a method of generating color matte signals includes the steps of : inputting hue , saturation , and luminance values ; calculating r , g and b color component values from the hue , saturation and luminance values ; calculating luminance , and color difference component values from the calculated r , g and b values ; and outputting the calculated y , cr , and cb values . the hue value is in two parts , the first of which defines one of six segments formed by dividing each side of the color triangle in half and the second of which define intermediate values within the segment . the r , g and b values are determined by calculating three color components from the saturation , luminance and the second part of the hue value , and assigning the three color components to registers for holding r , g and b values in dependence on the segment defined by the first of the hue value .