A spectrum analyzer for producing a first two-dimensional array of time varying spectral analysis image input signals, a reference image generator for producing a second two-dimensional array of spectral analysis image reference signals, and a time-integrative correlator, which can be non-coherent or coherent, or correlating the two groups of image representitive signals to determine the degree of matching between an input image and a library reference image. The spectrum analyzer can include an interferometer, a tunable optical filter, or a time-wavelength-multiplexing holographic lens for viewing the input image. A monolithic non-holographic version provides a rugged, compact and portable image analyzer for examining many types of images.
A system for performing real time optical comparisons using an optical correlator permits comparing a sampled image to a wide variety of reference images through the utilization of a multiple quantum well spatial light modulator which is utilized to rapidly present a large number of reference images for correlation. The utilization of the multiple quantum well spatial light modulator as the spatial light modulator in a van der Lugt image correlator in combination with a spectrometer permits optical comparisons at 300,000 frames per second versus 10,000 frames per second, the best case for liquid crystal based spatial light modulators.
A compact, broadband laser source is realized by using a rare earth dopant to define a laser gain spectrum and by using holographic imprinting techniques to form a wavelength selection element for selecting a particular wavelength from within the gain spectrum. Artificial broadening of the gain spectrum can be achieved by establishing varied (e.g., randomized) domains of space charge within a rare earth-doped laser gain medium. Compactness can be enhanced by fabricating the laser gain medium and wavelength selection elements within a single member, such as a photorefractive crystal substrate. Flexibility in the selection of a wavelength can be obtained by holographically imprinting multiple sets of wavelength selection elements.
A spectral correlator comprises a specimen and an optical device configured to collect light from the specimen and to optically determine a similarity of a received first spectra of the light collected from the first spectra and a second known spectra.
An optical processor adapted to emulate an artificial neural network (ANN) having a plurality of interconnected layers, each layer having one or more artificial neurons, the processor having a spatial light modulator (SLM) optically coupled, via an optical mask, to a photodetector array. In one embodiment, the SLM has a plurality of pixels, each pixel being configurable to emulate an output portion of a corresponding artificial neuron in a signal-sending ANN layer. The optical mask has a hologram that encodes the weights corresponding to interlayer connections in the ANN and spatially modulates the light transmitted by the SLM. The photodetectors of the array spatially resolve the interference pattern produced by the spatially modulated light, with each photodetector being configurable to emulate an input portion of a corresponding artificial neuron in a signal-receiving ANN layer.
