Abstract: A stereoscopic display system unambiguously tags the perspective view for left and right video fields by encoding at least one of the video fields with a unique code, then detecting the code in order to drive shuttered eyewear in synchrony therewith.

Abstract: A method and apparatus which allows different amounts of filtering to be applied to specific parts of a foreground image, thus minimizing visible noise in the backing area, while preserving fine detail information of foreground objects. The method and apparatus identify three areas within the foreground, namely unobscured backing (screen) area, screen to foreground subject transition area, foreground subject area. The area where full amount of filtering is desired is the backing area, including shadows. This is the area where the background image will be added, and if noise is present in this area, it will be added to the background image. The transition area from the screen to the foreground object requires variable amounts of filtering, depending on the width of the transition. For sharply focused edges and very fine detail, the transition width is very small, and any filtering applied there will cause blurring and softening of these edges and details. Therefore, no filtering is applied to those areas.

Abstract: An improved technique for mixing picture signals directed at a monitor screen. Two analog video signals (such as an analog VGA input and an analog RGB signal produced in response to a stored digital still or moving image) may be multiplexed in analog form. An analog chromakey mixer detects a background color in the first video signal (such as the analog VGA input), and replaces the portion of that first video signal with the second video signal. The time delays of the first video signal and the second video signal may be adjusted so that they reach the monitor screen (by means of an a multiplexer output) at the same time. An alignment detector may attempt to align two known signals (such as a VGA sync signal and a signal generated for this purpose), and may adjust a set of time delays in the analog chromakey mixer until the time difference between the first and second video signals falls below a threshold.

Abstract: A method and apparatus used in the field of image compositing which eliminates the need to obtain an original clear frame of the backing during production, by synthesizing during post production a clear frame of the backing from a frame of the foreground scene that includes the subject as well as the backing. This synthetic clear frame eliminates the problems of obtaining a registered clear frame during production, and thereby permits the ready application of nonuniformity correction to image compositing in both motion pictures and graphic arts. The invention is also directed to a method and apparatus used in the field of image compositing which reduces the processing time for developing the inhibit signal that prevents the corrections from being applied to the subject, the control signal E.sub.c, and a number of other functions that are computed from the colored backing.

Abstract: A foreground live-video image, made up of a "blue back" part, a "hand/arm" part, and a "shadow" part of the "hand/arm" part, is chroma-key composited with a background live-video image. The "blue back" part is displayed to be transparent on the display screen. The "hand/arm" part is displayed to be opaque. The "shadow" part is displayed to be translucent. Whereas a first comparator determines a key color of the "blue back" part, a second comparator determines a key color of the "shadow" part. According to the output code of the first and second comparators, a data selector selects, pixel data of the background live-video image (Va) for the "blue back" part, pixel data of the foreground live-video image (Vb) for the "hand/arm" part, and pixel data found by multiplying each of the pixel data of Va and the pixel data of Vb by a respective weight and summing those products, as respective output pixel data.

Abstract: In a chroma-key method for inserting a background picture signal into key color-characterized key regions of a foreground picture signal, in which method fading operations are performed between the picture signals in proportional zones in dependence upon a control signal, while intermediate colors occurring in the proportional zones in the foreground signal are transformed into new intermediate colors which constitute a transition from the color of the foreground picture signal to that of the background signal, an optimal adaptation of the proportional zone to the respective color location of a foreground picture signal region is ensured in that individual proportional zones for regions of different color locations in the foreground picture signal are fixed in such a way that the distance between the color location of each region and the color location of the key color is determined individually for each region, and in that the control signal is generated for each region in dependence upon the color location

Abstract: In a method of separating a foreground picture signal FG from a mixed picture signal MG which has a key color KC as well as transition colors to this key color in key regions, the foreground picture signal is removed from the key color and the transition colors in accordance with the equationFG=MG-k*KC.Herein, k is a control signal which has a value of about 1 in the region of the key color KC and a value of about 0 at the transition boundaries. The transition boundaries in the C.sub.b /C.sub.r color plane are constituted by two straight lines through the origin of the C.sub.b /C.sub.r, color plane which, relative to a vector D.sub.KC of the key color extending from the origin of the C.sub.b /C.sub.r color plane to the color location KC of the key color, are arranged at angles .omega..sub.o and .omega..sub.u, respectively. The straight lines through the origin of the C.sub.b /C.sub.

Abstract: In a method of separating a foreground picture signal FG from a mixed picture signal MG having a key color KC and transition colors to this key color in key regions, the components of the key color and the transition colors are vectorially subtracted from the mixed picture signal in dependence upon a control signal k which, with a continuous variation, assumes values of between 1 in the region of the key color KC and O at mixed boundaries. Color errors due to a gamma pre-correction are obviated in that the vectorial subtraction is performed in accordance with the equation FG=MG-k*KC(f), in which KC(f) is chosen in dependence upon the color intensity as far as its angle in the C.sub.b /C.sub.r color plane is concerned.

