Reproduction of optical information by one-beam optics with reduced crosstalk as recorded in multi-phases and multi-levels at staggered lattice points, and apparatus and recording medium therefor

摘要

Learning marks are recorded in a learning region preceding a data recording region of the track. The positions of information recording lattice points are staggered by one lattice point between two contiguous tracks. At reading of recorded information, a two-dimensional information leakage amount is detected by the reproduced signals from a learning mark preceding a target information recording lattice point on a track, and from the information recording lattice points immediately before and after the learning mark in question. The equalization coefficients are calculated from leakage amount thus obtained. The crosstalk present in a reproduced signal for the target lattice point is removed by using this equalization coefficients and a pair of reproduced signals from intermediate lattice points which are located immediately before and after the current lattice point and which are not used to record information marks. Inter-symbol interference left in the crosstalk- removed reproduced signal is further removed by use of the reproduced signals from a plurality of information recording lattice points which are located immediately before and after the target lattice point.