EP4593533A1

EP4593533A1 - Pixelated lighting device

Info

Publication number: EP4593533A1
Application number: EP25152892.3A
Authority: EP
Inventors: Aleksandar Ostojic; Dzmitry Viktorovich Aliakseyeu
Original assignee: Signify Holding BV
Current assignee: Signify Holding BV
Priority date: 2024-01-29
Filing date: 2025-01-20
Publication date: 2025-07-30
Also published as: WO2025162751A1

Abstract

A method of controlling individually controllable lighting units of a pixelated lighting device comprises obtaining (103) an input signal indicating one or more target light output characteristics, ascertaining (101) one or more initial light output characteristics, ascertaining (105) a target transition duration between the initial and target light output characteristics being rendered, determining (107) a difference between the initial and target light output characteristics, determining (109) whether to apply a direct transition or a stepwise transition between the initial and target light output characteristics based on the difference and the target transition duration, determining (111) one or more light settings based on the target light output characteristics and the determined transition, and controlling (113) the lighting units according to the light settings.

Description

FIELD OF THE INVENTION

The invention relates to a pixelated lighting device comprising a plurality of individually controllable lighting units and a central controller for controlling the plurality of lighting units.
The invention further relates to a method of controlling a plurality of individually controllable lighting units of a pixelated lighting device.
The invention also relates to a computer program product enabling a computer system to perform such a method.

BACKGROUND OF THE INVENTION

With the introduction of LED technology, it has become possible to produce light strips to illuminate houses and offices. An advantage of light strips is that they can illuminate a large wide space relatively uniformly. Initially, all LEDs of a light strip were only able to emit one color, e.g. white. Later, certain light strips allowed a user to change the color emitted by the LED nodes, but all LED nodes still emitted the same color. The next advance in light strips was 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.
Current pixelated light strips are often able to render dynamic light effects, e.g., natural effects like candle and fire, dynamic scenes comprising of slow-moving palette colors, such as the dynamic scenes described in WO 2023/052160 A1 , and/or entertainment effects related to music and light integration. However, if a pixelated lighting device comprises a large number of small, direct view, light sources, e.g., e.g. a Christmas tree string, visible transition steps, e.g. brightness steps, may be created, which may negatively impact the user experience.
For example, certain Christmas tree light strings have a 10Hz limit on how quickly all pixels can be updated, which means that it takes the light string 100 milliseconds to update all pixels. If the default switch-on behavior is to transition from off to indicated brightness in 400 milliseconds, this normally creates a pleasant effect of lights gradually switching on. However, on these Christmas tree light strings, this effect will only include 4 brightness steps: 25%/50%/75%/100%. Such a transition will create visible brightness steps which may negatively impact the user experience, especially when switching on to the full brightness.

