Abstract:
This invention includes means, apparatus and devices for performing the steps of the method described above, such as for example, wide angle image projection apparatus for projecting wide angle images for the enactment of a sail; sound projection apparatus for creating sound elements of the virtual reality in at least two directions, synchronized with the image projection apparatus; means for creating olfactory elements of the virtual reality synchronized with the image projection apparatus; and means for creating hot air and cold air synchronized with the image projection apparatus; and furthermore, wide angle screen means juxtaposed with the wide angle projection apparatus for displaying the wide angle images, the wide angle screen means having a focal region within view of the projected images; seating means disposed in the focal region for seating viewers of the images, the focal region being exposed to the elements of virtual reality, including the olfactory elements, and the hot air and cold air. The apparatus according to the invention may further include wide angle image projection apparatus, wherein the wide angle is up to a 360° in a horizontal plane, and the wide angle image projection apparatus, including upward directed projection means for projecting overhead images of the enactment, synchronously coupled to the wide angle projection apparatus. The apparatus according to the invention may further include digital signal detection means coupled to digital image projection apparatus operative for receiving digital control signals embedded in the projected digital images, the digital control signals being operative for digitally controlling functions of at least one of the means for creating the olfactory elements of virtual reality.

Description:
This application is a continuation-in-part of Ser. No. 09/184,603 filed Nov. 2, 1998, now U.S. Pat. No. 6,073,403 dated Jun. 13, 2000 based on provisional application No. 60/065,354 filed Feb. 20, 1998 and disclosure document #431703 filed Feb. 21, 1998. 
    
    
     The invention relates to an amusement and virtual reality ride, and more particularly to a method and apparatus for enacting a ship at sea, the ship impacting an iceberg, and the ship sinking after impacting the iceberg. The ride may also include an enactment of an underwater ride to the sunken ship. The method may further include an enactment of a dive through the ocean and a view of the sunken ship resting on the sea bottom. 
     BACKGROUND OF THE INVENTION AND KNOWN ART 
     Recent years have seen an evolution of enactments of happenings and events of more than ordinary interest. 
     The field of creating and/or re-enacting such sensations of reality has become known as the field of “virtual reality”. 
     A related development has led to the creation of so-called theme parks, wherein participants are treated to enactments of happenings of more than ordinary interest, often times as enactments of historical events, sometimes in futuristic settings, sometimes in historical or pre-historic settings, and at other times as settings of pure fantasy. 
     It is accordingly a primary object of the present invention to expand the concept of virtual reality to further enhance the concept of virtual reality by adding new effects and elements thereto as described in more detail below. 
     It is a further object of the present invention to apply the concept of the above enhanced virtual reality to an enactment of the sinking of the ocean liner Titanic. 
     It is another object of the invention to apply the present enhanced concept of virtual reality to an enactment of a travel from the ocean surface to the wreck of the ocean liner Titanic now resting on the sea bottom in the northern Atlantic Ocean. 
     SUMMARY DESCRIPTION OF THE INVENTION 
     The invention relates to a method for enacting an ocean sail of a ship using elements of virtual reality, the method which comprises the steps of enacting the ship departing a port of embarkation, enacting the ship crossing a body of water, enacting the ship impacting an iceberg, enacting the ship sinking and enacting rescue efforts of surviving passengers and crew. 
     The method further includes the step of forming the ship in likeness of the ocean liner Titanic, including the step of forming the iceberg in likeness of the iceberg that impacted the ocean liner Titanic. 
     The method further includes forming elements of virtual reality, such as elements of visual, acoustic, olfactory, tactile, physical motion and temperature reality. 
     The method may additionally include the steps of forming an element of visual reality by means of wide angle image projection apparatus for projecting images of the enactment in rapid succession, creating an illusion of live motion, and forming the element of acoustic reality by means of sound apparatus synchronized with the projection apparatus. In particular, the element of acoustic reality includes sound effects projected from any direction in the space above and from below the ground plane. The sound effects may further include enhanced echo effects. 
     The method according to the invention may further include the steps of forming elements of olfactory reality by means of air-moving apparatus synchronized with the projection apparatus, and drawing the air from smell-generating sources. 
     The method according to the invention may additionally include steps of forming the element of temperature reality by means of air-moving apparatus, synchronized with the projection apparatus, and drawing the air from air-heating, air-cooling and air pressure controlling sources. 
