| 摘要 |
A technique for developing an analytic model of an image by operating directly upon the pixel map representation output by an optical sampling device, such as a scanner. The resulting analytic representation is hierarchical, below a certain level, with each element an analytic expression representing a portion of the image. Above a certain level, the model is a simple array, to facilitate certain types of graphical manipulations. The model is developed by arranging pixel values into a number of groups called tiles. A number of operations are then performed on each tile, to determine how it can best be represented as an analytic expression. For example, if all pixel values in a tile are approximately continuously varying, they be represented as a three-dimensional linearly sloped surface. However, if one or more intensity boundaries run through the tile, analytic expressions, such as a straight line or a parabolic line segment, are derived from the tile's pixel values to describe the edges. |
