US 5777665 A
The present invention enables eye contact between conferees during a teleconference using a terminal equipped with a beamsplitter for reflecting an image of a video display so that only the reflection and not a direct view of the display is seen by the conferee. The camera is positioned behind the viewing side of the beamsplitter to capture the conferee's image through the beamsplitter. The direct view of the display is blocked by an image blocking film applied between the beamsplitter and the display. Blocking the direct view of the video display greatly improves teleconferencing by eliminating the distraction of simultaneously viewing both the video display and the reflection of the display.
1. A kit for use with an image display to provide an improved eye contact teleconferencing terminal for allowing a first conferee to maintain eye contact with an image of a second conferee imaged by the image display, the kit comprising:
a semireflective transparent panel and means for positioning the semireflective transparent panel to form an angle of between about 30 and 60 degrees with the image display thereby defining a first surface of the semireflective transparent panel which faces the image display and a second surface of the semireflective transparent panel which faces away from the image display;
a video camera and mounting means for holding the video camera disposed on a side of the semitransparent panel opposite the image display to capture an image of the first conferee through the second surface of the semireflective transparent panel; and
a layer of image blocking film disposed between a front surface of the image display and the semireflective transparent panel allowing the image of the second conferee to pass through and reflect from the semireflective panel while blocking a direct view of the image display from the first conferee.
2. The kit of claim 1, wherein the side of the semireflective transparent panel opposite the image display is enclosed in opaque material to improve a quality of the reflection on the semireflective transparent panel by shielding the second surface of the semireflective transparent panel from ambient light.
3. The kit of claim 1, wherein image blocking film is applied to the second surface of the semireflective transparent panel to improve a quality of the reflection on the semireflective transparent panel by shielding the second surface of the semireflective transparent panel from ambient light.
4. The teleconferencing terminal of claim 1, wherein the semireflective transparent panel is bowed to optically expand a compressed image on the image display, thereby elongating the reflection on the semireflective transparent panel.
5. The teleconferencing terminal of claim 1 further comprising a means for reproducing sound disposed in proximity to the image display with a direction of sound propagation directed towards the semireflective transparent panel for reflecting sound from said panel so that the first conferee perceives the sound as issuing from the image reflected by the semireflective transparent panel.
6. An improved eye contact teleconferencing terminal for allowing a first conferee to maintain eye contact with a second conferee imaged by the teleconferencing terminal, the teleconferencing terminal comprising:
a substantially planar image display for producing an image of the second conferee;
a semireflective transparent panel forming an angle of between about 30 and 60 degrees with the image display thereby defining a first surface of the semireflective transparent panel which faces the image display and a second surface of the semireflective transparent panel which faces away from the image display;
a video camera disposed on a side of the semireflective transparent panel opposite the image display, the video camera capturing an image of the first conferee through the second surface of the semireflective transparent panel an image of the first conferee who is disposed on the image display-side of; and
a layer of image blocking film disposed between a front surface of the image display and the semireflective transparent panel allowing the image of the second conferee to pass through and reflect from the semireflective panel while blocking a direct view of the image display from the first conferee.
7. The teleconferencing terminal of claim 4, wherein the side of the semireflective transparent panel opposite the image display is enclosed in opaque material to improve a quality of the reflection on the semireflective transparent panel by shielding the second surface of the semireflective transparent panel from ambient light.
8. The teleconferencing terminal of claim 6, wherein image blocking film is applied to the second surface of the semireflective transparent panel to improve a quality of the reflection on the semireflective transparent panel by shielding the second surface of the semireflective transparent panel from ambient light.
9. The teleconferencing terminal of claim 6, wherein the semireflective transparent panel is bowed to optically expand a compressed image on the image display, thereby elongating the reflection of the image display.
10. The teleconferencing terminal of claim 6 further comprising a means for reproducing sound disposed in proximity to the image display with a direction of sound propagation directed towards the semireflective transparent panel for reflecting sound from said panel so that the first conferee perceives the sound as issuing directly from the image reflected by the semireflective transparent panel.