     The method according to the invention can further include steps of controlling the acoustic, olfactory, temperature, visual and physical motion virtual reality elements by means of cues embedded in an electronic memory being scanned in synchronism with the image projection apparatus. 
     The method according to the invention may further include the step of forming the element of visual virtual reality as a three dimensional image, projecting the image on a three dimensional image screen, and forming the element of acoustic virtual reality as a three dimensional sound signal. 
     The inventive concept may further include polarizing the images into complementary polarized images being polarized at respective 90° angles to each other, forming a viewing area within a focal region of the three dimensional image screen, and providing a seating facility for at least one person within the focal region. 
     The invention may additionally include a method of agitating the seating facility and controlling the agitating by means of cues embedded in the aforesaid computer memory. 
     The invention further includes means, apparatus and devices for performing the steps of the method described above, such as for example, wide angle image projection apparatus for projecting wide angle images for the enactment of a sail; sound projection apparatus for creating sound elements of the virtual reality in at least two directions, synchronized with the image projection apparatus; means for creating olfactory elements of the virtual reality synchronized with the image projection apparatus; and means for creating hot air and cold air synchronized with the image projection apparatus; and furthermore, wide angle screen means juxtaposed with the wide angle projection apparatus for displaying the wide angle images, the wide angle screen means having a focal region within view of the projected images; seating means disposed in the focal region for seating viewers of the images, the focal region being exposed to the elements of virtual reality, including the olfactory elements, and the hot air and cold air. 
     The apparatus according to the invention may further include wide angle image projection apparatus, wherein the wide angle is up to a 360° in a horizontal plane, and the wide angle image projection apparatus, including upward directed projection means for projecting overhead images of the enactment, synchronously coupled to the wide angle projection apparatus. 
     The apparatus according to the invention may further include digital signal detection means coupled to digital image projection apparatus operative for receiving digital control signals embedded in the projected digital images, the digital control signals being operative for digitally controlling functions of at least one of the means for creating the olfactory elements of virtual reality. 
     The invention may further include forming a likeness of the sunken ship resting on a sea bottom; forming a tubular person passage to the likeness of the sunken ship, the tubular passage having walls being at least in places of transparent material for enabling a view of at least the sunken ship, and a view of sea life around the sunken ship. 
     The invention may further include an apparatus wherein the focal region includes sound damping elements for dampening inherent local echoes created in the focal region. 
     The apparatus preferably includes a control and sound strip synchronously coupled to the projection apparatus, the control and sound strip having a plurality of sound tracks for generating sound effects stored on the sound tracks, a clock track having control clock elements, and a frame identity track including an image frame identity number specific to each image frame embedded in the frame identity track. 
     The invention may further include frame alignment means coupled to the frame identity track for aligning frames of same identity to the frame identity track. 
     The image and sound projection apparatus may additionally include means for generating elements of virtual reality, comprising at least one image projector for projecting a plurality of serially connected image frames disposed on a respective image strip; at least one sound projector for reading an equal plurality of serially connected sound frames disposed on a respective sound strip in synchronism with the image frames, wherein the image frames and the sound frames are mutually paired by means of identical frame identity numbers disposed on each pair of image and sound frames; frame identity number reading and synchronizing means coupled to each image and sound projector for maintaining the image and sound projector in frame synchronism; and virtual reality element generating means coupled to the frame identity number reading means for generating elements of virtual reality in synchronism with the image and sound frames. 
     The image and sound projection apparatus according to the invention may include a plurality of image projectors, each arranged to project a part of a total image by means of a respective image strip, each image strip composed of a plurality of serially connected image frames, each image frame having a frame identity number track identifying each frame with a sequentially incremented frame number. 
     The image and sound projection apparatus according to the invention may further include frame numbers which are binary numbers disposed on a continuous number track extending lengthwise on each image strip, and wherein equally numbered image frames together form a contiguous projected moving image, and wherein each binary frame identity number begins with a frame start bit followed by at least one counting bit, wherein the plurality of the counting bits is sufficient to identify the highest numbered frame in a complete series of image frames, and wherein the frame start bit is longer than the counting bits. 
     The image and sound projection apparatus according to the invention may further include on the sound strip a continuous clock track composed of clock bits arranged in a continuous sequence of clock bits in longitudinal alignment with the counting bits, and wherein further each of the sound frames includes a plurality of continuously connected sound tracks, each sound track being recorded from sounds coming from different directions so as to form in combination an omni-directional sound impression. 
