Abstract:
A display device for capturing and displaying images along a single optical axis. The device includes a display panel having a front side and a back side, said display panel capable of being placed in a first display state which allows displaying of an image on said front side for viewing of an image and a second transmissive state wherein said display panel becomes substantially transmissive so as to allow capture of an image of an object positioned in front of said front side of said display panel. An image capture device is provided for capturing said objective image through said display panel when said display device is in the second transmissive state. An image supply source is provided for providing an image to said display panel when said display panel is in said first display state and a mechanism for alternating placing said display panel between said first display state and second transmissive state such that an image can be viewed on said display screen and said object can be captured in a manner such that said alternating between said first display state and said second transmissive state is substantially imperceptible to a user of said display panel.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This is a Continuation-in-Part of application Ser. No. 10/264,058 filed Oct. 3, 2002 now U.S. Pat. No. 7,042,486 which is a continuation of application Ser. No. 09/452,091 filed Nov. 30, 1999 (abandoned). 

   FIELD OF THE INVENTION 
   The present invention relates to an electronic image capture and display device, and in particular an image capture and display device of the type employing an electronic camera to capture an image of a subject and an electronic image display device to display images. 
   BACKGROUND OF THE INVENTION 
   U.S. Pat. No. 4,864,410, issued Sep. 5, 1989 to Andrews et al., illustrates a technique using a beam splitter, electronic camera, and a video display (CRT) to simultaneously capture and view a subject on the same optical axis similar to the function of a conventional optical mirror. The images captured by the camera can be processed prior to display to provide special effects such as the distortions employed in a fun-house mirror. The problem with this technique is that the displayed image appears to be located at a distance behind the beam splitter, compromising the “mirror-like” function of the unit. In addition, the video display device must be masked off or it may be viewable by the user also detracting from the “mirror experience”. It is well known and desirable to use a touch screen as a means for providing an interface between a user and a display device such as a CRT, however with the arrangement described by Andrews et al., the interface with a touch screen located between the user and the beam splitter does not provide a satisfactory feel, since when the subject places her finger on the touch screen, the image of the subject&#39;s finger does not appear to be located at the screen, rather it appears to be displaced to the rear of the screen. 
   Using a conventional rear projection screen and a digital projector would provide a display image that would appear in a viewing plane like a conventional mirror, and would function in a satisfactory manner with a touch screen interface, but a conventional rear projection screen would prevent the camera from “seeing” the subject, unless a hole was provided in the center of the screen. This is not a very satisfactory solution. 
   U.S. Pat. No. 5,801,758 issued Sep. 1, 1998 to Heirich discloses a system for image capture and display. The system includes an image capture apparatus, an image projection apparatus, and an optical switching device that switches an optical path between the image capture and the image projection apparatus. A highly transparent surface, such as a sheet of clear glass is used as a display screen through which the image capture apparatus can view a user, and onto which the image of the user is projected. The problem with this arrangement is that the highly transparent surface allows the user to directly view the projection lens of the image projection apparatus. Any image formed on the highly transparent surface is overwhelmed by the bright appearance of the projection lens. 
   Another problem in the prior art is the ability to capture an image of person on the same optical axis on which the person is viewing a display device. For example, with regard to video conferencing, a capture camera is positioned at an optical axis different from which the person is viewing the other individual on the video conference call. The problem with the described situation is that the person viewing the display while being recorded by an off-axis camera appears to fail to make eye contact with the recording camera and whoever may be viewing that image. There is a similar problem with an individual using a teleprompter. A person reading from a teleprompter is looking in a direction off axis from the optical axis of a camera capturing the image of the reader. 
   There is a need therefore for an improved image capture and display device that avoids the shortcomings of the prior art. 
   SUMMARY OF THE INVENTION 
   In accordance with one aspect of the present invention there is provided a display device for capturing and displaying images along a single optical axis, comprising: 
   a display panel having a front side and a back side, said display panel capable of being placed in a first display state which allows displaying of an image on said front side for viewing of an image and a second transmissive state wherein said display panel becomes substantially transmissive so as to allow capture of an image of an object positioned in front of said front side of said display panel; 
   an image capture device for capturing said objective image through said display panel when said display device is in the second transmissive state; 
   an image supply source for providing an image to said display panel when said display panel is in said first display state; 
   a mechanism for alternating placing said display panel between said first display state and second transmissive state such that an image can be viewed on said display screen and said object can be captured in a manner such that said alternating between said first display state and said second transmissive state is substantially imperceptible to a user of said display panel. 