SUMMARY OF THE INVENTION

It is advantageous to provide a pixelated lighting device, which can be used to create better transitions between two light effects in certain circumstances.
It is advantageous to provide a method, which can be used to create better transitions between two light effects in certain circumstances.
In a first aspect, a pixelated lighting device comprises a plurality of individually controllable lighting units and a central controller for controlling the plurality of lighting units. The central controller is configured to obtain an input signal indicative of a target light effect, the input signal indicating one or more target light output characteristics, the one or more target light output characteristics comprising a target brightness and/or a target color, ascertain one or more initial light output characteristics of an initial light effect, the one or more initial light output characteristics comprising an initial brightness and/or an initial color, and ascertain a target transition duration between the one or more initial light output characteristics being rendered and the one or more target light output characteristics being rendered.
The central controller is further configured to determine a difference between the one or more initial light output characteristics and the one or more target light output characteristics, determine whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference and the target transition duration, wherein for the stepwise transition light settings are rendered at different moments as different steps, determine one or more light settings for the plurality of lighting units based on the one or more target light output characteristics and the determined transition, and control the plurality of lighting units according to the one or more light settings.
This system assesses the impact on the user experience of a stepwise transition based on at least a target transition duration and a difference between one or more initial light output characteristics and one or more target light output characteristics and decides whether to apply this stepwise transition or a direct transition based on this assessment. When a stepwise transition would not look good, e.g. if the transition steps would be quite noticeable, the direct transition may be applied instead. A direct transition may be applied if the target transition duration is at most 800 milliseconds, for example.
The direct transition is an instant transition in the sense that it has a very short duration, e.g. less than 100 milliseconds. For example, direct on or off may actually need 100 milliseconds to execute due to time needed to address all pixels of the pixelated lighting device. The direct transition may be rendered instantaneously, e.g. as soon as possible after receipt of the input signal, for example. The input signal may also indicate the initial light output characteristics and/or the target transition duration. The pixelated lighting device may be a light string, for example.
The central controller may be configured to ascertain the initial light effect's homogeneousness and the target light effect's homogeneousness and determine the difference between the one or more initial light output characteristics and the one or more target light output characteristics based on the initial light effect's homogeneousness and the target light effect's homogeneousness. If all pixels switch from a first color to a second color, i.e. both the initial light effect and the target light effect are homogenous, the transition is homogenous across all pixels and the impact of a lower amount of transition steps is therefore more visible for the user.
When a transition is heterogenous, each pixel might have individual starting and end values. If at least one of the initial light effect and the target light effect is heterogenous, it may be beneficial to determine a difference between initial and target light characteristics per pixel and then use certain metrics (e.g. no more than 20% of pixel transitions are estimated to look bad when a stepwise transition would be applied) to decide between a stepwise or direct transition.
The central controller may be configured to obtain information indicative of a rate at which each of the plurality of lighting units can render successive light settings, and determine whether to apply the direct transition or the stepwise transition in dependence on the rate. This may be beneficial when the same central controller is used in multiple types of pixelated lighting devices, e.g. in pixelated lighting devices with different quantities of lighting units, for example.
The central controller may be configured to decide on a quantity of steps for the stepwise transition based on the target transition duration and the rate at which each of the plurality of lighting units can render successive light settings, and determine the one or more light settings for the stepwise transition further based on the decided quantity of steps. For example, if the target transition duration is 400 milliseconds, and the rate is 100 milliseconds, the decided quantity of steps may be 4.
Alternatively, e.g. if the central controller is made specifically for the pixelated lighting device, the central controller may be able to decide on a quantity of steps for the stepwise transition based on just the target transition duration, e.g. using a mapping from target transition duration to quantity of steps.
The central controller may be configured to decide on the quantity of steps further based on the difference. For example, less than the maximum quantity of steps may be used if the difference between initial and target light output characteristics is relatively small. Alternatively, the maximum quantity of steps (considering the target transition duration and the rate) may always be used.
The central controller may be configured to control the plurality of lighting units to render the stepwise transition with a prolonged transition duration, the prolonged transition duration being longer than the target transition duration. The prolonged transition duration may be limited, e.g. at most 30% or one second longer than the target transition duration. The additional transition duration (and/or maximum thereof) may be determined based on the type of light effect and/or on factory/user configuration, for example.
The central controller may be configured to determine a moment at which to control the plurality of lighting units to render the direct transition, the moment occurring during the target transition duration, and control the plurality of lighting units according to the one or more light settings at the determined moment to render the direct transition. Thus, the direct transition may be rendered instantaneously, e.g. as soon as possible after receipt of the input signal, or may be rendered later during the target transition duration.