     The image and sound projection apparatus according to the inventive concept, preferably includes a viewing location for an audience of at least one person, and seating facilities in the viewing location for accommodating the person, wherein the seating facilities are disposed in a focal area of the viewing location. 
     The image and sound projection apparatus according to the inventive concept preferably includes a drive motor for each of the image and sound projectors, and synchronizing means for maintaining the image and sound strip in synchronism, wherein the synchronizing means includes reading means for reading the frame identity numbers, comparison means for comparing the frame identity numbers, and motor speed control means coupled to the comparison means for maintaining the image and sound strips in synchronism. 
     The image and sound projection apparatus according to the invention may include virtual reality element control means having at least means for controlling air temperature, olfactory control means, tactile control means, air pressure control means and echo control means, and wherein the virtual reality element control means include a computer having an input coupled to the frame identity number reading means for continuously reading the frame identity numbers, wherein each of the virtual reality elements has assigned thereto a given frame identity number for enacting a respective virtual reality sub-routine by means of the computer, and wherein the computer has outputs coupled to virtual reality enacting facilities for activating corresponding virtual reality sub-routines. Furthermore, the computer includes a dedicated memory dedicated to storing a plurality of virtual reality subroutines, each subroutine having a specific subroutine address cross-correlated with a corresponding frame identity number. 
     Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment, shown schematically in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES 
     FIG. 1 is a perspective view of an ocean liner, an iceberg, a lake and an underwater person passage between the ocean liner and the iceberg; 
     FIG. 2 is a top-down view of a viewing space showing image projection apparatus, screens and sound apparatus; 
     FIG. 3 is an elevation of the viewing space according to FIG. 2, further showing seating arrangement and ancillary effect apparatus; 
     FIG. 4 is a diagrammatic view of part of the ancillary effect apparatus, including apparatus for providing olfactory effect sources and air treatment apparatus; 
     FIG. 5 is a block diagram of a control computer with various virtual reality effect control interfaces; 
     FIG. 6 is a diagrammatic view of five (5) image strips each having sprocket holes, a digital image frame ID-number track, and a combined sound and control strip; 
     FIG. 7 is a diagrammatic view of details of the sound and control strip, showing five sound tracks, a master clock track and a frame ID-number track. 
     FIGS. 8 a  and  b  show respective side and front views of an active seat and activators; 
     FIG. 9 is a diagrammatic view of a row of active seats and parts of the common hydraulic control and drive apparatus; 
     FIG. 10 is a diagrammatic view of a film strip drive for a single strip; 
     FIG. 11 is a schematic block diagram of a control arrangement for maintaining several sprocket-driven strips in synchronism; 
     FIG. 11 a  is a timing diagram showing clock pulses, frame start pulses and frame I-D address pulses; 
     FIG. 12 is a flow chart showing major steps of the overall control process; and 
     FIG. 13 is a diagram showing generation of enhanced echoes. 
    
    
     Before explaining the disclosed embodiment of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown, since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a likeness  11  of an ocean liner, in particular the ocean liner Titanic, immediately prior to its impact with a likeness of the iceberg  12 . 
     In one embodiment of the invention as presently contemplated, the likeness  11  of the ocean liner Titanic is structured as a hotel and the likeness  12  of the iceberg may likewise be structured as a hotel. For enhanced reality, a lake  14  is surrounding the ocean liner and the likeness  12  of the iceberg. 
     A subsurface, tubular person passage  13 , having transparent windows  16  connects the two structures  11  and  12 . The person passage enables persons using the passage to view an underwater environment with sea plants and sea animals in their own habitat, or simulated or enhanced with virtual reality effects. 
     FIGS. 2 and 3 show respectively in plan view and elevation, a viewing region generally at  21 , having one or several seats  18  for viewing persons watching an enactment displayed on one or more viewing screens  19 , respectively designated  19 W,  19 E,  19 N and  19 S, and an upper screen  19 U. It has been found that a curved screen, e.g. screen  19 W provides a more realistic view than a flat screen. A wider screen, e.g. a wide angle screen composed of screens  19 W,  19 N and  19 S provides an even more realistic view, and a 360° angle screen additionally including screen  19 E and upper screen dome  19 U provides a maximum of realism, although at increased expense and complexity. 
