Abstract:
Movable items on a stage have their position detected in three dimensions, and multiple different lights can be shined at the moving items even after they are moved. Shadowing can be detected and compensated.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application 60/833,626, filed Jul. 26, 2006. The disclosure of the prior application is considered part of (and is incorporated by reference in) the disclosure of this application. 
    
    
     BACKGROUND 
     In a stage environment, such as in a Broadway style show, other play, or basically any venue where a stage is used, there are two things that must occur on the stage. First, there must be lighting, otherwise the audience would not be able to see what was going on the stage. In addition, however, many props on the stage may need to be moved at different times. For example, for different scenes, different props may be used or may be in different locations. Some shows require that the prop be moved as part of the show, and therefore the prop is dynamically moved. The movement may be done manually, or may be done via computer control. 
     SUMMARY 
     The present application describes a system that monitors movement of stage props, and automatically synchronizes movement of a controllable light beam with the actual location of the stage prop. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects will now be described in detail with reference to the accompanying drawings, wherein: 
         FIG. 1  shows a block diagram of the system in operation; and 
         FIG. 2  shows a flow diagram. 
     
    
    
     DETAILED DESCRIPTION 
     The general structure and techniques, and more specific embodiments which can be used to effect different ways of carrying out the more general goals, are described herein. 
       FIG. 1  shows a stage environment which is intended to host a Broadway show. The stage includes at least one prop shown as  105 . The prop is controllable based on the motion control system. A winch  110  may control motion of the prop in the y direction, up-and-down relative to the stage. A pulley system  115  may control movement of the prop in the x and z direction, that is stage left/stage right, as well as front to back. Of course, the movement may be in any subset of these directions. In this way, the prop can be moved. The movement for the prop may be controlled by a controller  120 , which can be a stage lighting controller, or can be a manual controller. 
     The stage may also include locations for performers, shown as  125 , as well as other props which are also controllable. 
     The stage is also illuminated by a plurality of controllable moving lights. These lights may be controllable in pan and tilt, so that the pointing direction of the light can be controlled in a x,y,z direction. The lights are on trusses which may be located in various areas relative to the stage and pointing at the stage. For example, there may be a truss  130  at stage right, which hold a moving light  131 . A truss  135  may be located at stage left, holding a moving light  136 . Both of the moving lights  131  and  136  are controlled by the controller  120 , from and typically via a computer at a connection such as DMX  512 . 
     In operation, the prop  105  may be moved to any desired location. However, some of the luminaires, in the drawings  131 ,  136 , have the task of illuminating that prop. Manual control may be used to cause the luminaires to follow the motion of the prop. 
     According to an embodiment, the prop  105  has an associated location detector part  106 . Location detector part  106  may be any of a number of commercially available location detection mechanisms. In one embodiment, location detection part  106  triangulates between fixed points  107 ,  108 ,  109  which are placed on the stage, in order to determine the position in of the associated prop. However, other location detection devices are also well known, including orthogonal coils of the type used for medical detection, GPS, and others. 
     Location detection part  106  wirelessly communicates a signal indicative of either the location, or some raw signal from which the location can be determined, to a local receiver  140 . The receiver  140  in turn, sends either the information or the location to the controller  120 . The raw information can be, for example, coordinate information, or triangulation information between beacons. 
     Controller  120  therefore receives real-time information indicative of the x,y position of the prop. Controller  120  may therefore include a CPU that runs the routine shown in  FIG. 2 . At  200 , the controller receives the prop position.  205  compares the prop position to a previously-received prop position, to determine if the prop position has changed since a previous time. If not, the controller&#39;s flow continues at  210 . However, if the position of the prop has changed, then the controller calculates new pointing locations for each of the lights here  131  and  136 . In general, since the lights are each in a different place, the new pointing positions of these lights will each be different for each light. In an embodiment, the flowchart of  FIG. 2  may be carried out relatively frequently, for example every 300 ms. In this way, the light can track, in real-time, the prop position as it moves. When the prop position is moved manually, the lights will automatically follow the prop position. The controller may also use a computer to move the prop itself. However, because the props may be heavy devices, and use winches which are not consistent movers, the movement of the prop may not match exactly with the commanded location. This system enables the lights, which can be more precisely controlled, to exactly match the movement of the prop. 
     By controlling multiple lights in this way, shadowing on the prop may be minimized. For example, if the prop is illuminated by only one light such as  131 , it may cast an undesirable shadow behind the prop. Illuminating the prop using multiple lights, however, is relatively difficult when done manually. The present system may avoid the shadowing and may automatically follow the props. 
     The above has described prop following, but it should be understood that different items on the stage, such as the performer  125 , may also include a locator such as  126 . A bank of lights shown as  143  may be dedicated to the performer. 
     In addition, the lights which are associated with each prop or performer may change as the prop or performer moves on the stage. 
     According to another embodiment, the controller  120  calculates which of the lights  131 ,  136  would produce the minimum shadowing effect on the prop, and assigns a lighting of the prop to those lights which would produce the minimum shadow effect, and adaptively changes which lights illuminate the prop as the prop moves. 
     The general structure and techniques, and more specific embodiments which can be used to effect different ways of carrying out the more general goals are described herein. 
     Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventor intends these to be encompassed within this specification. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art. For example, the above has described using this system to follow a prop or performer, however, it can also be used to follow any other device, such as a moving vehicle or cart, or any other kind of device. 
     Also, the inventor intends that only those claims which use the words “means for” are intended to be interpreted under 35 USC 112, sixth paragraph. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims. The computers described herein may be any kind of computer, either general purpose, or some specific purpose computer such as a workstation. The computer may be an Intel (e.g., Pentium or Core 2 duo) or AMD based computer, running Windows XP or Linux, or may be a Macintosh computer. The computer may also be a handheld computer, such as a PDA, cellphone, or laptop. 
     The programs may be written in C or Python, or Java, Brew or any other programming language. The programs may be resident on a storage medium, e.g., magnetic or optical, e.g. the computer hard drive, a removable disk or media such as a memory stick or SD media, wired or wireless network based or Bluetooth based Network Attached Storage (NAS), or other removable medium. The programs may also be run over a network, for example, with a server or other machine sending signals to the local machine, which allows the local machine to carry out the operations described herein. 
     Where a specific numerical value is mentioned herein, it should be considered that the value may be increased or decreased by 20%, while still staying within the teachings of the present application, unless some different range is specifically mentioned. Where a specified logical sense is used, the opposite logical sense is also intended to be encompassed.