   In accordance with another aspect of the present invention, there is provided a method for displaying and capturing an image along a single optical axis, comprising the steps of: 
   providing a display panel that can be alternately placed in a first display state and a second transmissive state, said display panel when in said first display state allows an image to be displayed on said display panel and when placed in said second transmissive state allows transmission of an image of an object through said panel; 
   providing an image capture device for capturing said image through said display panel of an object positioned in front of said display panel when said display panel is in said second transmissive state; and 
   alternating said display panel between said first display state and said second transmissive state such that said image can be displayed on said display panel and an image of and an object can be transmitted from the front side through said display panel for capturing by said image capture device in a manner such that said alternating between said first display state and said second transmissive state is substantially imperceptible to a user of said display panel. 
   In accordance with yet another aspect of the present invention, there is provided a display device for transmitting and capturing an image, comprising: 
   a display panel having a front side and a back side, said display panel capable of being placed in a first display state which allows displaying of an image on said front side for viewing of an image and a second transmissive state wherein said display panel becomes substantially transmissive so as to allow capture of an image of an object positioned in front of said front side of said display panel; 
   an image capture device for capturing said objective image through said display panel when said display device is in the second transmissive state; 
   an image supply source for providing an image to said display panel when said display panel is in said first display state, said image supply source being placed on an optical axis other than that of said image capture device; 
   a mechanism for alternating placing said display panel between said first display state and second transmissive state such that an image can be viewed on said display screen and said object can be captured in a manner such that said alternating between said first display state and said second transmissive state is substantially imperceptible to a user of said display panel. 
   These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims and by reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the detailed description of the preferred embodiments of the invention presented below, reference is made to the accompanying drawings in which: 
       FIG. 1  is a schematic diagram of an image capture and display device according to the present invention; 
       FIG. 2  is a schematic diagram of a modified image capture and display device made in accordance with the present invention; 
       FIG. 3  is a schematic diagram of another modified image capture and display device made in accordance with the present invention; and 
       FIG. 4  is a schematic diagram of yet another modified image capture and display device made in accordance with the present invention 
       FIG. 5  is a schematic diagram of still another modified image capture and display device made in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , the image capture and display device, generally designated  10 , according to the present invention is housed for example in a cabinet  12 . It will be understood that the capture and display device may be a component of a larger device such as a photobooth (not shown). An electronic camera  14  such as a KODAK DIGITAL SCIENCE DVC323 Digital Video Camera available from the Eastman Kodak Company, Rochester, New York, and a display panel  16  such as an OLED panel available from the Eastman Kodak Company, Rochester, New York, are located in the cabinet  12  with respect to an optical element such as a fully silvered mirror  18  in a known manner such that they share a common optical axis  20 . The display panel  16  is positioned in a front opening  13  of the cabinet  12 . Display panel  16  is electronically switchable between a first state and a second state. Display panel  16  may comprise for example a matrix of Organic Light Emitting Diodes that change state when an electrical current is applied. In the “power off” state (transmissive state), the material is substantially transparent and suitable for viewing there through. In the “power on” state, the display panel  16  will display an image for viewing by an individual (viewer)  24  positioned in front of display panel  16 . The interior and contents of the cabinet  12  is unlighted and preferably painted a matte black so that when the display panel  16  is in the “power off” state, an individual  24  does not see the interior of the cabinet. In a preferred embodiment, the brightness of display panel  16  is such that any small amount of light within cabinet  12  will go unnoticed. It is preferred to use a camera of high sensitivity so that the ambient illumination of the user is adequate for high quality image capture. An optional lamp may be provided for illuminating the user  24  during image capture by camera  14 . Lamp  30  is turned on only during image capture by camera  14  so as to minimize interference with the image on display panel  16 , and to minimize the light impinging upon the eyes of user  24 . 
   In the preferred embodiment, display panel  16  is fully transparent so that it does not interfere with the capture of the image of user  24  by camera  14 . If this is not the case, and only a portion of display panel  16  is transparent, the portions of display panel  16  that are not transparent must be taken into account. For example, if the transistors used to turn individual transparent OLED devices on and off are themselves not transparent, the result is that only the portions of display panel  16  that comprise the OLED devices will allow capture of user  24  by camera  14 . The effect will be that of looking through a fine pitch screen. Thus, the screen must be interpolated out of the captured image, or the image must be somewhat blurred by electronic, optical, or computational means so that the presented image of the user appears without the screen artifact. 