     As described in more detail below, a circular screen with an upper dome screen  19 U, when formed of flat, hard surfaces generates an undesirable inherent internal echo which is most pronounced in the viewing region  21 . Applicant has determined that wall surfaces and screen material having soft surfaces will tend to dampen the undesirable echoes. For enhanced realism, applicant contemplates, as described in more detail below, to add to the recorded sound effects, where applicable, an artificial recorded echo, embedded in the sound signal. 
     At or near the center of the viewing region  21 , a wide-angle image projection device  22  is located, advantageously suspended in thin cables, not shown, of which one or more cables serve to provide conductors for drive power and control signals to and from the image projection device  22 . 
     The image projection device  22  is shown as composed of five (5) individual projectors, respectively designated  22 W,  22 N,  22 E,  22 S and  22 U. 
     The above described arrangement of 360° projection requires high quality optical lenses in the projectors, especially when high image quality wide viewing angles are required. 
     As an alternative compromise, applicant contemplates that fewer projectors each projecting a less wide beam may provide a projected image of less than 360° wide angle, depending on the degree of realism and image quality desired. As another alternative, it is contemplated that the forward facing projector  22 E may be arranged to project a less angle-wide, but sharper image. 
     Recorded sound effects synchronized with the projected images is injected into the viewing region  21  by means of loudspeakers of which speakers  23 W,  23 N,  23 E,  23 S and  23 U are shown. Since a single speaker  23 , within the present state of the art, is unable to provide a satisfactory wide-frequency range, it is contemplated that each speaker  23  is realized as an assembly of two (2) or more speakers each generating a sound frequency band within its own range, as well known from the art of high fidelity sound reproduction. Each of the e.g. five speakers  23  is driven from a dedicated one of e.g. five sound tracks as described in more detail below. In that manner, directed sound vectors coming from any direction, even if desired from below, can be generated for greatly enhanced realism from the five speaker assemblies  23  each derived from its dedicated sound track. 
     As contemplated, each speaker assembly  23  is connected to a dedicated frequency filter arrangement driven by a dedicated amplifier, each filter having an input connected to the sound track dedicated thereto. 
     As part of the inventive concept, the air in the viewing region  21  is continuously circulated and processed in various ways in order to provide maximum virtual realism, by means of an air treatment system seen in FIG. 3 as device  24 , which injects treated air at air inlet  26 , while the treated air exits at air exit  27 , connected to an exit blower  49  for air pressure control. 
     FIG. 4 shows details of the air processing system  24 . An air blower  26  draws in fresh air through an air filter  30 , from where the air flows through a plenum  28 . An array  29  of containers a,b,c . . . n containing olfactory essences, preferably in liquid form, such as for example essence from flower petals to generate a pleasant landly aroma e.g., sulfur dioxide dissolved in water to indicate vulcanic activity, smells of seaweed dissolved in liquid to indicate presence of a beach, distilled water for generating a spray simulating fog at sea, and so forth, which are each connected through a small electric pump  31  to a respective spray nozzle  32  located in the plenum  28 . Each pump  31  is connected to a respective output of an olfactory control interface  33 , of a control system shown in FIG. 5, and described in more detail below. The olfactory system is controlled by cues embedded in a control track on a sound and control strip, as also described in more detail below. 
     From the plenum  28  the air passes through a manifold composed of three branches, of which branch  34  receives air directly from the plenum  28  under control of a control valve  38 . Another branch  36  contains a cooling coil  39  connected to a cold water or liquid source  41  under control of a control valve  42 . A third branch  43  contains a heating element  36  connected to a hot water or electric heating source, and is controlled by control valve  46 . Control valves  38 ,  42  and  46  are also controlled by cues on the control track via the computer interface  47 , connected to a digital control computer  50  shown in FIG. 5, which is ultimately controlled by instructions stored in a special effect control memory  89  as described below. 
     If such an instruction in the control memory signals that, for example, a cold environment is being entered, the cold control valve  42  is opened, and the viewing region  21  is suddenly filled with cold air. Conversely, if a hot environment is entered, a cue from the control memory opens the hot air valve  46 , and the viewing region  21  is filled with hot air. 
     It is readily seen that the numerous combinations of olfactory stimuli, and combinations of different air temperatures combined with the projected wide angle moving image displays and the multidirectional sounds with superimposed echoes as described above, together are capable of providing a wide range of highly realistic impressions on viewers seated in the viewing region  21 . 
