WO2008142616A1

WO2008142616A1 - Method and unit for control of ambient lighting

Info

Publication number: WO2008142616A1
Application number: PCT/IB2008/051912
Authority: WO
Inventors: Bram Kater; Ramon A. W. Clout; Dragan Sekulovski; Mauro Barbieri; Srinivas R Gutta; Johannes Weda
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2007-05-22
Filing date: 2008-05-15
Publication date: 2008-11-27
Anticipated expiration: 2009-11-22

Abstract

A method for control of ambient lighting is proposed that can be used to automatically generate ambient lighting effects naturally following video content. The method includes determining a lighting effect concept based on data representing a genre of the video content, and then calculate control parameters for controlling the ambient lighting according to the determined lighting effect concept. The genre of the video content may be 5 based on analyzing the video content according to known methods, and/or based on external information, e.g. Electronic Program Guide services. It may be preferred to allow different genre classifications at program level as well as section levels so as to allow different lighting effect concepts in different sections of one TV program. In some embodiments the genre dependencyis implemented by selecting between different predefined lighting effect 10 concepts, e.g. color calculation concepts. In some embodiments the genre dependency is implemented by a filter modifying at least some of the ambient controlparameters generated by a fixed calculation concept. A user input may be used to influence e.g. the determination oflighting effect concept in response to the genre of the video content.

Description

Method and unit for control of ambient lighting

FIELD OF THE INVENTION

The present invention relates to a method and a unit for control of ambient lighting, e.g. ambient lighting for a display device including an image display region. Further, the invention relates to a display device comprising such an ambient lighting control unit.

BACKGROUND OF THE INVENTION

Ambient lighting or ambilight is a well-known concept that enhances the viewing experience when watching TV by means of ambient lighting, i.e. controllable light sources positioned outside the boundaries of the TV screen. In ambilight, lamps are normally located behind the TV set, and an extension of the image is projected on the wall behind the TV. The color and intensity of the ambilight is determined based on the actual video information according to a certain algorithm, such that the ambilight supports the image being displayed on the TV screen. Most often there is a Red-Green-Blue (RGB) triplet of CCFL lamps on each side of the display. In other words, there is one pixel of colored light projected onto the wall for each side of the display (i.e. left, right, top, and bottom).

Several lighting effect concepts, or ambient lighting control strategies, have been suggested for controlling the rather simple and low cost ambilight sources derived based on the video signal applied to the display, the purpose being to visually support the image being produced by the display, e.g. on a frame to frame basis. WO 2005/069639 describes an example of a lighting effect concept where the color of the ambient lighting for each of the four sides of the video display is based on an average color of the outer region of the image, and thus the ambient lighting appears to extend the content of the displayed image.

In another lighting effect concept example, the ambient lighting all around the display has the same color and intensity, this color and intensity being determined based on an average color and intensity of the entire image. In an even simpler concept, the ambient lighting has a fixed and preset color and intensity, independent on the image produced by the display. Further, in some TV sets with ambient lighting, different preset lighting effect concepts can be selected by the user, so as to allow the user to gain the best experience from the ambient lighting according to personal preferences.

SUMMARY OF THE INVENTION

Following the above explanation, it may be seen as an object of the present invention to provide an ambient lighting control method and system providing the user with an improved visual ambient lighting experience in which the ambient lighting effect follows the video content without the need for manual involvement in selecting between different lighting effect concepts.

According to one aspect the invention provides a method for controlling ambient lighting in response to video content, the method including determining a lighting effect concept based on data representing a genre of the video content, and - calculating control parameters for controlling the ambient lighting according to the lighting effect concept.

Such method is advantageous for automatic ambient lighting control since it takes into account the genre of the video content being displayed. Thus, e.g. the lighting effect concept can be selected depending on the current video content, such that the ambient lighting suits the specific genre of the video content. Considering e.g. an explosion scene it is obvious that the same piece of video content in a news bulletin and in an action film should preferably not be accompanied by the same type of ambient lighting effect, i.e. the preferred lighting effect concept is highly genre dependent. Thus, with the introduction of genre dependent determination of the lighting effect concept, it is possible to provide a "news bulletin concept" and an "action film concept" that will serve to provide different ambient lighting effects for an explosion scene in a news program and in an action film, e.g. a fixed color with low intensity lighting effect concept for the news program, and a high intensity, fast responding, full color type of lighting effect concept in the action film.

For example, when watching a TV film disrupted by commercials, the best ambient lighting experience requires different lighting effect concepts for the film and for the commercials. E.g. it may be preferred that the ambient lighting is dimmed, set to constant light or completely switched off during commercials, while a more dynamic lighting effect concept with higher light intensity and brighter colors may be preferred to underline the content of the film. Thus, by determining the lighting effect concept based on the current genre of the video content, it is possible to provide automatic ambient lighting that suits the video content in a natural way.

