GB2267160A - Light system configuration - Google Patents

Abstract

The position and beam direction of each of a set of lights 14, 16 eg stage lights is learnt in a configuring step to facilitate the correct projecting of the lights during a show. A sensor 24 is placed at each target point 26 of the lights 14, 16 and each light is scanned through its entire range of movement. Sensor output data is transmitted to a control console 20 and data relating to the position and direction of each light when centred on each target position is stored to be used to produce the required lighting effects during the actual performance. <IMAGE>

Description

MOVABLE LIGHT.CONFIGURATION APPARATUS AND METHOD This invention relates to methods of and apparatus for automatically configuring one or more moving lights.

With the advent of moving lights in the live performance field, the number of lighting effects possible from a given number of lights has increased dramatically.

A single moving light can now change its beam's colour, size and shape in addition to moving the beam to different positions on stage; previously, such effects could only be produced with multiple lights or a manned spotlight. Due to its superior utility, the moving light has been rapidly accepted in the entertainment industry, making light shows previously inconceivable or impractical now commonplace.

Moving lights have experienced such success in spite of their primary drawback: high cost. The complex nature of moving light fixtures make them expensive to use; numerous skilled technicians are required both to maintain and operate the lights. In particular, one very labourintensive task is aiming the light beams at the desired stage positions (target positions) during set-up.

Every time a moving light is placed in a new location the information required to aim the light beam must be programmed into a control console or the light itself. This involves aiming every light beam at every target position it illuminates during a performance, a process which can often take hours when large numbers of lights or positions. are involved. What is more, most control systems lack universal "preset" position settings for each light. Thus, each one must be separately positionally programmed for each individual lighting scene.

The aiming task is particularly burdensome if the lights are installed in a new location every day, as with a multi-city concert tour. A change in any one of the following factors may cause the lights to be incorrectly aimed position and angle of a light on the truss on which the light is mounted, height of the truss, stage size, and position of musicians on stage. Rarely, if ever, will there be no change. Hence, the tedious manual aiming process must be constantly repeated and is subject to human error. Eventually fatigue or inattention will cause an operator to aim a light incorrectly. Plus, difficulties of exactly centering a light on a target position often mean that aiming will not be completely accurate.

Many lighting desks come equipped with a remote control unit linked to the control console. This allows the lighting designer or operator to aim the lights while on stage instead of at the console that may be located some distance from the stage. While the remote unit makes the process easier, it is still entirely manual and subject to all of the disadvantages listed above. A few modern control systems keep a universal set of position data for each light to make programming new scenes easier; however, this does not address the problem of programming the position information initially which must be done in every new venue.

In U.S. patent 4,947,302 all lights must first be placed at their exact, specified location on the truss.

This positional data must then be entered into the control console along with the coordinates of the target positions.

Unfortunately, it is very difficult and prohibitively time consuming to place lights at their specified locations and angles on the truss with enough accuracy to avoid causing wide aiming discrepancies. Also, the lights are currently not calibrated sufficiently accurately to reproduce the exact angles of pan and tilt that the mathematical computations require. Moreover, the time it takes to program all the position, angle, and calibration data is not eliminated.

This invention provides an apparatus for configuring a lighting display comprising one or more movable lights, including sensor means triggerable upon a predetermined operation of a light and placeable in one or more desired target positions, and control means to receive and interpret data from the sensor means and to transmit instructions to the lights or control console so as to configure the lights according to desired positions. The sensor means may include a plurality of light sensors.

This apparatus may be used to automatically aim the beam of a light in the following way: the control means, eg. a control console programmed with suitable software, sends control signals to a moving light to shine that light beam over its whole range of movement. As this light beam falls on a sensor, the sensor sends a signal to the console enabling the console to determine what set of control signals (the positional data) are required to aim the beam at the sensor. This positional data may be stored and can subsequently be used to aim the beam of the light at that particular target position when required eg. during a show. This process may then be repeated with the same light for each light sensor in each desired target position, and subsequently with further lights for each light sensor.Consequently, it is possible to automatically aim a set of moving lights at every position that they must illuminate during a show and record the appropriate positional data.

This invention also relates to a method of configuring a lighting display comprising one or more moveable lights including the steps of scanning a light through part of its range of movement and transmitting data regarding the operation of the light from sensor means, placeable in one or more desired target positions to control means.

In the accompanying drawings: Fig. 1 is a perspective view of a moving light system according to one embodiment of the present invention.

Fig. 2 is a flow diagram illustrating the operation of the program used in the embodiment of the invention in Fig. 1.

Referring now to Fig. 1 which illustrates one possible moving light system 10 used to light a stage 12.

