Abstract:
In movie house or similar installation for projecting still or moving normal visible images on a screen, a laser device is used to project an infrared spoiling image simultaneously with the normal visible image. When a camcorder is used to record the screen to make illegal copies of the normal visible images, the light sensitive elements of the camcorder convert the invisible spoiling image into a corresponding normal visible image thereby spoiling it.

Description:
RELATED APPLICATIONS  
       [0001]    This application claims priority to provisional application Ser. No. 60/464,913 filed Apr. 23, 2003 and incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a method and apparatus in the field of motion picture projection and, and more particularly, to a method and apparatus for spoiling copies of a motion picture made from projected images using a video camera.  
           [0004]    2. Description of Prior Art  
           [0005]    A big problem facing the motion picture industry is that of piracy. Unauthorized copies are often made during the postproduction and the distribution of a motion picture. Because prints of motion pictures are sometimes previewed before the official release and received by exhibitors in advance, illicit copies of films are often available on disc or over the Internet prior to their release in theaters. Frequently, unauthorized copies are made by pirates in a screening room or movie house during the normal showing of the motion picture, by using a hand-held standard video camera, or camcorder. While the quality of the motion pictures made this way is very poor, apparently there are still sufficient customers who are willing to tolerate them to make the effort of the pirates worthwhile. Once an illicit copy of a motion picture film is obtained, it is illegally distributed through various means. The recorded film is converted into any one of various digital formats such as DVD, VCD or Divx, and distributed on DVD, CD ROMs or over the Internet. This illegal activity causes substantial financial damage to motion picture distributors and exhibitors. It was proposed that one way of combating film piracy in this manner is to spoil the copy as it is recorded. For example, U.S. Pat. No. 6,018,374 by Wrobleski, describes projecting an infrared spoiling image onto the screen during the exhibition of the normal images of a motion picture. This image is invisible to the viewers. However, camcorders use light-sensing elements such as an array of CCDs that translate infrared light to the visible spectrum. In this case, the infrared spoiling image is superimposed as a visible spoiling image on top of the normal images as they are being copied by the camcorder. However, consumer camcorders are provided with an infrared blocking filter, which greatly reduces the amount of infrared energy reaching the light sensing elements. This filter diminishes significantly the intensity of the infrared spoiling image and, as a result, the corresponding visible spoiling image has also a much lower intensity then the normal images being copied. Hence, the spoiling visible image becomes almost invisible, and therefore this technique is not very effective.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention provides a method and apparatus for creating intense infrared spoiling images on a motion picture screen simultaneously with the normal images of the motion picture. Preferably, the spoiling images are ‘painted’ over at least a substantial portion of the screen using a fast moving spot generated by an infrared (IR) laser beam. A camcorder copying the normal images must be used with a slow shutter speed to prevent a flicker effect caused by the fact that the camcorder and film projector run asynchronously. As a result, the moving IR laser spot appears as a bright visible spoiling image superimposed on the copied images.  
           [0007]    The laser beam is generated by an infrared laser generator incorporated in an optical deflection system, similar to the ones used to produce laser light shows for entertainment purposes. A controller is provided to operate the deflection system and produce bright complex, optionally moving IR images. Because the CCD imaging sensors used in the consumer camcorders typically used to produce pirated copies of theatrical films are very sensitive near infrared range, it is desirable that the laser used to create the infrared patterns emit in this range. For example, solid state lasers that emit in the near infrared are readily available.  
           [0008]    In one embodiment of the invention, the optical deflection system includes rotating or oscillating mirrors actuated by precision galvanometers. The mirrors are moved by the application of a voltage to the galvonometer. Two of these galvonometer/mirror combinations can be configured in such a way as to deflect a laser beam along X and Y axes.  
           [0009]    The electronic drivers for the galvanometers receive commands from a controller. The controller can be are controlled by a computer so that complex graphic patterns may be drawn by the laser beam.  
           [0010]    During the presentation of a motion picture, the laser system projects the non-visible infrared laser image onto the viewing screen. Many different still and/or moving patterns may be generated by the laser. The light from the laser is of a wavelength that will be invisible or unnoticeable to human observation during the motion picture presentation but will be recorded by a video recording device, such as a camcorder. For example, light in a range of 750-900 nanometers generated by a laser with an appropriate intensity or power can have the desired effect. Thus, when the movie image is recorded by the recording device, the video copy of the motion picture will contain the image generated by the laser. Since the laser generated image will be distracting to the viewer of the video copy of the motion picture, the commercial value of an unlawful copy may be reduced. Alternatively, the optical deflection system includes a mount for the laser generator that is capable of rotating or oscillating along two orthogonal axes, and motors coupled to the mount and responsive to commands. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a diagram side-sectional view of a movie house showing the apparatus delivering the spoiling image;  
         [0012]    [0012]FIG. 2A shows an image being showed on the screen of FIG. 1;  
         [0013]    [0013]FIG. 2B shows an infrared spoiling image painted on the screen by the laser spot;  
         [0014]    [0014]FIG. 2C shows the resultant visible spoiling image superimposed on the image of FIG. 2A;  
         [0015]    [0015]FIG. 3 shows a first embodiment of a device for generating a moving IR laser spot; and  
         [0016]    [0016]FIG. 4 shows a second embodiment of a device for generating a moving IR laser spot.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    [0017]FIG. 1 shows a typical movie house  10  with a vertical screen  12 , a projection room  14  with a projector  16 , and a laser device  18 . The projector projects a sequences of images forming a motion picture on screen  12 . A viewer  20  is using a camcorder  22  to record or copy the images on the screen  12 .  