     One further impression relating to the air flow is provided by means of air exit control valve  48  (FIG. 3) inserted in the air outflow  27  briefly mentioned above, and also controlled by the computer  50 . By partially closing that valve  48  the air pressure in the viewing region  21  can be increased a small amount giving the viewers an impression of downward motion, e.g. in an airplane landing or an elevator going downward. Conversely, a suction blower  49  connected to the outlet  27  can be used to slightly lower the air pressure in the viewing region  21  will give the impression of ascending, e.g. in an airplane or elevator of the like. It follows that the valve  48  and blower  49  are both controlled by the special effect control memory  89  as described in more detail below. 
     Still another powerful element in further enhancing the virtual reality sensation by viewers in the viewing region is contemplated in the form of imparting physical movements to the seating facilities  18  in the viewing region  21 . 
     As seen in side view FIG. 8 a,  a seat  18  is seen from the right hand side, and in FIG. 8 b  from the front. Each seat  18  is connected to the base or floor by means of e.g. three hydraulic cylinders, namely cylinder RR at the rear, and two front hydraulic cylinders FR to the right hand side and FL to the left hand side of the seat  18 . 
     The cylinders are attached to the base e.g. floor  49  and to the underside  52  of the chair  18  by means of respective ball joints  51 . A respective pair a,b,c, each composed of two hydraulic lines  53 ,  54  lead from each cylinder to a hydraulic control system shown in more detail in FIG.  9 . All cylinders of the same designation are connected in parallel to one of a set of hydraulic control valves  56 . The control valves are of the type known as proportional control valves, each proportional valve  56  having a valve spool (not shown) proportionally driven by an electric solenoid  57 . The control valves are all connected in conventional manner to a common hydraulic pump  58  and a hydraulic tank  59  containing the hydraulic fluid that circulates through the system. The solenoids  57  are all connected to a seat control interface  84  of the computer  50 , which drives the control valves  56  with proportional control voltages as directed by instructions stored in the special effect memory  89 . 
     Since the hydraulic cylinders are joined to the chairs and the base by means of ball joints  51 , it follows that each chair has too many degrees of freedom of movement in order to retain its position and that therefore some further restraints must be added to each chair. Such restraints can be added in the form of links shown in dashed lines in FIGS. 8 a  and  8   b.  Two links  61 ,  62  connect the upper ball joint  51  of the rear cylinder RR with respective lower ball joints  51  of cylinders FR and FL, and an additional link  63  connects the upper joint of cylinder FL with the lower joint of cylinder FR. With this linkage, the hydraulic control is capable of moving all chairs  18  in unison in numerous ways under control of control valves  56 , which are in turn controlled by the solenoids  57 , connected to the system&#39;s main control system shown in FIG. 5 in response to cues embedded in the special effects control memory  89  as described in more detail below. 
     In regard to the hydraulic chair control system it should be noted that the chair backs are shown upward tapered which allows adjacent chairs more sideways freedom, and the chairs can therefore be placed more closely together for more efficient use of the available seating space. 
     Since hydraulic cylinders may have minute leakage around the piston or shaft seals, all chairs can from time to time be reset by raising them all, when not occupied, to e.g. the top position, and then lowered to halfway down. Alternatively one or more chairs may have a halfway position switch (not shown) indicating if the chair is out of position. It follows that the chairs can be combined in twos or threes or more, each combination sharing one or two sets of hydraulic cylinders. 
     Referring now to FIGS. 6 and 7, the image strips, and the control and sound strip will be described in more detail. 
     In a conventional projection system, the image projector has an image strip disposed on a film drawn from a film feeding cartridge to an uptake cartridge in conventional manner. A conventional film strip conventionally has to one side a narrow sound track next to the image track which occupies the greater part of each image frame of the film. The film images are drawn by a stepping mechanism, one image frame at a time, through an optical illumination and lens system to be displayed on a screen in conventional manner. Since the sound track must be read in continuous motion a loop of the film strip before or behind the stepping mechanism is provided so that the sound track can be scanned in continuous motion, while the image frames are displayed one at a time in rapid succession so as to create a projected image visually appearing as a continuously moving action. 
