of an illumination mode and an on-screen entertainment mode, it is in step 510 determined that step 360 or step 430 are to be based primarily on the determined rendering quality.

[0094] The method may still further comprise an optional step of determining a target threshold for the quality of the light having a second color and / or a second color temperature. The target threshold may for instance be determined based on the determined user activity. Alternatively, or additionally, the target threshold may also be based on internal input, such as data related to a lighting scene, and / or external input, such as a user input or sensor input received by the control system. In such a case, the step 360 of selecting, using the data processing device, a second set of primaries of the at least one second set of primaries, and / or the step 430 of selecting, using the data processing device, a third set of primaries of the at least one second set of primaries may further be based on the determined target threshold.

[0095] Furthermore, the method may also comprise, by using the lighting control system 100, any one or more of: enable or disable controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux, control a level of optimization of controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux, visualize a current level of optimization of controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux, and showing a pre-view of the result of switching, using the data processing device, from the first set of primaries to one or both of the selected second set of primaries and the selected third set of primaries.

[0096] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0097] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claims

CLAIMS1. A method for automatically controlling at least a color and / or a color temperature in an environment (10) comprising a lighting system (200) with one or more controllable lighting devices (11-16), wherein the one or more controllable lighting devices (11-16) comprise a plurality of light sources (110-112; 120-122; 130-133; 140-142; 150-152; 160-163) adapted for, when active, emitting light, the plurality of light sources forming a plurality of sets of primaries, the method comprising: determining (300), using a data processing device, one or more of a first color and a first color temperature of the light emitted by an active first set of primaries of the plurality of sets of primaries operated at a first ratio of primaries, determining (320), using the data processing device, one or more second set of primaries of the plurality of sets of primaries, the one or more second set of primaries being configured to, when active and operated at one of a plurality of second ratios of primaries, emit light having a second color and / or a second color temperature, wherein the second color is the same as or within a predefined color threshold of the first color and the second color temperature is the same as or within a predefined color temperature threshold of the first color temperature, and wherein the plurality of second ratios of primaries is different from the first ratio of primaries, determining (340), using the data processing device, a user activity in the environment (10), determining (350), using the data processing device, an energy consumption of each of the one or more second set of primaries when operated at one of the plurality of second ratio of primaries and emitting light having the second color and / or the second color temperature, and selecting (360), using the data processing device, a second set of primaries of the one or more second set of primaries based on the determined energy consumption and on the determined user activity, the selected second set of primaries being determined to have a determined energy consumption being lower than the energy consumption of the first set of primaries, andswitching (370), using the data processing device, from the first set of primaries to the selected second set of primaries.

2. A method according to claim 1, the method further comprising: determining (310), using a data processing device, one or more of a first brightness and a first luminous flux of the light emitted by the active first set of primaries of the plurality of sets of primaries when operated at the first ratio of primaries and, determining (330), using the data processing device, one or more second set of primaries of the plurality of sets of primaries, the one or more second set of primaries further being configured to, when active and operated at one of the plurality of second ratio of primaries, emit light having a second brightness and / or a second luminous flux, wherein the second brightness is the same as or within a predefined brightness threshold of the first brightness and the second luminous flux is the same as or within a predefined luminous flux threshold of the first luminous flux, and determining (350), using the data processing device and based on the determined user activity, an energy consumption of each of the one or more second set of primaries when emitting light having the second brightness and / or the second luminous flux.

3. A method according to any one of the above claims, wherein the at least one user activity is determined by the data processing device by at least one of: detection by using a context / activity awareness system (22), receiving and processing user input, inferring directly from a mode of operation of the lighting system (200), and being assigned to a light scene.

4. A method according to any one of the above claims, wherein the at least one user activity is determined by the data processing device by detection by using a context / activity awareness system (22), and wherein the context / activity awareness system comprises one or more sensors (23, 24).

