Abstract:
A system and method for volumetric display of video images extracted from arbitrary background environments comprising an arrangement for extracting a video image in real time from an arbitrary background and creating a stream of extracted image data in response thereto and a free space or volumetric display operationally adapted to display the stream.

Description:
REFERENCE TO RELATED APPLICATION 
     This Application is a Continuation-In-Part of U.S. patent application Ser. No. 09/363,456, entitled SYSTEM AND METHOD FOR EXTRACTING IMAGES WITHOUT MONOCHROMATIC BACKGROUND, filed Jun. 29, 1999 now abandoned, by W. Benman and U.S. patent application Ser. No. 09/795,290, entitled FUNCTIONAL THREE-DIMENSIONAL WEB SITE WITH DYNAMIC IMAGE EXTRACTION AND TRANSPLANTATION, filed Mar. 20, 2000 now abandoned, by W. Benman and U.S. patent application Ser. No. 09/905,692, entitled SYSTEM AND METHOD FOR PROVIDING A FUNCTIONAL VIRTUAL ENVIRONMENT WITH REAL TIME EXTRACTED AND TRANSPLANTED IMAGES, filed Nov. 28, 2000 now U.S Pat. No. 6,798,407, by W. Benman. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to image processing systems and techniques. More specifically, the present invention relates to systems and techniques for acquiring and displaying video image data. 
     2. Description of the Related Art 
     Many works of science fiction and science fantasy show someone speaking with a remote user via images of the remote user seemingly projected in free space. Despite the frequent appearance of these images over decades of film and television production, no real practical system has been developed to date that is capable of capturing and extracting a user&#39;s image from an arbitrary (non-monochromatic) background, transmitting the image over a communication channel and displaying the image in free space. 
     A display of live image data projected into free space offers the potential for a significantly enhanced communication experience. Hence, there is a need in the art for a system or method for acquiring and extracting video images from arbitrary backgrounds and displaying the images in free space or in a volumetric space. 
     SUMMARY OF INVENTION 
     The need in the art is addressed by the present invention, a system and method for volumetric display of video images extracted from arbitrary background environments comprising: means for extracting a video image in real time from an arbitrary background and creating a stream of extracted image data in response thereto and a free space or volumetric display operationally adapted to display the stream. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an illustrative implementation of an imaging system constructed in accordance with the teachings of the present invention. 
         FIG. 2  is a diagram that depicts a preferred embodiment of an imaging system constructed in accordance with the teachings of the present invention. 
         FIG. 3  is a diagram which shows an illustrative application of the teachings of the present invention in connection with a free space display. 
         FIG. 4  provides an illustrative frame of background image data as stored by the background memory in accordance with the teachings of the present invention. 
         FIG. 5  depicts an illustrative camera output of a frame of live image data. 
         FIG. 6   a  illustrates the output of a subtractor utilized by the image processor of the illustrative embodiment of the invention depicted in  FIG. 1 . 
         FIG. 6   b  illustrates a differentiated and filled difference image as output by the fill logic utilized by the image processor of the illustrative embodiment of the invention depicted in  FIG. 1 . 
         FIG. 6   c  illustrates a foreground isolated image as output by the image processor of the illustrative embodiment of the invention depicted in  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Illustrative embodiments and exemplary applications will now be described with reference to the accompanying drawings to disclose the advantageous teachings of the present invention. 
     While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility. 
     In accordance with the present teachings, live image data is extracted from arbitrary backgrounds in accordance with the teachings of U.S. patent applications Ser. Nos. 09/363,456, 09/795,290, and 09/905,692 filed Aug. 18, 1999, May 12, 2000 and Nov. 28, 2000 respectively by Benman and U.S. Pat. No. 5,966,130 the teachings of all of which are hereby incorporated herein by reference. As discussed more fully below, the extracted image data stream is then transmitted via a wired or wireless network to a receiver and displayed in a free space display. 
       FIG. 1  is a block diagram of an illustrative implementation of an imaging system constructed in accordance with the teachings of the present invention. The system  10  includes a digital video camera  12  adapted to provide single or multiple frames of video data in digital form. Numerous companies such as ADS Technologies, iBot, Intel and others make such cameras. In the alternative, a camera with an analog output may be used if the output thereof is converted to digital form with an analog to digital converter or other such suitable device. Those skilled in the art will appreciate that the invention is not limited to the type of digital imaging device used. 
     The output of the camera  12  is input to a background image memory  14 . For this image, the user remains outside the field of view of the camera as this memory is used to stored a frame of static image data that is to be removed from the live video frames as discussed more fully below. 
       FIG. 3  is a diagram which shows an illustrative application of the teachings of the present invention in connection with a free space display. 
