657 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.

Example embodiments of a large dynamic range sequential wavefront sensor for vision correction or assessment procedures are disclosed. An example embodiment optically relays a wavefront from an eye pupil or corneal plane to a wavefront sampling plane in such a manner that somewhere in the relaying process, the wavefront beam from the eye within a large eye diopter range is made to reside within a desired physical dimension over a certain axial distance range in a wavefront image space and/or a Fourier transform space. As a result, a wavefront beam shifting device can be disposed there to fully intercept and hence shift the whole beam to transversely shift the relayed wavefront.

A free-space adaptive optical laser communication system having signal transmission and reception channels at all terminals in the communication system, wherein wavefront sensing (WFS) and wavefront correction mechanisms are employed along signal transmission and reception channels of all terminals in the communication system (i.e. adaptive optics) to improve the condition of the laser beam at the receiver (i.e. reduce the size of the spot a the detector plane). in the illustrative embodiment, the WFS mechanisms employ a novel WFS control process, in which active updating of reference positions and subaperture locations on the wavefront sensor. These WFS mechanism can be used in diverse application environments, including but not limited to FSO laser communication systems.

In one embodiment, an apparatus for optimizing vision correction procedures comprising: a narrow beam of light directed to a patient's retina; a dynamic defocus and compensation offsetting device configured to offset the defocus of a wavefront from an eye, a wavefront sensor configured to measure the local tilt of a number of subwavefronts sampled around an annular ring (the diameter of which can be dynamically changed) over the wavefront with the defocus offset; and a display device configured to display a two dimensional (2D) data points pattern in real time with each data point location representing a corresponding local tilt of the sampled subwavefronts. A proper defocus offset, not passive compensation, can reveal the predominant feature(s) of other wavefront aberration component(s), thus enabling a refractive surgeon to fine tune the vision correction procedure and minimize the remaining wavefront aberration(s) in real time. Meanwhile, by sampling the wavefront around annular rings and displaying the local tilt of the sampled subwavefronts on a monitor in the form of a 2D data points pattern, a refractive ophthalmic surgeon can easily correlate the measurement result to the two major refractive errors, namely spherical and cylinder refractive errors, including the axis of astigmatism.

A sequential wavefront sensor comprises a light beam scanning module, a sub-wavefront focusing lens, a detector with more than one photosensitive area and a processor for calculating the sequentially obtained centroids of a number focused light spots from the sub-wavefronts to determine the aberration of the input wavefront. A sequential wavefront sensing method comprises the steps of; sequentially projecting a number of sub-wavefronts onto a sub-wavefront focusing lens and a detector with more than one photosensitive areas, calculating the centroid of the focused light spot from each sub-wavefront, and processing the centroid information to determine the aberration of the wavefront. In particular, a method for auto-focusing and/or auto-astigmatism-correction comprises the steps of sequentially projecting a number of sub-wavefronts around an annular ring of a wavefront to a sub-wavefront focusing lens and a detector, calculating the centroid of focused light spot from each sub-wavefront to figure out the centroid trace and hence the defocus and/or astigmatism, adjusting the focus and/or astigmatism of the optical imaging system before the wavefront sensor so that the measured defocus and/or astigmatism is minimized.

A modular fundus camera including an adaptive optical module that detachably interfaces to a fundus camera body and image capture subsystem. The fundus camera body directs light produced from a first light source into the human eye and that collects and collimates retinal reflections. The adaptive optical module includes a wavefront sensor, controller and phase-compensating optical element. The wavefront sensor measures phase aberrations in the retinal reflections and operates in a closed-loop fashion with the controller to control the phase-compensating optical element to compensate for such phase aberrations to produce phase-compensated retinal reflections for output to the image capture subsystem.

The multi-target tracking and discrimination system (MOST) fuses with and augments existing BMDS sensor systems. Integrated devices include early warning radars, X-band radars, Lidar, DSP, and MOST which coordinates all the data received from all sources through a command center and deploys the GBI for successful interception of an object detected anywhere in space, for example, warheads. The MOST system integrates the optics for rapid detection and with the optical sensor array delivers high-speed, high accuracy positional information to radar systems and also identifies decoys. MOST incorporates space situational awareness, aero-optics, adaptive optics, and Lidar technologies. The components include telescopes or other optical systems, focal plane arrays including high-speed wavefront sensors or other focal plane detector arrays, wavefront sensor technology developed to mitigate aero-optic effects, distributed network of optical sensors, high-accuracy positional metrics, data fusion, and tracking mounts. Field applications include space monitoring, battlefield artillery, battlefield management, ground defense, air defense, space protection, missile defense, gunfire detection, and the like.

An improved ophthalmic instrument including an extended source producing light that is formed as an image on the retina of the human eye and reflected there from to produce retinal reflections derived from the extended source, and a wavefront sensor that estimates aberrations in the retinal reflections. The wavefront sensor includes a plurality of subapertures that form a plurality of images of the extended source from the retinal reflections, an imaging device that captures the plurality of images and outputs image data representing the images, and an image processing computer that generates an estimate of the gradient field of the retinal reflections by applying image correlation techniques in the digital domain to the image data. The image processing computer preferably generates an estimate of the local tilt of the retinal reflections incident on a given subaperture by deriving a correlation product for a given image formed by the given subaperture and identifying a peak correlation point of the correlation product. The dimensions of the image of the extended source formed on the retina of the human eye is preferably larger that a diffraction limited spot yet small enough so that different parts of the image do not experience substantially different aberrations while passing through the eye. In addition, the angular size of the image of the extended source is preferably limited so that the plurality of images formed by the subapertures do not overlap.

