Patent ID: 7778133

Claim:
An optical information recording/reproducing apparatus adapted to record and/or reproduce multilevel information taking three or more levels on or from an optical information recording medium adapted to record and/or reproduce information using a light spot on or from information pits formed on a track of the optical information recording medium, the information pits being formed in cells virtually formed at regular intervals on the track, the respective levels being represented by varying the length of information pits as measured in a direction along the track information pits or varying the area of the information pits such that a reproduced signal has a different amplitude level depending on the length or the area of information pits, comprising: a reproduced signal correction circuit adapted to correct a reproduced signal obtained by performing sampling at a center of each cell; an error power calculation circuit adapted to calculate error power on the basis of the difference between a corrected reproduced signal output from said reproduced signal correction circuit and an ideal value of each level of the cell; and a decoder adapted to perform decoding on the basis of a value obtained by said error power calculation circuit.