Patent Publication Number: US-2007109657-A1

Title: System and method for providing a three dimensional image

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a method and system for providing a three dimensional (3-D) image, and more particularly, to a method and system for providing a 3-D image based on a viewer&#39;s eye distance.  
      2. Description of the Related Technology  
      A 3-D image provides a viewer with a sense of depth and distance between objects, as well as a sense of three dimensions with respect to each object (e.g., person). Presently, most images are only two dimensional and various studies have been carried out to determine how to overcome their lack of a depth component.  
      Most technologies which enable the perception of a 3-D image are based on the fact that a human being has two eyes. The principle of this perception is that the eyes are horizontally spaced apart a predetermined distance from each other. For example, the distance is about 7.5 cm and 5 cm for adults and children, respectively, such that images of a scene received at the retinas are views from different angles. An image of the object one sees is transferred to the cerebrum via a visual nerve.  
      Thus, in a conventional method of providing a 3-D image to a viewer, two images are presented in a shutter or refraction manner so as to be seen independently by the left and right eyes.  
      Although there is a conventional method of realizing a 3-D image by using LCD eyeglasses, this additional apparatus is not widely available and is costly. Even when this conventional apparatus is used, if separation of the left and right images is not complete, images overlap each other or the image flickers due to the phenomenon of optical interference.  
     SUMMARY OF CERTAIN INVENTIVE ASPECTS  
      One aspect of the invention provides a system for providing a three dimensional image from at least two plane images. In one embodiment, the system comprises i) first and second image display devices configured to substantially simultaneously output first and second plane images, each plane image produced at different positions with respect to an object, ii) a first mirror configured such that the output first plane image is incident to the first mirror and reflected in a selected direction, iii) a second mirror configured such that the output second plane image is incident to the second mirror and reflected in the selected direction, and iv) an adjustment mechanism configured to adjust the distance between the first and second mirrors, wherein the first and second display devices are located on opposite sides of the first and second mirrors.  
      Another aspect of the invention provides a method of providing a three dimensional image from at least two plane images. In one embodiment, the method comprises i) substantially simultaneously outputting first and second plane images, each plane image produced at different positions with respect to an object, ii) configuring a first mirror such that the output first plane image is incident to the first mirror and reflected in a direction, iii) configuring a second mirror such that the output second plane image is incident to the second mirror and reflected in the direction, and iv) adjusting the distance between the first and second mirrors such that the distance between the center points of a viewer&#39;s eyes is equal to or substantially the same as the distance between the center points of the displayed images.  
      Another aspect of the invention provides a system for providing a three dimensional image from at least two plane images. In one embodiment, the system comprises i) a first image display device configured to output a first plane image of an object, ii) a second image display device configured to output a second plane image of the object, the first and second images being produced at different positions with respect to the object, wherein the first and second image display devices are configured to output substantially simultaneously the first image and the second image, respectively, iii) a mirror arranged such that the first plane image is incident from the first image display device to the mirror and reflected in a selected direction, and iv) an adjustment mechanism configured to adjust the distance between the mirror and the second image display device based on the distance between the center points of a viewer&#39;s eyes, wherein the first and second display devices are located on opposite sides of the mirror, and wherein the second display device is arranged to output the second plane image in the selected direction. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1A  illustrates a typical configuration of a system for providing a 3-D image using a pair of plane mirrors.  
       FIG. 1B  is conceptual diagram for explaining the distance between the center points of each plane image displayed on the mirrors.  
       FIG. 2  illustrates a 3-D image generation system according to one embodiment of the invention.  
       FIG. 3A-3C  illustrate an exemplary configuration of a moving mechanism of a 3-D image generation system according to one embodiment of the invention.  
       FIG. 4A-4B  illustrate an exemplary configuration of a moving mechanism of a 3-D image generation system according to another embodiment of the invention.  
       FIG. 5  illustrates an exemplary configuration of a 3-D image generation system according to still another embodiment of the invention.  
       FIG. 6  illustrates an exemplary configuration of a moving mechanism of a 3-D image generation system according to still another embodiment of the invention.  