11. An improved eye contact teleconferencing terminal for allowing a first conferee to maintain eye contact with a second conferee imaged by the teleconferencing terminal, the teleconferencing terminal comprising:
a substantially planar image display;
a semireflective transparent panel forming an angle of between about 30 and 60 degrees with the image display;
a video camera disposed opposite the image display on a first side of the semireflective transparent panel, the video camera capturing, through the semireflective transparent panel, an image of the first conferee who is disposed on a second side of the semireflective transparent panel; and
an image blocking layer comprised of micro-louvers disposed between a front surface of the image display and the semireflective transparent panel allowing the image of the second conferee to pass through and reflect from the semireflective panel while blocking a direct view of the image display from the first conferee.
12. The teleconferencing terminal of claim 11, wherein means are provided for altering an angular relationship between the semireflective transparent panel and the image display.
1. Field of the Invention
The present invention concerns the area of teleconferencing and, more specifically, an improved video teleconferencing device that permits eye contact.
2. Description of Related Art
A primary concern in video-teleconferencing ergonomics is a lack of eye contact between conferees. Eye contact is not possible with common terminal configurations, because the camera is placed at the perimeter of the display that images a distant conferee, so that the camera does not interfere with a local conferee's viewing of the display. With this configuration the conferees fail to look directly into the camera, which results in the appearance of the conferees looking away and appearing disinterested in the conversation.
Although numerous technologies have been proposed to correct the eye contact problem, many of these technologies suffer from poor image capture quality, poor image display quality, excessive expense, or unacceptably increased terminal bulk. One commonly used component in eye contact systems is a beamsplitter. A beamsplitter is a semireflective transparent panel sometimes called a one way mirror or a semisilvered mirror. Although even a plain sheet of transparent material such as glass can be employed, it is more common to apply coatings to a transparent substrate to increase its reflectivity.
A common beamsplitter eye contact arrangement consists of a beamsplitter that is mounted in front of a display oriented at about 45 degrees to the display surface. The conferee using the terminal looks through the beamsplitter to view the display. A camera is disposed in front of the beamsplitter and captures an image of the conferee reflected in the semireflective beamsplitter. This technology has a number of drawbacks. First, the 45-degree angle of the beamsplitter placed in front of the display necessarily increases the bulk of the display. Second, if the beamsplitter is illuminated by ambient light, the quality of the image captured by the camera may be seriously degraded. This problem may be avoided by a hood of an opaque material extending from the display to the edge of the beamsplitter so that ambient light does not degrade the reflected image. However, an opaque hood makes the beamsplitter appear even more intrusive with the angled beamsplitter forming a visible barrier in front of the display surface. Whether the display is a computer desktop monitor or a big screen television, the awkwardness of the protruding beamsplitter and camera remain an inefficient use of space.
U.S. Pat. No. 5,117,285 to Smoot attempted to reduce the bulk of this type of terminal by applying polarizers to the display and camera, so that the beamsplitter can be angled more acutely, approximately 30 degrees, without having light from the display interfere with the reflection of the conferee. A drawback to this arrangement is the inherent loss of light caused by the polarizer which further reduces the display image brightness, which has already been reduced by the beamsplitter. Even though this technology reduces the angle of the beamsplitter, it still adds considerable bulk to the terminal and a transparent barrier still remains in front of the display. Also, terminal bulk is further increased by the camera placement, which must protrude far from the display to capture the reflection of the conferee in the 30-degree angled beamsplitter. This becomes a nuisance with desktop conferencing, because the camera is positioned in the conferee's work space where a keyboard is usually placed.
Another eye contact beamsplitter arrangement resolves this protruding camera problem by mounting it behind the beamsplitter. In this arrangement, the display is reflected by the beamsplitter for viewing by the conferee. The light of the reflection conceals the camera behind the beamsplitter. The camera thus captures the image of the conferee through the beamsplitter. If a flat panel display is used or if a CRT display is mounted in a desk's surface and aimed upward, the bulk of this system can be reduced substantially.
However, even with these improvements this arrangement suffers from an additional significant problem: namely the conferee can simultaneously observe the displayed image both in two ways, either by directly viewing the display or by viewing the reflection of the display on the beamsplitter. That is, as the conferee looks at the reflected image, it is easy to glance at an angle and directly view the display below the beamsplitter. The dual visible images in this arrangement is a severe distraction, as the conferee's attention is divided between the light of two images. If the conferee gazes directly at the display (as opposed to the reflection of the display), eye contact will be disrupted because the camera will capture an image of the conferee that appears not to look at the face of the remote conferee.
