| 摘要 |
PATENT 3522 The disclosed keyed, true-transparency combine and keyer receive a plurality of image information signals Vi, each having a corresponding input key signal Bkj, over a respective channel. The image signals can be dynamically ranked in a defined prioritized order, even on a field-by-field basis. However, rather than switch the individual image signals as their prioritized order changes, the order of the channels is dynamically and switchably interchanged within a keyer means by switchably interchanging a plurality of substantially identical keyer units while generating a plurality ofprocessed true transparency image key signals Pki. The keyer units are substantially identical in the sense that, while there may be some structural distinctions among the keyer units, there is a commonality of function among the keyer units within a keyer means. The keyer means also generates any needed processed background key signals PkB. The respective keyer units are switchably changeable to produce true transparency processed key signals, which are generated such that processed key signal Pki for an i-th channel is produced by the i-th respective one of the plurality of substantially identical keyer units within the keyer means. The i-th keyer unit is adapted to modify the value of its input key signal Bkj with the values of the input key signals Bkj in the higher priority channels to generate a true transparency processed key signal Pki for the i-th priority channel. A keyer unit within the keyer means generates the true transparency processed image key signal Pki for the i-th image signal so that: where B0 = 0 and so that Pk1 + Pk2 + ... + PkN + PkB = 1.0. The combiner also cuts each respective image signal Vj and background signal VB by its respective processed key signal and combines the plurality of cut signals to generate the special video effect of an image information combine Vc so that VC = Pk1V1 + Pk2V2 + ... + PkN VN + PkBVB. PATENT 3522 In one case, using the input key signals, a key-taken signal can be generated by multiplying a key-requested signal and a key-available signal while a key-now-available signal can be generated by algebraically subtracting the key-taken signal from the key-available signal. In another case, also using the input key signals, a key-taken signal can be generated by algebraically subtracting a key-now-available signal from a key-available signal while a key-now-available signal can be generated by multiplying the key-available signal and another key signal, which other key signal is equal to one minus the key-requested signal. In either case, the generated key-now-available signal can be coupled from a higher priority i-th channel to a lower priority (i+1)-st channel as the key-available signal for the lower priority (i+1)-st channel and the respective processed key signal Pki can be produced in response to the key-taken signal.
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