Noise reduction in coherent systems

Details Noise reduction in coherent systems Noise reduction in coherent systems

1983-10-25

1984-10-23

Arnold, Bruce Y.

350 381, 350320, 350448, G03H 132

Patent

active

044784902

ABSTRACT:
A method of producing coherent radiation signals which have reduced coherent noise content. The method involves modulation of the position of an apodizer or aperture disposed in the optical path of the radiation provided by the coherent radiation source. The modulation causes diffraction patterns created by the apodizer or aperture to be unstable, hence reducing the noise content of the transmitted radiation. In particular, a method of producing holographic exposures containing reduced coherent noise content is disclosed. The positions of apertures or apodizers utilized in producing the holographic exposure are modulated during the exposure process. The modulation is on the order of wavelengths of the illuminating radiation used to produce the exposure. The position modulation creates a slight fogging of the exposure due to the noise, but the desired hologram is recorded with little or no decrease in efficiency. Also, a method of producing an apodizer for use in generating the holographic exposure is disclosed. During preparation of the apodizer, it is modulated in position with respect to the illuminating radiation. The position is modulated on the order of wavelengths of the illuminating radiation. The modulation procedure reduces the noise content of the apodizer.

REFERENCES:
patent: 3640599 (1972-02-01), van Ligten
patent: 3666344 (1972-05-01), Mottier
patent: 3754814 (1973-08-01), Leith
patent: 3819248 (1974-06-01), Takeda et al.
Gruber, L. S. et al., "On the Apodization of Coherent Imaging Systems", Optical Engineering Sep./Oct. 1974, vol. 13, No. 5, pp. 451-454.
Matsumura, M. "Speckle Noise Reduction by Random Phase Shifters", Japanese Journal of Applied Physics vol. 13, No. 3, pp. 557-558, Mar. 1974.
Schulman et al., "Noise Diffraction Patterns Eliminated in Coherent Optical Systems", NASA Tech. Brief 71-10236, Goddard Space Flight Center, Jul. 1971.

Affiliated with

Also associated with

Rating

Noise reduction in coherent systems does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Noise reduction in coherent systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Noise reduction in coherent systems will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1595990