204 results about "Speckle reduction" patented technology

Despeckle elements, laser beam homogenizers and methods for despeckling are provided. The despeckle element includes a transparent material having a first surface including a plural number of optical steps and a second surface having a plural number of microlenses. Each of the number of optical steps is in a one-to-one correspondence with at least one of the microlenses. One of the first surface and the second surface is configured to receive collimated light having a coherence length and a remaining one of the first surface and the second surface is configured to pass the collimated light separated into a plurality of beamlets corresponding to the number of microlenses. A height of each step of at least two of the optical steps is configured to produce an optical path difference of the collimated light longer than the coherence length.

A method for implementing a speckle reduction filter are described. The method includes receiving a processed data stream from a processor, dividing the processed data stream into data subsets, simultaneously filtering the data subsets by using a speckle reduction filter to produce filtered data subsets, and producing an image data stream based on the filtered data subsets.

A laser projection system is disclosed having reduced apparent speckle. The system includes a laser emitting a first beam on an optical element. The optical element emits a second beam incident on a scanner that scans the beam onto a projection screen. The optical element may be an exit pupil expander, delay plate, or have a locally electrically modulated index of refraction. In other embodiments, the laser has a tunable wavelength distribution that is changed for each frame displayed by the projection system to reduce apparent speckle. In still other embodiments, the angular content of a beam incident on a scanner is modulated to produce a time varying speckle pattern.

The invention relates to techniques for speckle reduction in holographic optical systems, in particular holographic image display systems. We describe a holographic image display system for displaying an image holographically on a display surface, the system including: a spatial light modulator (SLM) to display a hologram; a light source to illuminate said displayed hologram; projection optics to project light from said illuminated displayed hologram onto said display surface to form a holographically generated two-dimensional image, said projection optics being configured to form, at an intermediate image surface, an intermediate two-dimensional image corresponding to said holographically generated image; a diffuser located at said intermediate image surface; and an actuator mechanically coupled to said diffuser to, in operation, move said diffuser to randomise phases over pixels of said intermediate image to reduce speckle in an image displayed by the system.

This invention greatly improves the quality of images obtained using optical systems illuminated by coherent light. It does so by removing the undesirable psuedo-random variations in the final image due to interference speckle and inhomogeneities in the spatial intensity distribution of the light source. A bundle of light-guiding fibers is interposed between the illumination source and the imaging system. Non-uniform propagation within the fiber bundle creates a psuedo-random phase variation across the illumination beam, which gives rise to a dynamic interference speckle pattern superimposed upon the desired image acquired by the optical system. Rotating the fiber bundle around the axis of propagation, whilst simultaneously integrating the output of the photosensitive detector over a period of time, substantially removes variations due to source inhomogeneities and coherent interference.

A projection display including a one-dimensional light modulator includes an optical arrangement for projecting light from a laser onto the modulator in the form of a line of light. Light from the laser is divided to create in effect a two-dimensional array of mutually incoherent light sources. Light from one axis of the array is projected onto the modulator to form the length of the line of light and light from the other axis of the array is projected onto the modulator to form the width of the line of light. Division of the light is accomplished without the use of any moving component.

Disclosed herein are systems and related methods for reducing speckle on display screen. More specifically, screen vibration is used to reduce speckle, and in accordance with the disclosed principles, the vibration may be achieved by using wave-based actuation (e.g., acoustic or electromagnetic waves) to vibrate the screen. In an exemplary embodiment, a speckle reducing system may comprise at least one actuating element located proximate to, but not in physical contact with, a display screen. In addition, the at least one actuating element may be configured to generate waves directed towards the display screen. When the waves impact the display screen, the waves impart vibration to the display screen.

Speckle effect in display system is reduced by utilizing the instability of phase-coherent light and the transmission of the instable phase-coherent light through a multi-mode optical fiber with a suitable length.

An imaging engine includes a plurality of linear imaging arrays, image formation optics, at least one illumination module and supporting circuitry that are embodied within a modular engine housing. The plurality of linear imaging arrays and image formation optics are mounted on an optical bench (which is integral to the engine housing) and provide field of views corresponding to the plurality of linear image arrays. The at least one illumination module produces planar light illumination that substantially overlaps the field of views corresponding to the plurality of linear imaging arrays. The supporting circuitry includes: timing signal generation circuitry that supplies timing signals to the linear imaging arrays in order to read out the row image data produced by such arrays (such row image data may be read out at a constant line rate or at a variable line rate); illumination control circuitry that supplies current to the illumination sources in the at least one illumination module; analog-to-digital conversion circuitry, which optionally filters row data image signal supplied thereto (to remove unwanted noise components) and converts the row image data supplied thereto into digital form; and data buffering circuitry, for storing the digital row image data generated by the analog-to-digital conversion circuitry and communicating the row image data stored therein over a data communication bus. One linear image array (e.g., linear imaging array C) may have a variable line rate that is controlled by the timing signals supplied thereto such that the image capture operations performed by the one linear imaging array (e.g. linear imaging array C) maintain a substantially constant aspect ratio, to thereby compensate for aspect ratio distortions that result from variations in velocity of engine with respect to target object(s). The variable line rate is based upon velocity estimates derived from processing of the pixel data values of other linear imaging arrays disposed therein. The supporting circuitry may optionally include a line rate adjustment module, preferably realized as part of a programmed controller, that is operably coupled to timing signal generation circuitry and adjusts the variable line rate of the one linear image device (e.g., linear imaging array C); output illumination control module, preferably realized as part of the programmed controller, that is operably coupled to the illumination control circuitry and adjusts the optical power level and/or illumination time period for the illumination that overlaps one or more of the FOVs of the linear imaging arrays of the engine for speckle reduction/constant white levels; and/or imaging processing circuitry, operably coupled to the data buffering circuitry over the data communication bus, that realizes portions of image-based mechanisms/techniques for image velocity estimation, aspect ratio compensation, jitter estimation and compensation, bar code detection, OCR, and image lift.