FIG. 1 illustrates a prior art eye contact beamsplitter arrangement in which the image of a conferee is captured by a camera 4 by means of a reflection in a beamsplitter 6. At the same time the conferee's image is captured, that conferee is able to look through the beamsplitter 6 to view a display 2. A hood 8, usually covered with an opaque material, is typically included to shield the beamsplitter 6 from ambient light. The drawbacks to this arrangement include the increased bulk of the terminal (although a flat panel will minimize this problem), the addition of a transparent barrier in front of the display which affects viewing the display surface, the appearance of the display being recessed far into the terminal creating a tunnel effect and, lastly, the awkward positioning of the camera 4 which intrudes into the conferee's work space.
FIG. 2 is a prior art eye contact beamsplitter arrangement that attempts to reduce the protrusion of the beamsplitter 6 by adding a polarizer 9. Here when properly configured with a second polarizer 11 on the camera 4, the camera 4 can be aimed more directly toward the display 2 without picking up the image on the display 2 through the beamsplitter. Despite some reduction in the angle of the beamsplitter 6, the unit still suffers from excessive bulk, a transparent barrier between the conferee and the viewing surface of the display 2. Also, the camera 4 protrudes awkwardly from the terminal on a stand 12, invading the conferee's work space.
FIG. 3 presents a beamsplitter arrangement in which the conferee views the reflection of the display 2 by the beamsplitter 6. The camera 4 is substantially concealed from view behind the beamsplitter 6 and is aimed through the beamsplitter 6 to directly capture the image of the conferee. As is illustrated, the significant drawback of this arrangement is the fact that the light from the display 2 is visible to the conferee simultaneously at the display 2 and as the reflection of the display 2 in the beamsplitter 6 by the conferee. These two visible images compete for the conferee's attention and add distraction while conferencing, thereby reducing the quality of the conferencing experience.
It is an object of the present invention to provide a teleconferencing beamsplitter eye contact terminal with an image blocking film, so that light from the display source is concealed from the point of view of the conferee while simultaneously allowing a reflection of the display on a beamsplitter that is viewed by the conferee.
It is a further object of this invention to provide an eye contact terminal consisting of at least a camera and display configured in a single unit.
It is a further object of this invention to provide an eye contact terminal built integrally with various types of consumer electronic devices.
It is a further object of this invention to provide a eye contact terminal that has separate components for ease of upgrading.
It is a further object of this invention to enable convenient positioning of the beamsplitter in relation to the display.
It is a further object of this invention to provide a teleconferencing beamsplitter that is shielded from ambient light.
Lastly, it is an object of the present invention to use an image blocking film to enable a camera to capture a reflection of a conferee in a beamsplitter aimed directly toward the display.
The present invention enables eye contact between conferees during a conference with a terminal that utilizes a beamsplitter that reflects the image of the display in such a way that only the reflection and not the display is seen by the conferee. The camera is positioned behind the viewing side of the beamsplitter in order to capture the conferee's image through the beamsplitter. To block unwanted light directly from the display, an image blocking film is applied between the beamsplitter and the display so that light from the display is concealed from the conferees's direct view. This concealment greatly improves this teleconferencing beamsplitter arrangement by eliminating the distraction of viewing both the display and the display reflection. Also, the camera is positioned behind the beamsplitter, so it does not disturb the work space of the conferee, thereby greatly improving this beamsplitter arrangement's practicality for desktop and other types of conferencing.
The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings.
