Patent Publication Number: US-2006012753-A1

Title: Stereoscopic imaging

Description:
BACKGROUND  
      The presentation of stereoscopic imagery—three dimensional still pictures and motion video—has been achieved through the use of dual projector systems, single projection systems with the aid of shutter glasses, an other relatively complicated systems. Such systems are typically out of reach of the average consumer. Often, they are expensive and difficult to set up, operate, and maintain. Conventional two dimensional video cameras and projectors, however, are within the reach of many consumers. Unfortunately, these conventional devices do not enable consumers to record and then display stereoscopic imagery. 
    
    
     DESCRIPTION OF THE DRAWINGS  
       FIG. 1  depicts an exemplary stereo image according to an embodiment of the present invention.  
       FIG. 2  illustrates an exemplary stereoscopic adapter coupled to a projector according to an embodiment of the present invention.  
       FIG. 3  illustrates an exemplary mirror pair placement according to an embodiment of the present invention.  
       FIG. 4  is perspective view of the exemplary stereoscopic adapter and the projector of  FIG. 2  according to an embodiment of the present invention.  
       FIG. 5  illustrates a first light path through the exemplary stereoscopic adapter and projector of  FIG. 2  projecting a right perspective of an image on a target according to an embodiment of the present invention.  
       FIG. 6  illustrates a second light path through the exemplary stereoscopic adapter and projector of  FIG. 2  projecting a left perspective of an image on a target according to an embodiment of the present invention.  
       FIG. 7  simultaneously illustrates a first and a second light path through the exemplary stereoscopic adapter and projector of  FIG. 2  superimposing the left and right image perspectives on a target according to an embodiment of the present invention.  
       FIG. 8  illustrates an exemplary pair of viewing glasses according to an embodiment of the present invention.  
       FIG. 9  illustrates the exemplary stereoscopic adapter coupled to an image capture device according to an embodiment of the present invention 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      INTRODUCTION: Audiences enjoy viewing three dimensional images. Unfortunately systems for capturing and projecting three dimensional images have been too costly for the average consumer. Embodiments of the present invention provide an adapter that can be coupled to an image capture device such as a digital camera to capture stereo images. The stereo images may be still frame or motion video. The adapter can then be coupled to a projector allowing the captured stereo images to be projected on a screen.  
      The following description is broken into sections. The first section describes an exemplary stereo image. The second section describes the components of an exemplary stereoscopic adapter, and the third section describes the operation of the exemplary adapter.  
      STEREO IMAGE:  FIG. 1  illustrates an exemplary stereo image  10 . Image  10  can be a physical image such as a photo or slide or it might be a digital image capable of being displayed on a monitor or projected on a screen. Image  10  has two cells,  12  and  14 . Cell  12  contains a right perspective image  16  and cell  14  contains a left perspective image  18 . Alternatively, cell  12  could contain left perspective image  18 , and cell  14  could contain right perspective image  16 .  
      Right and left perspective images  16  and  18  are two representations of an object as seen from two different points not on a straight line with the object. For example, right perspective image  16  may represent the object as seen by an individual&#39;s right eye, and left perspective image  18  may represent the object as seen by the individual&#39;s left eye.  
      Cells  12  and  14  are in a top and bottom relative orientation meaning that when positioned to be viewed, cell  12  is on top of cell  14 . In the example shown, image  10  has an approximate four to three aspect ratio meaning it has a viewing width of four units and a viewing height of three units. This aspect ratio matches the aspect ration of many CCD (Charge Coupled Device) arrays in digital cameras. The top and bottom orientation of cells  12  and  14  allows each cell  12  and  14  to have an aspect ratio of approximately 4 to 1.5—a ratio more suitable for “wide screen” viewing. It is noted that cells  12  and  14  may instead be a side-by side relative orientation. When positioned to be viewed, cell  12  would be beside cell  14  rather than on top.  
      COMPONENTS:  FIGS. 2-4  illustrate an exemplary stereoscopic adapter  20  for use in capturing and projecting stereo images such as stereo image  10  of  FIG. 1 . Referring first to  FIG. 2 , adapter  20  is coupled to projector  22 . Projector  22  represents generally any device capable of projecting a selected image (such as image  10 ) onto a target. In the simplified example of  FIG. 2 , projector  22  is a slide projector and includes lamp  24  and lens  26 . Here image  10  is on a slide. Lamp  24  directs a light flux through image  10 . Lens  26  is then responsible for focusing the flux to cast an image  10  on a screen or other target. It is noted that lens  26  can represent one or more lenses. Alternatively, image  10  may be a digital image and projector  22  may be a digital projector.  