   An optional touch screen  23  may be provided over display panel  16 . The touch screen  23  can be of the type having an array of infrared transmitters and detectors arranged around the periphery of the display panel  16 , or a transparent pressure sensitive panel disposed over the display panel  16 . The display panel  16  is located with respect to common optical axis  20 , for allowing the electronic camera  14  to capture the image of a subject  24  through the display panel  16  when in the transparent state and for displaying an image by the digital display panel  16  for viewing by individual (user)  24  along a viewing axis. In the embodiment illustrated, digital display panel  16  comprises OLED device. An example of a suitable organic light emitting diode (OLED) display device/panel for practicing the present invention is illustrated in the Kodak EasyShare LS633 zoom digital camera. 
   Returning to  FIG. 1 , control of the image capture device  14  and display device  16 , and digital image processing is provided by a computer  26 , such as a standard microprocessor or personal computer. The output of the camera  14  and the input to the digital display panel  16  are connected and controlled by computer  26 . The computer  26  can function as both a controller and/or as an image processing computer. It will be understood that a separate controller and digital image processing electronics can be provided. A digitally controlled driver  28  is provided for driving the display panel  16  to switch it back and forth between its first transparent state and second viewing state. 
   In operation, the computer/controller  26  and driver  28  first switches the display panel  16  to its transparent state by signaling driver  28  to de-energize the screen, then captures an image from camera  14 , and then switches the display panel  16  to its viewing state, and back again via a signal to driver  28  to the display device  16 , making it transparent. This cycle is then repeated preferably at a rate of at least 24 complete cycles per second to provide the appearance of a smooth and “flicker free” display. That is, in a manner such that said alternating between said first display state and said second transmissive state is substantially imperceptible to a user of said display panel. The captured images may be processed by the computer  26  prior to display using known image processing techniques. The capture image may be forwarded to second image capture and display device  10 ′ (not shown) for viewing by another party and capture of the other party for view by the individual at the first device  10 . The second device  10 ′ being substantially identical in performance as the first device  10 . In this way there may be two way video conferencing wherein both parties are looking at the display device thereby providing a more pleasing on-screen appearance for both parties. The display is more pleasing because both users  24  and  24 ′ (not shown) are looking directly at the display of the other user and effectively making eye contact since the display and capture device are on the same optical access. 
   Alternatively, the device  10  may be operated in a manner to provide a mirrored image of the individual in front of display panel  16 . The mirrored image may be modified to incorporate desired effects, for example, the image may be geometrically distorted as in a fun house mirror. Alternatively, background scenes may be added using known blue screen techniques, colors may be modified or pre-stored image elements, such as mustaches, hats, glasses etc. may be digitally added. Also articles of clothing may be added to the image of the subject, for example to show how the subject would appear in the article of clothing. Note that the processed image does not need to immediately follow the capture, but may be delayed by several frames to allow time for the digital processing to be preformed. 
   Referring to  FIG. 2  there is illustrated a schematic view of a modified device  100  wherein like numerals indicate like parts and operation as previously described with respect to device  10 . In this embodiment, display panel  16  comprises a liquid crystal display (LCD)  116  is provided in place of an OLED. In this embodiment, a diffuser  112  is used for providing a substantially uniform light source for illuminating LCD  116 . When LCD  116  and diffuser  112  are in the off non-energized state, they are at least partially transparent so the camera  14  can capture an image of the individual  24 . This image will have the pattern associated with the color filter array of the LCD. This must be taken into account when processing the captured image. When camera  14  is off and it desired to display an image on LCD  116 , the LCD  116  and diffuser  112  are in the energized state. The LCD  116  has pixels that can be turned on so that varying levels of light will pass through the pixels to form an image. Preferably red, green, and blue pixels are provided so that color image may be generated on LCD  116 . Light from lamp  30  is used to backlight the image formed by LCD  116  and is diffused by diffuser  112 . In operation the LCD  116  diffuser  112  and lamp  30  are cycled between the energized and de-energized states with the camera capturing an image during the de-energized state and an image being displayed during the energized state. The lamp  30  may also be used to illuminate the user for at least a portion of the time the camera captures an image. Here as with the OLED, the rate of cycling between the energized and non-energized state is at a rate so that “flicker” of the image is not perceived by the viewer. A rate of at least 24 or more cycles per second is preferred. 
