Telediffusion De France

Etablissment Public Telediffusion De France

Guy R Macheboeuf

Lucien F Mignot

A mixer device designed for a TV production control room mixes incoming video signals of PAL, NTSC or MAC standard. To avoid any differences in video signal propagation time through a known video grid, the latter is suppressed, and a grid with narrower band width switches chopping signals selectively controlling attenuations of the incoming video signals in analog multipliers. The chopping signals are derived in operator circuits as a function of effect and dissolve signals designed to chop image planes to be superposed into a resultant image. In particular, amplitude complementarity of the chopping signals between two predetermined levels is ensured, whatever the dissolves and effects selected, and a proportion of a black image signal, transmitted normally during line and field blankings, is mixed during a black fade or a darkening to be created in the resultant image.

Video signal mixer device

A television picture superimposing system comprises a video mixer including two variable gain amplifying circuits receiving two input picture signals having a given peak-to-peak amplitude, and an adding circuit for mixing the amplified picture signals into a resulting picture signal. The improvement resides in providing a circuit for deriving a single gain control signal based upon a linear combination of two signals derived respectively from the two input picture signals so that the resulting signal has the given peak-to-peak amplitude. The control signal is respectively applied, via an analog inverting circuit and directly, to gain control inputs of the variable gain amplifying circuits.

System for superimposing plural television pictures with extent of

A television system combines signals representing a picture derived from a foreground scene moving in front of a backing, with a background scene. An input processing circuit mixes a color from the background scene, preferably different from the backing color, with certain colors in the composite foreground and backing picture. A first combiner responsive to the picture and background scene representing signals determines picture zones where false colors are created at transition points between the foreground scene and the backing. At transitions, e.g. a transparent object, between the foreground and background scenes in the resultant picture transmitted by the system, the colors are modified progressively such that a viewer no longer sees the edges or the reflections due to the backing, but rather a slight blur blending perfectly with the background and foreground scene colors.

Video signal combining system

The system combines first and second composite video signals into a resulting composite video signal. The first composite video signal represents a foreground scene having a first trichromatic moving picture region which envelopes a second trichromatic backing region through a trichromatic transition region. The second composite video signal represents a background scene. A gain controlling circuit produces from first component video signals first and second analog signals (1-.alpha.), (.alpha.) which control in proportion the amplifications of the first and second composite video signals to obtain second output composite video signals. The first analog signal has first and second levels when the first component video signals are representative of the first and second picture regions and has intermediate levels lying between the first and second levels when the first component video signals are representative of the transition region. A video mixer mixes the first and second output composite video signals into the resulting composite video signal.

Composite video signal combining system

A video titling device for color television pictures wherein the color transmission system is of the SECAM, NTSC or types in which the luninance signal and chrominance signal making up the composite video signal are separate signals. A part of the luminance signal spectrum Y is extracted from the input video signal having a chrominance subcarrier S.P. carried through a single filtering step without modifying the composite input signal. Thus from the composite input video signal of luminance signal Y and chrominance signal S.P. (Y + S.P.) through a single filter, the subtraction of the amplitude of a direct predetermined luminance signal K from the amplitude of luminance signal Y provides a (Y-K) signal. This Y-K signal is then cut out by switching means at a reference voltage under the control of a switching signal representing those selected pictures for the titling operation, and the aforesaid cut out signal is then subtracted from the input video signal (Y + S.P.). Whenever the switching signal selects the reference voltage, the output video signal is identical to the input video signal (Y + S.P.). Whenever the switching signal selects signal (Y-K), the output video signal transmits the special effects pictures with a predetermined luminance K and a chrominance equal to that corresponding to the composite input video signal.

Growing community of inventors

Vitry-sur-Seine, France

Guy R Macheboeuf