Patent Document ID: 20070177478
Application ID: 11622765
Patent Flag: 0

Claim One:
1. A method of reproducing multi-level information recorded by changing one of a width and area of an information pit in a track direction and a phase of the information pit in virtual cells provided on a track of an optical information medium at predetermined intervals, comprising the steps of: setting the optical information medium including a plurality of cells, each of which is recorded with an N-value (N≧3), and a cell recorded with an M-value (M<N) for each group including the plurality of cells; obtaining a reproduction signal when a center of a light spot is moved to a center of the cell recorded with the M-value; and correcting a reproduction signal level of the cell recorded with the N-value, which follows the cell recorded with the M-value based on a difference between a cell center value and a reference value obtained from learning information.