| 摘要 |
A video display apparatus receives a transmitted colour video signal coded using three system primaries (Rs, Gs, Bs) and decodes the signal for display on a device using four display primaries. The four display primaries are independent, in that no display primary can be expressed as a combination of another two display primaries, and so define a quadrilateral in a chromaticity diagram. A fifth, imaginary display primary is determined as a linear combination of the third and fourth display primaries and the quadrilateral divided into triads defined respectively by the first, fourth and fifth, first, fifth and second, and second, fifth and third display primaries. The received video signal is decoded by three matrix arithmetic units (12, 14, 16), one for each triad, and drive signals for the first to fourth display primaries calculated. For each pixel, an arithmetic unit output producing no negative display drive signals is then selected and its output switched by switches (20, 22, 24) to drive a four-primary display device (2). |
