A system and a method for controlling an array of light sources to render color gradient light

Abstract

The invention provides a system (2.41,81) for controlling an array (281) of light sources (11-19) to render color gradient light (231,232,271), the array (281) comprising at least four individually controllable light sources. The system (2,41,81) comprising an input interface (3,43,83,89) configured to obtain at least four gradient stop colors (C1,C2,C3,C4) and a gradient contrast option; a processor (5,45,85) configured to (i) receive the at least four 5 gradient stop colors and the gradient contrast option from the input interface, (ii) determine color contrasts (CC12,CC13,CC14,CC23,CC24,CC34) between pairs (C1-C2, C1-C3,C1- C4,C2-C3,C2-C4,C3-C4) of the at least four gradient stop colors, (iii) determine a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts and the gradient contrast option, (iv) determine a mapping of the at least four 10 gradient stop colors onto at least four light sources of the array of light sources based on the gradient stop color sequence, and a control interface (6,44,84) configured to control the array of light sources to render the gradient stop colors on the at least four light sources.

Description

[0001] 2024PF80184

[0002] 1

[0003] A system and a method for controlling an array of light sources to render color gradient light

[0004] FIELD OF THE INVENTION

[0005] The invention relates to a system for controlling an array of light sources to render a color gradient, the array comprising at least four individually controllable light sources. The invention further relates to a method of controlling an array of light sources to render a color gradient, the array comprising at least four individually controllable light sources.

[0006] BACKGROUND OF THE INVENTION

[0007] With the introduction of LED technology, it has become possible to produce light strips. Further advances in technology have enabled the pixelated light strip. Pixelated light strips comprise multiple individually controllable segments, each such segment generally referred to as a ‘pixel’ of which e.g. the color and / or intensity of light emitted may be controlled. Each segment comprises one LED or multiple LEDs of the same or different colors.

[0008] The individual addressability and color change functionality of such LED lighting strips opens the possibility for a wide range of different control options to provide a variety of different interesting and attractive luminous effects.

[0009] One type of effect of particular interest is that of color gradients, wherein a lighting strip is controlled to vary the color outputs of LEDs between two defined points so as to gradually transition from a first color at a first point to a second color at a second point. A color gradient effect is thereby created extending across the strip.

[0010] Products able to render color gradients are already on the market. For example, rendering a color gradient is possible by using a Philips Hue Gradient Lightstrip in combination with the Hue app. The user is able to select colors using the Hue app and the app then determines a color gradient based on these colors.

[0011] US10959302B2 discloses a lighting device which comprises an array of controllable light emitting pixels, each pixel having an adjustable light output color. A controller is configured to receive a limited set of light output colors and to locally process 2024PF80184

[0012] 2 these light output colors to form a color gradient pattern to be displayed across pixels of the array.

[0013] US2020 / 0294466A1 discloses technologies for controlling diodes and producing colored light. The color control software instructs a set of diodes to produce smooth gradients between adjacent colors in a color sequence.

[0014] However, more complex gradient light effects require a significant amount of input from the user. It is therefore desired to provide a system in which an attractive color gradient light effect can be created with limited or no user input.

[0015] SUMMARY OF THE INVENTION

[0016] It is an object of the present invention to at least partly overcome one or more of the aforementioned disadvantages of the prior art, or to provide a useful alternative.

[0017] In a first aspect of the invention, the invention provides a system for controlling an array of light sources to render color gradient light, the array comprising at least four individually controllable light sources. The system comprises an input interface configured to obtain at least four gradient stop colors (C1,C2,C3,C4), a processor configured to (i) receive the at least four gradient stop colors from the input interface, (ii) determine color contrasts (CC12,CC13,CC14,CC23,CC24,CC34) between pairs (C1-C2, C1-C3,C1- C4,C2-C3,C2-C4,C3-C4) of the at least four gradient stop colors, (iii) determine a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts and (iv) determine a mapping of the at least four gradient stop colors onto at least four light sources of the array of light sources based on the gradient stop color sequence. The system further comprising a control interface configured to control the array of light sources to render the gradient stop colors on the at least four light sources.

[0018] The system of this invention provides an advanced way of rendering color gradients. By determining a gradient stop color sequence based on the color contrast it is possible to render attractive gradient light effects with little intervention from the user.

[0019] The term ‘color gradient’ is a term of the art and is to be interpreted in accordance with its commonly understood meaning. In particular, a color gradient (or color progression or color ramp) refers generally to a range of colors extending across a corresponding range of consecutive positions within a space, and having colors which progress or transition from at least a first color to at least a second color.

[0020] Likewise, the term ‘color contrast’ is a term of the art and is to be interpreted in accordance with its commonly understood meaning. The color contrast typically describes 2024PF80184

[0021] 3 the difference between different color hues. High color contrast means that the colors used are distinctly different from each other, while low color contrast means that the colors are similar or blend together. Color contrast can be determined using various methods known to the skilled person.

[0022] The processor may be configured to order the gradient stop color in the gradient stop color sequence according to their color contrast. The processor may be configured to determine the color contrast between the at least four gradient colors by determining a color contrast between each two gradient stop colors of the at least four gradient stop colors, thus between all possible pairs of gradient stop colors. In other words, the processor may be configured to determine the color contrasts between the gradient stop colors by determining color contrasts between each one of the gradient stop colors and each other one of the gradient stop colors to determine a gradient stop color sequence. The processor may be configured to map the at least four gradient stop colors onto the at least four individually controllable light sources of the array of light sources based on the gradient stop color sequence.

[0023] The control interface may be configured to receive one or more of the gradient stop colors, the gradient stop color sequence and the mapping from the processor . The control interface is configured to control the array of light sources to render the gradient stop colors on the at least four light sources in accordance with the mapping and the gradient stop color sequence.

[0024] ID arrays, e.g. light strips, are currently the light arrays that are used most often to render color gradients. The array of light sources may thus be a linear array and the pixels controlled by the system may be pixels distributed along the length of an elongate lighting strip. In these cases, the pattern of color points may be a linear pattern, extending in a single dimension only (a dimension, which when mapped to the array of light emitting pixels, is aligned parallel with the length of the elongate lighting strip). Two of the at least four light sources may be edge light sources, thus light sources located at an end of the array of light sources.

