Edge Detection of Level Ruler with Digital Level

The digital level displacement surveys, the rod barcode image’s marginal check are affects its measuring accuracy the important link. According to the rod barcode image’s rectangular characteristic, proposed that uses based on the LOG operator zero crossing intersection examination algorithm, analyzed in the examination process to have “the false peripheral point” the question, gave three kinds to amend a plan, a plan use peripheral point’s first derivative was the extreme value characteristic, the plan two use peripheral point three step derivative non-vanishing characteristic, about the plan three use peripheral points the domain product non-characteristic. The experimental verification three methods have gone to “the false peripheral point” validity.