FIG. 1 illustrates a prior art beamsplitter arrangement in which the conferee views the display through a beamsplitter;
FIG. 2 illustrates a prior art beamsplitter arrangement that is configured with polarizers to reduce the angle of the beamsplitter from the display;
FIG. 3 illustrates a prior art beamsplitter arrangement in which the conferee is intended to view only the reflection of the display yet can still see light emanating directly from the display;
FIG. 4 illustrates the present invention in which image blocking film is used to conceal the display from direct viewing by the conferee;
FIG. 5 illustrates an embodiment of the present invention that conceals view of the display of light from all four sides;
FIG. 6 illustrates the present invention configured with the display laying flat and aimed upwards;
FIG. 7 illustrates the present invention configured with the display aimed downward;
FIG. 8 illustrates the present invention configured as a display of a laptop computer;
FIG. 9 illustrates the present invention configured as a separate unit that can be added to a display;
FIG. 10 illustrates a display with modifications to assist in the positioning of the reflection for desired viewing;
FIG. 11 illustrates an extension arm system which permits numerous positioning options of the beamsplitter in relation to the display;
FIG. 12 illustrates opaque material placed behind the beamsplitter;
FIG. 13 illustrates a beamsplitter with image blocking film applied behind the viewing side, so that ambient light is substantially reduced;
FIG. 14 illustrates sound from a speaker bouncing off the beamsplitter;
FIG. 15 illustrates a beamsplitter that is bowed, so that a compressed image is expanded when reflected;
FIG. 16 illustrates image blocking film angled in relation to the display to prevent reflections back onto the image blocking film; and
FIG. 17 illustrates an alternative beamsplitter arrangement wherein the image blocking film is used to prevent light from the display from being captured by the camera.
The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventors for carrying out their invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide an improved beamsplitter-based teleconferencing device that uses image blocking film to eliminate distracting images.
An eye contact beamsplitter arrangement has been invented to overcome the problem of a conferee simultaneously viewing both the display and its reflection. An image blocking film 10 permits a display 2 to be viewed from one or more directions and prevents the interference of unwanted images. As seen in FIG. 4, a conferee can view the reflection from the display 2 on a beamsplitter 6. The conferee cannot, however, see the display 2 emitted directly, because direct light is blocked by the image blocking film 10. The conferee's attention, as a result, is now focused solely on the reflection and not distracted by a view direct from the display 2. A camera 4 in this arrangement is advantageously mounted behind the beamsplitter 6 away from the conferee's work space.
FIG. 5 illustrates the use of the image blocking film 10 to block the image when viewed from a side of the display 2. The image blocking film 10 that makes the present invention possible is a material that exhibits the uncommon property of being selectively transparent depending on an angle at which the material is viewed. That is, when the gaze of an observer is normal to a surface of the image blocking film 10, the film appears to be totally transparent and any object on the opposite side of the film, such as the display 2, is readily visible. However, if the observer views the image blocking film 10 at an angle to the film's surface, the image blocking film 10 has an appearance ranging from opaque to translucent: the observer's view of any object on the opposite side of the image blocking film 10 is obscured. The image can be blocked from two, three, or all four sides, if desired. For the present invention, it is critical that the image blocking film 10 block the image from at least the angle from which the conferee is viewing the display reflection, so that the display viewing surface itself is concealed from direct view. An advantage to placing the image blocking film 10 on the right and left sides of display 2 is that the image will be blocked from the reflection on the beamsplitter 6 when the display 2 is viewed at an angle from either side. This feature adds security and privacy to a teleconference which proves useful in a busy office area, since a passersby cannot easily view the image.
The image blocking film 10 is available from several sources and can be based on various technologies. Whether the film is plastic or glass, the image blocking film as it is presented here is a material that permits transmission of light from at least one direction and reduces or eliminates light transmission from at least one other direction. Eyesaver International Inc. has an image blocking film named "Private Eye" that diffuses light from various directions. From the perspective of the conferee, when using this film, light directly from the display (as opposed to the reflected image) appears milky and diffused, eliminating the focused image. The diffused light, even though visible to the conferee, adequately conceals the image. Another image blocking film 10 is made by 3M Inc. and named "Light Control Film" and is preferred, because it can eliminate virtually all light transmission from a desired angle. This particular image blocking film 10 contains closely spaced black microlouvers and a wide selection of louver angles are available, and even more options are available by layering films. This means that the precise angle at which the image blocking film 10 "shuts off" can be selected in advance. When the image blocking film 10 "shuts off, " it ceases to transmit light so that if the observer views the image blocking film 10 from an angle greater than the "shut off" angle the film appears to be opaque. When using this film the conferee sees only the black surface of the microlouvers which entirely conceals the image from the display 2 when viewed from the position of the conferee. The same effect can be produced by an array of tiny microlouvers supported, for example, by their ends. In that case the image blocker would not actually be a "film" but would fall within the bounds of the present invention.
