2762results about "Optical measurements" patented technology

A motor may be configured to drive a drive shaft and an engagement member supported on the drive shaft. A detectable feature comprising a rotary member may be supported on the drive shaft such that movement of the drive shaft by the motor changes a state of the detectable feature. At least one sensor may be arranged to detect the state of the detectable feature. Circuitry may be configured to provide a signal in response to a change in the state of the detectable feature detected by the at least one sensor.

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.

Wavefront measuring systems and methods are disclosed which may be employed, for example, in detecting phase aberrations in a spectacle lens and in an eye. Various embodiments include disposing a modulation pattern in the path of a return beam from the spectacle lens or the eye, and imaging a diffraction pattern at a self-imaging plane relative to the modulation pattern with a detector. The diffraction pattern is analyzed and the results are used to produce a representation of the wavefront phase characteristics that describe aberrations in the lens or eye being measured. Illumination and processing techniques for improving the measurement results are dislcosed. Various embodiments comprise systems adaptable to both measure aberrations in lenses in spectacles as well as in a patient's eyes.

A non-invasive emitter-photodiode sensor which is able to provide a data-stream corresponding to the actual wavelength of light emitted thereby allowing calibration of the sensor signal processing equipment and resulting in accurate measurements over a wider variation in emitter wavelength ranges.

Preferred embodiments of the present invention are directed to systems for phase measurement which address the problem of phase noise using combinations of a number of strategies including, but not limited to, common-path interferometry, phase referencing, active stabilization and differential measurement. Embodiment are directed to optical devices for imaging small biological objects with light. These embodiments can be applied to the fields of, for example, cellular physiology and neuroscience. These preferred embodiments are based on principles of phase measurements and imaging technologies. The scientific motivation for using phase measurements and imaging technologies is derived from, for example, cellular biology at the sub-micron level which can include, without limitation, imaging origins of dysplasia, cellular communication, neuronal transmission and implementation of the genetic code. The structure and dynamics of sub-cellular constituents cannot be currently studied in their native state using the existing methods and technologies including, for example, x-ray and neutron scattering. In contrast, light based techniques with nanometer resolution enable the cellular machinery to be studied in its native state. Thus, preferred embodiments of the present invention include systems based on principles of interferometry and / or phase measurements and are used to study cellular physiology. These systems include principles of low coherence interferometry (LCI) using optical interferometers to measure phase, or light scattering spectroscopy (LSS) wherein interference within the cellular components themselves is used, or in the alternative the principles of LCI and LSS can be combined to result in systems of the present invention.

A method of and apparatus for improving vision and the resolution of retinal images is described in which a point source produced on the retina of a living eye by a laser beam is reflected from the retina and received at a lenslet array of a Hartmann-Shack wavefront sensor such that each of the lenslets in the lenslet array forms an aerial image of the retinal point source on a CCD camera located adjacent to the lenslet array. The output signal from the CCD camera is acquired by a computer which processes the signal and produces a correction signal which may be used to control a compensating optical or wavefront compensation device such as a deformable mirror. It may also be used to fabricate a contact lens or intraocular lens, or to guide a surgical procedure to correct the aberrations of the eye. Any of these methods could correct aberrations beyond defocus and astigmatism, allowing improved vision and improved imaging of the inside of the eye.

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.

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 chip-size wavelength detector includes a film with laterally varying transmission properties and a position-sensitive detector. The film transmits a different wavelength as a function of lateral position across the film. The position of a spot of light transmitted through the film will shift, depending on the wavelength of the light. The shift is measured by the position-sensitive detector.

An angle absolute encoder comprises an encoded code rod that has code marks, such as pairs of fine code lines and coarse code lines. Light is reflected from or transmitted through the code marks and detected by a light detector to determine absolute angle position.