Iterative design method for an image filter to improve the bit error rate in holographic data storage systems

An image filter design method is proposed to improve the bit error rate (BER) in holographic data storage (HDS). In previous image restoration methods for HDS, a highly precise point spread function (PSF) was used as the deconvolution filter, so performance was strongly dependent on the accuracy of the PSF. In the proposed method, in contrast, the image filter is designed without using PSF information, due to the similar spatial frequency distributions of HDS data pages. A simple iteration algorithm was developed to obtain an optimized image-filter shape, and the performance of the designed image filter was verified by both simulation and experimentation. The experimental results demonstrated that the BER improved sixfold and greater than tenfold for a Nyquist factor of 1.1 and 1.2, respectively. Additionally, an improvement of >30 % in storage density was projected using the proposed filter, compared with conventional HDS systems.