      Adapter  20  includes splitter  28 , filters  30 A and  30 B, and housing  32 . Splitter  28  represents a component capable of diverting a first portion of a light flux from projector  22  along a first light path and diverting a second portion of the light flux from the projector along a second light path. The first and second light paths are selected so that the first and second portions of the light flux cast superimposed images. Examples of the first and second light paths are described below with reference to  FIGS. 5-7 . Referring back to  FIG. 1  as an example, the first portion of image  10  may include the contents of cell  12  and the second portion may include the contents of cell  14 . Splitter  28  is configured to cause the contents of cells  12  and  14  to be superimposed over one another when projected on a screen or other target.  
      Filter  30 A represents generally any component capable of filtering light flux diverted along the first light path by splitter  28 . Filter  30 B represents generally any component capable of filtering light flux diverted along the second light path by splitter  28 . For example, filters  30 A and  30 B may be polarizing filters having opposing linear or circular polarizing characteristics. Alternatively, filters  30 A and  30 B may be color filters—one red and the other blue for example. In this way each of the images superimposed on a screen by splitter  28  is filtered differently than the other.  
      Housing  32  represents generally any structure capable of supporting and holding splitter  28  and filters  30 A and  30 B stationary relative to one another. Housing also includes coupler  34  which represents generally any structure capable of coupling housing  32  to projector  22 . As shown, coupler  34  is configured with threads to allow a user to screw adapter  20  onto projector  22 .  
      In the example shown, splitter  28  includes mirror pairs  36 A,  36 B and  38 A,  38 B. Mirrors  36 A and  36 B are positioned in housing  32  to define the first light path for diverting the contents of first cell  12  of image  10  ( FIG. 1 ). Mirrors  38 A and  38 B are positioned in housing  32  to define the second light path for diverting the contents of second cell  14  of image  10  ( FIG. 1 ).  
      Referring now to  FIGS. 1, 2  and  3 , mirrors  36 A and  38 A are in a relative top and bottom orientation and positioned to intercept from projector  22  a light flux projecting image  10 . Mirror  36 A is positioned to intercept a first portion of the light flux projecting the contents of first cell  12  of image  10 , and mirror  38 A is positioned to intercept a second portion of the light flux projecting the contents of second cell  14  of image  10 . Mirror  36 A is positioned and aimed to reflect the first portion of the light flux toward mirror  36 B. Similarly, mirror  38 A is positioned and aimed to reflect the second portion of the light flux toward mirror  38 B. Mirrors  36 B and  38 B are positioned and aimed to reflect the first and second portions of the light flux toward a common target. More particularly, mirrors  36 B and  38 B are aimed to allow the first and second portions of the light flux to cast superimposed images on that target. Furthermore, the center points of mirrors  36 B and  38 B are spaced apart a distance (D). Distance (D), for example may approximate the average distance between the eyes of an intended audience member.  
      It is noted that mirrors  36 A and  36 B may instead be in a side-by-side relative orientation and positioned to intercept from projector  22  a light flux projecting image cells that are also in side-by-side relative orientation. Mirrors  36 B and  38 B would then each be positioned and aimed to reflect the light flux to cast superimposed images on a target.  
       FIG. 4  provides a perspective view of adapter  20  and projector  22 . As shown, filters  30 A and  30 B are removable from housing  32  to reveal apertures  40 A and  40 B. With filters  30 A and  30 B removed, adapter  20  can be coupled to an image capture device such as a digital camera for use in capturing stereo images such as stereo image  10  of  FIG. 1 . An example of adapter  20  coupled to an image capture device is discussed below with reference to  FIG. 9 .  
      OPERATION: The operation of exemplary embodiments will now be described with reference to  FIGS. 5-9 . Starting with  FIG. 5 , projector  22  casts a light flux projecting image  10 . Mirror pair  36 A,  36 B are positioned to intercept a first portion of the light flux projecting the contents of first cell  12  of image  10  ( FIG. 1 ) diverting the first portion of the light flux along light path  42  defined by mirror pair  36 A,  36 B. Light path  42  passes through filter  30 A filtering the first portion of the light flux. Ultimately, mirror pair  36 A,  36 B causes the filtered first portion of the light flux to cast projected image  44  on target screen  46 .  
