Closed Loop Optical Disk Based Associative Memory

Closed Loop Optical Disk Based Associative Memory
Author: Mark A. Neifeld
Publisher:
Total Pages: 4
Release: 1992
Genre:
ISBN:

The optical disk is a simple computer addressable binary storage medium with very high capacity. More than 10 (to the 10th power) bits of information can be recorded on a 12cm diameter optical disk. The natural two dimensional format of the data recorded on optical disk makes this media particularly attractive for the storage of images and holograms, while parallel access provides a convenient mechanism through which such data may be retrieved. Parallel access to data stored on optical disk has been shown to provide interesting solutions to problems in neural networks, database retrieval and pattern recognition. In this paper we will discuss a closed loop associative optical memory based on the optical disk. When presented with a partial or noisy version of one of the images stored on the optical disk, the optical system evolves to a stable state in which those stored images which best match the input are temporally locked in the loop.

Real-time, Large Memory, Optical Pattern Recognition

Real-time, Large Memory, Optical Pattern Recognition
Author: Don Allen Gregory
Publisher:
Total Pages: 294
Release: 1984
Genre: Optical pattern recognition
ISBN:

A large memory optical recognition system has been developed and tested. The memory consists of an array of stored holographic Fourier transform matched filters in a VanderLugt type correlator. The filters are stored (on high resolution Kodak plates) and addressed using a novel holographic multi-focus lens. This element acts as a diffraction grating, splitting the input beam into 25 elements and as a lens, producing the Fourier transform of each of the 25 elements. The filters are created and addressed using a HeNe laser and a Hughes liquid crystal light valve (LCLV) to produce a coherent image from a television monitor. The LCLV also allows the filters to be addressed in real time thereby making the use of a transparency as an input scene unnecessary. This provides for real time recognition. Thus far, more than 70 matched filters have been stored on a single holographic plate and addressed in parallel and in real time with good correlations resulting. This research and the results obtained should contribute to allowing serious consideration to be given to the use of optical recognition systems for a wide variety of civilian and military applications. (Author).