By 'lighting effect concept' is understood the algorithm, strategy or mapping used to control the ambient lighting, e.g. in response to the video content. The concept may be very simple, e.g. "switched off, or it may include a complicated relationship between parameters controlling the ambient lighting and attributes of the video content. Especially, the lighting effect concept may define parameters for influencing the ambient lighting with respect to at least one of: color, light intensity, spatial distribution, and temporal evolution. By 'data representing a genre' is understood an indicator of the semantic content of the video content. E.g. the indicator can indicate genres such as: news, documentary, film, sports, commercials etc. The genre data may be received for a TV program from an external information source, e.g. an Electronic Program Guide (EPG), or the genre may be determined or estimated based on a content analysis of the video content, such as known in the art. In preferred embodiments, the method further includes generating the data representing a genre of the video content. This generation of the data representing the genre may be based on an analysis of the video content, and/or it may be based on external information, e.g. information provided by an Electronic Program Guide (EPG) in case the content is a TV program, e.g. provided from the Internet. Alternatively, the genre data may be provided by as additional data on the same medium, e.g. a DVD, as the video content.

In some embodiments, the method includes performing an image analysis on the video content, and wherein the calculation of the control parameters is based on a result of the image analysis. Many lighting effect concepts are based on determining the ambient lighting control parameters based on attributes of the images being displayed, and thus such concepts require that the video content is concurrently analyzed with respect to those attributes in order to be able to calculate the control parameters according thereto.

In some embodiments, a user input is received, and the calculation of the control parameters is then based on this user input. Hereby the user can influence the choice of the lighting effect concept and/or influence at least some of the control parameters thereof according to his/her personal preferences. Especially, the calculation of the control parameters may be influenced by the user input by the determination of lighting effect concept being based on the user input. Thus, the user input may be used to influence the choice of lighting effect concept for a given genre, e.g. by defining a set of relations between genre and lighting effect concepts, or by altering a pre-defined set of relations. In preferred embodiments, the determination of a lighting effect concept is based on selecting one from a predefined set of lighting effect concepts. Thus, it is possible to provide a table of corresponding lighting effect concepts and genres. Thereby, the task of determining the lighting effect concept is very simple, once the genre of the video content is determined.

The method may include determining different lighting effect concepts for separate sections of the video content. For example, in case the video content is a TV program, the program may include separate sections with different genres or sub genres assigned thereto, and thus the method may determine different lighting effect concepts to these separate sections in order to best possible match the ambient lighting to the content of the separate sections, e.g. "news report" and "weather report" of a news program. If the video content is a film, it may be preferred to assign separate lighting effect concepts to "introduction", and "ending" parts, e.g. to use the ambient lighting to emulate normal cinema lighting in such parts. According to a second aspect, the invention provides a control unit arranged to control ambient lighting in response to video content, the control unit comprising a processor arranged to determine a lighting effect concept based on data representing a genre of the video content, and - calculate control parameters for controlling the ambient lighting according to the lighting effect concept.

It is appreciated that the same advantages as mentioned for the first aspect apply as well for the second aspect, and it is also understood that embodiments equivalent to those described for the first aspect apply as well for the second aspect. In a third aspect, the invention provides an ambient lighting system arranged for providing ambient lighting in response to video content, the system comprising a control unit according to the second aspect, and light sources arranged to receive the control parameters and emit light accordingly. In a fourth aspect, the invention provides a display device arranged to display video content, the device comprising a display region arranged to display an image according to the video content, and the ambient lighting system according to the third aspect, wherein the light sources at least partly peripherally surround the display region.

In one embodiment, the display device is selected from: computer monitor display, cathode ray tube (CRT) display, a liquid crystal display (LCD), a plasma discharge display, a projection display, thin-film printed optically-active display, or a display using functionally equivalent display technology. Especially, the display device may be a TV set.

In a fifth aspect, the invention provides a computer executable program code arranged to perform the method according to the first aspect. The program code may be suited for a dedicated processor or it may be suited for a general purpose processor, e.g. a processor in a Personal Computer (PC).

In a sixth aspect, the invention provides a data carrier including data representing the computer executable program code according to the fifth aspect. The data carrier may be such as: a hard disk, a CD, a DVD, a memory card, a memory stick etc.