      Moving to  FIG. 6 , mirror pair  38 A,  38 B are positioned to intercept a second portion of the light flux projecting the contents of second cell  14  of image  10  ( FIG. 1 ), diverting the second portion of the light flux along light path  48  defined by mirror pair  38 A,  38 B. Light path  48  passes through filter  30 B filtering the second portion of the light flux. Ultimately, mirror pair  38 A,  38 B causes the filtered second portion of the light flux to cast projected image  50  on target screen  46 .  
       FIG. 7  is a composite of  FIGS. 5 and 6 . Mirror pairs  36 A,  36 B, and  38 A,  38 B have intercepted first and second portions of the light flux projecting image  10 . Mirror pairs  36 A,  36 B divert the first portion along light path  42 . Mirror pairs  38 A,  38 B divert the second portion of the light flux along light path  48 . Mirror pairs  36 A,  36 B, and  38 A,  38 B are positioned and aimed to combine the filtered first and second portions of the light flux so that projected images  44  and  50  are superimposed over one another on target screen  46 . It is noted that where filters  30 A and  30 B are polarizing filters, screen  46  is selected so that it preserves the polarization of light projected upon it.  
      As noted above, filters  30 A and  30 B filter the first and second portions of the light flux in differing manners. For example, filter  30 A might provide linear or circular polarization in a given direction. Filter  30 B might then provide linear or circular polarization in an opposing direction.  
      To enjoy a three dimensional presentation provided by the projection of superimposed images  44  and  50  an audience member can benefit from the aid of a filtering viewer.  FIG. 8  illustrates an exemplary viewing filter in the form of viewing glasses  52 . Glasses  52  include viewing filters  54  and  56 . Viewing filter  54  is configured to compliment filter  30 A ( FIG. 7 ) meaning that light flux projected through filter  30 A can be viewed through viewing filter  54 . Viewing filter  54  is configured to oppose filter  30 B ( FIG. 7 ) meaning that light flux projected through filter  30 B is blocked by viewing filter  54 . Similarly, viewing filter  56  is configured to compliment filter  30 B and to oppose filter  30 A.  
      Referring to  FIGS. 7 and 8  together, an audience member donning viewing glasses  52  is able to see projected image  44  (a right perspective image) with her right eye through viewing filter  54  and see projected image  50  (a left perspective image) with her left eye through viewing filter  56 . Viewing filter  54  blocks projected image  50 , and viewing filter  56  blocks projected image  44  allowing the audience member to enjoy a three dimensional presentation.  
      Moving to  FIG. 9 , adapter  20  is coupled to image capture device  58 . Filters  30 A and  30 B ( FIGS. 4-7 ) have been removed, revealing apertures  40 A and  40 B. Image capture device  58  represents generally any device capable of recording a still image or motion video. For example, image capture device  58  may be a conventional film camera, a digital camera, a video camera, or a digital video camera. Among other components not shown, image capture device  58  includes capture medium  60  and lens  62 . Capture medium  60  represents generally any component on which an image can be recorded or otherwise captured. Capture medium  60 , for example, may be film or a CCD (charge coupled device) array. Lens  62  may include one or more lenses and is responsible for focusing an incoming light flux on capture medium  60 .  
      As described above with reference to  FIG. 5-7 , splitter  28  includes mirror pair  36 A,  36 B which defines first light path  42  and mirror pair  38 A,  38 B which defines second light path  48 . Mirror pair  36 A,  36 B collects and diverts a light flux casting right perspective  64  on target  66  along first light path  42 . Mirror pair  38 A,  38 B collects and directs a light flux casting left perspective  68  on target  66  along second light path  48 . Mirrors  36 A and  38 A are positioned and aimed in housing  32  so that they allow lens  62  to focus the light flux casting the left and right perspectives on capture medium. More particularly mirrors  36 A and  38 A may be aimed to allow lens  62  to focus the light flux casting the left and right perspectives on capture medium in a relative top and bottom orientation to record a stereo image such as image  10  seen in  FIG. 1 .  
      CONCLUSION: As described above, embodiments of the present invention provide an adapter for allowing a user to record stereoscopic imagery in the form of still pictures or motion video using a readily available image capture device. The user can then couple the same adapter to a projector to enjoy a three dimensional viewing experience. Although, embodiments of the present invention have been shown and described with reference to the foregoing exemplary implementations, it is to be understood that other forms, details, and embodiments may be made without departing from the spirit and scope of the invention which is defined in the following claims.