An apparatus adapted for confocal imaging of a non-flat specimen comprising a light source for producing a light beam, imaging optics adapted to focus the light beam into at least one spot on a surface of a specimen, and a detector adapted to receive and detect light reflected from the specimen surface. The light source comprises an optical system for converting a coherent beam into a plurality of beams, each of which is modified by a moving diffuser within a range of movement that is correlated to the detector's integration time.

Certain embodiments include a system and method for improved compound imaging using a plurality of imaging modes. In an embodiment, a plurality of echo signals are received in response to a plurality of beams formed based on different imaging modes corresponding to different steering angles, such as steered or non-steered angles. The plurality of echo signals is compounded to form a compound image. In an embodiment, the imaging mode includes at least one of harmonic, fundamental, coded harmonic, and variable frequency imaging. Parameters may be generated for the plurality of beams formed based on different imaging modes corresponding to different steering angles. Additionally, the parameters may be stored. The echo signals may be filtered. Imaging mode may be controlled based on steering angle. Employing different imaging modes based on steering angles for spatial compound imaging helps reduce grating lobe artifacts while improving speckle reduction effect.

Optical MEMS scanning micro-mirror comprising:—a movable scanning micro-mirror (101) pivotally connected to a MEMS body (102) substantially surrounding the lateral sides of the micro-mirror;—an transparent prism (500, 600) substantially covering the reflection side of the micro-mirror;—wherein said prism has its outer face non-parallel to the micro-mirror neutral plane N-N, thereby providing a dual anti-speckle and anti-reflection effect, namely against parasitic light. The invention also provides the corresponding micro-projection system and method for reducing speckle.

A method and apparatus for reducing speckle during inspection of articles used in the manufacture of semiconductor devices, including wafers, masks, photomasks, and reticles. The coherence of a light beam output by a coherent light source, such as a pulsed laser, is reduced by disposing elements in a light path. Examples of such elements include optical fiber bundles; optical light guides; optical gratings; an integrating sphere; and an acousto-optic modulator. These various elements may be combined as desired, such that light beams output by the element combinations have optical path length differences that are greater than a coherence length of the light beam output by the coherent light source.

The invention discloses a SAR (Synthetic Aperture Radar) image speckle suppression method based on dictionary learning in wavelet domain, which mainly solves the problems that the edge is not clear enough and the homogenous region is not smooth enough in the existing speckle reduction technology. The implementation process of the method comprises the following steps of: firstly, segmenting an original SAR image Y by a variogram method to obtain a smooth mark matrix SY and an edge mark matrix EY; performing N-level stationary wavelet transformation on the original SAR image Y to obtain sub-band images WY(s); modeling for a non-logarithmic additive noise in the WY(s) by zero-mean-value Guassian distribution; using an approximation KSVD (Singular Value Decomposition) algorithm to obtain a learner's dictionary D's and a sparse representative matrix Lambda's of each sub-band image WY(s), obtaining a reconstructed sub-band image according to the D's and the Lambda's, and obtaining an edge region of the sub-band images WY(s) by the edge mark matrix EY, and substituting the edge region in the reconstructed sub-band image to obtain modified sub-band images W'Y(s); performing inverse stationary wavelet transformation on the W'Y(s) to obtain the speckle- reduced image. The method has the advantages that the edge information after speckle reduction is complete and the homogenous region issmooth, and can be used for the pretreatment process of SAR image understanding.

A method for displaying an image including: forming at least three light beams by diffraction at a single linear light modulator, wherein the at least three light beams have substantially equal intensity and are substantially the same color; projecting the at least three light beams toward a display surface to form an image line; and, scanning the image line across the display surface to form an image thereby.

Various embodiments of the present invention relate to a laser driver, and more particularly, to systems, devices and methods of applying low current pulses to a laser modulation current to reduce the speckling noise on the projected images.

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. The present invention allows for 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, apparatus probe catheter, and method are 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 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.

A representative embodiment of the invention provides a projection system having a laser source that incorporates a tunable liquid lens and a spatial light modulator adapted to modulate light generated by the laser source to project an image on a viewing screen. The tunable liquid lens is adapted to vary focal length, alignment or position with respect to an optical element that is external to the lens, ability to diffuse light, and/or polarization rotation angle.