| 摘要 |
A method and apparatus for defining a contour in a coloured image (10,11) to separate a selected region having a selected colour or colours from other regions when the colour component content of each pixel of the image (10,11) is defined by digital data at a first resolution. The method comprises defining a region of the image (10,11) containing colours which are to be located in the selected region and for each of the pixels in the defined region deriving a digital colour component representation at a second resolution higher than the first resolution by combining colour component data from one or more adjacent pixels. Each digital colour component representation at a second resolution is then designated as a selected colour value. An edge following algorithm is performed to define a contour within the image (10,11) by deriving a digital colour component representation at a second resolution for each pixel under consideration, as before, determining whether each digital colour component representation is a selected colour value and designating a pixel as lying on the contour by reference to the arrangement of neighbouring pixels having selected colour values. <IMAGE> |
