Abstract: The present invention converts an image into a transparency, or “foreground image”, on which the readability of text and other detail is preserved after compositing with a background, while maintaining color information of broad areas of the image.

Abstract: The present invention converts an image into a transparency, or “foreground image”, on which the readability of text and other detail is preserved after compositing with a background, while maintaining color information of broad areas of the image.

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: 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: 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: 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: 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 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: 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.