5. A method according to any one of the above claims, and further comprising: determining (400), using the data processing device and based on the determined user activity, a rendering quality of each of the one or more second set ofprimaries when operated at one of a plurality of second ratios of primaries and emitting light having the second color and / or the second color temperature, selecting (430), using the data processing device, a third set of primaries of the one or more second set of primaries based on the determined lowest acceptable rendering quality, the selected third set of primaries being determined to have the highest of the determined rendering qualities of the one or more second set of primaries, and switching (440), using the data processing device, from the first set of primaries to one or both of the selected second set of primaries and the selected third set of primaries.

6. A method according to claim 5, the method further comprising: determining (410), using the data processing device, based on the determined user activity, a rendering quality of each of the one or more second set of primaries when operated at one of a plurality of second ratios of primaries and emitting light having the second brightness and / or the second luminous flux, the said step of determining (410) being performed before the step of selecting (430).

7. A method according to claim 4 or 5, wherein the rendering quality is defined by at least one of a functional role and a decorative the role of the primaries of the two or more sets of primaries in a current lighting scene.

8. A method according to claim 7, wherein, in dependence of the user activity and / or the current lighting scene, the second set of primaries and the third set of primaries are (i) the same set of primaries, or (ii) different sets of primaries.

9. A method according to any one of the above claims, wherein the lighting system (200) is configured to be operated in a plurality of modes, the method further comprising: determining (500), by means of the data processing device, an enabled mode of the plurality of modes, and determining (510), by means of the data processing device and based on the determined enabled mode, whether the step of selecting (360), using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the stepof selecting (430), using the data processing device, a third set of primaries of the one or more second set of primaries, should be based primarily on the determined energy consumption or on the determined rendering quality.

10. A method according to claim 9, wherein the plurality of modes comprise one or more of an illumination mode, an ambiance mode, an out-of-home mimicking mode, an on-screen entertainment mode and a music synchronization mode, and wherein: if the determined enabled mode is any one of an ambiance mode, an out-of- home mimicking mode, and a music synchronization mode, the step of selecting (360), using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the step of selecting (430), using the data processing device, a third set of primaries of the one or more second set of primaries, are determined to be based primarily on the determined energy consumption, and if the determined enabled mode is any one of an illumination mode and an onscreen entertainment mode, the step of selecting (360), using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the step of selecting (430), using the data processing device, a third set of primaries of the one or more second set of primaries, are determined to be based primarily on the determined rendering quality.

11. A method according to any one of claims 5 to 10, and further comprising: determining (420), using the data processing device, a pre-set lower threshold of the rendering quality, and wherein the step of selecting (430), using the data processing device, a third set of primaries of the one or more second set of primaries is further based on the determined pre-set lower threshold of the rendering quality, such that the selected third set of primaries being determined to have a determined rendering quality being above the pre-set lower threshold of the rendering quality.

12. A method according to any one of the above claims, and further comprising: providing a lighting control system (100) configured to control the lighting system (200) and thus the plurality of lighting devices (11-16), wherein the lighting control system (100) is configured to any one or more of:enable or disable controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux, control a level of optimization of controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux. visualizing a current level of optimization of controlling one or more of the second color, the second color temperature, the second brightness and the second luminous flux, and showing a pre-view of the result of switching, using the data processing device, from the first set of primaries to one or both of the selected second set of primaries and the selected third set of primaries.

13. A method according to any one of the above claims, and further comprising: determining a target threshold for the quality of the light having a second color and / or a second color temperature, the target threshold being determined based at least on the determined user activity, wherein the step of selecting (360), using the data processing device, a second set of primaries of the one or more second set of primaries, and / or the step of selecting (430), using the data processing device, a third set of primaries of the one or more second set of primaries is further based on the determined target threshold.

14. A lighting control system (100) comprising a data processing device (1), a memory unit (21), and a display (2), wherein the memory unit comprises computer executable code stored thereon, the computer executable code being configured to, when executed on the data processing device, cause the data processing device to perform a method according to any one of claims 1 to 13.

15. A computer program product comprising computer executable code configured to, when executed on a data processing device, cause the data processing device to perform the steps of a method according to any one of claims 1 to 13.

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