       FIG. 7  illustrates an exemplary configuration of a 3-D image generation system according to still another embodiment of the invention.  
       FIG. 8  illustrates an exemplary configuration of a 3-D image generation system according to still another embodiment of the invention.  
       FIG. 9A  illustrates an exemplary configuration of a 3-D image generation system according to yet another embodiment of the invention.  
       FIGS. 9B and 9C  are conceptual diagrams for explaining the distance adjustment between the mirrors according to one embodiment of the invention.  
    
    
     DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS  
      Referring to  FIG. 1A , a pair of plane or 2-D display devices  10  and  12  (D 1 , D 2 ) are located on opposite sides of first and second mirrors  14  and  16 . In one embodiment, the display devices  10  and  12  output first and second plane images to the first and second mirrors  14  and  16 , respectively. In one embodiment, each plane image is produced at different positions with respect to an object by a pair of stereoscopic cameras (not shown), and the first and second plane images form a set of stereoscopic images. In one embodiment, the plane images may be inverted, before outputting, in the display devices  10  and  12 . The first and second plane images, output from the first and second display devices  10  and  12 , respectively, are incident to the first and second mirrors  14  and  16 , respectively. Each of the mirrors  14  and  16  reflects the incident images toward a viewer&#39;s left and right eyes  18  and  20 , respectively, as shown in  FIG. 1A . The viewer can synthesize the two plane images and perceive a three-dimensional image. The detailed operation of an embodiment of the  FIG. 1  system is disclosed in U.S. Pat. No. 6,778,253 issued on Aug. 17, 2004, which is hereby incorporated by reference.  
      Referring to  FIGS. 1A and 1B , distance (W d ) represents the distance between the center points  15  and  17  of each of the plane images displayed on the mirrors  14 ,  16 . In one embodiment, the center points  15  and  17  of each of the plane images can be the center points of the first and second plane mirrors  14  and  16  as shown in  FIG. 1B . In this embodiment, W d  is the distance between the center points of each of the mirrors  14  and  16 .  
      Referring to  FIG. 1A , W a  represents the distance between the center points of each of a viewer&#39;s eyes  18  and  20 . The distance W a  varies from person to person. Normally the distance increases as a person grows and it does not change when he or she reaches a certain age. The average distance of an adult may be 70 mm. Some people may have a distance of 80 mm, other people may have a distance of 60 mm. There may be several methods to measure and provide the distance (W a ) as described in detail in Applicant&#39;s (published) U.S. application Ser. No. 10/280,246, filed on Oct. 24, 2002, which is hereby incorporated by reference.  
      The display system shown in  FIG. 1A  provides a 3-D image without considering the value W a . This means that the distance value (W d ) is fixed to be the same for all viewers regardless of the fact that they have a different W a  value. This may cause several undesirable problems such as headaches or dizziness, and deterioration of a sense of three dimension. In order to produce a more realistic three-dimensional image and to reduce headaches or dizziness of a viewer, the mirror distance or two plane image distance W d  is preferable to be determined by considering the distance W a . The consideration of the W a  value may provide a viewer with better and more realistic three-dimensional images.  
      One aspect of the invention provides a 3-D image generation system which adjusts the mirror distance (W d ) based on the distance (W a ) between a viewer&#39;s eyes.  FIG. 2  illustrates a 3-D image generation system according to one embodiment of the invention. In one embodiment, the mirror distance (W d ) is either manually or automatically adjusted based on the distance (W a ) between a viewer&#39;s eyes  18  and  20 . In one embodiment, the mirror distance value (W d ) is adjusted so as to be substantially the same as the eye distance value (W a ).  