[0025] However, the concept of the invention is not limited to linear arrays. It is envisaged that the array of light emitting pixels may be comprised by any of a range of different forms of lighting device, and may extend to define a more two-dimensional arrangement. In this case, the gradient stop color sequence may be a two-dimensional pattern.

[0026] It is noted that although in the case of the system comprising an elongate lighting strip, it is envisaged that the gradient stop color sequence may be a one-dimensional 2024PF80184

[0027] 4 sequence, the array of light emitting pixels may in fact be two dimensional, extending both longitudinally along a length of the at least one strip, and laterally along a width. To simplify generation of the color gradient pattern, the same color may be mapped to all pixels occupying the same lateral column or row.

[0028] The light sources of the array of light source may each comprise one or more light emitting elements configured to enable each light source to emit light of any of a range of different light output colors.

[0029] The array may comprise at least four, such as at least 6, preferably at least 10, most preferably at least 20 individually controllable light sources. The system may further comprise a control interface configured to control the array of light sources to render the gradient stop colors on the at least four, the at least, the at least 10, or the at least 20 light sources respectively.

[0030] The light sources of the array of light sources may comprise solid state light source, such as LED light source. Such LED light sources may each comprise one or more LEDs configured to enable each LED light source to emit light of any of a range or spectrum of different light output colors. In preferred examples, each LED light source is operable to emit light across the full visible light spectrum. The LED sources may in examples comprise RGB (red, green, blue) LEDs, which are characterized in comprising red, green and blue LED elements which may be encapsulated in a single unit and sharing a common anode. Preferably, each LED light source has a controllable light output intensity (or output power) in addition to a controllable light output color.

[0031] Although LED light sources represent one example of a suitable light emitting pixel, in further examples the light sources may be of a different variety. The light sources may comprise light sources of a different variety, for instance a different kind of solid state light source (such as a COB LED or a laser diode), or any other kind of light source. The light sources may be a different kind of electroluminescent light source for example.

[0032] The gradient stop color sequence may be determined based on one of (i) maximizing the color contrasts, (ii) minimizing the color contrasts, and (iii) providing an increase in the color contrasts along the length of the color gradient light.

[0033] The processor may be configured to determine the gradient stop color sequence according to different contrast options, enabling additional enhancement and customization possibilities of the gradient light effect.

[0034] The processor may be configured to automatically choose the best contrast option based the gradient stop colors. The processor may further be configured to propose a 2024PF80184

[0035] 5 palette of at least four gradient stop colors, i.e. to the user via the user interface. The processor may for example be configured to suggest a proposed palette having (i) a high color contrast and / or (ii) a low color contrast and / or (iii) an increase in the color contrast along the gradient stop color sequence.

[0036] The input interface may further be configured to obtain a gradient contrast option and the processor may be configured to receive the gradient contrast option from the input interface. The gradient contrast option may thus for example be a contrast preference of a user or any other input that indicates a gradient contrast option. The gradient stop color sequence of the at least four gradient stop colors may in such examples be based on the determined color contrasts and the gradient contrast option.

[0037] The gradient contrast option may be obtained for every gradient light that is rendered on the array of light sources. Alternatively the gradient contrast option may be obtained once as a preference of a user and may subsequently be used to control the array of light sources to render all further gradient light settings. The user may be able to change the gradient contrast option via the input interface.

[0038] The gradient contrast option may comprise one of (i) maximizing the color contrasts, (ii) minimizing the color contrasts, and (iii) providing an increase in the color contrasts along the length of the color gradient light. The gradient stop color sequence may then be determined based on the gradient contrast option.

[0039] Maximizing the color contrasts may comprise calculating and selecting the gradient stop color sequence in which the sum of the color contrasts between neighboring gradient stop colors in the gradient stop color sequence is maximized. In other words, selecting the gradient stop color sequence with the highest sum of color contrast values.

[0040] Minimizing the color contrasts may comprise calculating and selecting the gradient stop color sequence in which the sum of the color contrasts between neighboring gradient stop colors in the gradient stop color sequence is minimized. In other words, selecting the gradient stop color sequence with the lowest sum of color contrast values.

[0041] Alternative the gradient stop color sequence may be chose to provide a continuous increase or decrease in the color contrasts between neighboring gradient stop colors along the (full) length of the gradient stop color sequence.

[0042] Instead of the sum of color contrasts also other statistical measures may be employed, such as the standard deviation of color contrasts, the mean value of color contrasts, or the sum of squares of color contrasts.

[0043] The input interface may further comprise a user interface. 2024PF80184

[0044] 6

[0045] Adding a user interface to the system provides opportunities to involve the user into selecting and customizing different aspects of the gradient stop colors and / or the gradient stop color sequence.

[0046] The user interface may be communicably coupled with the controller and the processor may be configured to obtain input indicative of the at least four gradient stop colors from the user interface via the input interface.

[0047] The user inface may comprise a color space.

[0048] It is desired for the user to select and customize the different aspects of the color gradient light in an easy and user-friendly manner. To this end, the user interface may be configured to display a color space.

[0049] The color space may for example be an ICTCP, HSV, Lab, CIE XYZ, or CIE YUV color space. The color space may be presented in a suitable shape and form, e.g. in a circle, wheel, or triangle.

[0050] The user interface may comprise a control element arranged to adjust one or more of the at least four gradient stop colors in order to vary the color contrast.

[0051] Enabling the user to adjust the gradient stop colors via a control element comprised by the user interface provides an easy and intuitive way to customize the color gradient light. The user interface may further comprise a control element to vary the contrast options as described above.

[0052] The control element may work in conjunction with the above-mentioned color space. The user may for example be able to adjust the gradient stop colors by moving representations of the gradient stop colors within the color space. However, also other implementations may be envisaged, such as drop down menus, text fields, radio buttons, sliders, or other control elements suitable for adjusting colors on a user interface.

[0053] By adjusting one or more gradient stop colors, the color contrast between one or more pairs of the at least four gradient stop colors can be varied, i.e. increased and / or decreased.

[0054] A sum of the color gradient light may be white light having a correlated color temperature in a range from 2700K to 5000K, preferably in a range from 2000K to 6500K and preferably a color rendering index of at least 70, preferably at least 80, most preferably at least 90.