As a first example, the central controller may be configured to obtain information indicative of a type of the target light effect and determine the moment based on the type of the target light effect. For instance, the central controller may be configured to determine the moment to be at the end of the target transition duration or at half the target transition duration if the type of the target light effect is an entertainment light effect, the entertainment light effect being based on audio and/or video content and to be rendered while the audio and/or video content is being reproduced on an audio and/or video device. This may be done to help ensure that synchronization between the pixelating lighting device and the audio and/or video device is maintained.
As a second example, the central controller may be configured to determine whether one or more other lighting devices of another type are also participating in rendering the target light effect and determine the moment based on whether one or more other lighting devices of another type are also participating in rendering the target light effect. This may be done to help ensure that synchronization between the pixelating lighting device and other lighting devices is maintained.
The central controller may be configured to determine the moment to be at the end of the target transition duration or at half the target transition duration in this case. For instance, the central controller may be configured to determine the moment to be at the end of the target transition duration or at half the target transition duration if at least one of the one or more other lighting devices of another type does apply the stepwise transition, e.g. if it is a non-pixelated lighting device or a pixelated lighting device with relatively few lighting units.
As a third example, the central controller may be configured to determine the moment based on the target transition duration. For example, if the target transition duration is shorter than a certain threshold, the direct transition may be rendered instantaneously, and if it is longer, the moment may be determined based on the type of the target light effect and/or another parameter.
As a fourth example, the pixelating lighting device may be comprised in a lighting system and the central controller may be configured to receive a target light configuration from another device in the lighting system and determine the moment based on the target light configuration. This is beneficial if the lighting system knows what the desired behavior for determining the moment (e.g. render immediately or render in-between) is but the pixelated lighting device does not have enough information to determine this. The other device of the lighting system may then pass this information as part of the target light configuration.
In a second aspect of the invention, a method of controlling a plurality of individually controllable lighting units of a pixelated lighting device comprises obtaining an input signal indicative of a target light effect, the input signal indicating one or more target light output characteristics, the one or more target light output characteristics comprising a target brightness and/or a target color, ascertaining one or more initial light output characteristics of an initial light effect, the one or more initial light output characteristics comprising an initial brightness and/or an initial color, and ascertaining a target transition duration between the one or more initial light output characteristics being rendered and the one or more target light output characteristics being rendered.
The method further comprises determining a difference between the one or more initial light output characteristics and the one or more target light output characteristics, determining whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference and the target transition duration, wherein for the stepwise transition light settings are rendered at different moments as different steps, determining one or more light settings for the plurality of lighting units based on the one or more target light output characteristics and the determined transition, and controlling the plurality of lighting units according to the one or more light settings. Said method may be performed by software running on a programmable device. This software may be provided as a computer program product.
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.
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 a plurality of individually controllable lighting units of a pixelated lighting device.
The executable operations comprise obtaining an input signal indicative of a target light effect, the input signal indicating one or more target light output characteristics, the one or more target light output characteristics comprising a target brightness and/or a target color, ascertaining one or more initial light output characteristics of an initial light effect, the one or more initial light output characteristics comprising an initial brightness and/or an initial color, and ascertaining a target transition duration between the one or more initial light output characteristics being rendered and the one or more target light output characteristics being rendered.
The executable operations further comprise determining a difference between the one or more initial light output characteristics and the one or more target light output characteristics, determining whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference and the target transition duration, wherein for the stepwise transition light settings are rendered at different moments as different steps, determining one or more light settings for the plurality of lighting units based on the one or more target light output characteristics and the determined transition, and controlling the plurality of lighting units according to the one or more light settings.
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 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.
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.
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.
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), Swift, Dart, 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 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).
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.
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.
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.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of devices, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention are apparent from and will be further elucidated, by way of example, with reference to the drawings, in which:

