661 results about "Wavefront sensor" patented technology

A new way of mixing instrumental and digital means is described for the general field of wave front sensing. The present invention describes the use, the definition and the utility of digital operators, called digital wave front operators (DWFO) or digital lenses (DL), specifically designed for the digital processing of wave fronts defined in amplitude and phase. DWFO are of particular interest for correcting undesired wave front deformations induced by instrumental defects or experimental errors. DWFO may be defined using a mathematical model, e.g. a polynomial function, which involves coefficients. The present invention describes automated and semi-automated procedures for calibrating or adjusting the values of these coefficients. These procedures are based on the fitting of mathematical models on reference data extracted from specific regions of a wave front called reference areas, which are characterized by the fact that specimen contributions are a priori known in reference areas. For example, reference areas can be defined in regions where flat surfaces of a specimen produce a constant phase function. The present invention describes also how DWFO can be defined by extracting reference data along one-dimensional (1D) profiles. DWFO can also be defined in order to obtain a flattened representation of non-flat area of a specimen. Several DWFO or DL can be combined, possibly in addition with procedures for calculating numerically the propagation of wave fronts. A DWFO may also be defined experimentally, e.g. by calibration procedures using reference specimens. A method for generating a DWFO by filtering in the Fourier plane is also described. All wave front sensing techniques may benefit from the present invention. The case of a wave front sensor based on digital holography, e.g. a digital holographic microscope (DHM), is described in more details. The use of DWFO improves the performance, in particular speed and precision, and the ease of use of instruments for wave front sensing. The use of DWFO results in instrumental simplifications, costs reductions, and enlarged the field of applications. The present invention defines a new technique for imaging and metrology with a large field of applications in material and life sciences, for research and industrial applications.

An improved ophthalmic instrument for in-vivo examination of a human eye including a wavefront sensor that estimates aberrations in reflections of the light formed as an image on the retina of the human eye and a phase compensator that spatially modulates the phase of incident light to compensate for the aberrations estimated by the wavefront sensor Optical elements create an image of a fixation target at the phase compensator, which produces a compensated image of the fixation target that compensates for aberrations estimated by the wavefront sensor. The compensated image of the fixation target produced by the phase compensator is recreated at the human eye to thereby provide the human eye with a view of compensation of the aberrations the human eye as estimated by the wavefront sensor. The phase compensator preferably comprises a variable focus lens that compensates for focusing errors and a deformable mirror that compensates for higher order aberrations. The optical elements preferably comprise a plurality of beam splitters and a plurality of lens groups each functioning as an afocal telescope. In addition, instruments and systems are provided that exploit these capabilities to enable efficient prescription and / or dispensing of corrective optics (e.g., contact lens and glasses).

A system for mapping a three-dimensional structure includes a projecting optical system adapted to project light onto an object, a correction system adapted to compensate the light for at least one aberration in the object, an imaging system adapted to collect light scattered by the object and a wavefront sensor adapted to receive the light collected by the imaging system and to sense a wavefront of the received light. For highly aberrated structures, a number of wavefront measurements are made which are valid over different portions of the structure, and the valid wavefront data is stitched together to yield a characterization of the total structure.

An ophthalmic instrument (for obtaining high resolution, wide field of area multi-spectral retinal images) including a fundus retinal imager, (which includes optics for illuminating and imaging the retina of the eye); apparatus for generating a reference beam coupled to the fundus optics to form a reference area on the retina; a wavefront sensor optically coupled to the fundus optics for measuring the wavefront produced by optical aberrations within the eye and the imager optics; wavefront compensation optics coupled to the fundus optics for correcting large, low order aberrations in the wavefront; a high resolution detector optically coupled to the imager optics and the wavefront compensation optics; and a computer (which is connected to the wavefront sensor, the wavefront compensation optics, and the high resolution camera) including an algorithm for correcting, small, high order aberrations on the wavefront and residual low order aberrations.

Example embodiments include a dynamic wavefront sensor, a controllable wavefront offsetting element and a controller that controls the controllable wavefront offsetting element to offset selected non-plane wave aberration components in order to allow remaining non-plane wave aberration components to be more efficiently detected and measured.

An iris imaging system used for biometric identification provides a combined iris imager and wavefront sensor. The detector array allows for independent readout of different regions, such that a wavefront sensor region can be read out fast while allowing signal to integrate on the iris imaging region. Alternatively, the entire array may be used for wavefront sensing during an acquisition phase, and then at least a portion of the array may be switched to be used for iris imaging during a subsequent imaging phase. An optical periscope optionally allows various optics to be inserted in front of the combined iris imager and wavefront sensor. In another embodiment, the glint image of an on-axis or near on-axis illumination source is picked off at the image plane and directed to the wavefront sensor optics, while allowing all of the light from the iris field to pass through to the iris imaging camera.