| 摘要 |
<p>An image processing system (10,20) comprises a framestore (11) or other source of image data in a first colour format (RGB) and is arranged to convert the data into data representing at least one colour separation. A colour rotator 14, such as a colour transform matrix, is provided for rotating on a pixel-by-pixel basis the first colour format data (RGB) into data in a second colour format (NPQ) selected such that one of the colours thereof corresponds to the colour of the at least one colour separation. A look-up table (15) determines from the most significant parts of the data from the rotator (14) a range of colour values in the second colour format which includes the value of the colour separation pixel. An interpolator (16) receives data defining the range of values from the look-up table and in response to the least significant parts of the data from the colour rotator (14) interpolates the data from the look-up table to determine the value of the colour separation pixel. One described embodiment is concerned with generating separation data representing colour separations for use in printing. Another described embodiment is concerned with generating separation data representing a chroma key signal for use in combining two video signals. <IMAGE></p> |