       FIG. 4  provides an illustrative frame of background image data as stored by the background memory  14 . 
     In the illustrative embodiment of  FIG. 1 , a frame of live image data containing foreground imagery is stored in a second memory  16 . 
       FIG. 5  depicts an illustrative camera output of a frame of live image data. This frame contains at least a portion of the background image of  FIG. 4  partially obscured by an image of a user in the foreground thereof. In accordance with the present teachings, the background imagery is removed by an image processor  20  and the foreground image is transplanted into another (e.g., computer generated) environment. 
     In  FIG. 5 , a subtractor  16  digitally subtracts signals stored in the first and second memories representing the color and intensity of individual picture elements (pixels) and provides the output to a filter. The effect of the subtraction is to eliminate the background imagery leaving a color distorted image of any foreground imagery therein. (In this context, foreground imagery is any imagery not present at the time the system was calibrated by capturing the frame of background imagery.) 
       FIG. 6   a  illustrates the output of the subtractor  16 . This image is processed by the filter  24  to remove the color and brightness distortion therein resulting from the subtraction process. This image is differentiated to provide an edge defined image. Fill logic  28  fills the image, between the edges thereof, with homogeneous values (e.g., logical ‘1’s) and logical zeros outside the image to provide a template as depicted in FIG.  6   b . The template is multiplied by the foreground image to provide an output image as depicted in  FIG. 6   c.    
       FIG. 2  is a diagram which depicts a preferred embodiment of an imaging system constructed in accordance with the teachings of the present invention. In the preferred embodiment, the system  30  includes the digital camera and background image memory  14  of  FIG. 1 . However, in the preferred embodiment, the image processor  20  is implemented with a comparator  40 , AND gate  42  and microcontroller  50 . The background image is stored as per  FIG. 1 . However, in the preferred embodiment, the comparator scans the dynamic live video image and compares it to the stored background image on a pixel by pixel basis. If there is a match, the comparator  40  outputs a logical one, which is inverted at the input to the AND gate  42 . If there is no match, the comparator outputs a logical zero, which turns on the AND gate  42 . This enables the current pixel of live video data to be passed by the AND gate as the output of the image processor  20 . 
     Those skilled in the art will appreciate that system would be clocked for proper timing and latches and other delay elements may be required for this purpose as well. These elements may be provided by one of ordinary skill in the art as needed for a given application without undue experimentation. A controller  50  controls each element of the circuit along with the clock timing in response to user input or software control. 
     Thus, a stream of extracted video images is created. The received stream is then input either directly or via a wired or wireless network into a display capable of projecting the image into free space. Such a display is currently made and sold as a Heliodisplay by IO 2  Technology. As an alternative, a volumetric display may be employed. Volumetric displays are currently made by several manufacturers including, Actuality Systems and others. As discussed in a white paper by Gregg E. Favalora et al. of Actuality Systems, Inc. in “100 Million-Voxel Volumetric Display” published at http://www.actuality-systems.com/admin/publications/Actuality 13  Whitepaper_AeroSense — 2002.pdf and presumably in 2002 in Cockpit Displays IX: Displays for Defense Applications (of the SPIE&#39;s 16th Annual International Symposium on Aerospace/Defense Sensing, Simulation, and Controls) by Society of Photo-Optical Instrumentation Engineers, Volumetric displays are the set of three-dimensional display technologies that produce volume-filling imagery. (This term is not to be confused with “volume rendering,” a computer-graphics technique of a similar name that is commonly used in medical imaging and petroleum visualization.) Barry Blundell and Adam Schwarz offer the following definition: “[a] volumetric display device permits the generation, absorption, or scattering of visible radiation from a set of localized and specified regions within a physical volume.”3 The definition might need to be extended to include: (1) holographic video systems 4, which use piecewise approximation to synthesize the wavefronts that emanate from a 3-D scene, and (2) the set of re-imaging systems that use volume-filling imagery as the source 5. Simply put, volumetric displays create imagery that appears to float in a volume. Typically the imagery can be seen from a wide variety of angles. Furthermore, goggles are generally not required to perceive the 3-D imagery. Several publications provide surveys of existing volumetric display architectures. The authors point out the work of M. Halle 6, K. Langhans et al 7, and Blundell and Schwarz 3 as particularly instructive. The majority of volumetric displays exploit persistence of vision by projecting 0-, 1-, or 2-D components of a scene rapidly enough that the retina fuses them into a 3-D perception. 
     Although free space and volumetric displays are known, these displays have not heretofore been used to display video images extracted in real time from arbitrary (heterogeneous) backgrounds. 
     Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications and embodiments within the scope thereof. 
     It is therefore intended by the appended claims to cover any and all such applications, modifications and embodiments within the scope of the present invention. Accordingly,