Abstract: A method for displaying a series of images on a projection screen as a function of a position of a presenter in front of the projection screen. First, the width of the screen is divided into a number of segments of selected widths. The positions of each of the segments is stored in a memory. The position of the presenter is compared with the stored segments to identify the segment currently occupied by the presenter.

Abstract: A method of positioning an image of a subject, placed before a selected backing, to a desired position with respect to an image of a background scene appearing on a camera view screen, using a digital camera. An image is observed on the camera's view screen and at least one of the subject and the camera are physically positioned to place the subject's image at the desired position with respect to the image of said background scene. An image of the positioned subject in front of said background scene is captured in the camera. A composite image of the subject and the background scene is then formed. Additional subjects may be captured and composited using the prior composite as the background scene for each added subject.

Abstract: A method for displaying a series of images on a projection screen as a function of a position of a presenter in front of the projection screen. First, the width of the screen is divided into a number of segments of selected widths. The positions of each of the segments is stored in a memory. The position of the presenter is compared with the stored segments to identify the segment currently occupied by the presenter.

Abstract: A method for projecting an image onto a front projection screen without the image being projected onto a presenter and without the presenter casting a shadow. Left and right rectilinear corrections of an image are simultaneously projected onto the screen from each of two positions that are off-axis on opposite sides of the centerline of the screen such that both projections register as a single image. A center of mass of the presenter's silhouette is generated. A vertical join line is located on the screen directly behind said presenter's center of mass. The portion of the projected image from the left projector that extends to the right of the join-line is inhibited. The portion of the projected image from the right projector that extends to the left of the join-line is also inhibited thereby providing the full projected image on the screen from the left and right image segments, without either segment projecting said image onto the presenter, and without casting the presenter's shadow onto the screen.

Abstract: A pattern is projected onto a screen by a projector using an illumination having a non-visible wavelength. A camera, displaced several inches from the projector, observes the projected pattern whose signals are then stored to create a reference frame. The pattern is then projected onto the screen a second time with a presenter present. The camera observes the projected pattern whose signals are then stored to create a current frame, including the presenter, and signals obtained from the reference frame are compared to determine their difference. In unobscured screen areas, the pattern images match. The pattern on the presenter is displaced because of the displaced camera, and no longer matches the reference pattern, thereby identifying the presenter's silhouette area.

Abstract: A pattern is projected onto a screen by a projector using an illumination having a non-visible wavelength. A camera, displaced several inches from the projector, observes the projected pattern whose signals are then stored to create a reference frame. The pattern is then projected onto the screen a second time with a presenter present. The camera observes the projected pattern whose signals are then stored to create a current frame, including the presenter, and signals obtained from the reference frame are compared to determine their difference. In unobscured screen areas, the pattern images match. The pattern on the presenter is displaced because of the displaced camera, and no longer matches the reference pattern, thereby identifying the presenter's silhouette area.

Abstract: Changes in a current image frame from variations in room light level, and automatic camera adjustments, are determined and incorporated into a clear (reference) frame, thereby resulting in a zero difference in the background region when the clear frame and a current frame are subtracted. Any deviation from zero defines the beginning edge of a transition from background to subject. The location of the outer edge of a transition area is further refined by subtracting derivatives of the RGB signals in each frame, and by the use of a fourth color channel when available. The difference of derivitives (dcu-dcl) identifies the subject to background transition area, whose edges define the inner and outer boundary lines. Shadow areas on the backing are retained and may be transferred to the inserted background scene. Small areas on the backing having the same color and luminance as the subject are prevented from printing through the subject by a second “derivative” alpha channel for the small areas.

Abstract: The present invention is a method and apparatus for automatically defocusing a background scene as the background scene is being composited with a foreground subject during the photography of the subject, where the background scene becomes increasingly defocused as the subject appears to approach the camera. A source of background image signals is connected to a background input of a compositing device capable of averaging a selected group of background pixels. A source of foreground image signals is connected to a foreground input of the compositing device. A matte signal generated by the compositing device is accessed and the matte signal is used to determine the ratio of foreground subject area to image frame area. The area ratio is then used to select, for each pixel in said background image, a number of adjacent pixels to be averaged to form an average pixel level. The signal levels at each pixel in the background scene are replaced with the average pixel level.

Abstract: A video signal is generated representative of a background scene, such as a weather map, which provides an outline of all the detail in the map. This outline detail is made visible to a foreground subject by projecting it onto a white screen behind the subject in a selected color such as green. The projector is selectively inhibited so as to prevent the background detail from projecting onto the foreground subject. The white screen and the green detail lines are removed and replaced by the background scene by an image compositing process. Prompts are visible to the foreground subject, but not visible to a home viewing audience.