         [0018]    In order to spoil the images being recorded by the camcorder  22 , the laser device  18  generates a moving IR laser beam onto screen  12 . The laser device  18  is mounted on the ceiling as shown so that it is completely or almost completely invisible to the patrons. Alternatively, the laser device can be disposed inside a platform  24 , as indicated at  18 AA, or at other locations within the movie house. The invention is typically applicable to restricted screenings in commercial theatres, private screening rooms in studios, or other locations.  
         [0019]    [0019]FIG. 2A shows a typical visible image  30  from projector  16  on screen  12 . This image  30  is preferably a normal image that is part of a motion picture, although it could be a still image as well. FIG. 2B shows an invisible IR spoiling image  32  generated by laser device  18 . As discussed above, although the laser device generates only a laser beam terminating in a laser spot on the screen, this spot moves very rapidly. The shutter (not shown) of the camcorder  22  is opened for a sufficiently long enough time so that the image of the spot falls on several CCDs (not shown) or other light sensing elements which translate the resulting IR spoiling image  32  into a corresponding visible spoiling image  34 . In this manner the camcorder superimposes the corresponding visible spoiling image  34  onto the normal image  30  from the projector  26 . The resulting composite image includes both images  30  and  34  simultaneously, as shown in FIG. 2C. Preferably, the spoiling images  32 ,  34  extend over a substantial portion of the screen  12  to insure that as much of the normal image  30  is spoiled as possible. The visible spoiling image  34  appears in the camcorder  22  as a bright line, typically white, that renders the composite image  36  hard or annoying to watch. The visible spoiling image  34  can remain the same for a substantial time period, or it can be changing relatively rapidly, (for example, every couple of frames, or every couple of seconds) to render the images  36  even more confusing.  
         [0020]    The laser device  18  can be operated independently of the projector  16 , or the two devices can be operated simultaneously.  
         [0021]    [0021]FIG. 3 shows a first embodiment of the laser device  18 . In this embodiment, device  18  includes a laser generator  100  and a laser beam deflection system including a controller  102  with a memory  104 , a first galvanometer  106 , a first mirror  108 , a second galvanometer  110  and a second mirror  112 . The memory  104  is used to store one or more spoiling images  32 ,  34 , such as the one shown on FIGS. 2B and 2C, or FIG. 3. Controller  102  accesses the memory  104  and retrieves data defining these images as needed and generates corresponding control signals. The elements of the laser deflection system are available, for example, from Cambridge Technology, Inc., Cambridge, Mass. 02138. The galvanometers  106 ,  110  each have an inductive coil that generates a magnetic field and rotate a respective shaft. The angle of rotation of the shaft is related to the control signal received by the respective galvanometer. In FIG. 3, vertical galvanometer  106  has a shaft  107  oriented along a vertical axis and supporting mirror  108 . Horizontal galvanometer  110  has a shaft  111  disposed along a horizontal axis and supporting mirror  112 . The mirrors on the galvanometers have a coating that reflects as much infrared energy as possible.  
         [0022]    The device  18  operates as follows. The controller  102  (which may be initiated by an external command) sends control signals to the galvanometers  106 ,  110  corresponding to a particular image. Meanwhile, the laser generator (which may be, for example, an LED or other kind of semiconductor laser) generates a laser beam in the infrared region, e.g., having a wavelength of about 750-900 nanometers. This laser beam first hits mirror  108 .  
         [0023]    The mirror  108  is reciprocated rapidly by galvanometer  106  directing the beam in a vertical plane toward mirror  112 . Mirror  112  is reciprocated rapidly by its galvanometer  110  and directs the beam toward the screen  12  as shown. The movement of the mirrors  110 ,  112  is controlled in a manner so as to paint the selected invisible spoiling image on the screen  12  superimposed on the normal image  30  from the projector  16 . FIG. 4 shows an alternate embodiment for the laser device. In this embodiment, device  18 A includes an IR laser generator  150  and a laser deflecting system consisting of a controller  152  with a memory  154 . The controller  152  receives imaging information from memory  154 . The laser generator  150  is rotatably mounted on a U-shaped bracket  156  by a horizontal shaft  158 . The bracket  156  is mounted on a vertical shaft  160 . A first oscillating motor  162  is coupled to shaft  158  and, in response to commands from controller  152 , it rotates or oscillates the shaft  158  and laser generator  150  to sweep its beam in a vertical plane. Similarly, a second oscillator motor  164  rotates or oscillates shaft  160  in response to commands from controller  152 . In this manner, the controller  152  causes the laser beam generator to paint an IR image on screen  12 . In one embodiment, the IR image from either device  18  or  18 A can cover the whole screen  12 . In another embodiment, several devices can be provided, each device generating respective IR images that are painted on respective portions of the screen  12 . The IR images from different laser devices can overlap. In FIG. 1, device  18  is shown mounted on, or near the ceiling of the  10 , while device  18 AA can be disposed at the bottom of the screen  12  as shown.  
         [0024]    Although the invention has been described with reference to particular forms, it is to be understood that these are merely illustrative of an application of the principles of the invention. Numerous modifications, may be made and other arrangements may be devised without departing from the spirit and scope of the invention.