A pivoting light 14 (in which much of the fixture pivots around the truss) and a moving mirror light 16 (where only a mirror moves to deflect the light) are affixed to the truss 18 which is either suspended from above or supported from below by scaffolding or pillars. The moving light system 10 is controlled by a computerized control desk 20 and each light receives control signals through a light fixture data link 22.

This embodiment of the light configuration system uses a light sensor 24 to transmit light measurements to be interpreted by the control console 20. Before a performance, a light sensor 24 is placed at a position to be illuminated (target position), such as on stage on the top of a microphone stand 26. A plurality of sensors may be used and they can be placed anywhere on or off the stage as long as there is a direct line of sight between each light sensor 24 and the light(s) which are to illuminate that target position. Information is preferably relayed from each light sensor 24 through its own sensor data link 30 to a sensor control pack 28 which transmits information to the control console 20 via control pack data link 32.

Once the aiming process is complete the light sensor(s) 24 will normally be removed from their positions.

In Fig. 2 a flow diagram illustrates the operation of a program used in the embodiment of the invention shown in Fig. 1. In this embodiment, the program is run on a microprocessor incorporated into the control console 20. However, in other embodiments the program could be run on a microprocessor based either remotely on or in the sensor control pack 28, with the final results transferred to the control console 20.

The microprocessor begins by determining which lights need to be aimed and the number of sensors that will be used. The data regarding the relevant lights and their required target positions is received from the control console 20 which has been programmed with target positions, for example "drums", rather than the individual light's required pan and tilt axis settings for each position. Each sensor is then linked to one of these target positions.

A check is carried out initially to ensure that all of the sensors are active and functioning properly.

Next, all the lights to be aimed are set to their scanning settings such as "open iris", "white light", or "no gobo" silhouettes. The beam of each light is turned off (masked) until it is its turn to be aimed. Before each light starts its aiming procedure an ambient light measurement is taken and each sensor's sensitivity is automatically adjusted. The sensor sensitivity will be set at a level that only registers a "hit" when a light beam from a scanning light passes over it.

The program continues by unmasking a lights beam, activating all the sensors to be aimed at by that light, and aiming the light at its first position. The light is then moved consecutively, or scanned, through all of its possible positions. If the light has a large or infinite number of positions then positional steps are generated. When a sensor is "hit" by the light beam, ie.

the sensor's light reading is greater than its ambient light level, the sensor identity and scanning position of the light is recorded. A centering algorithm is then used to center the light beam on the sensor, and the resulting positional data is stored in the control console 20. Now the console knows what information to send to that light to cause it to point at the sensor. For example, if sensor three was just scanned, "drums" might equal "pan setting of 20 and tilt setting of 100" on light number one. The sensor is then deactivated (its signals are ignored by the console), the light beam is reaimed at its position prior to centering, and the process is continued until the light beam has "hit" all its sensors or aimed at all its possible scan positions. The light beam is then masked and the same procedure occurs for each subsequent light.

Generating the coordinates to scan the light can be done in several ways. The light beam must move in such a way as to illuminate every surface that lies within the total range of movement of that light. The preferred pattern of movement is an outwardly moving path approximately spiral in shape, since this will illuminate all the sensors in the shortest time possible. Scanning could also be done using a television-style raster scan or any other pattern of movement that aims the light beam over the whole range of movement of the light.

One embodiment of the "spiral" scanning method is as follows: the first position illuminated is the central aiming point, the center of the light's pan and tilt axes.

Subsequent positions are generated in concentric circles around this point. The diameter of each circle is calculated so that as the light beam is moved the beam edge just overlaps with the surfaces illuminated in the previous concentric circle. Positions within each concentric circle are also calculated so that the edge of the light beam in one position just coincides with the surface illuminated in the previous position. The widest concentric circle at the end of the "spiral" scan may become clipped into polygons, since the moving light may have a rectangular range of movement as opposed to a circular one.

In order to generate the spiral pattern, the scanning algorithm will have to be programmed with data concerning the light that it is controlling. The first datum is the light's beam angle at its widest setting.

Next are the pan and tilt output ratios, namely the relationship of changes in programmed levels of pan and tilt to changes in actual' angles of pan and tilt. This data is either published, or can be calculated as a ratio by dividing the total angular range of pan and tilt by the total range of programmable levels. Note that the pan output ratio will usually be different to the tilt output ratio.

With this data it is a simple task for the algorithm to determine what change in pan or tilt value is required to move frpm one scan position to the next. The th pan and tilt values to generate the i- position around the j- concentric circle is: pan value = (maximum pan value/2) + r cos 6 pan output ratio (maximum tilt value/2) + r cos # tilt value (maximum tilt value/2 + r sin # where r = j (beam angle) and O = 0 for j=O, e = 2i tan 1 (1/2j) degrees for j > O The central position corresponds to i = O, j = 0.