Abstract: Changes in a current image frame from variations in room light level, and automatic camera adjustments, are determined and incorporated into a clear (reference) frame, thereby resulting in a zero difference in the background region when the clear frame and a current frame are subtracted. Any deviation from zero defines the beginning edge of a transition from background to subject. The location of the outer edge of a transition area is further refined by subtracting derivatives of the RGB signals in each frame, and by the use of a fourth color channel when available. The difference of derivitives (dcu−dcl) identifies the subject to background transition area, whose edges define the inner and outer boundary lines. Shadow areas on the backing are retained and may be transferred to the inserted background scene. Small areas on the backing having the same color and luminance as the subject are prevented from printing through the subject by a second “derivative” alpha channel for the small areas.

Abstract: A method for automatically implementing and coordinating the techniques of creating the illusion of illumination changes on a foreground subject that should occur when the subject moves throughout the various illumination levels on the background of a composite image.

Abstract: A teleconferencing system in which the video image of a subject in front of a selected background scene is extracted from that scene and transmitted to other locations where selected backgrounds are stored. By compositing the subject and background images at each remote location, both image elements, being originals, will show no loss of detail when projected. For a front projection screen, the projector is inhibited from illuminating a presenter.

Abstract: A teleconferencing system in which the video image of a subject in front of a selected background scene is extracted from that scene and transmitted to other locations where selected backgrounds are stored. By compositing the subject and background images at each remote location, both image elements, being originals, will show no loss of detail when projected. For a front projection screen, the projector is inhibited from illuminating a presenter.

Abstract: An objectionable outlining effect, seen as dark edges and white edges outlining everything in a scene, is eliminated by clipping or limiting the spikes generated by excessive enhancement. Specifically, a method is used for improving the quality of an enhanced video image, while simultaneously maintaining or improving image sharpness, by clipping the RGB levels of the enhanced video image, at the points of enhancement, to upper and lower level bounds representing the signal levels of the video signal prior to its enhancement.

Abstract: A video projector shows the desired scene on a projection screen. An infrared source close to the video projector uniformly floods the projection screen with non-visible infrared radiation. An infrared sensitive camera, also close to the video projector, observes the projection screen and sees only the uniform infrared illumination of the screen. Upon entry of a subject into the projected video image, the infrared reflected from the subject will not match that of the projection screen and thus the subject area is identified. All pixels of the projected scene, in the area occupied by the subject, are inhibited before reaching the video projector. The subject may then look directly at an audience without being blinded by the projector.

Abstract: An objectionable outlining effect, seen as dark edges and white edges outlining everything in a scene, is eliminated by clipping or limiting the spikes generated by excessive enhancement. Specifically, a method is used for improving the quality of an enhanced video image, while simultaneously maintaining or improving image sharpness, by clipping the RGB levels of the enhanced video image, at the points of enhancement, to upper and lower level bounds representing the signal levels of the video signal prior to its enhancement.

Abstract: In an image being displayed on a monitor, each observed background color is identified using a cursor to select the dominant colors. Each foreground color is also identified by using the cursor as a selector. For each pixel, several Candidate mattes are computed one for each background color. Each Candidate matte is computed from a single background color and the set of selected foreground colors using any known method. Of the several Candidate mattes, the greater of these Candidates becomes the matte signal for a given pixel. If this matte is 1.0, then the pixel is part of the background. If the matte is zero, then the pixel is part of the subject. If the matte is between 1.0 and 0.0, then the pixel is in a transition area and the contribution of the background to the pixel is that pixel's matte level. A ‘Processed Foreground’ is generated by removing the contribution of the background from each pixel in the image, resulting in the subject appearing against a black field.

Abstract: A computer implemented method to extract a selected subject from its background, by removing the background, including that portion of the background visible through semi transparent areas of the subject, and generating a matte signal containing a record of background levels outside of and within semitransparent subject areas. The observed RGB signal levels of a pixel in the semitransparent transition between a subject and its background, are a mixture of color contributed by the subject, and by the background. The estimated subject color, and the estimated background color, and the observed color of a transition pixel (pixRGB), may be shown as three points in a three dimensional color space.

Abstract: In most cases, the estimated subject color and/or the estimated background color for a given pixel will have a certain amount of error, which could result in either not enough background removal, or removal of all of the background and some of the foreground. By manually or automatically altering the estimated subject color and/or background color, the errors in matte calculation and subsequent removal of the background, can be minimized or eliminated. Manual alteration of a subject or background color is achieved by using a cursor to select a true color from the background, for example, and inserting it in one or more areas in the background area being partially obscured by the subject. Automatic alteration of one of the estimated subject or background colors involves its computation as a projection in color space of the observed transition pixel color, onto a plane defined by the subject and background reference colors or other defined planes.

Abstract: A method of removing the foreground subject and its shadow from a series of image frames including a subject before a colored backing being photographed by a moving camera during a live broadcast. Such removal results in a series of image frames of the colored backing without the subject, each image frame corresponding to an image frame containing the subject. The method steps employed identify, for each frame, those pixels in the frame occupied by elements of the subject. Those pixels are set to an RGB level of zero, to create an image of the colored backing in which the subject area is reduced to black. The image of the colored backing is then smeared to obliterate the defined edges of the subject's shadow and to smear the color of the backing into the black area previously occupied by the subject to generate a clear frame.