36 results about "Wavefront analysis" patented technology

A method and apparatus for identifying tissue structures in advance of a mechanical medical instrument during a medical procedure. A mechanical tissue penetrating medical instrument (22) has a distal end for penetrating tissue in a penetrating direction. An optical wavefront analysis system (32-50) provides light to illuminate tissue ahead of the medical instrument and receives light returned by tissue ahead of the medical instrument. An optical fiber (30) is coupled at a proximal end to the wavefront analysis system and attached at a distal end to the medical instrument proximate the distal end of the medical instrument. The distal end of the fiber has an illumination pattern directed substantially in the penetrating direction for illuminating the tissue ahead of the medical instrument and receiving light returned therefrom. The wavefront analysis system provides information about the distance from the distal end of the medical instrument to tissue features ahead of the medical instrument.

A method for enhancing vision of an eye includes a laser delivery system having a laser beam for ablating corneal material from the cornea of the eye. Measurements are made to determine an optical path difference between a plane wave and a wavefront emanating from the retina of the eye for a location at a surface of the cornea. An optical correction is provided to the laser delivery system for the location based on the optical path difference and refractive indices of media through which the wavefront passes. The optical correction includes dividing the optical path difference by a difference between an index of refraction of corneal material and an index of refraction of air. The laser beam is directed to the location on the surface of the cornea and corneal material ablated at the location in response to the optical correction to cause the wavefront to approximate the shape of the plane wave at that location.

Methods and apparatus to perform wavefront analysis, including phase and amplitude information, and 3D measurements in optical systems, and in particular those based on analyzing the output of an intermediate plane, such as an image plane, of an optical system. Measurement of surface topography in the presence of thin film coatings, or of the individual layers of a multilayered structure is described. Multi-wavelength analysis in combination with phase and amplitude mapping is utilized. Methods of improving phase and surface topography measurements by wavefront propagation and refocusing, using virtual wavefront propagation based on solutions of Maxwell's equations are described. Reduction of coherence noise in optical imaging systems is achieved by such phase manipulation methods, or by methods utilizing a combination of wideband and coherent sources. The methods are applied to Integrated Circuit inspection, to improve overlay measurement techniques, by improving contrast or by 3-D imaging, in single shot imaging. Data supplied from the esp@cenet database—Worldwide

Method and systems are presented for analysing a wavefront using a spectral wavefront analyser to extract optical phase and spectral information at a two dimensional array of sampling points across the wavefront, wherein the relative phase information between the sampling points is maintained. Methods and systems are also presented for measuring an eye by reflecting a wavefront of an eye and measuring the wavefront at a plurality of angles to provide a map of the off-axis relative wavefront curvature and aberration of the eye. The phase accuracy between wavelengths and sample points over a beam aperture offered by these methods and systems have a number of ocular applications including corneal and anterior eye tomography, high resolution retinal imaging, and wavefront analysis as a function of probe beam incident angle for determining myopia progression and for designing and testing lenses for correcting myopia.

The invention relates to a method for producing high-geometric precision elements made from a neutral material. Using different types of prosthetic restoration, said elements are intended to fill the damage caused in teeth by dental caries or tissue alteration having other causes. The inventive elements are also intended to be used to produce high-precision dental crowns or other related dental devices. The method is characterised in that: a model (10), which is designed to fill the missing dental tissue that has been destroyed, is made either in vivo, updating and defining a new volume (2) that is bordered by healthy tissue and having a tapered wall, or in vitro, taking an impression in the mouth of a dental preparation using an impression compound, said impression then being cast in plaster, and updating and defining a new volume (2) using said positive plaster model; the measurements of said model (10) are then taken in 3D using a three-dimensional measuring apparatus (4, 15, 17) with light wavefront analysis and volume analysis which is carried out using shots, a projector (15) being positioned at an angle to a camera (17) and said projector (15) and camera (17) being mechanically and geometrically linked to a revolving platform (18) that is used to support the model by means of a frame (19) in order to obtain good triangulation; the data are processed electronically (12) to remodel the morsels of volume; the files are subsequently modified electronically to determine exactly the desired profile; and the final element to be implanted is machined with a digitally-controlled machine (6, 23, 24, 22).

Systems for performing combined phoropter and refractive measurements to ascertain the aberrations present in the eye of a subject. The systems use a pair of phoropter wheel assemblies, one for each eye, each assembly comprising a number of lens wheels incorporating the series of lenses and wedges required to compensate for a range of refractive vision aberrations. The vision of each eye is corrected by a combination of a subjective phoropter measurement, iteratively performed with an objective wavefront analysis measurement to determine the residual aberrations existing after the initial phoropter correction. The system is able to automatically align the axes of each wavefront analyzer with is corresponding eye, by means of centering the pupil image in the wavefront analyzer camera, and to determine the pupil distance. By changing the focusing point on the wavefront analyzer of the light refleeted from the eye, the corneal profile can be measured.

The invention provides a method and device for detecting a wave plate surface phase delay amount, and the method and the device are used for detecting a phase delay amount of each point on the surfaceof a wave plate to be detected. The method comprises a step of generating a plane light wave by using a ZYGO interferometer, a step of processing the plane light wave into a linearly polarized lightwave, adjusting a beam diameter to obtain a polarized light wave of a limited light wave aperture and irradiating the polarized light wave of the limited light wave aperture to the wave plate to be detected, wherein the wave plate to be detected comprises a first surface and a second surface, and a step of adjusting the positions of the ZYGO interferometer and the wave plate to be detected such that a reflected light spot of the first surface and a reflected light spot of the plane light wave coincide, adjusting the positions of the ZYGO interferometer and the wave plate to be detected such that a reflected light spot of the second surface and the reflected light spot of the plane light wave coincide, and calculating the phase delay amount of each point in the first surface and the secondsurface of the wave plate to be detected. According to the method and device, the three-dimensional detection of a large-aperture wave plate surface phase delay amount is achieved, and a basis is provided for the wavefront analysis and compensation of a wide beam optical detection system using the wave plate.

One aspect of the invention relates to a method for measuring the optical quality of a given region (13) of a glazing unit (10) of a road or rail vehicle, which region is intended to be positioned in the optical path of an image acquisition device, the measuring method being implemented by a measuring device (40) comprising an emitter (41) and a wavefront analyzer, the measuring method comprising: - a step of emitting, with the emitter (41), a beam of light rays in the direction of said given region (13), - a step of analyzing, with the wavefront analyzer, the wavefront of the light rays transmitted by said given region (13), comprising: - a sub-step of generating a wavefront error map, - a sub-step of determining, on the basis of the wavefront error map, at least one optical defect map, of any optical defects present in said region (13) of the glazing (10).