This arrangement is preferably used with a flat panel display such as an active matrix liquid crystal or plasma display, among others. Flat panels permit the size of the terminal to be reduced and offers aesthetic design opportunities not possible with other eye contact display systems. Of course, more bulky displays such as CRT displays and rear projection screen displays may also be used with the present invention. The added size of the terminal caused by bulky displays may not be a disadvantage in some circumstances. Also, a bulky display can be hidden by being built into a table with the screen surface flush with the table surface, giving the appearance that the entire terminal consists of a floating beamsplitter. Both flat panels and more bulky displays can be built into tables and into cabinets mounted sideways and even upside down. In each configuration, image blocking film 10 is applied to the display, blocking its image from the conferee's direct view and leaving only the reflection on the beamsplitter 6 in view. Custom applications of this invention will be apparent to one of ordinary skill in the art.
FIG. 6 illustrates the present invention configured as a flat panel self-contained unit. The display 2 rests on a surface, such as a desk or computer. On top of the display viewing surface is the image blocking film 10 that functions in the manner previously described. The beamsplitter 6 is attached to the display 2 by hinges 14. The hinges 14 permit adjustment of the beamsplitter 6 in relation to the display 2. Although 45 degrees is the "critical angle" for setting the beamsplitter 6 relative to the display 2, positions between about 30 and 60 degrees are useful depending on the exact setup employed. A flexible rod 26 holds the camera 4 in place and also carries electronic signal wires to the display 2 which contains all electronic circuitry for the display and the camera 4. The flexible rod 20 is attached to the display 2 by a connector 22. The flexible rod 20 is one of many possible mechanisms that can position the camera 4 behind the beamsplitter 6. Its advantage is that it can be bent into numerous positions, allowing the camera to be adjusted both vertically and horizontally. A power line 16 supplies current to both the display 2 and the camera 4. A first port 18 allows the camera image to be cabled to the teleconferencing equipment so that the captured image may be viewed on a distant terminal. A second port 19 receives the incoming image signal, so that the distant conferee may be imaged on the display 2.
FIG. 7 illustrates a self-contained unit as seen in FIG. 6, except that the display 2 is mounted above the beamsplitter 6 with the display viewing surface aimed downward into the reflection of the beamsplitter 6. In this configuration the display 2 is connected to and supported by the one end of the beamsplitter 6 and two support legs 24 that rest on the desktop, computer, or other flat surface. This configuration's operation is identical to the configuration of FIG. 6, except that no means of adjusting the beamsplitter 6 in relation to the display 2 is provided.
The present invention may also be built into devices that have other functions besides image display and image capturing. An example of this is seen in FIG. 8, where the present invention is built as a part of a laptop computer 26 with a keyboard 28. In this configuration, the beamsplitter 6 folds down onto the image blocking film 10 with the built-in display underneath and integral with the laptop computer 26. The beamsplitter 6 has a latch hook 25 connected to it, which is received in a latch hole 27 when the beamsplitter 6 is folded down by hinges 14. The flexible rod 20 and camera 4 retracts into a slot (not shown) in the back when the device is not in use. Besides integrating the present invention into a laptop computer, it may, in addition, be built into numerous portable devices such as palmtops, personal digital assistants, teleconferencing camcorders, and wireless teleconferencing systems. Nonportable devices, as well, such as videophones, all-in-one home computers, and televisions, to name only a few, will benefit from the present invention.
FIG. 9 illustrates a configuration where the main parts of the current invention can be configured as a separate kit to be added by the consumer to upgrade the existing display 2 and provide the practicality of modularity with interchangeable elements. As illustrated, the kit would contain the image blocking film 10 which is placed on top of the viewing surface of the display 2 secured by a VELCRO™ hook-in-loop fastener (not shown), or other appropriate fastening means can be used. The beamsplitter 6 used in the kit is free-standing and held in place by stand legs 32 which are attached to the beamsplitter 6 by screws 34. The kit is completed by the camera 4 which is connected to the flexible rod 20 which, in turn, is connected to a flexible rod base 30.
Those skilled in the art will appreciate the design options made possible by the present invention. For example, the display 2 can be mounted flush with a desk surface with the image blocking film 10 seamlessly part of the desk's surface. From the conferee's perspective, the entire terminal would appear to consist of only the beamsplitter 6 and the camera 4. Also, the display 2 can be built into decorative housings and cabinetry and mounted aiming downward or sideways towards the beamsplitter 6. It is also conceivable that the image blocking film 10 can be manufactured in designer colors.
