Abstract: Methods for segmenting the reflected light of an illumination source having a characteristic wavelength from background illumination (i.e. clutter) in structured lighting systems can comprise pulsing the light source used to illuminate a scene, pulsing the light source synchronously with the opening of a shutter in an imaging device, estimating the contribution of background clutter by interpolation of images of the scene collected at multiple spectral bands not including the characteristic wavelength and subtracting the estimated background contribution from an image of the scene comprising the wavelength of the light source and, placing a polarizing filter between the imaging device and the scene, where the illumination source can be polarized in the same orientation as the polarizing filter.

Abstract: An apparatus and method for characterizing light beam collimation and alignment. A liquid crystal device receiving a light beam from a collimation lens has a lenslet array generated thereon. A corresponding array of point spread functions are detected by a charge coupled device camera, from which light beam collimation and alignment are characterized. The data may be further used to adjust the collimation lens to correct misalignment.

Abstract: An adaptive optics system which simultaneously measures the phase function and corrects the phase distortion of a wavefront using a liquid crystal device placed in an interferometer. The liquid crystal device inserts the conjugate phase function in the path and obtains a null in the interference pattern.

Abstract: An optical signal preprocessor for computing the input functions required to utilize an extended Kalman filter algorithm. An incoming stream of time-varying images is integrated to form a reference image, which is then subtracted from each subsequently sampled image. The result is digitized for use with the extended Kalman filter algorithm. The reference image is also fed through a spatial filter and then input to two light valve image subtraction systems to produce difference image approximations of two partial derivatives. These derivative functions are then digitized and utilized as inputs to the extended Kalman filter algorithm.

Abstract: A photoparamp array multiplexer to provide photoparametric amplification in n array of photodiode diodes connected in parallel which essentially eliminates the need for an array of preamplifiers.

Abstract: A low frequency photoparametric amplifying upconverter comprising an indium ntimonide or silicon photodiode, source of pumping voltage and clamping device to clamp the diode in a self biased condition, all functioning to amplify an input signal applied to the photodiode.