221results about How to "Speckle reduction" patented technology

A system and a method for creating a stable and reproducible interface of an optical sensor system for measuring blood glucose levels in biological tissue include a dual wedge prism sensor attached to a disposable optic that comprises a focusing lens and an optical window. The disposable optic adheres to the skin to allow a patient to take multiple readings or scans at the same location. The disposable optic includes a Petzval surface placed flush against the skin to maintain the focal point of the optical beam on the surface of the skin. Additionally, the integrity of the sensor signal is maximized by varying the rotation rates of the dual wedge prisms over time in relation to the depth scan rate of the sensor. Optimally, a medium may be injected between the disposable and the skin to match the respective refractive indices and optimize the signal collection of the sensor.

A method and apparatus for reducing speckle uses polarization averaging. A polarizing beam splitter divides a first polarized laser output into a second polarized laser output and a third polarized laser output. A plurality of mirrors creates an optical path difference between the second and third polarized laser outputs. The optical path difference is at least about a coherence length for the first polarized laser output. The second and third polarized laser outputs are combined into a fourth laser output, which illuminates a depolarizing screen. If a human eye or an optical system having a intensity detector views the depolarizing screen, the eye or the intensity detector will detect reduced speckle, which results from uncorrelated speckle patterns created by the second polarized laser output and the third polarized laser output. A first alternative embodiment of the invention functions without the optical path difference being at least about the coherence length. In the first alternative embodiment, a piezoelectric transducer varies an optical path length by at least about a half wavelength of the first polarized laser output. By varying the optical path length by a sufficient frequency, the eye or the intensity detector will detect the reduced speckle. A second alternative embodiment combines two orthogonally polarized laser outputs, from two lasers, into a combined laser output. The combined laser output illuminates the depolarizing screen. A third alternative embodiment rotates the first laser output with a rotation frequency to form a rotating polarized laser output, which illuminates the depolarizing screen.

A method and system for reducing speckle in an image produced from a coherent source of radiation is provided. The method includes coupling a source beam received from a coherent optical source into an optical fiber. A position of at least a portion of the fiber may be modulated using a ditherer. The source beam may be refracted by a lens after it is decoupled from the optical fiber, such that the source beam is aimed at a microlens diffuser. In accordance with a particular embodiment, the source beam may be projected from the microlens diffuser onto a spatial modulator. The spatial modulator may be positioned to project the source beam via an imaging lens, to a target.

A method and apparatus for reducing speckle due to MSL, without any loss of resolution, by averaging over different angles of the incident light at low input resolution, while collecting the backscattered light at a full resolution of a lens is described. The present invention allows discrimination against the speckle due to coherent MSL.

A method and apparatus that reduces laser speckle by using stimulated Raman scattering in an optical fiber. The pulse repetition frequency of the laser is adjusted to control aspects of the laser light such as color or despeckling. In DLP projection systems, an optical monitor may be used to send information to a bit sequence, and the bit sequence may control the pulse repetition frequency of the laser based on the optical monitor signal.

A laser projector having a configurable spatial light modulator (SLM) adapted to display various spatial modulation patterns and redirect illumination from a laser to form an image on the viewing screen. The laser projector drives the SLM to change spatial modulation patterns at a rate that causes the corresponding sequence of projected images to fuse to mitigate appearance of speckle in the resulting fused image. The SLM can be designed to redirect the illumination using either diffraction or specular reflection of light from the displayed spatial modulation pattern. In one embodiment, the SLM is a MEMS device having an array of individually addressable mirrors supported over a substrate and adapted to move (e.g., translate and / or rotate) with respect to the substrate.

