FIELD OF THE INVENTION

The invention relates to a method for controlling a lighting device based on control commands, and more specifically to controlling a rotatable lighting device such as a moving head. The invention further relates to a controller for controlling the lighting device, a system comprising the controller and the lighting device, a file comprising the control commands and a computer program product for performing the method.

BACKGROUND OF THE INVENTION

Light effects are used, for example, to enhance stage performances and such light effects are tailored to match the stage where the performance is conducted. When a performance moves to another venue, the stage is rebuilt at that new venue and as such the lighting devices are kept in the same position relative to the stage. If however any lights are in a different position at the new venue, e.g. due to stage construction constraints related to the new venue, such lights are then manually realigned.

UK patent application GB 2500566 A discloses an automated lighting control system comprising automated lighting fixtures and a touch user interface. The touch user interface allows manipulation of the direction in which light is emitted by the automated lighting fixtures. The input provided using said two dimensional touch user interface is in Cartesian coordinates. Said input is converted into Polar coordinates to control the automated lighting fixtures. This allows local, manual control of an automated lighting control system at a single location.

When light effects are used for enhancing events that occur at a number of venues in parallel (e.g. movie theatres), such manual configuration is undesirable as it is, for example, costly and error prone. There is a need for an improved method for providing harmonized light effects across such a multitude of locations.

SUMMARY OF THE INVENTION

Rotatable lighting devices, such as moving heads, provide a cost effective method of rendering controllable light effects. When such devices are installed across various venues (e.g. in various screening room(s) of movie theatres), it is desirable to be able to control all these rotatable lighting devices in a similar manner using a single control command (e.g. a lighting control script). This allows, for example, a lighting control script for rendering light effects in a movie theater to be designed only once for a specific movie. The same lighting control script is then provided to the various theatres, even though the screening room(s) of these theatres have different shapes and sizes. The script can be executed without further manual intervention for adapting individual control commands to accommodate these different shapes and sizes of the screening rooms. The lighting effects as generated at the various locations can vary to a degree that these variations are not perceivable (e.g. by a person watching a movie in the movie theatre). Still, there are constraints that are to be met. In particular, continuing the example, certain areas in the screening room, such as the screen the movie is projected on, should not be illuminated by the light emitted by the rotatable lighting device.

In a first aspect, a method for controlling a rotatable lighting device is provided. Control of the lighting device refers to controlling the light output provided by the lighting device (e.g. intensity, beam shape, color) and controlling the rotation of the lighting device. The lighting device is rotatable around at least one axis. An example of such a rotatable lighting device is a so-called moving head, which can be controlled to rotate around two axis, more specifically to pan (i.e. rotate in a horizontal plane) and tilt (i.e. rotate in a vertical plane). The rotatable lighting device is positioned at a first position in a room. It is controlled such that light is emitted towards a first area of the room (e.g. the walls of a screening room), but not a second area of the room (e.g. the screen in the screening room).

The method comprises: receiving a control command for generating a light effect with the rotatable lighting device, the control command comprising control data for controlling a virtual rotatable lighting device located at a second position in the room. This allows for standardized control commands (e.g. scripts) to be distributed to, for example, movie theatres of various sizes and shapes. Costs (monetary, development time, etc.) associated with creating tailored control commands (or scripts) are thereby avoided.

The method further comprises: determining an area in the room, based on a set of spatial data of the room and on the control data, where the virtual rotatable lighting device will generate a virtual light effect if controlled according to the control data. The spatial data of the room comprises spatial data of the position of at least the second area (e.g. allowing the determination to be made if the determined area at least partially overlaps with the second area) and the position and orientation of the virtual rotatable lighting device and the position and orientation of the rotatable lighting device in the room. Examples of a set of spatial data are a map, a set of coordinates of surfaces (e.g. wall, screen), etc.

This allows the determination to be made if the light effect would interact with an object or activity in an undesirable way; such as the light being emitted towards a highly reflective object (e.g. a mirror) causing reflected light to create a disturbance for people present in the room, or the light being emitted towards a screen on which a movie is being projected. If the determined area is part of the first area and not the second area, the control data is converted based on the offset of the first position compared to the second position such that the rotatable lighting device will generate the light effect in the determined area when controlled according to the converted control data. As such, the rotatable lighting device does not have to be in the same position as the virtual rotatable lighting device related to the control of which the control data is comprised in the control command. As a further example, in a screening room in a movie theatre there can be two moving heads positioned below the ceiling at the back of the screening room at the far left and far right. For each of these, control commands can be sent (e.g. by a controller synchronized with the movie projection system). Each control command, related to one of the moving heads, can then, for example, comprise control data for a virtual rotatable lighting device positioned in the center of the screening room.