The aspects of the present invention described above may each be combined with any of the other aspects or with sub aspects thereof. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which

Fig. 1 illustrates a block diagram of a first ambient lighting control unit embodiment,

Fig. 2 illustrates a block diagram of a second ambient lighting control unit embodiment,

Fig. 3 illustrates a block diagram of a third ambient lighting control unit, and Fig. 4 illustrates a block diagram of a display device embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS Fig. 1 shows a block diagram of a simple ambient lighting control unit embodiment CU for controlling ambient lighting AL in response to a video input signal V. The input signal V representing video content is received by the control unit CU and applied to a genre generator GG that performs an analysis on a sequence of images of the video content according to an algorithm and assigns and generates in response a genre indicative of the video content, e.g. a genre from a predefined set of genres. This genre is applied to a lighting effect concept determining unit DLC that determines a lighting effect concept based on the genre. E.g. the DLC unit determines the concept based on a simple tabulated connection between genre and concept. Finally, the determined concept is applied to an ambient lighting control parameters calculator CLC that calculates the control parameters to control the ambient lighting AL. As shown, the CLC unit takes the video signal V as input and applies the determined concept to the video signal V in the calculation of the ambient lighting control parameters.

The process of generating data representing the genre of video content can be performed by analyzing the video content in a variety of ways such as described e.g. in 1) "Cartoon detection using low-level AV features", F. Snijder, P. Merlo, Third International Workshop on Content-Based Multimedia Indexing (CBMI 2003), September 2003, Rennes, France, 2) "Classification of video genre using audio", M. Roach and J. Mason, Eurospeech, 2001, or 3) "Classification of TV programs based on audio information using hidden Markov model," Z. Liu, J. Huang, and Y. Wang, in IEEE Workshop Multimedia Signal Processing (MMSP-98), Los Angeles, CA, Dec. 7-9, 1998, pp. 27-32.

Alternatively, genre of a TV program can be determined using Electronic Program Guide service of broadcasts, see e.g. "TV Anytime Forum", http://www.tv- anytime.org. Fig. 2 shows a second control unit CU embodiment, where a video signal V is taken as input and control signals for control of ambient light sources AL are output in response. A genre classification GC is performed based on the video input signal V and a signal representing external information EI from an external source of information. E.g. such source of information may be an EPG service can be used to determine overall genre of a TV program, while the video signal V itself can be analyzed so as to be able to determine sub genres for different sections of the program. The classified genre is then applied to a lighting effect concept determination unit DLC that selects the calculation concept to be used in the color calculation CC, e.g. by adjusting one or a few parameters depending on the genre. The video signal V is analyzed in a color analyzer CA where color features of the video signal are determined. These features are applied to the color calculation unit CC that applies the determined concept to the extracted features and generates ambient lighting control signal accordingly. The lighting concept determination DLC may be based on a simple table as below, describing predefined parameter settings for each genre to be used in the color calculation CC:

Genre Lighting effect concept

Movie "Leaky TV", e.g. according to WO 2005/069639

Documentary Lighting Estimation

Commercial Increased brightness

The "Leaky TV" concept can be used in the case of movie-genre to emphasize the special effects, and in the case of sport events or documentaries the "Lighting Estimation" can be applied to simulate the environment of the video for the viewer.

In Fig. 2 it is further seen that the DLC can take an input UI from the user. This can be used to affect the predefined parameter settings, e.g. with respect to preferred color in case of "constant color" concepts, or with respect to general light intensity. Further, the user input UI may be used to over-rule the automatic genre based lighting effect concept and select another predefined concept. Still further, the user input UI may be used to alter and/or construct the lighting effect concept determination DLC. E.g. the user may re-define the table describing predefined parameter settings for each genre to be used in the color calculation CC, e.g. the user may define or re-define the relation between genre and lighting effect concept to be used for each genre.

Fig. 3 illustrates a third control unit embodiment CU. Again, a genre classification GC is performed based on the video signal V and additional external information EI. As in Fig. 2 the video signal is also analyzed in a color analyzer CA to extract specific features of the video signal V. These features are then used in the color calculation CC, which in this embodiment can be a fixed algorithm that calculates control ambient lighting control parameters according to the extracted video features. The genre dependency in this embodiment is introduced by a genre dependent modification filter GDMF which is a filter following the color calculation CC and before applying the control signals to the ambient light sources AL. The properties of this GDMF filter depends on the classified genre and on user input UI in a manner similar to that explained for the second embodiment. This filter GDMF may e.g. allow an increase in intensity or saturation of all produced ambient lighting effects, or to decrease the color differences in time, to create smoother or less dynamic light effects. In case the genre classification is enabled to distinct between commercials and regular program broadcast, e.g. as described in "Real time commercial detection using MPEG features", N. Dimitrova, S. Jeannin, J. Nesvadba, T. McGee, L. Agnihotri, G. Mekenkamp, Proc. 9th Int. Conf. On Information Processing and Management of Uncertainty in knowledge-based systems (IPMU 2002), pp. 481-486, Annecy, France, light can be dimmed accordingly thus emulating what is usually done in cinemas.