[0055] The sum of the color gradient light being white light has multiple advantages, amongst others that the color gradient light emitted by the array of light sources may combine into (functional) white light in the far field of the array of light sources, while the 2024PF80184

[0056] 7 decorative effect of the color gradient light in the near field of the array of light sources is maintained.

[0057] The term “sum of the gradient color light” needs to be understood as a combination of the light emitted by the light sources of the array of light sources.

[0058] The processor may be configured to achieve a sum of the color gradient light being white light e.g. by selecting the at least four gradient stop colors accordingly, and / or by adjusting the relative intensities of the at least four gradient stop colors.

[0059] The processor may be configured to determine the color contrasts based on light reflectance values the at least four gradient stop colors, wherein a first gradient stop color has a first light reflectance value LR1, wherein a second gradient stop color has a second light reflectance value LR2, wherein LR1 is higher than LR2, and wherein the color contrast is determined according to CC=(LR1-LR2) / LR1*1OO.

[0060] As already described above, color contrast is a term known in the art and color contrast can be determined using various methods. In the context of this invention, the color contrasts may preferably be determined based on the light reflectance value of each of the at least four gradient stop colors. Determining color contrasts based on light reflectance value has been described by Arthur & Passini (Wayfinding, 1992) as a very suitable method to calculate the contrast between two different colors and this method is currently widely used in the art.

[0061] Notwithstanding the above, alternative methods of determining color contrasts between the gradient stop colors may equally be possible, for example by determining a distance between (pairs ol) gradient stop colors in a suitable chromaticity system.

[0062] In such examples, the processor may be configured to map the at least four gradient stop colors onto a color space and determine color distances between the at least four gradient stop colors in the color space. The color space may be an ICTCP, HSV, Lab, CIE XYZ, or CIE YUV color space, for example. Depending on the color space, the distance may be determined as Euclidian distance or using other methods known in the literature.

[0063] An amount of color contrast between a first gradient stop color being mapped to a first light source of the array of light sources and a second gradient stop color being mapped to a second light source of the array of light sources may correspond to a physical distance between the first light source and the second light source on the array of light sources.

[0064] The system may thus determine the mapping from gradient stop colors to light sources based on the contrast amount. This is done such that the array of light sources reflects 2024PF80184

[0065] 8 these contrast amounts in the distance of the light sources on the array. This allows the system to automatically create a smooth color gradient even if the gradient stop colors, e.g. the light scene color palette, combine similar colors with contrasting colors.

[0066] In other words, the processor may be configured to map the at least four gradient stop colors onto the at least four light sources based on the amount of color contrast, (i.e. color contrast value, or color distance in a color space) such that the amount of contrast between two of the at least four gradient stop colors mapped to two of the at least four light sources corresponds to a distance between the two light sources on the array of light sources.

[0067] The array of light sources may comprise other light sources. The processor may be configured to control, via the control interface, the array of light sources to render interpolated colors on the other light sources of the array of light sources, the interpolated colors being determined based on the at least four gradient stop colors.

[0068] The array of light sources may comprise more light sources than the number of light sources to which gradient stop colors are (directly) mapped. The array comprises at least four individually controllable light sources, but may comprise at least 10, preferably at least 50, most preferably at least 100 individually controllable light sources. The at least four gradient stop colors may be mapped to four of those light sources. The remaining light sources of the array may be referred to as additional, other, or intermediate light sources.

[0069] With respect to the additional light sources of the array, the processor may be configured to control, via the control interface, the array of light sources to render interpolated colors on other light sources of the array of light sources, the interpolated colors being determined based on the at least four gradient stop colors by interpolation. The interpolation may be performed in the same color space or in a different color space as the determination of the color contrast.

[0070] The processor may be configured to obtain an orientation of the array of light sources, and map the at least four gradient stop colors onto the at least four light sources of the array of light sources based on the orientation.

[0071] The input interface may be configured to obtain sensor data, and the at least four gradient stop colors may be selected based on the sensor data.

[0072] Selecting the at least four gradient stop colors based on sensor data enhances the capabilities of the system to render more advanced color gradient light effects with limited to no user input.

[0073] The processor may be configured to select and / or sort the gradient stop colors based on the sensor data. One or more sensors may be communicably coupled with the 2024PF80184

[0074] 9 processor, i.e. via the input interface. In principle, any type of sensor data may be suitable to be used in the context of this invention, but preferably the sensor data includes one or more of motion, activity, presence, (day)light or ambient light, ambient colors, or temperature.

[0075] In examples, the system, more specifically the input interface, may comprise a sensor configured to generate the sensor data. The sensor may be an optical sensor, preferably a camera.

[0076] The processor may further be configured to obtain personal data from a user, and automatically select the at least four gradient stop colors based on the personal data.

[0077] The system may obtain personal data, such as personal characteristics or preferences of the user and may be configured to create color gradient light automatically based on the obtained personal data.

[0078] The system may further comprise a clock module. The processor may be configured to select the at least four gradient colors and / or to vary the gradient stop color sequence depending on time input of the clock module.

[0079] The processor may thus be configured to automatically create color gradient light which is for example based on the time of day or on the season of the year.

[0080] The system may further comprise the array of light sources rendering the color gradient light.

[0081] A first light source of the at least four individually controllable light sources may be comprised by a first lamp or luminaire, a second light source of the at least four individually controllable light sources may be comprised by a second lamp or luminaire, a third light source of the at least four individually controllable light sources may be comprised by a third lamp or luminaire, and a fourth light source of the at least four individually controllable light sources may be comprised by a fourth lamp or luminaire.

[0082] Alternatively, the at least four light sources may be comprised in a single lamp or luminaire.

[0083] The color gradient light may thus be rendered by a single lamp or luminaire comprising the at least four light sources or by multiple lamps or luminaires, each comprising one or more of the at least four light sources. The latter enabling the spatial distribution of a color gradient light effect across multiple lighting devices in a space.