An enhanced resolution scanned image of an object is produced by a scanning laser microscope which includes an illumination arm for scanning an object with a focused probe beam and a detection arm for receiving light from the object. The detection arm includes a detector which collects and detects light from the object to produce pixel data for a plurality of pixels. In addition, the detection arm includes a wavefront sensor for sensing phase variations of the light from the object to produce wavefront data for scanned pixel locations. From the wavefront shape of the collected light at each pixel location, a high frequency spectrum is determined which corresponds to uncollected scattered light from small scale features of that pixel location. An enhanced resolution image of a region of interest is produced based on the high frequency spectra of the scanned pixel locations.

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 improved, adaptive optics control system having a signal-to-noise ratio-tuned wavefront corrector is disclosed. The system comprises a wavefront corrector, a wavefront sensor, a wavefront reconstructor and a wavefront controller. The wavefront corrector has a surface controlled by a plurality of actuators. The wavefront slope sensor has a subaperture separation mechanism for defining a plurality of subapertures through which the distorted wavefront can pass, each subaperture corresponding to an actuator of the wavefront corrector. The wavefront slope sensor produces a wavefront sensor output signal for each subaperture indicative of the distortion of the wavefront. The wavefront reconstructor is adapted to receive the wavefront sensor output signals and calculate corresponding phase estimates based thereon, each phase estimate having a signal-to-noise ratio. The wavefront reconstructor generates a plurality of correction signals to be applied to each of the actuators of the wavefront corrector, each correction signal having a bandwidth. The wavefront controller is adapted to selectively adjust the bandwidth of each correction signal based on the signal-to-noise ratio of the corresponding phase estimate of the actuator to which it is to be applied. A method of optical wavefront distortion correction is also disclosed.

Devices, systems, and methods that facilitate optical analysis, particularly for the diagnosis and treatment of refractive errors of the eye. An optical diagnostic method for an eye includes obtaining a sequence of aberration measurements of the eye, identifying an outlier aberration measurement of the sequence of aberration measurements, and excluding the outlier aberration measurement from the sequence of aberration measurements to produce a qualified sequence of aberration measurements. The sequence of aberrations measurements can be obtained by using a wavefront sensor. An optical correction for the eye can be formulated in response to the qualified sequence of aberration measurements.

Plural electronic or optical images are provided in a streak optical system, as for instance by use of plural slits instead of the conventional single slit, to obtain a third, fourth, etc. dimension—rather than only the conventional two, namely range or time and azimuth. Such additional dimension or dimensions are thereby incorporated into the optical information that is to be streaked and thereby time resolved. The added dimensions may take any of an extremely broad range of forms, including wave-length, polarization state, or one or more spatial dimensions—or indeed virtually any optical parameter that can be impressed upon a probe beam. Resulting capabilities remarkably include several new forms of lidar spectroscopy, fluorescence analysis, polarimetry, spectropolarimetry, and combinations of these, as well as a gigahertz wavefront sensor.

A system and method for providing a wavefront corrected high-energy beam of electromagnetic energy. In the illustrative embodiment, the system includes a source of a first beam of electromagnetic energy; an amplifier for amplifying said beam to provide a second beam; a sensor for sensing aberration in said second beam and providing an error signal in response thereto; a processor for processing said error signal and providing a correction signal in response thereto; and a spatial light modulator responsive to said correction signal for adjusting said beam to facilitate a correction of said aberration thereof. In more specific embodiments, the source is a laser and the sensor is a laser wavefront sensor. A mirror is disposed between said modulator and said sensor for sampling said beam. The mirror has an optical thin-film dielectric coating on at least one optical surface thereof. The coating is effective to sample said beam and transmit a low power sample thereof to said means for sensing aberration. The processor is an adaptive optics processor. The spatial light modulator may be a micro electro-mechanical system deformable mirror or an optical phased array. In the illustrative embodiment, the source is a master oscillator and the amplifier is a power amplifier beamline. An outcoupler is disposed between the oscillator and the amplifier.

The invention relates to a wavefront measuring method based on a Hartmann wavefront sensor. According to the method, light spot array images detected by an array type photoelectric detector in the Hartmann wavefront sensor are used for obtaining the intensity distribution information of each light spot and the mass center position offset relative to the calibration time, the inclination aberration information of a sub wavefront in the corresponding sub aperture can be obtained according to the mass center offset, the high order aberration information of defocusing, astigmatism and the like ofthe sub wavefront in the corresponding sub aperture can be obtained by a phase inversion algorithm according to the intensity distribution information of the light spot, the inclination aberration information and the high order aberration information are combined to form sub wavefronts, and finally, all sub wavefronts are reconstructed by a wavefront reconstruction method or a wave surface split joint method for forming the whole aperture wavefront information. The method has the advantages that the light spot dispersion distribution information which originally puzzles the light spot mass center calculation is utilized, more information quantity of the sub wavefronts in the sub aperture is obtained, the wavefront detection precision of the Hartmann wavefront sensor is favorably improved,or the requirement on the aperture number is favorably reduced.