The number of positions around each circle j is 360/6, rounding upwards.

The number of circles in the scan is (maximum pan value/2) * pan output ratio/r, rounding upwards.

Using these formulae with different types of light is simply a matter of inputting the appropriate output ratios and beam angles for each type. Anyone skilled in the art could easily adapt these formulae for beams that are not circular. Also, slightly reducing the specified beam angles can eliminate problems caused by differences among lights of the same type. If the lights have been previously aimed while in their current configuration, the old aiming positions could be used as the central position to speed the aiming process.

The centering algorithm is used once a sensor has been hit. Again, there are several possible methods for conducting this operation. One possibility is to have the light beam home in 9n the most intense light reading and then center on it. Unfortunately, this may not work since the light intensity is often not the highest at the center of the beam. The preferred method is to calculate the center of the light beam in the following manner.

(1) The beam is moved by only tilting it, in one direction and then the other, until the sensor has detected both edges of the light beam moving across it; the controller records the tilt values corresponding to the edges. The movement increments should be the minimum achievable for the light. The controller calculates the tilt centerline by averaging the edge values.

(2) The beam is then moved to the tilt centerline, and the process is repeated for the pan axis, thus obtaining the pan centerline.

(3) The centerpoint is the intersection of the pan and tilt centerlines.

While the above algorithm will be sufficient in most cases, some situations complicate it, such as if the first axis movement in the above method is at a tangent to the light beam, rather than intersecting it, or when the light is near the end of its range of movement. Methods for dealing with these situations can easily be developed and incorporated into the algorithm by someone skilled in the art.

Variations on the apparatus described in the above embodiment are clearly possible. For example, some ways of accomplishing the same task may require some manual entry or may be done using a separate system independent of the control console. Different hardware could be used, such as a heat sensor instead of a light sensor. Likewise, positional information could be stored on the lights themselves rather than in the control console. Also, the system could be expanded to cover other parameters such as colour or beam focus and or could be used during a performance as an effect in itself. If the sensors were placed on an exact grid they could be used to trigonometrically compute the location of every moving light scanned.

Similarly, the invention is useful for other applications. The sensors could be used with laser systems also requiring substantial set-up time for aiming their laser beams. Also, the light sensors could be combined with their own remote controlled reflectors to deflect the laser beams to another position. In addition, the invention could be used for architectural lighting purposes.

Claims (14)

CLAIMS:

1. A method of configuring a lighting arrangement comprising one or more movable lights, including the steps of (1) placing sensor means in one or more desired target positions at which a light is to be aimed, (2) scanning the light through at least a part of its range of movement, and (3) transmitting data relating to the operation of the light from sensor means to control means for controlling the movement of the light.

2. A method according to claim 1 including the step of centering the light on the sensor means in a particular target position.

3. A method according to claim 1 or claim 2 in which the sensor means are placed in a plurality of target positions and the light is centred on the sensor means in each required target position.

4. A method according to any of the above claims including the step of storing data relating to the operation of the lighting arrangement for future operation of one or more of the lights.

5. A method according to any of the above claims further including initial step of taking an ambient light measurement and adjusting the sensitivity of the sensor means accordingly.

6. A method according to any of the above claims in which the light is scanned according to an outwardly expanding spiral path.

7. A method according to any of the above claims further including the step of repeating steps (1) to (3) for each of the movable lights in the lighting arrangement.

8. An apparatus for configuring a lighting arrangement comprising one or more movable lights, the apparatus including sensor means placeable in one or more desired target positions at which a light is to be aimed and sensitive to a predetermined operation of a light, and control means for configuration of the light or lights according to data obtained from the sensor means.

9. An apparatus according to claim 8 wherein the control means is usable to store the data from the sensor means relating to the operation of the light or lights.

10. An apparatus according to claim 9 wherein the control means includes predetermined control data relating to desired configuration of the lighting display which is usable in conjunction with the stored data from the sensor means.

11. An apparatus according to any one of claims 8 to 10 including a sensor means control pack for reception of data from the sensor means and transmission of data to the control means.

12. An apparatus according to any one of claims 8 to 11 wherein the sensor means includes a plurality of light sensors each placeable in a desired target position.

13. A method of configuring a lighting arrangement substantially as herein described with reference to Figs. 1 and 2 of the accompanying drawings.

14. An apparatus for configuring a lighting arrangement substantially as herein described with reference to Figs. 1 and 2 of the accompanying drawings.