The genre dependency according to the third embodiment is easy to implement in existing systems since the CA and CA components of an existing lighting effect concept, e.g. "Leaky TV", can be used and while the GC and GDMF are introduced to genre dependently modify the ambient lighting control parameters generated by the existing components. As explained above, the user may influence the GDMF filter by a user input UI in order to affect the ambient lighting effect determined by the control unit CU.

Fig. 4 illustrates in block diagram form a display device DD, e.g. a TV set with an LCD display region DR and ambient light source ALl, AL2 placed on sides of the TV set. The display device DD includes the control unit CU which can be implemented as one of the mentioned embodiments, or as a combination of the described embodiments. The control unit CU takes a video input signal V as input and generates ambient lighting control parameters for control of the sources ALl, AL2 accordingly. The control unit CU further takes a user input UI that allows the user to influence the ambient lighting effect generated by the control unit CU, such as explained above.

To sum up: a method is proposed for control of ambient lighting that can be used to automatically generate ambient lighting effects that in a natural way follow video content. The method includes determining a lighting effect concept based on data representing a genre of the video content, and then calculate control parameters for controlling the ambient lighting according to the determined lighting effect concept. The genre of the video content may be based on analyzing the video content according to known methods, and/or based on external information, e.g. Electronic Program Guide services. It may be preferred to allow different genre classifications at program level as well as section levels so as to allow different lighting effect concepts in different sections of one TV program. In some embodiments the genre dependency is implemented by selecting between different predefined lighting effect concepts, e.g. color calculation concepts. In some embodiments the genre dependency is implemented by a filter modifying at least some of the ambient control parameters generated by a fixed calculation concept. A user input may be used to influence e.g. the determination of lighting effect concept in response to the genre of the video content.

Certain specific details of the disclosed embodiment are set forth for purposes of explanation rather than limitation, so as to provide a clear and thorough understanding of the present invention. However, it should be understood by those skilled in this art, that the present invention might be practiced in other embodiments that do not conform exactly to the details set forth herein, without departing significantly from the spirit and scope of this disclosure. Further, in this context, and for the purposes of brevity and clarity, detailed descriptions of well-known apparatuses, circuits and methodologies have been omitted so as to avoid unnecessary detail and possible confusion.

Reference signs are included in the claims, however the inclusion of the reference signs is only for clarity reasons and should not be construed as limiting the scope of the claims.

Claims

CLAIMS:

1. Method for controlling ambient lighting (AL) in response to video content (V), the method including determining a lighting effect concept (DLC) based on data representing a genre of the video content (V), and - calculating control parameters (CPC, CC) for controlling the ambient lighting

(AL) according to the lighting effect concept.

2. Method according to claim 1, further including generating (GG) the data representing a genre of the video content (V).

3. Method according to claim 2, wherein the data representing a genre of the video content (V) is generated based on an analysis (CA) of the video content (V).

4. Method according to claim 2, wherein the data representing a genre of the video content (V) is based on external information (EI).

5. Method according to claim 1, further including performing an image analysis (CA) on the video content, and wherein the calculation of the control parameters (CC) is based on a result of the image analysis (CA).

6. Method according to claim 1, further including receiving a user input (UI), and wherein the calculation of the control parameters (DLC, CC) is further based on the user input (UI).

7. Method according to claim 6, wherein the determination of lighting effect concept (DLC) is based on the user input (UI).

8. Method according to claim 1, wherein the determination of a lighting effect concept (DLC) is based on selecting one from a predefined set of lighting effect concepts.

9. Method according to claim 1, wherein the lighting effect concept defines parameters for influencing the ambient lighting (AL) with respect to at least one of: color, light intensity, spatial distribution, and temporal evolution.

10. Method according to claim 1, including determining different lighting effect concepts for separate sections of the video content (V).

11. A control unit (CU) arranged to control ambient lighting (AL) in response to video content (V), the control unit (CU) comprising a processor arranged to determine a lighting effect concept (DLC) based on data representing a genre of the video content (V), and calculate control parameters (CPC, CC) for controlling the ambient lighting (AL) according to the lighting effect concept.

12. An ambient lighting system arranged for providing ambient lighting (AL) in response to video content (V), the system comprising a control unit ( CU) according to claim 11 , and light sources (AL) arranged to receive the control parameters and emit light accordingly.

13. A display device (DD) arranged to display video content (V), the device (DD) comprising a display region (DR) arranged to display an image in according to the video content (V), and the ambient lighting system (CU, ALl, AL2) according to claim 10, wherein the light sources (ALl, AL2) at least partly peripherally surround the display region (DR).

14. Computer executable program code arranged to perform the method according to claim 1.

15. Data carrier including data representing the computer executable program code according to claim 14.