      For example, if person A&#39;s W a  (e.g., 60 mm) is provided to the system, the W d  distance is adjusted to be substantially or exactly the same as 60 mm (e.g., 59.5-60.5 mm). As another example, if person B&#39;s W a  (e.g, 70 mm) is provided to the system, the W d  value is adjusted to be substantially or exactly the same as 70 mm (e.g., 69-71 mm). As another example, if person C&#39;s W a  (e.g., 80 mm) is entered, the mirror distance (W d ) is adjusted to be substantially or exactly the same as 80 mm (e.g., 79-81 mm). Throughout the specification, the term “substantially the same” will be interchangeably refer to “substantially or exactly the same.” 
      In one embodiment, the mirror distance (W d ) is initialized as 70 mm. In this embodiment, since the above B&#39;s W a  value is 70 mm, no adjustment is made to the mirror distance. For the person A, since his W a  value is less than the initialized value (70 mm), the mirrors  26  and  28  are moved such that the mirror distance (W d ) is narrowed from the initialized state until W d  is substantially the same as the A&#39;s W a  value (60 mm). For the person C, since his W a  value (80 mm) is greater than the initialized value (70 mm), the mirror distance (W d ) is widened from the initialized state until W d  is substantially the same as the A&#39;s W a  value (80 mm). In this way, the mirror distance (W d ) is adjusted so as to be substantially the same as the eye distance value (W a ). Thus, a viewer can perceive a sense of three dimensions from the two plane images, displayed on the mirrors  26  and  28 , wherein the distance (W d ) is substantially the same as the distance (W a ).  
       FIGS. 3A and 3B  illustrate an exemplary configuration of a moving mechanism (or adjustment mechanism) of a 3-D image generation system according to one embodiment of the invention.  FIGS. 3A and 3B  represent a plan view and a front view of the moving mechanism, respectively. In one embodiment, the moving mechanism  30  is configured to manually move the pair of mirrors  26  and  28  such that the W a  value is substantially the same as the W a  value.  
      In one embodiment, the moving mechanism  30  contains a moving assembly  31  (see  FIG. 3C ), an adjusting knob  32 , and a pair of connecting members  34  and  36 . In one embodiment, the adjusting knob  32  and the pair of connecting members  34  and  36  can be formed from a rigid material such as plastic, metal or wood. In one embodiment, the moving assembly  31  is located inside the moving mechanism  30 . In one embodiment, the moving assembly  31  moves the mirrors  26  and  28  in a latitudinal direction by the rotation of the adjusting knob  32 . The bottom portions of the mirrors  26  and  28  are connected to the top surfaces of the connecting members  34  and  36 , respectively (see  FIGS. 3A and 3B ), such that the mirrors  26  and  28 , and the connecting members  34  and  36  can simultaneously move in a latitudinal direction. In one embodiment, one clockwise rotation of the adjusting knob  32  can increase a certain amount, for example, 10 mm, in the W d  value. In another embodiment, one counter clockwise rotation of the adjusting knob  32  can decrease the same amount in the W d  value.  
      In one embodiment, the moving assembly  31  includes a connecting rod  310 , a pair of worm gears  320  and  330 , a pair of wormwheels  340  and  350 , and a pair of rack gears  360  and  370 . In one embodiment, the connecting rod  310  is extended from the adjusting knob  32 , and includes the pair of worm gears  320  and  330 . In one embodiment, the worm gears  320  and  330  are integrally formed on the connecting rod  310 . The rack gears  360  and  370  are connected to the moving sections  34  and  36 , respectively, as shown in  FIG. 3C .  
      The worm gears  320  and  330  are engaged with the wormwheels  340  and  350 , respectively. In one embodiment, the first pair of the worm  320  and the wormwheel  340  are configured such that the counter clockwise rotation of the worm  320  moves the wormwheel  340  in a counter clockwise direction as shown in  FIG. 3C . In this embodiment, the second pair of the worm  330  and the wormwheel  350  are configured such that the counter clockwise rotation of the worm  330  moves the wormwheel  350  in a clockwise direction as shown in  FIG. 3C . This can be implemented by structuring the teeth of each of the first and second pairs in an opposite direction. In another embodiment, the first and second pairs of the worms  320 ,  330  and wormwheels  340 ,  350  can be configured such that the clockwise rotation of the worms  320  and  330  rotate the wormwheels  340  and  350  clockwise and counter clockwise, respectively. It will be appreciated that a skilled technologist can easily create various implementations of gear teeth of each worm or wormwheel depending on the embodiment.  