Although desktop conferencing terminals will greatly benefit from this invention, it may also be configured into big screen displays. These larger displays are important when several conferees are imaged on one display. The ergonomics of a life-size image of the conferees greatly improves the teleconferencing experience.
Those in the optical coating art will understand the vast variations possible for the beamsplitter 6 in regards to its substrate, coating, and manufactured process. Both plastic and glass substrates, as well as stretched mylar, have been used for the beamsplitter 6. The beamsplitter 6 can comprise a custom blend of optical coatings on a transparent substrate for superior reflectivity and transmission all the way down to off-the-shelf one-way mirrors with inconsistent and poor optical qualities. Also, the reflectivity and transmission, as well as other optical qualities of the beamsplitter 6, can be adjusted as needed. Despite these vast variations in the beamsplitter 6, the property of being both reflective and transparent remains the single most important constant.
The following description details the construction of one embodiment of this invention. A frame and stand for the beamsplitter 6 was constructed from acrylic plastic on which the beamsplitter 6 was mounted at about 40 degrees, so that the image is aimed slightly upward toward the face of the conferee. The beamsplitter 6 comprises a titanium coating on a float glass substrate. The coating was optically designed for approximately 40% reflectivity and 60% transmission. The plastic support frame was designed to straddle a Shard active matrix LCD panel Model QA-1750BL lying flat on a table top. The image blocking film 10 used was 3M Light Control Film (type LCF ABRO O OB90 CLR GLS 030) and was positioned on the viewing surface of the active matrix display, so that the image of the display is blocked from the conferee's direct view. Behind the beamsplitter 6 am ELMO CCD miniature camera Model TSN 402 was attached to a custom flexible rod 20 and base 30. The terminal was arranged as seen in FIG. 9 and was operated on a compressed video (MPEG) teleconferencing system.
Depending upon the angle between the beamsplitter 6 and the display 2, the reflection of the display 2 may have a trapezoidal shape. This subtle distortion is normally not a significant problem for most observers. However, if this distortion is unwanted, well-known image manipulation techniques can be used to "predistort" the image on the display 2 into a trapezoid with its longer side in a reversed position from a longer side of the trapezoid caused by the beamsplitter 6 angle. This way distortion caused by reflection will cancel out distortion imposed by image manipulation, and the reflected image will appear rectangular in shape. Also, manual controls may be provided for the conferee to choose the degree of predistortion so that the reflected image can be corrected at any angular setting of the beamsplitter 6. An automatic system can also be provided to simplify this procedure by sensing the angular relation of the beamsplitter 6 to the display 2 and automatically applying the optimum amount of predistortion to the image. Since a bezel or outer edge of the display 2 may also appear in the reflected image, it may be necessary to either provide a trapezoidal bezel or make the bezel matte black so it is not apparent in the reflection. It may also prove advantageous to manufacture display panels in a trapezoidal shape.
The reflection in beamsplitter 6 can also reflect not only the display 1, but also the surface on which the display 2 rests or is mounted, such as a desk top. If this reflection becomes an annoyance, a light-absorbing mat (not shown) extended around the display eliminates these unwanted reflections. Another method to eliminate these unwanted reflections is to put light-absorbing sides extended between the display 2 sides and the beamsplitter 6.
For greater flexibility in orienting the display 2 to the beamsplitter 6, the display 2 itself may be raised or lowered from the front or rear of the display 2. In FIG. 10 adjustable extension legs 36 are connected with stiff pivot hinges 38. The display 2 with these extension legs 36 can be raised and lowered from both the front and the rear. For even greater flexibility in positioning the beamsplitter 6 in relation to the display 2, one can allow the beamsplitter 6 to be adjusted by tilting, moving backwards and forwards, and closer and further from the display 2. Extension arms 42 and 40 provide all of these movements through the use of connected stiff pivot hinges 44, 46, and 48. The conferee can adjust tilt, up and down and back and forth, with this positioning mechanism. Other positioning mechanisms, as well, may be integrated according to the needs of the particular configuration.
