| 摘要 |
Apparatus for controlling the focus of a camera arranged to capture a sequence of frames comprises an image processor configured to form an image characteristic, for example contrast, for a plurality of blocks of a first frame. Each block comprises one or more pixels of the first frame. An image parameter is calculated for each block by combining the image characteristics of blocks lying within a predefined zone relative to that block and a focus controller is configured to derive a measure of focus for aselected frame area of the first frame by identifying a set of blocks whose respective predefined zones, when combined, substantially represent the selected frame area. A measure of focus is configured for the selected frame area by so combining the image parameters of the set of blocks; wherein the focus controller is configured to generate a signal for controlling camera focus in dependence on the measure of focus formed for the selected frame area of the first frame. |