The method further comprises: controlling the rotatable lighting device based on the converted control data. This allows the light effect to be generated, such that, for example, the standardized control command received leads to generation of light effect at a comparable position in the various venues. A person at a given movie theatre can then have a similar experience as a person watching the same movie in another movie theatre.

In various embodiments, the method further comprises: if the determined area is part of both the first and the second area, adjusting the control command such that the rotatable lighting device will emit light only in the determined area which is part of the first area when controlled according to the converted control command; and/or if the determined area is part of the second area and not the first area, ignoring the control command (such that no light effect is generated, and optionally sending an error message, for example to the device from which the control command was received). Such a conversion allows, for example, a wide beam light effect that emits light in both the first area and the second area to be converted to a narrow beam light effect that emits light in the first area only. As a further example, a light effect can relate to a moving spot light traversing part of the first area and traversing part of the second area in the room. The conversion can then comprise, for example, turning the light source of a moving head On' and panning the moving head until the light effect is about to enter the second area upon which the light source is turned Off . The moving head can then continue to turn and the light source is turned back On' when it is rotated to a degree such that the light effect continues its path in a continuation the first area again. An example of such a light effect is a search light effect moving along the wall on the left-hand side of the screen, across the screen and then along the wall on the right-hand side of the screen. The moving head will make the full movement, yet the light source will be turned off (or will be greatly dimmed) during the time period when the spot light effect would otherwise cross the screen.

In various further embodiments, the control data comprises a set of polar coordinates, the set of spatial data of the room comprises Euclidian coordinates and the set of polar coordinates are converted to Euclidian coordinates for determining the area in the room where the virtual rotatable lighting device will generate a virtual light effect if rotated according to the received control command. The first position and the second position can be in Euclidian coordinates; and/or the converted control command can comprise polar coordinates.

Polar coordinates provide for a rotation from a (fixed) reference point in at least one axis. This is especially advantageous for controlling a rotatable lighting device, such as a moving head, as such devices are typically controlled using pan and/or tilt commands. For example, controlling the rotatable lighting device to pan to a position of +20 degrees from a reference point will cause the area in which the rotatable lighting device will emit light to move along a horizontal pane. The control command can comprise polar coordinates, for example: +20 degrees / -40 degrees for a movement 20 degrees clockwise in a first plane from a reference point and 40 degrees counterclockwise in a second plane from the reference point. As a further example, the control command can comprise pan/tilt commands (pan 10 degrees and tilt -5 degrees) or a DMX command. Euclidean coordinates refer to coordinates referencing a point in Euclidean space, i.e. a two or three dimensional space. An example of such coordinates are Cartesian coordinates.

In a further embodiment, the rotatable lighting device is a moving head and the method further comprises: converting the converted control data to one or more DMX commands for controlling the moving head, wherein the rotatable lighting device is controlled based on the one or more DMX commands. Digital Multiplex, DMX or DMX512 refers to a standard for digital communications for controlling, for example, stage lighting and effects. In this especially advantageous embodiment, a DMX command for controlling the virtual rotatable lighting device can be sent and the method allows for control of the rotatable lighting device via DMX, wherein the DMX command has been converted based on the set of spatial data of the room and the offset of the rotatable lighting device compared to the virtual rotatable lighting device. A person skilled in the art will realize that the method can similarly be applied where control commands based on other (proprietary) standards are received and/or need to be sent to control the rotatable lighting device. As an example, the control commands received can be DMX commands and the control of the rotatable lighting device could be direct control of the hardware (e.g. a stepper motor and a light source driver). As a further example, the control command could be a light effect script and the rotatable lighting device is controlled using DMX commands.

In various beneficial embodiments, the room is a screening room and the second area comprises a screen. The second position, i.e. the position where the virtual lighting device is positioned, can then be the center of the ceiling of the (screening) room.

