Study On Pixel Matched Volume Holographic Storage System With Magnification Error

Compared with other storage technologies, volume holographic data storagetechnology has many advantages, such as large digital storage volume, high datatransfer rate and short access time, etc. Holographic data storage is promised to be thedominant storage technology for next generation and has been researched by variousresearch institutions all around the world. The latest research results in related areasshow the main reason why the BER (Bit-Error-Rate) is extremely high in holographicdata storage system is that the pixels of SLM and CCD/CMOS image sensor can notstrictly aligned. General speaking, the pixels can be matched one to one byappropriate zooming. However, in the process of reconstruction from input data pages,there are quite a lot factors leading to the misalignment of pixels, such as opticaldesign or fabrication, mechanical motion of optical components, holographic effectssuch as Bragg-degenerate reconstruction and media effects such as shrinkage inphotopolymers.In order to retrieve pixel-matched data page, we proposed a novel scheme whichcan achieve better pixel registration. In this paper, we mainly:1. Analyzed main factors that affect BER and pixel registration compared differentmethods which can decrease BER and identified a method compatible to the presentsystem.2. In order to decrease BER of raw retrieved data, we studied the shiftcompensation algorithm and extended it to an expansive compensation algorithm forholographic data storage system with magnification error. With the combination ofboth algorithms, we concluded a general compensation algorithm for arbitrarilymisaligned data pages. We analyzed and verified this algorithm by the means of bothsimulations and experiments.3. Designed and implemented a novel CMOS-image-sensor-based data readoutsystem in which we controlled the sensor to output high transfer rate data with FPGA.This paper not only reviewed all the methods related to the pixel registration inholographic data storage, but also proposed some novel ideas in optical design andimage processing, which would be a useful reference in later application.Nevertheless, the paper also gives some recommendations and prospects for thefuture work.