Patent ID: 7251059

Claim:
A method of classifying image data, the image data relating to a set of pixels forming an image in two dimensions, each pixel having a gray level associated therewith, comprising: for a center pixel, entering gray levels associated with neighboring pixels into a first algorithm to yield a result, the neighboring pixels having a predetermined spatial relationship with the center pixel, the result being indicative of a likelihood that the center pixel is part of a line image; wherein the first algorithm determines that each of a first subset of the neighboring pixels which is radially symmetric around the center pixel differs in gray level from the gray level of the center pixel by less than a predetermined threshold amount; and entering gray levels associated with a second set of neighboring pixels into a second algorithm, wherein the second algorithm determines that, for a second subset of neighboring pixels along one dimension relative to the center pixel, the gray levels of the pixels in the subset increase along the dimension in a first direction, and that, for a third subset of neighboring pixels along one dimension relative to the center pixel and on an opposite side of the center pixel as the second subset, the gray levels of the pixels in the third subset increase along the dimension in a second direction opposite the first direction.