Fig. 1 is a block diagram of an embodiment of the system;
Fig. 2 is a flow chart of a first embodiment of the method;
Fig. 3 is a flow chart of a second embodiment of the method;
Fig. 4 is a flow chart of a third embodiment of the method;
Fig. 5 is a flow chart of a fourth embodiment of the method; and
Fig. 6 is a block diagram of an exemplary data processing system for performing the method of the invention.

Corresponding elements in the drawings are denoted by the same reference numeral.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 shows an embodiment of the pixelated lighting device. The pixelated lighting device 1 comprises a plurality of individually controllable lighting units 11-19 (also referred to as pixels) and a central controller 2 for controlling the plurality of lighting units 11-19. The pixelated lighting device 1 may be a light string, for example. The lighting units may be LEDs or LED segments, for example. For the sake of simplicity, the pixelated lighting device 1 of Fig. 1 comprises only nine lighting units. In practice, a pixelated lighting device will often have more than nine lighting units.
In the example of Fig. 1, the pixelated lighting device 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 is also 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 pixelated lighting device 1 via the wireless LAN access point 23 and the bridge 21. In an alternative example, the pixelated lighting device 1 is controlled without a bridge, e.g. directly via Bluetooth or via the cloud.
The controller 2 comprises a receiver 3, a transmitter 4, a processor 5, a control interface 6, and a memory 7. The processor 5 is configured to obtain an input signal indicative of a target light effect, e.g. from the mobile device 25, and ascertain one or more initial light output characteristics of an initial light effect. The input signal indicates one or more target light output characteristics. The one or more target light output characteristics comprise a target brightness and/or a target color and are ascertained from the input signal. The one or more initial light output characteristics comprise an initial brightness and/or an initial color. The one or more initial light output characteristics may be determined from the input signal or obtained from memory 7, for example.
The processor 5 is further configured to ascertain a target transition duration between the one or more initial light output characteristics being rendered and the one or more target light output characteristics being rendered, determine a difference between the one or more initial light output characteristics and the one or more target light output characteristics, and determine whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference and the target transition duration.
The target transition duration may be determined from the input signal, for example. For the stepwise transition, light settings are rendered at different moments as different steps. The processor 5 is further configured to determine one or more light settings for the plurality of lighting units 11-19 based on the one or more target light output characteristics and the determined transition and control the plurality of lighting units 11-19 according to the one or more light settings.
The central controller 2 may use power-line communication to set the PWM (Pulse Width Modulation) values for each lighting unit of the pixelated lighting device, e.g. by injecting command data (the PWM values) on top of a 24V power line. Each of the lighting units 11-19 may then extract the PWM value that is intended for it from the power line. Each lighting unit typically has a hard-coded address e.g. between 0-249 for 250 LED string. Address 0 is for the lighting unit 11, which is closest to the controller 2, and address 8 is for lighting unit 19 (or 249 for a 250 LED string), which is farthest from the controller 2.
Power-line communication is relatively slow; it takes about 100 milliseconds to transfer PWM values for all 250 LEDs of a 250 LED string. Since it takes 100 milliseconds to set all LEDs to the desired PWM values, the maximum refresh rate for lighting content is limited to 10Hz.
In the embodiment of the controller 2 shown in Fig. 1, the controller 2 comprises one processor 5. In an alternative embodiment, the controller 2 comprises multiple processors. The processor 5 of the controller 2 may be a general-purpose processor or an application-specific 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 embodiment, multiple receivers and/or multiple transmitters are used instead of a single receiver and a single transmitter.
In the embodiment shown in Fig. 1, a separate receiver and a separate transmitter are used. In an alternative embodiment, 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.
A first embodiment of the method of controlling a plurality of individually controllable lighting units of a pixelated lighting device is shown in Fig. 2. The method may be performed by the central controller 2 of Fig. 1, for example.
A step 101 comprises ascertaining one or more initial light output characteristics of an initial light effect. The one or more initial light output characteristics comprise an initial brightness and/or an initial color. A step 103 comprises obtaining an input signal indicative of a target light effect. The input signal indicates one or more target light output characteristics. The one or more target light output characteristics comprise a target brightness and/or a target color.
In the embodiment of Fig. 2, steps 101 and 103 are independent steps. In an alternative embodiment, the input signal obtained in step 103 indicates the one or more initial light output characteristics and step 101 comprises ascertaining the one or more initial light output characteristics from the input signal.
Step 105 comprises ascertaining a target transition duration between the one or more initial light output characteristics (ascertained in step 101) being rendered and the one or more target light output characteristics (obtained in step 103) being rendered. In the embodiment of Fig. 2, steps 105 and 103 are independent steps. The target transition duration may be a default transition duration or may be specified in another input signal, for example. In an alternative embodiment, the input signal obtained in step 103 indicates the target transition duration and step 105 comprises ascertaining the target transition duration from the input signal.
