Data Position Detection Using Fast Fourier Transform Cross-Correlation Method for Holographic Memory

摘要

Various recording methods are proposed for volume holographic memory. In these recording methods, two-dimensional digital data are used, and markers for data position detection are placed at the four corners. During the reproduction process, bit error rate is directly affected by the accuracy detection of this marker position. Therefore, it is necessary to devise a method that can achieve high-accuracy marker position detection. With the increase in the volume of page data, the distortion of reproduced images affects bit error rate to a great extent. Therefore, it has become necessary to place several markers in a data area. Under such circumstances, a new marker detection method that can replace the conventional template matching method is being sought. In this study, fast Fourier transform (FFT) cross-correlation method was examined for various data formats. By applying sub sampling and linear distortion correction of a reproduced image, we realized high-accuracy position detection and clarified the effectiveness of this method experimentally.