| 摘要 |
PURPOSE:To form a video camera most suitable for focussing even when an object to be photographed is present in any position in a photographed picture by focussing on the hue component of the object desired to be photographed. CONSTITUTION:In a color difference vector chart for identifying the hue, a (R-Y) signal and a (B-Y) signal are defined to be orthogonal axes, a chrominance signal is obtained by the vector sum of both the signals. Namely, an arbitrary color C is represented by C=(R-Y) sin theta+(B-Y) Cos theta. Accordingly, by deciding the theta, the ratio of the (R-Y) signal and the (B-Y) signal can be determined and the color can be identified. By focussing making an area including the identified color an angle of view to the focussing by the fixed angle of view, the dimension of the angle of view and the position thereof are changed according to the area of the identified chrominance signal. Thereby, an automatic focussing can be effectively obtained to the object intended by a photographer. |