In a second aspect, a controller for controlling a rotatable lighting device is provided. The rotatable lighting device is located at a first position in a room. The controller is arranged such that light is emitted by the rotatable lighting device towards a first area of the room, but not a second area of the room. The controller comprises: a first interface, a memory, a processor and a second interface. The first interface is arranged for receiving a control command for controlling a virtual rotatable lighting device located at a second position in the room. The memory is arranged for storing spatial data of the room. The processor is arranged for determining, based on the spatial data of the room and on the received control command, an area in the room to which the virtual rotatable lighting device will emit light if controlled according to the received control command. The processor is further arranged for, if the determined area is part of the first area and not the second area, converting the received control command based on the offset of the first position compared to the second position such that the rotatable lighting device will emit light in the determined area when controlled according to the converted control command. The second interface is arranged for controlling the rotatable lighting device based on the converted control command.

In a third aspect, a system is provided. The system comprises the controller and at least one rotatable lighting device. As an example, in a movie theatre, the controller can be part of the overall audio-visual system used to control the experience of the client in the screening room. The rotatable lighting device can be one of several moving heads arranged along the side walls of the screening room. In a fourth aspect, a file is provided comprising at least one control command for generating a light effect in a room equipped with the system. Such a file can be a script comprising a plurality of control commands for one or more rotatable lighting devices. In a movie theatre, for example, the file can be provided via an online channel based on the content to be played on the screen in a screening room, or, as a further example, the control commands can be part of a file comprising the audio and/or video content to be played on the screen.

In a fifth aspect, a computer program product is provided. The computer program product comprises instructions for causing a computer device to perform (any embodiment or combination of embodiments of) the method according to the first aspect.

For the avoidance of doubt, the virtual rotatable lighting device referred to, is a non-existent device. If it were an existing device, then controlling it according to the control command received would cause it to generate a light effect in the room. Instead however, the room is typically equipped with one or more rotatable lighting devices in other position(s). Therefore control commands or coordinates related to the virtual rotatable lighting device need to be converted such that they can be used to control the rotatable lighting device.

Further, the determination of where a light effect will be realized in the room and the decision on whether or not to generate the light effect can be made after or before the conversion of the control data.

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

In the drawings:

Fig. 1 shows schematically and exemplarily a side view of a room with an indication of the position of a virtual rotatable lighting device,

Fig. 2 shows schematically and exemplarily the view of Fig. 1 with an indication of the position a virtual light effect would be rendered by the virtual rotatable lighting device,

Fig. 3 shows schematically and exemplarily a top view of the room further providing an indication of the position of a rotatable lighting device,

Fig. 4 shows schematically and exemplarily the view of Fig. 3 further showing an indication of the rendering of a lighting effect, and Fig. 5 shows schematically and exemplarily a method for controlling a rotatable lighting device.

DETAILED DESCRIPTION OF EMBODIMENTS

In Fig. 1 a side view is shown of a room, in this example a screening room 110 in a movie theatre. The x, y an z axis are shown and indicated as such. The screening room 110 comprises a screen 120, e.g. for projecting the movie (video) onto. It is undesirable to emit light with the rotatable lighting device (directly) onto the screen, as this could negatively influence the experience of viewing the movie. In this example, the light emitted by the rotatable lighting device will in fact support the experience by emitting light towards, for example, the area surrounding the screen. An example of such a light effect is showing a search light moving across the walls of the movie theatre while a scene is playing in which a top view is shown of a prison with multiple search lights visible on screen. The additional search lights off screen create a more encompassing experience for the audience members.

If there were a rotatable lighting device on the ceiling at the center of the room, it would be located where the virtual rotatable lighting device 130 is positioned.

Controlling this rotatable lighting device to pan and/or tilt and emit light according to a control command would allow it to emit light in the direction of the contour of the half dome 140 (this half dome represents a polar coordinate space). If the virtual rotatable lighting device were to be controlled to pan and/or tilt from a reference point to the position it is in in Fig. 2 and it would then emit light, this virtual light (VL) would intersect with the half dome 140 in position 210. Based on the dimensions of the room 110, it can be determined that the light effect would then be realized in the room 110 at position 220. As this is outside the area comprising the screen 120, the lighting effect should be converted such that it can be rendered by a rotatable lighting device in the room.