An additional amenity that can improve a free-standing eye contact terminal employing the present invention is the addition of a simple turntable beneath the unit. The turntable allows the entire unit to swivel to face the conferee. This is especially useful in the case of group teleconferences where a number of individuals want direct "one-on-one" contact with a person at a remote terminal. The turntable allows the display 2 and the camera 6 to be instantly aimed towards any participant. This can be accomplished either manually or automatically. The image blocking film 10 is selected so that no one in the group can directly view the display 2. That is, two layers of image blocking film 10 are used so that the image is blocked from all viewing angles except for a line of sight normal to the surface of the display 2.
To enhance the apparent reflectivity of the beamsplitter 6, ambient light behind the beamsplitter 6 may be reduced, depending upon the optical properties of the beamsplitter 6 and the intensity of the ambient light. FIG. 12 illustrates the use of an opaque material 50 (such as black painted plastic) covering all of a rear surface of the beamsplitter 6 except for a small area through which the camera 4 is aimed. Ambient light is completely eliminated from behind the beamsplitter 6 and, thereby, substantially improves the apparent reflectivity of many types of the beamsplitter 6. An optional camera housing 52 may be built of light absorbing material, as well. If only ambient light from a specific direction need be eliminated, then image blocking film 10 can be applied to the back side of beamsplitter 6 as seen in FIG. 13. Other ambient light reduction methods may be used, such as mounting the present invention in an enclosed cabinet or providing a removable hood for the terminal.
Because the beamsplitter 6 is mounted at an angle toward the conferee it is possible to bounce sound off the beamsplitter 6. By doing so teleconferencing audio is greatly improved, because sound will seem to originate from the center of the beamsplitter 6 where the image of the distant conferee's mouth is located. FIG. 14 illustrates a speaker 55 aimed toward the beamsplitter 6 so that sound is bounced toward the conferee. Special directional speakers may be used to enhance this effect. The speaker 55 can also be mounted on the side of the display 2 (not shown) and additional speakers 55 may be used in various placements around the display 2.
An additional embodiment of the present invention employs a bowed beamsplitter 56 of FIG. 15. This enables the display 2 to be configured more narrowly than the common aspect ratio display 2. By squeezing the visible image with well-known image manipulation techniques, this smaller compressed image can be expanded to a larger image when reflected onto the bowed beamsplitter 56. This configuration is especially useful when a large image is desired, but the desk surface which the display rests on is limited in area.
Antireflective coatings can be applied as needed to suppress unwanted reflections from any of the optical surfaces involved. On the back side of the beamsplitter 6, opposite the reflection side, an antireflection coating can serve to eliminate the ghosting effect apparent with many types of beamsplitters. Also, an antireflective coating, substrate, film textures (i.e., matte finish), light-absorbing color, or similar functioning material can be applied on top of or as a part of the image blocking film 10 when it is necessary to reduce a "back reflection," which is an image reflected from the beamsplitter 6 back onto the image blocking film 10. FIG. 16 shows another method of dealing with back reflections. When the image blocking film 10 is angled (as opposed to parallel) in relation to the display 2, the back reflections are diminished or eliminated. An angle between the image blocking film 10 and the display can range from a few degrees to a much as 30 degrees or more. At large angles the image blocking film 10 advantageously incorporate slanted microlouvers to compensate for a change in angular relationship between the conferee and the image blocking film 10.
Another embodiment of the image blocking film 10 used for teleconferencing eye contact is seen in FIG. 17. The image blocking film 10 has significantly improved the prior art beamsplitter 6 arrangement, as seen in FIG. 2. Prior art technology based on polarizers significantly reduces the brightness of the display 2 since polarizers absorb at least half of the incident light. This, combined with the further brightness reduction caused by the beamsplitter 6, creates a noticeably dim image. The image blocking film 10 has a higher transmissivity than the polarizer 9, allowing a far brighter image. Also, a single substrate image blocking film 10 applied between the display 2 and the beamsplitter 6 does not suffer from the complexity of aligning the two polarizers 9 and 11. The image blocking film 10 allows the conferee to look through a single substrate to the display 2 image behind. From the perspective of the camera 4 the image is concealed by the image blocking film 10. Because the image is blocked, the camera 4 can be aimed more directly toward the display 2, i.e. between about 20 degrees and about 40 degrees, without picking up the light of the display 2 passing through the beamsplitter 6. As a result, the beamsplitter 6 can be angled more closely to the display 2, thereby reducing the protrusion of the beamsplitter 6. FIG. 17 shows the image blocking film 10 parallel to the front surface of the display 2. The image blocking film 10 may also be located on the side of the beamsplitter 6 facing the display 2 or at any position between.