Abstract: Disclosed is a video playback apparatus which functions to vary the brightness of the caption color of a displayed caption according to audio level of the playback. The video playback apparatus displays caption signals on a predetermined area of a TV screen, and includes a level detector for detecting audio levels and a controller for controlling color brightness of the caption signals in response to and accordance with the audio levels detected. Thus, the captioned video signal (e.g. music lyrics) is displayed more vividly than heretofore.

Abstract: An image processing system operates on first and second image data (V and Bg) to produce data defining a combined image. The first image data (V) represents a keyed image comprising a first object (F) keyed over a portion of a first background (B) in accordance with keying data (K). The second image data (Bg) represents a background. The system is arranged so that the second image data (Bg) is weighted by respective control data (.alpha.) related to said keying data (K) before being combined with the first image data (V). In another embodiment the first image data represents a second object independently keyed over the keyed image in accordance with second keying data and the control data is further related to the second keying data. In a further embodiment the first image data represents an image derived by cross fading between the first keyed image and a second keyed image.

Abstract: A linear image compositing system which corrects for nonuniform luminance and/or color of the colored backing without incurring the penalties of edge glow, edge darkening, loss of edge detail and other anomalies. A control signal is created directly proportional to the luminance of the colored backing and controls the level of the BG scene. Unless the control signal is corrected, the background scene will contain all the brightness and color variations occurring on the colored backing. Correction factors are developed by comparing the RGB video obtained from the backing before the subject is put in place, with the ideal values of RGB that would have been obtained from a perfect backing. These correction factors correct the RGB video when the scene is scanned with the subject in place. The control signal, being zero in the subject area, may be used to inhibit the corrections in the subject area.

Abstract: A chroma keyer with correction for background defects generates a control signal that does not include variations associated with the background defects. The chroma magnitude of a reference signal that represents a chroma key set with a color background scene without a foreground object is used as a divisor for a hue select signal generated by a hue selector from a chrominance component of an input signal that represents the chroma key set with the foreground object to produce a chroma key control signal. The chroma key control signal is combined with the reference signal to produce a control signal for background suppression. The chroma key control signal also is input to a key circuit to produce a key signal for shaping a new background scene.

Abstract: A circuit for analog chroma keying on color data permits display of graphics, generated from a computer system, and video on an output display. The analog chroma keying circuit receives the graphics signals and the video signals, wherein the graphics signals include color data to designate a color key. The analog chroma keying circuit includes a plurality of digital to analog converters that generate a plurality of color key limits for defining a range to detect the color data denoting the color key. The analog chroma keying circuit also includes a plurality of comparators coupled to receive the graphics signals and the color key limits for each primary color. The plurality of comparators generate a key on indicator when the graphics signals fall within the color key limits.

Abstract: For correcting vignetting in the upper or lower range of the pick-up area of optoelectric transducers of a multichannel color television camera with zoom lens are described, a representative signal is derived from the diaphragm aperture setting and from the zoom setting. Dependent on corresponding signals for the minimum diaphragm aperture, on the one hand, and the minimum values for wide-angle and telesetting of the zoom range, on the other hand, these representative signals generate control voltages with which the level of a field frequency sawtooth signal is controlled. Finally, this sawtooth-shaped control signal influences the video signal of each chrominance channel in the sense of a vignetting compensation.

Abstract: A method and apparatus to improve the control signal E.sub.c used in a video image compositing system so that the adjustment to achieve an E.sub.c of just zero for green objects and flesh tones, does not simultaneously reduce E.sub.c in grey scale subjects and cause print-through. The invention also reproduces a wide range of blue colors from pale blue to bright blue in the presence of a blue backing without raising a matte density control and without raising noise level. The invention also provides a second control signal, E.sub.k, that eliminates backing color spill from blond and brown hair, without affecting bright foreground white tones. The invention also generates a SHADOW CLEAN-UP signal that eliminates foreground shadows, while preserving most of the foreground detail information.

Abstract: A chroma keyer with fringe control offset adds a fringe control offset value to a correlation output produced by a hue selector. The hue selector compares the hues of a foreground image, representing a foreground object in front of a reference matte background, with a reference hue corresponding to the reference matte background to produce the correlation output. The adjusted correlation signal is then negatively clipped and provided at the output of the hue selector as a hue select signal that is used for deriving a chroma key signal and for providing background suppression to the foreground image.

Abstract: A switcher with depth processing includes a depth processor module. External depth data, or internally generated depth data, are input to the depth processor to generate a priority signal for combining key video signals as layers between a background and a foreground video signal. Further a composite depth signal is generated for the combined key video signals for subsequent processing so that additional key video layers may be intersected and intertwined with the key video layers in the combined video signals.