[0084] In a second aspect, the invention provides a method of controlling an array of light sources to render a color gradient light, the array comprising at least four individually controllable light sources, the method comprising: obtaining at least four gradient stop colors (C1,C2,C3,C4); 2024PF80184

[0085] 10 determining color contrasts (CC12,CC13,CC14,CC23,CC24,CC34) between pairs (C1-C2, C1-C3,C1-C4,C2-C3,C2-C4,C3-C4) of the at least four gradient stop colors; determining a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts; mapping the at least four gradient stop colors onto at least four light sources of the array of light sources based on the gradient stop color sequence; and controlling the array of light sources to render the gradient stop colors on the at least four light sources.

[0086] The method may be performed by software running on a programmable device. This software may be provided as a computer program product.

[0087] Moreover, a computer program for carrying out the methods described herein, as well as a non-transitory computer readable storage-medium storing the computer program are provided. A computer program may, for example, be downloaded by or uploaded to an existing device or be stored upon manufacturing of these systems.

[0088] A non-transitory computer-readable storage medium stores at least one software code portion, the software code portion, when executed or processed by a computer, being configured to perform executable operations for controlling an array of light sources to render a color gradient, the array comprising at least four individually controllable light sources.

[0089] The executable operations comprise obtaining input indicative of gradient stop colors of the color gradient, mapping the at least four colors onto at least four light sources of the array of light sources, and controlling the array of light sources to render the at least four colors on the at least four light sources.

[0090] The executable operations further comprise determining color contrasts between pairs of the at least four gradient stop colors and determining a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts.

[0091] As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a device, a method or a computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit", "module" or "system." Functions described in this disclosure may be implemented as an algorithm executed by a processor / microprocessor 2024PF80184

[0092] 11 of a computer. Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied, e.g., stored, thereon.

[0093] Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer readable storage medium may include, but are not limited to, the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of the present invention, a computer readable storage medium may be any tangible medium that can contain, or store, a program for use by or in connection with an instruction execution system, apparatus, or device.

[0094] A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0095] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber, cable, RF, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java(TM), Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In 2024PF80184

[0096] 12 the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0097] Aspects of the present invention are described below with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor, in particular a microprocessor or a central processing unit (CPU), of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer, other programmable data processing apparatus, or other devices create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0098] These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0099] The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0100] BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0102] Fig. 1 is a block diagram of a first example of the system;

[0103] Fig. 2 is a block diagram of a second example of the system; 2024PF80184

[0104] 13

[0105] Fig. 3 is a block diagram of a third example of the system;

[0106] Fig. 4 is a flow diagram of a first example of the method;

[0107] Fig. 5 is a flow diagram of a second example of the method;

[0108] Fig. 6 is a flow diagram of a third example of the method;

[0109] Fig. 7 shows aspects of determining color contrasts and the gradient stop color sequence;

[0110] Fig. 8 shows additional aspects of determining color contrasts;

[0111] Fig. 9 schematically illustrates an example gradient stop color sequence mapping; and

[0112] Fig. 10 shows an example of a conventional mapping of colors to an ID array and an example of an improved mapping based on color contrasts;

[0113] The schematic drawings are not necessarily to scale.

[0114] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0115] Fig. 1 shows a first example of the system for controlling an array of light sources to render color gradient light. In this first example, the system is a controller 2. The array comprises at least four individually controllable light sources (also referred to as pixels). In this first example, the system is part of a lighting device: controller 2 is part of a light strip 1. Alternatively, the system may itself be a lighting device. The light strip 1 comprises nine individually controllable light sources 11-19. Each light source may comprise a single light element, e.g. a direct emitting or phosphor converted LED. Alternatively, one or more of the light sources may comprise multiple light elements, for example RGB or RGBW light elements.

[0116] In the example of Fig. 1, the light strip 1 can be controlled via a bridge 21, e.g. using Zigbee technology. The bridge 21 is connected to a wireless LAN access point 23, e.g. via Ethernet or Wi-Fi. A mobile device 25 may also be connected to the wireless LAN access point 23, e.g. via Wi-Fi. Mobile device 25 may be a mobile phone, a tablet or a smart watch, for example. A user may be able to use an app running on mobile device 25 to control light strip 1 via the wireless LAN access point 23 and the bridge 21. Alternatively, the light strip 1 may be controlled without a bridge, e.g. directly via Bluetooth, via Wi-Fi, or via the cloud.

[0117] To simplify control of pixelated lighting devices, the app might not ask the user, and the user may not even be able to, specify a color per light source of the array, e.g. per pixel of the pixelated lighting device, but might instead ask the user to specify a limited number of colors, e.g. four, that the app will then use to create a color gradient. Similarly, 2024PF80184

[0118] 14 when a user recalls a scene, colors from the scene (e.g. manually picked or extracted from an image) may be automatically sorted and applied to the array of light sources to create a color gradient.

[0119] The controller 2 comprises a receiver (or input interface) 3, a transmitter 4, a processor 5, and a control interface 6. The processor 5 is configured to obtain, via the receiver 3, input indicative of at least four gradient stop colors of the color gradient, map the at least four gradient stop colors onto at least four light sources of the array of light sources 11-19, and control, via the control interface 6, the array of light sources 11 - 19 to render the at least four colors on the at least three light sources. The input may be received from the mobile device 25 or from the bridge 21, for example.

[0120] The processor 5 is further configured to determine color contrasts between pairs of the at least four gradient stop colors and determine a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts. The processor 5 is configured to map the at least four gradient stop colors onto the at least four light sources based on the gradient stop color sequence.

[0121] In the example of Fig. 1, the array of light sources is a linear (ID) array. In an alternative example, the array of light sources is a 2D or 3D array. If an ID array is flexible, it may optionally be treated as a 2D array. If a 2D array is flexible, it may optionally be treated as a 3D array. For example, a light strip placed around a TV is an ID array but could be treated as a 2D array. Similarly, a light strip used for decorating a Christmas tree is an ID array but could be treated as a 2D or 3D array. If the array is flexible, the selected colors and / or the mapping of the selected colors to the light sources may depend on the array’s configuration in space.

[0122] In the example of Fig. 1, all of the at least four light sources are comprised in a single lighting device, i.e. light strip 1. Alternatively, a first light source of the at least three light sources may be comprised in a first lighting device and a second light source of the at least three light sources may be comprised in a second lighting device.

