Mark length selection apparatus, mark length selection method, maximum mark length detection apparatus, and maximum mark length detection method

摘要

A mark length selection apparatus is provided with a mark length measuring unit for measuring mark lengths of a signal which is read from an optical disc; a mark length selection unit for dividing one of continuous two mark lengths by the other mark length, which mark lengths are measured by the mark length measuring unit, and selecting some mark lengths from the mark lengths measured by the mark length measuring unit, on the basis of a result of comparison performed between a result of the division and a predetermined threshold value, and outputting the selected mark lengths; and a maximum mark length detection unit for detecting a maximum mark length that is the longest mark length among the mark lengths outputted from the mark length selection unit 120. Therefore, a maximum mark length can be detected while eliminating improper mark lengths which are caused by flaws or contamination on the optical disk.