Step 107 is performed after steps 101 and 103 have been performed. Step 107 comprises determining a difference between the one or more initial light output characteristics (ascertained in step 101) and the one or more target light output characteristics (obtained in step 103). A step 109 is performed after steps 105 and 107 have been performed. Step 109 comprises determining whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference (determined in step 107) and the target transition duration (ascertained in step 105). For the stepwise transition, light settings are rendered at different moments as different steps.
When a stepwise transition would not look good, e.g. if the transition steps would be quite noticeable, a direct transition may be applied instead. A direct transition may be applied if the target transition duration is at most 800 milliseconds, for example. The direct transition is an instant transition in the sense that it has a very short duration, e.g. less than 100 milliseconds. For example, direct on or off may actually need 100 milliseconds to execute due to time needed to address all pixels of the pixelated lighting device.
Step 109 may comprise performing a calculation with a predefined set of parameters. For example, if the difference divided by the maximum quantity of steps (which depends on the target transition time), i.e. the step size, is larger than a step size threshold, then the direct transition may be applied, and if the step size is smaller than the step size threshold, then the stepwise transition may be applied. If the step size is smaller than the threshold, then the step is deemed perceptually unnoticeable. If the step size is larger than the threshold, then the step is deemed perceptually noticeable.
Alternatively, step 109 may comprise looking up in a lookup table which transition to apply. The lookup table may comprises a stepwise/direct transition flag per range of (light characteristic) difference values. The later approach may be applied, for example, if the relation is not linear and is based on empirical data (observations).
For instance, when the target transition duration is 400 milliseconds and the color is changed from turquoise to cyan (small perceptual difference), a stepwise transition may be applied. When the target transition duration is 400 milliseconds and the color is changed from blue to yellow (big perceptual difference which would have, at 400 milliseconds using 4 steps, big noticeable steps that look bad), a direct transition may be applied. In this example, it is assumed that the rate at which transitions can be executed is 10 Hz (i.e. maximum one transition per 100 milliseconds).
Step 109 may comprise determining to apply the direct transition only if the target transition duration does not exceed a (e.g. predefined) duration threshold. Short transitions (-400 milliseconds) can look very bad, but a one hour transition between two light effects will not look bad and is preferably not shortened, since this might considerably alter the content that the lighting device needs to render.
If both a difference in brightness and a difference in color are determined in step 107, then step 109 may comprise deciding to apply a stepwise transition if a stepwise transition is suitable for both the brightness difference and the color difference and deciding to apply a direct transition otherwise.
A step 111 comprises determining one or more light settings for the plurality of lighting units based on the one or more target light output characteristics (obtained in step 103) and the transition determined in step 109. For example, if it was decided in step 109 to apply a stepwise transition, a first set of one or more light settings may be determined for the first step based on the one or more initial light output characteristics and a calculated step size and each next set of one or more light settings may be determined for each next step based on the previous set of one or more light settings and the calculated step size. If it was decided in step 109 to apply a direct transition, the one or more light settings determined in step 111 may correspond to the one or more target light output characteristics.
A step 113 comprises controlling the plurality of lighting units according to the one or more light settings determined in step 111. The direct transition may be rendered instantaneously, e.g. as soon as possible after receipt of the input signal, for example. If the lighting units are controlled to render the stepwise transition, the lighting units may be optionally controlled to render the stepwise transition with a prolonged transition duration. The prolonged transition duration is longer than the target transition duration.
For example, if the requested transition time (i.e. the target transition time) is 1 second, the calculated step size (for the requested transition time) would be just a little above the step size threshold, and a perfect transition could be executed in 1.2 seconds, then the stepwise transition may be prolonged rather than applying a direct transition. The prolonged transition duration may be limited, e.g. at most 30% or one second longer than the target transition duration. The additional transition duration (and/or maximum thereof) may be determined based on the type of light effect and/or on factory/user configuration, for example. Additionally, one or more steps of one or more of the other embodiments of the method may be added to the embodiment of Fig. 2.
A second embodiment of the method of controlling a plurality of individually controllable lighting units of a pixelated lighting device is shown in Fig. 3. The embodiment of Fig. 3 is an extension of the embodiment of Fig. 2. In the embodiment of Fig. 3, step 107 of Fig. 2 is implemented by a step 133 and a step 131 is performed between steps 101 and 103 of Fig. 3 and step 133.