[0123] In the example of the controller 2 shown in Fig. 1, the controller 2 comprises one processor 5. In an alternative example, the controller 2 comprises multiple processors. The processor 5 of the controller 2 may be a general-purpose processor or an applicationspecific processor. The receiver 3 and the transmitter 4 may use one or more wireless communication technologies, e.g. Zigbee, for communicating with the bridge 21. In an alternative example, multiple receivers and / or multiple transmitters are used instead of a single receiver and a single transmitter. 2024PF80184

[0124] 15

[0125] In the example shown in Fig. 1, a separate receiver and a separate transmitter are used. In an alternative example, the receiver 3 and the transmitter 4 are combined into a transceiver. The controller 2 may comprise other components typical for a controller of a pixelated lighting device such as a power connector. The invention may be implemented using a computer program running on one or more processors.

[0126] In the example of Fig. 1, the system of the invention is a component of a pixelated lighting device. In alternative examples, the system of the invention may be a different or separate device, e.g. a pixelated lighting device, a mobile device, a bridge, or a cloud computer (cluster).

[0127] Fig. 2 shows a second example of the system for controlling an array of light sources to render color gradient light. In this second example, the system is a bridge 41. The bridge 41 controls a light strip 51, e.g. using Zigbee technology. The light strip 51 comprises a controller 52 and an array of individually controllable light sources 11-19.

[0128] The bridge 41 may be a Philips Hue bridge, for example. The bridge 41 is connected to the wireless LAN access point 23, e.g. via Ethernet or Wi-Fi. As described in relation to Fig. 1, the mobile device 25 is also connected to the wireless LAN access point 23, e.g. via Wi-Fi.

[0129] The bridge 41 comprises a receiver (or input interface) 43, a transmitter (or control interface) 44, a processor 45, and memory 47. The processor 45 is configured to obtain, via the receiver 3, input indicative of at least four gradient stop colors of the color gradient, map the at least four gradient stop colors onto at least four light sources of the array of light sources 11-19, and control, via the transmitter 6, the array of light sources 11-19 to render the at least four colors on the at least three light sources. The input may be received from the mobile device 25, for example. The input may be obtained by first receiving it from the mobile device 25, then storing it in memory 47, and then retrieving it from memory 47 when the color gradient light needs to be rendered. Alternatively, a color gradient may be determined based on the input as soon as the input is received and this color gradient may then be rendered immediately or at a later time.

[0130] The processor 45 is further configured to determine color contrasts between pairs of the at least four gradient stop colors and determine a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts. The processor 5 is configured to map the at least four gradient stop colors onto the at least four light sources based on the gradient stop color sequence. 2024PF80184

[0131] 16

[0132] The bridge 41 may comprise one processor 45 or may comprise multiple processors. The processor 45 of the bridge 41 may be a general-purpose processor, e.g. ARM-based, or an application-specific processor. The processor 45 of the bridge 41 may run a Unix-based operating system for example. The memory 47 may comprise one or more memory units. The memory 47 may comprise one or more hard disks and / or solid-state memory, for example.

[0133] The receiver 43 and the transmitter 44 may use one or more wired or wireless communication technologies such as Zigbee to communicate with the light strip 51 and Ethernet to communicate with the wireless LAN access point 23, for example. In an alternative example, multiple receivers and / or multiple transmitters are used instead of a single receiver and a single transmitter. In the example shown in Fig. 2, a separate receiver and a separate transmitter are used. In an alternative example, the receiver 43 and the transmitter 44 are combined into a transceiver. The bridge 41 may comprise other components typical for a bridge such as a power connector. The invention may be implemented using a computer program running on one or more processors.

[0134] Fig. 3 shows a third example of the system for controlling an array of light sources to render color gradient light. In this third example, the system is a mobile device 81. The mobile device 81 may be a mobile phone or a tablet, for example. A user may be able to use an app running on mobile device 81 to control light strip 51 via the wireless LAN access point 23 and the bridge 21. The bridge 21 has been described in relation to Fig. 1. In the example of Fig. 3, the light strip 51 is controlled via the bridge 21. The light strip 51 may alternatively be controlled without a bridge, e.g. directly via Bluetooth or via the cloud.

[0135] The mobile device 81 comprises a receiver (or input interface) 83, a transmitter (or control interface) 84, a processor 85, a memory 87, and a user interface in the form of a touchscreen display 89. The user interface 89 may be communi cably coupled with the processor 85 and the processor 85 may be configured to obtain input indicative of the at least four gradient stop colors from the user interface 89.

[0136] To this end, the user interface 89 may be configured to comprise a color space, for example an ICTCP, HSV, Lab, CIE XYZ, or CIE YUV color space. The color space may be presented in a suitable shape and form, e.g. in a circle, wheel, or triangle. The user interface 89 may further comprise a control element arranged to adjust one or more of the at least four gradient stop colors in order to vary the color contrast. The user interface may further comprise a control element to vary the contrast options. The control element and the color space may be integrated, such that a user may be able to adjust the gradient stop colors 2024PF80184

[0137] 17 by moving representations of the gradient stop colors within the color space. However, also other implementations are possible, such as drop down menus, text fields, radio buttons, sliders, or other control elements suitable for selecting colors on a user interface 89.

[0138] The processor 85 is configured to obtain, e.g. via the touchscreen display 89, input indicative of the at least four gradient stop colors of the color gradient, map the at least four gradient stop colors onto at least four light sources of the array of light sources 11-19, and control, via the transmitter 6, the array of light sources 11-19 to render the at least four colors on the at least three light sources.

[0139] The processor 85 is further configured to determine color contrasts between pairs of the at least four gradient stop colors and determine a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts. The processor 5 is configured to map the at least four gradient stop colors onto the at least four light sources based on the gradient stop color sequence.

[0140] The mobile device 81 may comprise one processor or may comprise multiple processors. The processor 85 of the mobile device 81 may be a general-purpose processor, e.g. from ARM or Qualcomm or an application-specific processor. The processor 85 of the mobile device 81 may run an Android or iOS operating system for example. The display 89 may comprise an LCD or OLED display panel, for example. The memory 87 may comprise one or more memory units. The memory 87 may comprise solid state memory, for example.