     The present system contemplates at least one but preferably a plurality of separate image strips each to be displayed by respective image projectors  22 E,  22 S,  22 W,  22 N and  22 U if a completely circular and upward projected image is to be provided. As seen in FIG. 6, this figure shows for example five image strips  76 , each to be projected by a respective projector. In accordance with the inventive concept, each image strip carries a sequence of image frames, wherein, according to the inventive concept, each image frame has a frame identity number FRID which is recorded as a binary number on a FRID track  71  next to the image frame track  76 . A typical projector  22  is shown in diagrammatic form in FIG. 10 showing a type as contemplated for use in the present invention. 
     In FIG. 10 a feeding spool  64  feeds a film strip  66  supported by idler wheels  65  is drawn continuously in direction shown by arrow “a” by a continuously driven sprocket wheel  67 , through a light scanner  68  composed of a light source  69   a,  and a light detector  69   b  which reads a light spot on a frame identity number track  71  on an image track  76  (FIG.  6 ). Next, the film strip forms a slack loop  75  before it reaches a step-driven sprocket wheel  70 , which feeds the film strip one image at a time past illumination optic  71 , composed of an image illuminator lamp  71   a  and projection optics  73 . A spring-loaded idler arm,  80  maintains the film in straight form before it is spooled onto an uptake spool  60 . A polarizing screen  74  may be placed at the output of the optics  73 , in order to project the images in polarized form, if 3-D imaging by means of polarized images are to be used, as described below. A synchronous drive motor SM drives the projector. 
     A projection system as used in the presently contemplated embodiment of the invention includes a plurality of at least two image projectors of the type described above. In order to maintain synchronism between the projectors it is possible and known to apply mechanical linkage between the drive components. Mechanical linkage, although simple in concept, has the drawback that if one film strip should slip in the drive mechanism the images will be out of synchronism, and the performance must be stopped until the strips are again aligned manually. 
     The present invention contemplates and discloses a multiple film drives by means of dedicated electric synchronous motors with an automatic synchronization arrangement which quickly automatically re-synchronizes an out of sync film strip, which will most often hardly be noticed by viewers. 
     In accordance with the inventive concept as briefly mentioned above, FIG. 6 shows a plurality of image strips  76 . Each image strip  76  shows in conventional manner all the images which in succession form the animation of a respective display. As contemplated, each strip  76  is projected frame by frame by its dedicated projector as described above. It follows that a bank of projectors  22  may share some common components such as spool magazines, power supplies, synchronizing controls, etc., the latter to be described in more detail below. 
     FIG. 6 shows a number of image strips E, S, W, N and U, the number depending on the number of simultaneous displays chosen for a performance. In order to keep all image tracks in synchronism, each image strip includes a frame number identity FRID track  71  that holds digital information formatted for keeping all image strips in synchronism with each other and with a sound and control strip  77 , FIG.  7 . 
     The synchronizing, i.e. sync. track  71  on all strips  76 ,  77 , contains in binary code a binary number that is incremented by 1 (one) for each next image frame, and such that the corresponding frames on all the image strips  76  and on the sound and control strip  77  are all marked with the same binary number. This binary number, which is the same for all corresponding frames  75  on all strips is used by an electronic control described below to maintain all strips in synchronism. 
     The sound and control strip  77 , seen in FIG.  6  and FIG. 7, is run on a strip drive similar to the image strip transport shown in FIG. 10, but without the image projection components. The sound and control strip  77  has no image tracks, but has a plurality of sound tracks,  77   a,  namely one for each image strip E, S, W, N and U. In addition, the sound and control strip  77  has a master clock track  70  and a frame master identity number track  71   c.    
     In a multidimensional projection system as disclosed herein it is important that all image strips E, S, W, N, U and the sound and control strip SC are in perfect synchronism, or else the images will not overlap with precision and the sound effects from different directions will not be in sync with the images, causing a very unsatisfactory presentation. It is therefore an aspect of the present invention to provide an automatically acting synchronization arrangement that maintains all strips in perfect synchronism. 
     Synchronism is maintained by means of a digital frame code FRID imprinted for each image frame on the master sync track  71   c  on the sound and control strip  77 , and on each image strip on the corresponding image frame. A master clock track  70  runs in parallel with the FRID track. 
     As presently contemplated the digital FRID signal will be in binary form, advancing by a count of one for each new image frame in the forward direction of the image presentation. Numerous formats are available for the binary number. The well-known ACSII format using a start bit for each image frame, but having a bit number at least as large as is required to accommodate the largest number of image frames of an entire performance, is presently contemplated. 