Step 131 comprises ascertain the initial light effect's homogeneousness and the target light effect's homogeneousness. Step 133 comprises determining the difference between the one or more initial light output characteristics and the one or more target light output characteristics based on the initial light effect's homogeneousness and the target light effect's homogeneousness. If all pixels switch from a first color to a second color, i.e. both the initial and target light effects are homogenous, the transition is homogenous across all pixels and the impact of a lower amount of transition steps is therefore more visible for the user.
When a transition is heterogenous, each pixel might have individual starting and end values. If at least one of the initial and target light effects is heterogenous, it may be beneficial to determine a difference between initial and target light characteristics per pixel and then use certain metrics (e.g. no more than 20% of pixel transitions are estimated to look bad when a stepwise transition would be applied) to decide between a stepwise or direct transition. Additionally, one or more steps of one or more of the other embodiments of the method may be added to the embodiment of Fig. 3.
A third embodiment of the method of controlling a plurality of individually controllable lighting units of a pixelated lighting device is shown in Fig. 4. The embodiment of Fig. 4 is an extension of the embodiment of Fig. 2. In the embodiment of Fig. 4, step 109 of Fig. 2 is implemented by a step 153, step 111 of Fig. 2 is implemented by a step 157, a step 151 is performed before step 153 and a step 155 is performed between steps 153 and 157.
Step 151 comprises obtaining information indicative of a rate at which each of the plurality of lighting units can render successive light settings, e.g. from a local (non-volatile) memory. Step 153 comprises determining whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference (determined in step 107) and the target transition duration (ascertained in step 105) in dependence on the rate indicated in the information obtained in step 151.
Step 155 comprises deciding on a quantity of steps for the stepwise transition based on the target transition duration (ascertained in step 105) and the rate at which each of the plurality of lighting units can render successive light settings (indicated in the information obtained in step 151). For example, if the target transition duration is 400 milliseconds, and the rate is 100 milliseconds, the decided quantity of steps may be 4.
In step 155, the quantity of steps for the stepwise transition is optionally decided based on the difference determined in step 107. For example, less than the maximum quantity of steps may be used if the difference between initial and target light output characteristics is relatively small. Alternatively, the maximum quantity of steps (considering the target transition duration and the rate) may always be used.
Step 157 comprises determining one or more light settings for the plurality of lighting units based on the one or more target light output characteristics (obtained in step 103), the transition determined in step 109, and the quantity of steps decided in step 155. Step 113 comprises controlling the plurality of lighting units according to the one or more light settings determined in step 157.
If the lighting units are controlled to render the stepwise transition, the lighting units may be optionally controlled to render the stepwise transition with a prolonged transition duration in step 113. The prolonged transition duration is longer than the target transition duration. Additionally, one or more steps of one or more of the other embodiments of the method may be added to the embodiment of Fig. 4.
A fourth embodiment of the method of controlling a plurality of individually controllable lighting units of a pixelated lighting device is shown in Fig. 5. The embodiment of Fig. 5 is an extension of the embodiment of Fig. 2. In the embodiment of Fig. 5, step 113 of Fig. 2 is implemented by a step 175, a step 173 is performed before step 175, and an optional step 171 is performed between steps 111 and 173.
Optional step 171 comprises obtaining information indicative of a type of the target light effect. Step 173 comprises determining a moment at which to control the plurality of lighting units to render the direct transition. The moment occurs during the target transition duration. Step 173 may comprise determining the moment based on the type of the target light effect optionally obtained in step 171.
For example, step 173 may comprise determining the moment to be at the end of the target transition duration or at half the target transition duration if the type of the target light effect is an entertainment light effect. A light effect is considered an entertainment light effect if it is based on audio and/or video content and to be rendered while the audio and/or video content is being reproduced on an audio and/or video device. An example of another type of light effect is an ambience light effect.
Additionally or alternatively, step 173 may comprise determining the moment based on the target transition duration ascertained in step 105. For example, if the target transition duration is shorter than a certain threshold, the direct transition may be rendered instantaneously, and if it is longer, the moment may be determined based on the type of the target light effect and/or another parameter.
Additionally or alternatively, step 173 may comprise determining the moment based on whether one or more other lighting devices of another type are also participating in rendering the target light effect. For example, step 173 may comprise determining the moment to be at the end of the target transition duration or at half the target transition duration in this case. For instance, the moment may be determined to be at the end of the target transition duration or at half the target transition duration if at least one of the one or more other lighting devices of another type does apply the stepwise transition, e.g. if it is a non-pixelated lighting device or a pixelated lighting device with relatively few lighting units.