[0141] The receiver 83 and the transmitter 84 may use one or more wireless communication technologies such as Wi-Fi (IEEE 802.11) to communicate with the wireless LAN access point 23, for example. In an alternative example, multiple receivers and / or multiple transmitters are used instead of a single receiver and a single transmitter. In the example shown in Fig. 3, a separate receiver and a separate transmitter are used. In an alternative example, the receiver 83 and the transmitter 84 are combined into a transceiver. The mobile device 81 may further comprise a camera (not shown). This camera may comprise a CMOS or CCD sensor, for example. The mobile device 81 may comprise other components typical for a mobile device such as a battery and a power connector. The invention may be implemented using a computer program running on one or more processors.

[0142] Fig. 4 shows a first example of the method of controlling an array of light sources to render color gradient light. The array comprises at least four individually controllable light sources. The method may be performed by the controller 2 of Fig. 1, the bridge 41 of Fig. 2, or the mobile device 81 of Fig. 3, for example. 2024PF80184

[0143] 18

[0144] An optional step 100 comprises obtaining information indicative of properties of the light array devices in the system, in the room, or in the proximity of a user or (personal) control device. Properties may include type, color rendering capabilities, absolute dimensions, proportions, light pixel distance, relative position (to user, user device or other lighting devices) and orientation, for example.

[0145] A step 101 comprises obtaining input indicative of gradient stop colors of the color gradient light. The gradient stop colors may be, for example, the pre-defined colors from a light scene (a “scene palette”) or may be a set of user-selected colors (e.g. scene colors selected by the user). The input colors may also come from a content input, such as the prominent colors extracted from a video stream or derived from a (user-selected) scene image or from a light script, e.g. associated with a song.

[0146] An optional step 103 comprises obtaining additional data via the input interface. In examples such additional data may be sensor data, data from a clock module, or personal data of a user of the system. The processor may be configured to select and / or sort the gradient stop colors based on sensor data. One or more sensors may be communicably coupled with the processor, i.e. via the input interface. The sensor may for example be an optical sensor, preferably a camera. The processor may further be configured to obtain additional input from a clock module, for example a time of day, the current date, or the season of the year. The processor may also be configured to obtain personal data, such as personal characteristics or preferences of a user.

[0147] Step 103 may also comprise obtaining additional input via the input interface on different contrast options. For example, a user may indicate to prefer a gradient stop color sequence which is (i) maximizing the color contrasts, (ii) minimizing the color contrasts, or (iii) providing an increase in the color contrasts along the length of the color gradient light.

[0148] A step 105 comprises determining color contrasts (CC12, CC13, CC14, CC23, CC24, CC34) between pairs (C1-C2,C1-C3,C1-C4,C2-C3,C2-C4,C3-C4) of the at least four gradient stop colors. The processor may be configured to determine the color contrast between the at least four gradient colors by determining a color contrast between each two gradient stop colors of the at least four gradient stop colors, thus between all possible pairs (i.e. all possible combinations) of gradient stop colors. As already described above, color contrast is a term known in the art and color contrast can be determined using various methods of which two examples are shown in Fig. 7 and Fig. 8, will be described in more detail below. The color contrasts may be represented by one numerical value for each of the determined color contrasts CC12, CC13, CC14, CC23, CC24, and CC34. 2024PF80184

[0149] 19

[0150] A step 107 comprises determining a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts. In other words, the at least four gradient stop colors are ordered or sorted based on the color contrast between each pair of gradient stop colors. As already described above, different gradient stop color sequences are possible. The sequence may for example be chosen based on the gradient options, such as maximizing or minimizing the color contrasts (i.e. the sum of the individual color contrast values of the pairs of gradient stop colors).

[0151] A step 109 comprises mapping (i.e. assigning) the at least four gradient stop colors onto at least four light sources of the array of light sources based on the gradient stop color sequence, optionally additionally based on the light array properties obtained in step 100.

[0152] The mapping may be done such that an amount of contrast between two gradient stop colors mapped to two light sources corresponds to a distance between the two light sources on the array. Thus, the color contrasts determined in step 103 may be used in step 107 and / or in step 109.

[0153] A step 111 comprises controlling the array of light sources to render the at least four gradient stop colors on the at least four light sources as mapped / assigned in step 109.

[0154] A second example of the method of controlling an array of light sources to render color gradient light is shown in Fig. 5. The method may be performed by the controller 2 of Fig. 1, the bridge 41 of Fig. 2, or the mobile device 81 of Fig. 3, for example. The second example shown in Fig. 5 is an extension of the first example of Fig. 4.

[0155] In the example of Fig 5, a step 133 comprises controlling the array of light sources to render the color gradient light. Step 133 comprises step 111 of Fig. 4 and a step 135. Step 111 comprises controlling the array of light sources to render the at least four gradient stop colors on the at least four light sources. Step 135 comprises controlling the array of light sources to render interpolated colors on other light sources of the array of light sources.

[0156] The interpolated colors are determined based on the at least four gradient stop colors by interpolation. The interpolated colors may be determined by a driver of a lighting device that comprises the light sources or by another device, e.g. a mobile device, light bridge, or cloud computer. An optional step 131 comprises determining the interpolated colors based on the at least four colors by interpolation. 2024PF80184

[0157] 20

[0158] If optional step 131 is performed, step 133 may comprise sending color values for each light source in the array to the light sources or to the lighting device that comprises the light source. If optional step 131 is not performed, step 133 may comprise sending only the at least four gradient stop colors to the lighting device that comprises the light sources, optionally along with position indicators indicative of which light sources should render the at least four gradient stop colors. For example, these position indicators may be coordinates / distances (e.g. in centimeters) relative to the start of the pixelated lighting device. As a further example, these position indicators may identify the pixels / light sources on which the (gradient stop) colors need to be rendered. The interpolation performed by the lighting device may use the same or a different color system than the one used in step 105 to determine the color contrasts of the at least four gradient stop colors.

[0159] A third example of the method of controlling an array of light sources to render color gradient light is shown in Fig. 6. The method may be performed by the controller 2 of Fig. 1, the bridge 41 of Fig. 2, or the mobile device 81 of Fig. 3, for example. The third example of Fig. 6 is an extension of the first example of Fig. 4. In the example of Fig. 6, step 109 of Fig. 4 is implemented by a step 181.

