| 摘要 |
The invention is directed to a method for comparing in a binary image a first pixel blob with a second pixel blob to determine whether they represent matching symbols. The method comprises the steps of dilating the first blob and checking if the second blob fits inside the dilated first blob, and dilating the second blob and checking if the first blob fits inside the dilated second blob. If the dilating steps result in a match, the method checks whether the match is erroneous or not by checking if the non-dilated first pixel blob contains a line not present in the non-dilated second pixel blob and vice versa. This latter step further comprises directly comparing corresponding sets of NxN crosses of two crossing lines in the non-dilated first and second pixel blobs, wherein each corresponding set of NxN crosses comprises a first NxN cross considered on the non-dilated first pixel blob and a second NxN cross considered on the non-dilated second pixel blob in the same position, and declaring an erroneous match if for at least one of the sets one of the two crossing lines of the first NxN cross has a different color from the other line of the two crossing lines of the second NxN cross, wherein N is a number of bits. |