In Fig. 3 a top view of the same room 110 as in the previous figures is shown. The room 110 comprises a rotatable lighting device 310, such as a moving head. It is situated in a different position, in this example, compared to the position of the virtual rotatable lighting device 130. Therefore, the control command for controlling the virtual rotatable lighting device has to be converted such that it can be used to control the rotatable lighting device. Fig. 4 shows the offset 310 between the rotatable lighting device and the virtual rotatable lighting device. A light effect (LE) can be realized by the rotatable lighting device 310 to match the location 210 where the virtual light (VL) would intersect with the room 110. Fig. 5 shows a method for controlling a rotatable lighting device, located at a first position in a room, such that light is emitted towards a first area of the room, but not a second area of the room. The method comprises: 510 receiving a control command for generating a lighting effect, the control command comprising control data for controlling a virtual rotatable lighting device (i.e. for controlling a rotatable lighting device if it were at a certain, predetermined position, such as attached to the ceiling in the middle of the room), 520 determining an area in the room (e.g. a position on the wall, floor, ceiling of the room) where the lighting effect will occur, 530 deciding on whether or not to render the lighting effect (e.g. based on where in the room the lighting effect will occur), or adjusting the control command (e.g. such that it will occur in a different area of the room), 540 converting the control data received in the control command to account for the difference in position between the virtual rotatable lighting device and the rotatable lighting device; and 550 controlling the rotatable lighting device based on the converted control data.

The following are examples of calculations supporting the method according to the first aspect. In the example provided, there is a moving head with a pan range

(horizontal pane) of -180 degrees to +180 degrees, wherein the positive pan is anti-clockwise (i.e. the moving head is facing the front of the room, e.g. where a screen is located, and positive pan rotates the moving head such it emits light towards the left wall). The tilt range of the moving head is -90 degrees to +90 degrees, wherein at a tilt of 0 the moving head is pointing down towards the floor and a positive tilt (at pan=0) controls the moving head such that it emits light towards the front of the room, e.g. the screen. Such a moving head can have a greater range, and such a greater range can but need not be used. For example, a script comprising control commands can include some control commands related to light effects which can be realized at all venues and some that can be realized at certain venues only (e.g. venues where a certain number of rotatable lighting devices are present, or where the rotating lighting device can pan and/or tilt to a certain degree).

A pan and tilt vector are received as part of the control command, the pan and tilt vector are comprised in the control data. The control command can further comprise data to control the light output (e.g. color data for color control, intensity data for intensity control and beam width data for beam width control). The control command received is standardized and can be sent to multiple installation (e.g. multiple movie theatres) each comprising different size and/or shape rooms, and/or having the moving head in a different position in the room. The pan vector (pan) and tilt vector (tilt) are converted to a Euclidian vector (Vxyz) as per Formula 1. The minus signs relate to the fact that the moving head of the example is mounted upside down against the ceiling of the screening room. Such positions and relations between the coordinate system and the position of devices is merely a matter of convention that should be consistently applied.

- sin(tilt) CQS(PGK) ^"*

Formula 1. Vxyz ⁼ \ — sinitilt)sm(_p n)

— CQs(ti!t)

The Euclidian vector (V _xyz ) is the intersection 210 of the virtual light beam (VL) and the half dome in Fig. 2 and Fig. 3. This position in polar space does not yet correspond to the point on the wall that will be illuminated. The room dimensions in this example are cubic and the vector can be extended until the length of one of the components equals 1, thus intersecting with the floor or wall (reference 220 in Fig. 2, Fig. 3 and Fig. 4).

, V„ /

Formula 2. xyi = *"/ , . . , , _Λ

The outcome needs to be corrected for room size and for the position of the moving head compared to the virtual rotatable lighting device. This yields a new vector that can be converted back into pan-tilt parameters for the moving head. An example of calculations that support this are shown in Formula 3, Formula 4 and Formula 5 below. Herein, Room _xyz defines the size of the target illumination and Head _xyz is the offset of the moving head with respect to the virtual rotatable lighting device (e.g. the center of the ceiling).

Formula 4. V* - ^V " ^x ^.

* ^y - " _xy∑

Formula 5.

The pan * and tz7t* vectors can be sent to the moving head to control its rotation such that the light will be emitted towards a position in the room as per the control command received. If needed, the pan and tilt vectors can be converted to DMX values, as per the exemplary Formula 6 and Formula 7 below.

Formula 6. DMX _Pn - = (PauM x— PauMi-in * ^Ρββ" * ^"1Β0 + ρ _αη Μΐη

360

Formula 7. DM¾ _h = (TiltMax - TiltMii) * + Ti!tMin

If the moving head would have an inverse pan or tilt direction, the min and max parameters should be interchanged.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.