      The wormwheels  340  and  350  are engaged with the rack gears  360  and  370 , respectively, as shown in  FIG. 3C . In one embodiment, the rotation of the wormwheels  340  and  350  moves the rack gears  360  and  370  in latitudinal (linear) directions which are opposite to each other as shown in  FIG. 3C . That is, the counter clockwise rotation of the wormwheel  340  moves the rack gear  360  in the left direction, and the clockwise rotation of the wormwheel  350  moves the rack gear  370  in the right direction as shown in  FIG. 3C . In the above embodiment, the wormwheels  340  and  350  server the role of i) as a wormwheel for the worms  320  and  330 , respectively, and ii) a pinion gear for the rack gears  360  and  370 , respectively.  
       FIG. 4A-4B  illustrate an exemplary configuration of a moving mechanism of a 3-D image generation system according to another embodiment of the invention.  FIGS. 4A and 4B  represent a plan view and a front view of the moving mechanism, respectively. In one embodiment, the moving mechanism  30  is configured to automatically move the pair of mirrors  26  and  28  such that the mirror distance (W d ) is equal to or substantially the same as the eye distance (W a ). In this embodiment, as shown in  FIG. 4B , the moving mechanism  30  includes a display unit  40 , a power button  42 , a start button  44 , and an input unit  46 . In one embodiment, the moving mechanism  30  includes a motor and a controller (not shown) which automatically operate the moving assembly  31 . In this embodiment, such a motor and controller can be configured to drive, for example, the worm gears  320  and  330 . A skilled technologist could readily implement an automatic moving mechanism in view of the manual moving mechanism shown in  FIG. 3C , and thus the description thereof will be omitted.  
      In one embodiment, the display unit  40  displays a mirror adjusting value (W d ), to be adjusted, which is provided via the input unit  46 . Referring to  FIG. 4B , the display unit  40  displays “70 mm.” The power button  42  is to turn on the moving mechanism  30 . The start button  44  is to start adjusting the mirrors  26  and  28 . Once a mirror adjusting value (W d ) is entered and the start button  44  is pressed down, the automatic moving mechanism  30  moves the mirrors  26  and  28  as much as the entered adjustment value, 70 mm in this embodiment. In one embodiment, the display unit  40 , the power button  42  and the start button  44  can be omitted. In this embodiment, entering a mirror adjusting value (W d ) via the input unit  46  can automatically move the mirrors  26  and  28  as entered.  
       FIG. 5  illustrates an exemplary configuration of a 3-D image generation system according to still another embodiment of the invention. In this embodiment, the system as discussed above is implemented in a head mounted display ( 50 ; HMD). In this embodiment, the display devices  22  and  24 , the mirrors  26  and  28 , and moving mechanism  30  are made relatively smaller than in other embodiments such that those parts ( 22 - 30 ) can fit in the HMD  50 .  
       FIG. 6  illustrates an exemplary configuration of a moving mechanism of a 3-D image generation system according to still another embodiment of the invention. In one embodiment, the moving mechanism  30  is configured to either automatically or manually move both i) the mirrors  26  and  28 , and ii) the display devices  22  and  24  such that the W d  value is substantially the same as the W a  value. In this embodiment, the mirrors  26  and  28  are connected to the display devices  22  and  24  via connecting members  50  and  52  so that the moving mechanism  30  simultaneously moves the devices  22 ,  24 , and the mirrors  26 ,  28 . In one embodiment, the moving mechanism  30  moves either manually or automatically the connecting members  50  and  52  in a latitudinal direction based on the mirror adjusting value (W d ) as discussed above.  