Speckle, a factor reducing image quality in optical coherence tomography (“OCT”), can limit the ability to identify cellular structures that are important for the diagnosis of a variety of diseases. Exemplary embodiments of the present invention can facilitate an implementation of an angular compounding, angular compounding by path length encoding (“ACPE”) for reducing speckle in OCT images. By averaging images obtained at different incident angles, with each image encoded by path length, ACPE maintains high-speed image acquisition and implements minimal modifications to OCT probe optics. ACPE images obtained from tissue phantoms and human skin in vivo demonstrate a qualitative improvement over traditional OCT and an increased signal-to-noise ratio (“SNR”). Accordingly, exemplary embodiments of an apparatus probe catheter and method can be provided for irradiating a sample. In particular, an interferometer may forward forwarding an electromagnetic radiation. In addition, a sample arm may receive the electromagnetic radiation, and can include an arrangement which facilitates a production of at least two radiations from the electromagnetic radiation so as to irradiate the sample. Such exemplary arrangement can be configured to delay a first radiation of the at least two radiations with respect to a second radiation of the at least two radiations.

The invention relates to a laser-based light source comprising a laser device (1) adapted for generating laser light of a predetermined laser wavelength and emitting this laser light as a laser beam; a light-conversion device (2) for converting at least part of the laser light into converted light; a laser-output sensor (7) for determining a laser-output signal proportional to the output of laser light emitted by the laser device (1); a converted-light sensor (6) for determining a converted-light signal proportional to the output of converted light emitted by the light-conversion device (7); and a controller (9) which is adapted for receiving the laser-output signal and the converted-light signal, for determining a safe-to-operate parameter, based on the laser-output signal and the converted-light signal, and for controlling the operation of the laser-based light source, based on a comparison of the safe-to-operate parameter with a at least one predefined threshold. In this way, a laser-based light source is proposed which enables reliable eye-safety in an easy way.

A method and system for reducing speckle in an image produced from a coherent source of radiation is provided. The method includes coupling a source beam received from a coherent optical source into an optical fiber. A position of at least a portion of the fiber may be modulated using a ditherer. The source beam may be refracted by a lens after it is decoupled from the optical fiber, such that the source beam is aimed at a microlens diffuser. In accordance with a particular embodiment, the source beam may be projected from the microlens diffuser onto a spatial modulator. The spatial modulator may be positioned to project the source beam via an imaging lens, to a target.

An external cavity laser may be swept rapidly in frequency and cavity length to prevent formation of modes providing improved spectral response and light characteristics.

We describe a holographic image projector, comprising: a laser light source to provide light at a laser wavelength; a first spatial light modulator (SLM) to display a hologram, wherein said first SLM is illuminated by said laser light source; intermediate image optics to provide a first intermediate real image plane at which a real image produced by said hologram displayed on said first SLM is formed; a wavelength-conversion material located at said first intermediate real image plane to convert said laser wavelength to at least a first output wavelength different to said laser wavelength; and second optics to project light from said real image at said output wavelength to provide a displayed image.

A laser projector having a configurable spatial light modulator (SLM) adapted to display various spatial modulation patterns and redirect illumination from a laser to form an image on the viewing screen. The laser projector drives the SLM to change spatial modulation patterns at a rate that causes the corresponding sequence of projected images to fuse to mitigate appearance of speckle in the resulting fused image. The SLM can be designed to redirect the illumination using either diffraction or specular reflection of light from the displayed spatial modulation pattern. In one embodiment, the SLM is a MEMS device having an array of individually addressable mirrors supported over a substrate and adapted to move (e.g., translate and / or rotate) with respect to the substrate.

A projection display surface for reducing speckle artifacts from a projector having at least one narrow band light source having an incident visible wavelength band, wherein the incident visible wavelength band has an incident peak wavelength and an incident bandwidth, comprising: a substrate having a reflective layer that reflects incident light over at least the incident visible wavelength band; and a fluorescent agent distributed over the reflective layer, wherein the fluorescent agent absorbs a fraction of the light in the incident visible wavelength band and emits light in an emissive visible wavelength band having an emissive peak wavelength and an emissive bandwidth; wherein return light from the projection display surface produced when incident light in the incident visible wavelength band is incident on the projection display surface contains light in both the incident visible wavelength band and emissive visible wavelength band, thereby reducing speckle artifacts.

A rear projection screen which includes a front lenticular surface, a diffusion region behind the lenticular surface, a non-diffusion region behind the diffusion region, and a rear phase grating surface, when used with high magnification projection systems, exhibits reduced speckle when compared to other rear projection screen without such a grating.