A METHOD OF WINDOWING IMAGE DATA IN A COMPUTER SYSTEM

摘要

In a method for rapid windowing of display information in a computer system image data is maintained in a hierarchical data tree structure. The complete image field (1), within which the image is defined, is divided into cells (7). The window is defined within this field and a field of possible interest (5) is defined around the window. Then, for each node in the tree, summary node data is computed which identifies those cells within the field of possible interest which are at least partially occupied by the part of the image defined at that node. By traversing the tree it is then possible to identify rapidly the image data to be windowed.