      One advantage of this embodiment is that a stereoscopic image can be provided to the viewer such that a photographing ratio (A:B:C) is substantially the same as a screen ratio (D:E:F). The photographing ratio includes three parameters (A, B, C). Parameters A and B are defined as horizontal and vertical lengths of the space, respectively, including an object, photographed by a camera (not shown). Parameter C is defined as the perpendicular distance between the camera and the object. The screen ratio includes three parameters (D, E, F). Parameters D and E are defined as horizontal and vertical lengths of the image displayed in a display device, respectively. Parameter F is defined as the perpendicular distance between the display device and a viewer&#39;s eye. By always maintaining the relationship of the adjustment of being “A:B:C=D:E:F” provides a more realistic 3D image to the viewer. The photographing ratio (A:B:C) and the screen ratio (D:E:F) are described in detail in Applicant&#39;s U.S. (published) application Ser. No. 10/280,246, filed on Oct. 24, 2002, which is hereby incorporated by reference.  
       FIG. 7  illustrates an exemplary configuration of a 3-D image generation system according to still another embodiment of the invention. In this embodiment, the  FIG. 6  system is implemented with a head mounted display ( 50 ; HMD). In this embodiment, the moving mechanism (not shown in  FIG. 7 ) is located inside the HMD  50  and the display devices  22  and  24  are connected to the HMD  50  via the connecting members  50  and  52 , respectively. The mirrors  26  and  28  are connected to the display devices  22  and  24 , respectively, so that the moving mechanism simultaneously moves the display devices  22  and  24 , and the mirrors  26  and  28 . In one embodiment, the HMD  50  includes a display guiding portion  70  which facilitates the images to be reflected from the mirrors  26  and  28  to a viewer&#39;s eyes, respectively. As in the  FIG. 6  embodiment, the moving mechanism can either manually or automatically move the connecting members  50  and  52  in a latitudinal direction.  
       FIG. 8  illustrates an exemplary configuration of a 3-D image generation system according to still another embodiment of the invention. In this embodiment, only one mirror  80  is provided in the system. The mirror  80  reflects an image incident from the display device  28  (D 2 ) to the viewer&#39;s right eye as shown in  FIG. 8 . In this embodiment, the display device  28  preferably inverts the image before outputting so that a proper orientation of the image by the mirror  80  can be obtained. The moving mechanism  30  moves the mirror  80  and the display device  26  such that the distance value (W d ) is substantially the same as the distance value (W a ).  
      The display device  26  (D 1 ) and the mirror  80  are connected to the moving mechanism  30  via connection sections  82  and  84 , respectively. In one embodiment, the moving mechanism  30  can move at least one of the display device  26  and the mirror  80  in a latitudinal direction, left and right with respect to the viewer&#39;s eyes to satisfy the above relationship (W d =W a ).  
       FIG. 9A  illustrates an exemplary configuration of a 3-D image generation system according to yet another embodiment of the invention. In this embodiment, the moving mechanism  30  moves both of the mirrors  26  and  28  in a longitudinal direction, i.e., backward or forward (X or Y directions in  FIG. 9A ) with respect to the viewer&#39;s eyes such that the center points of the images displayed on the mirrors  26  and  28  are moved in a latitudinal direction.  
      In one embodiment, it is assumed that the distance W d1 , shown in  FIGS. 9B and 9C , is set to as an initial distance, for example, 70 mm. In this embodiment, the movement of the mirrors  26  and  28  in the Y direction provides the same effect of adjusting the initial distance (W d1 ) to be shorter (W d2 ), as shown in  FIG. 9B . Furthermore, in this embodiment, the movement of the mirrors  26  and  28  in the X direction provides the same effect of adjusting the initial distance (W d1 ) to be longer (W d3 ) as shown in  FIG. 9C . This adjustment mechanism is disclosed in detail in Applicant&#39;s U.S. (published) application Ser. No. 10/280,241, filed on Oct. 24, 2002, which is hereby incorporated by reference.  
      While the above description has pointed out novel features of the invention as applied to various embodiments, the skilled person will understand that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made without departing from the scope of the invention. Therefore, the scope of the invention is defined by the appended claims rather than by the foregoing description. All variations coming within the meaning and range of equivalency of the claims are embraced within their scope.