| 摘要 |
<p>A thresholding algorithm selection apparatus (202) for the selecting the threshold algorithm to be applied to a specimen (102) in a digital imaging process is disclosed. The specimen (102) is preliminarily scanned and thresholded using a predetermined thresholding algorithm (302). The resulting preliminary digital image is divided into a number of cells or regions (604). Each cell (604) is classified according to its optical characteristics; e.g. textual, photographic, etc. The cell classification is effected in the preferred embodiment by comparing the average white and black run-lengths of each cell (604) to experimental average run-length values which are representative of the different types of specimens(102). The specimen (102) is re-scanned and thresholded with an appropriate thresholding algorithm (306) for each cell (604). Additionally, the digital imaging system (100) may contain an optical character recognition means, in which case the cell characterization step is used to trigger the optical character recognition means in a textual region, while causing the optical character recognition means to ignore non-textual cells (604).</p> |