[0160] Step 181 comprises mapping the at least four colors onto the at least four light sources based on the color contrasts such that an amount of contrast between two of the at least four colors mapped to two of the at least four light sources corresponds to a distance between the two light sources. Additionally, one or more steps of one or more of the examples of Figs. 4-5 may be added to the example of Fig. 6.

[0161] Fig. 7 visualizes several aspects of determining color contrasts and of determining a gradient stop color sequence. In this example, color contrasts are determined according to the method described by Arthur & Passini in their book Wayfinding from 1992. This method is widely adopted in the art as a reliable method for calculating the contrast difference between two colors. The formula is based on the light reflectance (LR) readings in percentages for each of the gradient stop colors involved. Color contrast is calculated by subtracting the darker color LR2 (lower light reflectance value) from the lighter color LR1 (higher light reflectance value), dividing the difference by the lighter color LR1, and multiplying by 100.

[0162] The table below shows typical light reflectance values of the most common colors. 2024PF80184

[0163] 21

[0164] The example of Fig. 7 shows four gradient stop colors 201-204. In this example, the first gradient stop color 201 is red (LR=13), the second gradient stop color 202 is orange (LR=34), the third gradient stop color 203 is yellow (LR=71), and the fourth gradient stop color 204 is green (LR=17). Fig. 7 shows three different examples of gradient stop color sequences 21-23 based on these four gradient stop colors 201-204. Any one of these three different examples may be selected based on different gradient options, such as maximizing the color contrasts, minimizing the color contrasts, or providing an increase in the color contrasts along the length of the color gradient light. Minimizing, maximizing, or providing an increase in the color contrasts may be based on the (sum of) color contrasts between neighboring gradient stop colors.

[0165] The first gradient stop color sequence 21 is C1-C2-C3-C4 and the relevant color contrasts of neighboring gradient stop colors are CC12, CC23, and CC34 having respective values of 62, 57, and 76 with a sum of 195. The second gradient stop color sequence 22 is C1-C4-C3-C2 and the relevant color contrasts of neighboring gradient stop colors are CC14, CC34, and CC23 having respective values of 24, 50, and 57 with a sum of 131. The third gradient stop color sequence 23 is C1-C4-C2-C3 and the relevant color contrasts of neighboring gradient stop colors is CC14, CC24, and CC23 having respective values of 24, 76, and 57 with a sum of 157.

[0166] In the example of Fig. 7, the first gradient stop color sequence 21 may thus be selected if it is desired to maximize the color contrast, while the second gradient stop color 2024PF80184

[0167] 22 sequence may be selected if minimizing the color contrast or providing an increase in the color contrast is desired.

[0168] Fig 8 shows an example of determining color contrasts by mapping the gradient stop colors onto a color space. The color space may be an ICTCP, HSV, Lab, CIE XYZ, or CIE YUV color space, for example. Fig. 9 shows an example in which four gradient stop colors C1-C4 are mapped to positions C11-C14, respectively, in a color space 200.

[0169] In such examples, determining the color contrasts may comprise determining color distances between the gradient stop colors mapped to the color space. Depending on the color space, the distance may be determined as Euclidian distance or using other methods known in the literature.

[0170] When calculating the color distances, some aspects of a color, such as lightness (brightness), may be excluded. For example, in the case of the Philips Hue system, each color is defined by x, y (capturing chromaticity) and B (capturing brightness) and the color distance may in this case be calculated as a geometrical distance on the xy plane. For preset (saved) scenes, color distance information may be stored as a part of the scene description. The calculation of the color distances may not need to be very precise (depending on the resolution of the array).

[0171] Fig. 8 shows lines representing the calculated distance between each pair of gradient stop colors in the color space 200. For example, a distance CC13 between positions Cll and C13 of gradient stop colors Cl and C3, a distance CC24 between positions C12 and C14 of gradient stop colors C2 and C4, a distance CC14 between positions Cll and C14 of gradient stop colors Cl and C4, and so forth.

[0172] Fig 9 schematically illustrates an example gradient stop color sequence mapping. In accordance with this example, the processor is configured to at least four gradient stop colors, based upon which the color gradient light is to be rendered. In the present example four gradient stop colors C1-C4 are received by the processor.

[0173] After receiving the four gradient stop colors C1-C4, the processor is configured to determine color contrasts between pairs of the four gradient stop colors and to determine a gradient stop color sequence 24 of the four gradient stop colors Cl - C4 based on the determined color contrasts. The gradient stop color sequence 24 may include at least two end points 26, 28 and two intermediate points 32, 34.

[0174] In this example, the gradient stop color sequence 24 a first (end) color point 26 associated with gradient stop color Cl and positioned at a location 0%, a second (intermediate) color point 32 associated with gradient stop color C4 and positioned at a 2024PF80184

[0175] 23 location 33%, a third (intermediate) color point 34 associated with gradient stop color C2 and positioned at a location 66 %, and a fourth (end) color point 28 associated with light output color C3 and positioned at a location 100%.

[0176] The thus formed gradient stop color sequence 24 provides a skeleton or framework around which the color gradient light may then be formed. In particular, each of the color points 26, 28, 32, 34 acts as a fixed color anchor point between which the remainder of the color gradient light will transition.

[0177] After assigning positions for (i.e. mapping) each of the received four gradient stop colors C1-C4 to form the gradient stop color sequence 24, the processor may then be configured to interpolate one or more sets of further light output colors 40, 42, 44, to fill the remainder of the gradient light space extending between each of the mapped gradient stop colors 26, 28, 32, 34. The further light output colors are selected by the processor so as to form a color gradient extending between each neighboring pair of gradient stop colors 26, 28, 32, 34. These gradient stop colors 26, 28, 32, 34 and interpolated color points 40, 42, 44 to be rendered on the other light sources may together define the color gradient light 36 extending along at least a part of the array of light sources.

[0178] Interpolating the further light output colors 40, 42, 44 to populate the remainder of the pattern of color points (illustrated by pattern 36) may be performed in accordance with any standard interpolation process known in the art. In particular, methods for interpolating comprehensive color gradients between a number of defined color points are well known, and may be found for example as features of any basic desktop graphics application. Methods and algorithms for interpolating color gradient patterns will be immediately apparent to the skilled person in the present field.

