Holographic recording method and filtering method
US6285474A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 2000 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | May 25, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2222/31
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and an apparatus capable of filtering based on desired spatial frequency characteristics without loss of Fourier spectrum frequency components, and of matched filtering of high recognition capability without losing functions of data recording and reconstruction as well as high-speed transmission and retrieval features and mass storage capacity characteristic of a holographic memory. Fourier transformed object light with 0.degree. polarization of a target image is stored as a hologram using reference light having a spatial polarization distribution such that a daughter wavelet on scale m has 90.degree. polarization. The hologram is retrieved using the Fourier transformed object light with 0.degree. polarization. The hologram yields diffracted light in the form of a spatial frequency component which corresponds to scale m and is polarized 90.degree. with respect to the other spatial frequency components. A polarizing element is used to extract only the spatial frequency component corresponding to scale m. Given reference light having a spatial polarization distribution in conformity with a shape of a spatial frequency filter, retrieval light of 0.degree. polarization is appl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.