Although this terminal still suffers from a protruding camera 4 on the stand 12, this protrusion can be reduced somewhat by using a small micro video camera. Instead of the stand 12, the camera 4 can be mounted on a movable base (not shown) which rests directly on the table or desk surface. A second mirror (not shown) may be used near the camera to correct the image reversal caused by the reflection of the beamsplitter 6. The hood 8 is an optional element and may be used if ambient light is excessive. Variations in terminal design made possible by this improved beamsplitter 6 arrangement will be apparent to those skilled in the art of teleconferencing ergonomics.
Depending upon the type of the beamsplitter 6 and the degree of transmissivity used, adjustments to the light sensitivity of the camera 4 may improve image quality. Also, adjustments to the brightness of the display 2 may improve the reflectivity of some types of beamsplitters. Such light sensitivity and brightness adjustments of camera 4 and display 2 will be apparent procedures to one of ordinary skill in the art.
As is the case with all eye contact terminal technology, true eye contact cannot occur between conferees unless both conferees have an eye contact terminal. Even if only one conferee has an eye contact terminal, however, that conferee can transmit a eye contact signal for at least the other conferee to enjoy. In a multiple conferee session, portions of the screen can be designated for simultaneously displaying several incoming conferees. A more complex approach to multiple conferees is to use multiple cameras side by side in order to transmit different points of view of the conferees as if sitting around a table. Although not shown, it will be apparent as to how side-by-side cameras would be configured behind the beamsplitter 6.
Because the display is reflected on the beamsplitter 6, the image will appear to the conferee to be reversed. Image reversal techniques (either physical such as a mirror or electronic) can easily remedy this problem by appropriately reversing the image before it is displayed so that, when reflected on the beamsplitter, the image will assume its correct viewing orientation.
When viewing the reflection of the display 2 from the sides, the reflection of the display 2 will fall off the edge of the beamsplitter 6 when the beamsplitter 6 is the same size as the display 2. A simple remedy for this is to make the beamsplitter 6 as wide as necessary, so that the entire image remains reflected even when viewing from the sides.
Various mechanisms have been explored for camera positioning and camera aiming. Motorized positioning and aiming systems have been developed to allow remote control of the camera. Also, autotracking systems permit the camera to follow the conferee as he or she moves about. The camera 4 can also be attached directly to the beamsplitter 6. When mounting the camera 4 to the beamsplitter 6 as seen in FIG. 12, the camera 4 aiming direction can operate independent of the positioning of the beamsplitter 6 such as in FIG. 11. Camera 4 can also be mounted in a position not directly behind the beamsplitter 6. In such a case mirrors or an image conduit can redirect the image passing through the beamsplitter 6 to the camera 4.
Additional teleconferencing components may be included as desired in terminals configured with the present invention. The camera 4 can be configured as a small detachable camcorder and thereby add the economy of serving multiple purposes. The camera 4 may, as well, be configured with remote controls. Lights can also be added as desired to enhance image capture quality. Lights may also be placed behind the beamsplitter 6 so long as they do not interfere with the display 2 image reflection. Microphones can be integrated into various terminal configurations with the present invention. Like the speakers 55 the microphones can advantageously aimed so that sound bounces off the beamsplitter 6. The addition of optical coatings, such as CRT radiation reduction filters, color filters and contrasts, and glare guard technologies, may be added as well. Also, 3-D displays and fresnel lenses that expand the size of the display image will readily integrate with this invention. Other modifications will be apparent as new teleconferencing, video camera, computer, and display technology transforms during this time of global telecommunication transition.
Of course, the teleconferencing terminal used as part of the current invention can be, and preferably is, a multipurpose personal computer running a graphical interface program such as Windows 95®. Therefore, the graphical interface can be used to place calls, select views, etc. That is, if a conference call is undertaken between several conferees, the various conferees can be displayed in separate windows on the screen. One particular conferee can be selected to occupy the entire display 2 by choosing the conferee's window using a keyboard, a mouse, a touch screen, or similar user input means.
Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.