   Preferably during capture, the pixels of each color area are placed in the condition where they pass the maximum amount of light, but this maximum will be a wavelength specific according to the color of the pixel. Thus, the image captured will have the effect of this array imposed upon the viewer  23 . One solution to this problem is to provide the LCD array with high resolution and camera  14  with low resolution. In this fashion, the individual pixels of the LCD array  116  blur together to create an image that does not appear to be captured through the LCD array. Alternatively a blurring filter in camera  14  may achieve the same result. Another solution is to take advantage of the known pattern of the LCD array  116 . In this case, camera  14  can be color or monochrome, and of a resolution high enough to resolve the pixels of the LCD array  116 . The image of user  23  is overlaid with the color pattern of LCD array  116 . When the image of user  23  is captured with a color camera, the missing values of red, blue, and green must be interpolated. In the case of monochrome capture, red, green and blue pixel values are determined from known positions of the colored pixels, and then the missing values can be calculated from the monochrome capture. Registration or calibration markings may be provided to ease computational complexity. Other color combinations such as cyan, magenta, and yellow can be used. 
   Referring to  FIG. 3 , there is illustrated a schematic of yet another modified capture and display device  200  similar to devices  10  and  100 , like numerals indicating like parts and operation as previously described. In this embodiment of device  200 , there is provided a rotating diffuser  212  that is provided in front of lamp  30  for not only diffusing the light but also acting as shutter for allowing light from the lamp  30  to be directed to the LCD  116 . A motor  214  controls the rate of rotation of diffuser  212  and is synchronized with the turning on and off of the LCD  116 . 
   Referring to  FIG. 4  there is illustrated a schematic of still another modified capture and display device  300  similar to devices  10 ,  100 , and  200  like numerals indicating like parts and operation as previously described. In this embodiment lamp  30  provides the light for back lighting LCD array  116 . A collimator  312  is provided for collimating the light before reaching a half silver mirror  314 . The light reflected off mirror  314  is displayed on LCD diffuser  112  during the image display cycle. During the image capture portion of the cycle, the diffuser  112  is changed to its transparent state so as to allow capture of an image by cameras  320  behind mirror  314 . Collimator  312  is essential to this embodiment so that the light passing through every pixel in LCD  116  is traveling in a parallel manner to light one small portion of the diffuser  112 . 
   Referring to  FIG. 5  there is illustrated a schematic of still another modified capture and display device  400  similar to devices  10 ,  100 ,  200  and  300  like numerals indicating like parts and operation as previously described. In this embodiment, camera  14  is placed directly on the optical axis of device  400  so that user  24  is looking straight into the camera as he observes the display on diffuser  112 . The sequence of display and capture is as described above. Projector  34  illuminates diffuser  112  during the display portion of the cycle. Projector  34  is placed off the optical axis of device  400  so that user will not perceive a hot spot in the illumination of diffuser  112 . Projector  34  is placed such that there is not a direct line from projector  34  through diffuser  112  to user  24 . In a preferred embodiment, the light from projector  34  strikes diffuser  112  from above. It is unlikely that user  24  will view display device  400  from below the optical axis, and there will be no perception of a hot spot. Mirrors (not shown) may be used to reduce the depth of device  400 . 
   The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention. 
   PARTS LIST 
   
       
         10  image capture and display device 
         10 ′ second image device 
         12  cabinet 
         13  front opening 
         14  electronic camera 
         16  display panel 
         18  fully silvered mirror 
         19  partially silvered mirror 
         20  common optical axis 
         21  light 
         22  light valve projection screen 
         23  touch screen 
         23  viewer 
         24  subject 
         24 ′ user 
         26  computer 
         28  digitally controlled driver 
         30  optional lamp 
         30  mechanical shutter 
         32  motor 
         34  projector 
         34  optical panel 
         36  liquid crystal device 
         38  transparent substrate 
         40  transparent substrate 
         42  liquid crystal material 
         44  transparent conductive layer 
         46  transparent conductive layer 
         48  alignment layer 
         50  alignment layer 
         52  alignment arrow 
         54  alignment arrow 
         56  polarizer 
         58  polarizer 
         60  electrical lead 
         62  electrical lead 
         100  modified device 
         110  LCD 
         112  diffuser 
         116  LCD 
         200  display device 
         212  rotating diffuser 
         214  motor 
         300  display device 
         312  collimator 
         314  silver mirror 
         320  cameras 
         400  display device