Additionally or alternatively, step 173 may comprise determining the moment based on a target light configuration received from another device, e.g. a light controller, in the same lighting system. This is beneficial if the lighting system knows what the desired behavior for determining the moment (e.g. render immediately or render in-between) is but the pixelated lighting device does not have enough information to determine this. The other device of the lighting system may then pass this information as part of the target light configuration.
Step 175 comprises controlling the plurality of lighting units according to the one or more light settings determined in step 111. If the transition determined in step 109 is the direct transition, step 175 comprises controlling the plurality of lighting units according to the one or more light settings at the moment determined in step 173. Additionally, one or more steps of one or more of the other embodiments of the method may be added to the embodiment of Fig. 5.
Fig. 6 depicts a block diagram illustrating an exemplary data processing system that may perform the method as described with reference to Figs. 2-5.
As shown in Fig. 6, the data processing system 300 may include at least one processor 302 coupled to memory elements 304 through a system bus 306. As such, the data processing system may store program code within memory elements 304. Further, the processor 302 may execute the program code accessed from the memory elements 304 via a system bus 306. In one aspect, the data processing system may be implemented as a computer that is suitable for storing and/or executing program code. It should be appreciated, however, that the data processing system 300 may be implemented in the form of any system including a processor and a memory that is capable of performing the functions described within this specification.
The memory elements 304 may include one or more physical memory devices such as, for example, local memory 308 and one or more bulk storage devices 310. The local memory may refer to random access memory or other non-persistent memory device(s) generally used during actual execution of the program code. A bulk storage device may be implemented as a hard drive or other persistent data storage device. The processing system 300 may also include one or more cache memories (not shown) that provide temporary storage of at least some program code in order to reduce the quantity of times program code must be retrieved from the bulk storage device 310 during execution. The processing system 300 may also be able to use memory elements of another processing system, e.g. if the processing system 300 is part of a cloud-computing platform.
Input/output (I/O) devices depicted as an input device 312 and an output device 314 optionally can be coupled to the data processing system. Examples of input devices may include, but are not limited to, a keyboard, a pointing device such as a mouse, a microphone (e.g. for voice and/or speech recognition), or the like. Examples of output devices may include, but are not limited to, a monitor or a display, speakers, or the like. Input and/or output devices may be coupled to the data processing system either directly or through intervening I/O controllers.
In an embodiment, the input and the output devices may be implemented as a combined input/output device (illustrated in Fig. 6 with a dashed line surrounding the input device 312 and the output device 314). An example of such a combined device is a touch sensitive display, also sometimes referred to as a "touch screen display" or simply "touch screen". In such an embodiment, input to the device may be provided by a movement of a physical object, such as e.g. a stylus or a finger of a user, on or near the touch screen display.
A network adapter 316 may also be coupled to the data processing system to enable it to become coupled to other systems, computer systems, remote network devices, and/or remote storage devices through intervening private or public networks. The network adapter may comprise a data receiver for receiving data that is transmitted by said systems, devices and/or networks to the data processing system 300, and a data transmitter for transmitting data from the data processing system 300 to said systems, devices and/or networks. Modems, cable modems, and Ethernet cards are examples of different types of network adapter that may be used with the data processing system 300.
As pictured in Fig. 6, the memory elements 304 may store an application 318. In various embodiments, the application 318 may be stored in the local memory 308, the one or more bulk storage devices 310, or separate from the local memory and the bulk storage devices. It should be appreciated that the data processing system 300 may further execute an operating system (not shown in Fig. 6) that can facilitate execution of the application 318. The application 318, being implemented in the form of executable program code, can be executed by the data processing system 300, e.g., by the processor 302. Responsive to executing the application, the data processing system 300 may be configured to perform one or more operations or method steps described herein.
Fig. 6 shows the input device 312 and the output device 314 as being separate from the network adapter 316. However, additionally or alternatively, input may be received via the network adapter 316 and output be transmitted via the network adapter 316. For example, the data processing system 300 may be a cloud server. In this case, the input may be received from and the output may be transmitted to a user device that acts as a terminal.
Various embodiments of the invention may be implemented as a program product for use with a computer system, where the program(s) of the program product define functions of the embodiments (including the methods described herein). In one embodiment, the program(s) can be contained on a variety of non-transitory computer-readable storage media, where, as used herein, the expression "non-transitory computer readable storage media" comprises all computer-readable media, with the sole exception being a transitory, propagating signal. In another embodiment, the program(s) can be contained on a variety of transitory computer-readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. The computer program may be run on the processor 302 described herein.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
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