[0179] Fig. 10 shows an example of a conventional mapping of colors to an ID array, e.g. a pixelated light strip, and an example of an improved mapping based on relating color contrast to a distance. Four gradient stop colors in the gradient stop color sequence Cl, C2, C3, and C4 are mapped to array 281. In the conventional equidistant mapping, gradient stop colors Cl and C4 are mapped to the edges of the array 281 and gradient stop colors C2 and C3 are mapped to one third and two third of the array 281, respectively. This results in the color gradient 231. In the improved mapping, the gradient stop colors C2 and C3 are mapped to a light source of the array 281 based on the amount of color contrast between Cl and C2, the amount of color contrast between C2 and C3 and the amount of color contrast between C3 and C4. In the example of Fig. 10, the gradient stop colors C2 and C3 have a low contrast 2024PF80184

[0180] 24 and are mapped to the light source at approximately 60 and 75% of the length of the array 281. This results in the color gradient 232.

[0181] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0182] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of embodiments of the present invention has been presented for purposes of illustration, but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the present invention. The embodiments were chosen and described in order to best explain the principles and some practical applications of the present invention, and to enable others of ordinary skill in the art to understand the present invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

2024PF8018425CLAIMS:

1. A system (2.41,81) for controlling an array (281) of light sources (11-19) to render color gradient light (231,232,271), the array (281) comprising at least four individually controllable light sources, the system (2,41,81) comprising: an input interface (3,43,83,89) configured to obtain (i) at least four gradient stop colors (C1,C2,C3,C4) and (ii) a gradient contrast option; a processor (5,45,85) configured to:(i) receive the at least four gradient stop colors and the gradient contrast option from the input interface,(ii) determine color contrasts (CC12,CC13,CC14,CC23,CC24,CC34) between pairs (C1-C2, C1-C3,C1-C4,C2-C3,C2-C4,C3-C4) of the at least four gradient stop colors,(iii) determine a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts and the gradient contrast option,(iv) determine a mapping of the at least four gradient stop colors onto at least four light sources of the array of light sources based on the gradient stop color sequence, and a control interface (6,44,84) configured to control the array of light sources to render the gradient stop colors on the at least four light sources.

2. The system (2.41,81) according to claim 1, wherein the gradient contrast option comprises one of (i) maximizing the color contrasts, (ii) minimizing the color contrasts, and (iii) providing an increase in the color contrasts along the length of the color gradient light.

3. The system (2.41,81) according to any one of the preceding claims, wherein the input interface (3,43,83,89) comprises a user interface (89).

4. The system (2.41,81) according to claim 3, wherein the user inface (89) comprises a color space.2024PF80184265. The system (2.41,81) according to claim 3 or 4, wherein the user interface (89) comprises a control element (000) arranged to adjust one or more of the at least four gradient stop colors in order to vary the color contrast.

6. The system (2.41,81) according to any one of the preceding claims, wherein a sum of the color gradient light (231,232,271) is white light having a correlated color temperature in a range from 2000K to 6500K and preferably a color rendering index of at least 80.

7. The system (2.41,81) according to any one of the preceding claims, wherein the processor (5,45,85) is configured to determine the color contrasts based on light reflectance values the at least four gradient stop colors, wherein a first gradient stop color has a first light reflectance value LR1, wherein a second gradient stop color has a second light reflectance value LR2, wherein LR1 is higher than LR2, and wherein the color contrast is determined according to CC=(LR1-LR2) / LR1*1OO.

8. The system (2.41,81) according to any one of the preceding claims, wherein an amount of color contrast between a first gradient stop color being mapped to a first light source of the array of light sources (281) and a second gradient stop color being mapped to a second light source of the array of light sources (281) corresponds to a physical distance between the first light source and the second light source on the array of light sources (281).

9. The system (2.41,81) according to any one of the preceding claims, wherein the array of light sources (281) comprises other light sources (40,42,44), and wherein the processor (5,45,85) is configured to control, via the control interface (6,44,84), the array of light sources (281) to render interpolated colors on the other light sources (40,42,44) of the array of light sources (281), the interpolated colors being determined based on the at least four gradient stop colors.

10. The system (2.41,81) according to any one of the preceding claims, wherein the input interface (3,43,83,89) is configured to obtain sensor data, and wherein the at least four gradient stop colors and / or the gradient contrast option are selected based on the sensor data.2024PF801842711. The system (2.41,81) according to any one of the preceding claims, further comprising a clock module (000), wherein the processor (5,45,85) is configured to select the at least four gradient colors and / or the gradient contrast option depending on time input of the clock module (000).

12. The system (2.41,81) according to any one of the preceding claims, wherein the system further comprises the array (281) of light sources (11-19) rendering the color gradient light.

13. The system (2.41,81) according to any one of claims 1 to 12, wherein (i) a first light source of the at least four individually controllable light sources is comprised by a first lamp or luminaire, (ii) a second light source of the at least four individually controllable light sources is comprised by a second lamp or luminaire, (iii) a third light source of the at least four individually controllable light sources is comprised by a third lamp or luminaire, and (iv) a fourth light source of the at least four individually controllable light sources is comprised by a fourth lamp or luminaire.

14. A system (2.41,81) (000) according to any one of claims 1 to 12, wherein the at least four light sources are comprised in a single lamp or luminaire.

15. A method of controlling an array of light sources to render a color gradient light, the array comprising at least four individually controllable light sources, the method comprising: obtaining (101) at least four gradient stop colors (C1,C2,C3,C4); obtaining (103) a gradient contrast option; determining (105) color contrasts (CC12,CC13,CC14,CC23,CC24,CC34) between pairs (C1-C2, C1-C3,C1-C4,C2-C3,C2-C4,C3-C4) of the at least four gradient stop colors; determining (107) a gradient stop color sequence of the at least four gradient stop colors based on the determined color contrasts and the gradient contrast option; mapping (109) the at least four gradient stop colors onto at least four light sources of the array of light sources based on the gradient stop color sequence; and controlling (111) the array of light sources to render the gradient stop colors on the at least four light sources.

Images