     A motor drive arrangement that automatically maintains perfect synchronism between all strips is part of the inventive concept and is shown in block diagram FIG. 11, wherein a synchronous drive motor SM is provided for each projector including the master drive motor SM-SC for the sound and control strip, which is driven by a constant master frequency generator MG at a strip speed in terms of frames per second selected for the system. 
     The electronic system for maintaining all strips in synchronism receives the continuously advancing frame ID numbers from all image strips on respective frame number leads E-FN . . . CS-FN and converts the frame numbers in respective digital-to-analog converters D-A to analog dc voltages corresponding to the respective frame identify numbers FRID. 
     The process of determining the frame ID numbers FRID for the moving strips is shown in more detail in FIG. 11 a,  wherein the systems&#39; clock pulses obtained from reading the master clock track  70  on the sound and control strip  77 , shown as CLK in FIG. 11 a,  are obtained from scanning clock track  70  on this strip  77  with scanner  68  in FIG.  10 . It should be noted that FIG. 11 a  shows, for the sake of simplicity, a relatively small number of clock pulses, i.e. ten (10) pulses for each frame which will not suffice in a practical setup, since the ten pulses will only allow a maximum frame count of 2 10 , which equals 1024 frames. A practical system would require a larger number of bits per frame according to the actual duration of a performance, as mentioned above. 
     Referring now to FIG. 11 a,  each frame starts with a frame start pulse FRST (FIG. 11 a ) which has a duration of two times the duration of one clock cycle, namely the clock pulse and a clock space as indicated by two vertical dashed lines x. At the end of a frame, e.g. the frame shown in track FRID (Frame Identity), between an arbitrarily chosen frame start pulse FRST and a following frame start pulse FRST+1 it is seen, as an example, that this frame has a binary ID number equal to the sum of bit values  1 ,  2 ,  8 ,  32  and  64  which equals a frame ID number equal to 107. At the beginning of the text frame start pulse FRST+1 a “clear sample and hold” gate  81 , FIG. 11, generates a reset signal created from the Boolean function [CLK]×(FRST+1) (brackets indicate logic inversion) i.e. “absence of a clock pulse” and “presence of frame start pulse FRST+1”. This reset signal is used to clear the sample and hold circuits S/H at reset terminal R of the analog value of the previous frame ID, and also resets steering counter STRG at terminal R. Next the following frame identity FRID values, now stored in the FRID registers  83 , which are present at the output of the D-A circuits  85  are entered into the S/H circuits  84 , which are set with a “Read FRID REGISTERS” pulse created as a function [CLK]×(FRST+1) (brackets indicate logic inversion) in gate  82  applied to the set terminal S of the sample and hold circuits SH. These registers were set with the last frame ID number during the previous frame under control of a steering register STRG, which is driven by clock pulses CLK. 
     Next the analog voltage of each image frame representing its respective FRID value is compared with the analog frame number voltage FRID from the control and sound strip CS-FN in respective analog comparators COMP  86 . 
     At the end of the FRST+1 pulse the FRID registers are all cleared at their R terminal by an output pulse from circuit  88  having as inputs an inverted clock pulse CLK and an inverted frame start pulse FRST+1. The length of the output pulse of circuit is limited by an RC circuit  89 , so as not to interfere with the next arriving frame identity pulses of the following frame. These next arriving frame identity pulses are steered into the proper positions in the FRID registers by the steering counter STRG  91   a  and the process described above to assure that all synchronous motors SM are maintained in the same phase, so that all images and virtual reality effects are maintained in synchronism. 
     The dc-output of each comparator is for practical reasons “smoothed” out in a low-pass filter, not shown for the sake of simplicity, and connected to the dc-control input of a respective phase-locked loop PLL  87 , in which it is combined with the internal dc-control for the internal voltage-controller oscillator in the PLL, which aids the PLL to respectively advance or retard the trailing or advanced strip until it is again in sync with the SM-SC drive. 
     It is to be understood that the process of maintaining all strips in sync could be preformed by other means, such as e.g. mechanical coupling between all projector drives, which could, however, lead to a cumbersome mechanical arrangement. Furthermore, this mechanical arrangement would not solve problems arising if one of the strips should slip in its respective sprocket drive, which happens from time to time. 