A pixelated lighting device (1) comprising a plurality of individually controllable lighting units (11-19) and a central controller (2) for controlling the plurality of lighting units, the central controller (2) being configured to:
- obtain an input signal indicative of a target light effect, the input signal indicating one or more target light output characteristics, the one or more target light output characteristics comprising a target brightness and/or a target color,

- ascertain one or more initial light output characteristics of an initial light effect, the one or more initial light output characteristics comprising an initial brightness and/or an initial color,

- ascertain a target transition duration between the one or more initial light output characteristics being rendered and the one or more target light output characteristics being rendered,

- determine a difference between the one or more initial light output characteristics and the one or more target light output characteristics,

- determine whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference and the target transition duration, wherein for the stepwise transition light settings are rendered at different moments as different steps,

- determine one or more light settings for the plurality of lighting units (11-19) based on the one or more target light output characteristics and the determined transition, and

- control the plurality of lighting units (11-19) according to the one or more light settings.
A pixelated lighting device (1) as claimed in any one of the preceding claims, wherein the central controller (2) is configured to:
- ascertain the initial light effect's homogeneousness and the target light effect's homogeneousness, and

- determine the difference between the one or more initial light output characteristics and the one or more target light output characteristics based on the initial light effect's homogeneousness and the target light effect's homogeneousness.
A pixelated lighting device (1) as claimed in claim 1 or 2, wherein the central controller (2) is configured to:
- obtain information indicative of a rate at which each of the plurality of lighting units (11-19) can render successive light settings, and

- determine whether to apply the direct transition or the stepwise transition in dependence on the rate.
A pixelated lighting device (1) as claimed in claim 3, wherein the central controller (2) is configured to:
- decide on a quantity of steps for the stepwise transition based on the target transition duration and the rate at which each of the plurality of lighting units (11-19) can render successive light settings, and

- determine the one or more light settings for the stepwise transition further based on the decided quantity of steps.
A pixelated lighting device (1) as claimed in claim 4, wherein the central controller (2) is configured to decide on the quantity of steps further based on the difference.
A pixelated lighting device (1) as claimed in any one of the preceding claims, wherein the central controller (2) is configured to control the plurality of lighting units (11-19) to render the stepwise transition with a prolonged transition duration, the prolonged transition duration being longer than the target transition duration.
A pixelated lighting device (1) as claimed in any one of the preceding claims, wherein the central controller (2) is configured to:
- determine a moment at which to control the plurality of lighting units (11-19) to render the direct transition, the moment occurring during the target transition duration, and

- control the plurality of lighting units (11-19) according to the one or more light settings at the determined moment to render the direct transition.
A pixelated lighting device (1) as claimed in claim 7, wherein the central controller (2) is configured to:
- obtain information indicative of a type of the target light effect, and

- determine the moment based on the type of the target light effect.
A pixelated lighting device (1) as claimed in claim 8, wherein the central controller (2) is configured to determine the moment to be at the end of the target transition duration or at half the target transition duration if the type of the target light effect is an entertainment light effect, the entertainment light effect being based on audio and/or video content and to be rendered while the audio and/or video content is being reproduced on an audio and/or video device.
A pixelated lighting device (1) as claimed in any one of claims 7 to 9, wherein the central controller (2) is configured to determine the moment based on the target transition duration.
A pixelated lighting device (1) as claimed in any one of the preceding claims, wherein the input signal indicates the initial light output characteristics.
A pixelated lighting device (1) as claimed in any one of the preceding claims, wherein the input signal indicates the target transition duration.
A pixelated lighting device (1) as claimed in any one of the preceding claims, wherein the pixelated lighting device (1) is a light string.
A method of controlling a plurality of individually controllable lighting units of a pixelated lighting device, the method comprising:
- obtaining (103) an input signal indicative of a target light effect, the input signal indicating one or more target light output characteristics, the one or more target light output characteristics comprising a target brightness and/or a target color;

- ascertaining (101) one or more initial light output characteristics of an initial light effect, the one or more initial light output characteristics comprising an initial brightness and/or an initial color;

- ascertaining (105) a target transition duration between the one or more initial light output characteristics being rendered and the one or more target light output characteristics being rendered;

- determining (107) a difference between the one or more initial light output characteristics and the one or more target light output characteristics;

- determining (109) whether to apply a direct transition or a stepwise transition between the one or more initial light output characteristics and the one or more target light output characteristics based on the difference and the target transition duration, wherein for the stepwise transition light settings are rendered at different moments as different steps;

- determining (111) one or more light settings for the plurality of lighting units based on the one or more target light output characteristics and the determined transition; and

- controlling (113) the plurality of lighting units according to the one or more light settings.
A computer program product for a computing device, the computer program product comprising computer program code to perform the method of claim 14 when the computer program product is run on a processing unit of the computing device.