A Pockels-effect light valve: Phototitus. Applications to optical image processing
| Autor: | J. Donjon, F. Dumont, J.-P. Hazan, G. Marie, M. Grenot, J. Pergrale |
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| Rok vydání: | 1973 |
| Předmět: |
Materials science
Scattering business.industry Holography Filter (signal processing) Pockels effect Electronic Optical and Magnetic Materials law.invention symbols.namesake Fourier transform Light valve Optics law symbols Contrast ratio Electrical and Electronic Engineering business Coherence (physics) |
| Zdroj: | IEEE Transactions on Electron Devices. 20:1037-1042 |
| ISSN: | 0018-9383 |
| Popis: | An electrooptic light valve is described, using the Pockels effect in a KD 2 PO 4 crystal cooled close to its Curie temperature and addressed by photoconduction in an amorphous selenium layer. The preliminary performance levels obtained are: resolution 40 lp/mm, maximum contrast ratio 70/1, writing time 10 µs, sensitivity 2 PO 4 plate prevents all loss of coherence in coherent optical data processing. Furthermore, suppression of the zero order in the Fourier transform of an image has been obtained by subtracting from that image a uniform one whose amplitude is equal to the average amplitude of the initial image; this results in the suppression of the optical noise introduced by the scattering of the zero-order term in coherent filtering experiments. Character-recognition experiments are described employing a filter hologram previously made using the same device. The high-speed capability of the device would permit the construction of automatic reading systems at least ten times faster than those generally available. |
| Databáze: | OpenAIRE |
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