     As described above, each image strip E, S, W, N and U has at one side a frame identity track ID which represents each frame by a continuously incrementing binary frame number as the images are projected. The control circuit of FIG. 11 maintains all image strips in the same image phase as the sound and control strip SC. The frame numbers serve an additional important purpose, namely that of controlling the various virtual reality effects described above, such as e.g. the air temperature, the olfactory effects and the movements of the seats, etc. In order to perform these controls, the frame identity numbers described above, which serve to maintain synchronism between all strips at the same time, also serve as address numbers transmitted to a computer  50  for activating the various effects that are invoked and controlled by the digital control computer  50  shown in FIG.  5 . 
     The digital control computer  50  shown in FIG. 5 includes a central processing unit CPU  91  of conventional construction, connected to a digital control bus  92 , which communicated with a number of interfaces that translate digital instruction on the bus  92  to analog control signals, such as the air control interface  93 , the seat control interface  84 , and the olfactory control interface  96 , in response to specific frame addresses arriving at the special effect interface  97 . 
     During operation, the frame addresses are continuously in sequence presented to the special effects interface SPL-EFF  97 . Whenever a frame address is at a given FRID count, marked as an effects count requiring special effect to be generated, as marked in computer memory  98 , the computer CPU  91  “points” to a location in the special effect memory  89 , which in turn activates a corresponding subroutine or subroutines as shown in the flow chart of FIG.  12 . The computer responds with control signals to perform the responses programmed into the special effect memory  89  for the corresponding subroutines. This is a very powerful feature that enables the system to execute single special effects or combinations of simultaneous effects, in that special effect subroutines can be prepared in advance by frame ID numbers ahead of the times that the effects are to be executed, and triggered into action by a subsequent trigger frame FRID number. If, for example, an impact event is to be performed, several subroutines can be assembled in advance in the special effect memory  99 , such that concurrent effects, e.g. motion of chairs, olfactory effects, etc. and released simultaneously on subsequent cues issued at certain preset image frame identity numbers. A virtually limitless range of special effects can be combined and released in response to instructions coordinated with the image frame ID numbers. 
     The invention is capable of presenting a performance in 3-dimensional format by means of various methods for selectively addressing a viewers eyes in mutually exclusive formats. Such formats are known e.g. as respective presentations with polarized images viewed through goggles having polarized lenses, or by means of goggles having liquid crystal lenses being alternately activated by appropriate electric controls. 
     If 3-D presentation is performed by means of polarized images, a projector as shown in FIG. 10 may have a rotating screen  74  in front of the projection optics  73 , wherein the polarizing screen has alternating filters with 90° angle polarization, synchronized with alternating image frames in 3-D format. If liquid crystal lenses are to be used, an electric signal can be transmitted (by wire or wirelessly) to each set of goggles to alternatingly view the 3-D images from a projector which, as above, alternatingly transmit the 3-D images in synchronism with the activation of the lenses of the goggles. 
     In accordance with a feature briefly mentioned above, the invention is well suited to provide a presentation with enhanced echo effects. Enhanced echoes effectively add to the realism of a presentation when judicially applied. 
     In order to apply enhanced echoes, it is important that the viewing space is arranged with inherent echo dampening since the inherent echoes generated due to internal sound reflections in the viewing space are confusing the hearing senses of a viewer. In order to reduce or eliminate inherent echoes it is contemplated to apply sound-absorbing elements in the viewing room. Such sound absorbing elements can be applied by means of sound-absorbing surfaces not used for image presentation, and further by means of projection screens that are, besides being light reflecting, also sound absorbing. Such screens can be formed as a two or more layers of screen material having a front woven layer of thin white fabric attached to one or more rear layers of thick felt-like fabric. 
     For enhanced echo generation, it is known to couple delay components to sound recording apparatus. FIG. 13 shows a recording stage  201  with e.g. 3 sound recording microphones  202  of which at least one microphone,  202   a,  is equipped with echo generating apparatus, having a pre-amplifier stage  203  with an output coupled to a variable delay line  204 . An output from that delay line coupled to a variable attenuator  206  having a variable output  207  coupled to a mixing stage for generating echoes of variable delay and intensity. 
     It is to be understood that the sound tracks and the frame identity number track will be scanned simultaneously in continuous motion of the track, as opposed to the image frames, that are advanced in step motion. It is therefore necessary that the frame identity numbers on the sound track are offset from the corresponding image frames a few frames in order to maintain synchronism between sound and the corresponding image frames.