219results about How to "Speckle reduction" patented technology

In accordance with the invention, a low coherence interferometer is used to non-invasively monitor the concentration of glucose in blood by shining a light over a surface area of human or animal tissue, continuously scanning the light over a two dimensional area of the surface, collecting the reflected light from within the tissue and constructively interfering this reflected light with light reflected along a reference path to scan the tissue in depth. Since the reflection spectrum is sensitive to glucose concentration at particular wavelengths, measurement and analysis of the reflected light provides a measure of the level of glucose in the blood. The measurement of glucose is taken from multiple depths within blood-profused tissue, and sensitivity is preferably enhanced by the use of multiple wavelengths. Noise or speckle associated with this technique is minimized by continuously scanning the illuminated tissue in area and depth.

A laser imaging system with reduced speckle is disclosed. The laser imaging system includes spatially superpositioned 1-D arrays or alternatively 2-D arrays of independent emitters of laser radiation, with each emitter having a spectral bandwidth Δλ_i centered at some arbitrary wavelength λ_0i. The elements of the array are allowed, by design, to have a slightly different central wavelength, thereby creating an ensemble bandwidth ΔΛ which is much greater than the bandwidth Δλ_i of any individual emitter in the array. The resulting increased bandwidth reduces speckle in a displayed image.

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.

A display system for providing a user viewable visible image, includes a view screen for receiving organic laser light and having a diffusing optical element so that the view screen, in response to organic laser light, produces a viewable visible image, wherein the diffusing optical element includes a viewing angle greater than 160° in a first viewing direction and greater than 100° in a second viewing direction orthogonal to the first direction; one or more organic laser light sources arranged in an array with each such laser light source including a vertical cavity design and means for projecting and modulating the intensity of the organic laser light from the array onto the view screen in a pattern to cause a visual image to be produced by the view screen; and means associated with the view screen for reducing speckle in the organic laser light.

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.

The present invention relates to non-contact optical scanning of an object for generation of a three-dimensional surface model of the scanned object. In particular the invention relates to a scanner for obtaining the three-dimensional geometry of at least a part of the surface of an object, said scanner comprising: —at least one light source, preferably a laser light source with adjustable power, —projection means for directing light from the at least one light source to a moving spot on the surface of the object, —at least one image sensor adapted to record at least one image of at least a part of the surface, —detection means, other than the at least one image sensor, for monitoring at least a part of the light reflected from the surface, —regulation means for adjusting the intensity of the at least one light source based on the amount of light reflected from the surface, and—means for transforming the at least one image to a three-dimensional model of the surface.

The invention discloses a double-color laser light source which comprises a blue laser and a red laser which emit blue laser light and red laser light respectively; and a fluorescent wheel, the surface of which is coated with green fluorescent powders, wherein the green fluorescent powders emit green fluorescence when excited by the blue laser light. The double-color laser light source also comprises a speckle dissipation system. The speckle dissipation system comprises a first diffusion portion which is controlled to rotate, is arranged in a beam shaping optical path of the blue laser light and red laser light and is used for diffusing the blue laser light and the red laser light; and a second diffusion portion which is controlled to rotate, is arranged before a blue laser light, red laser light and green fluorescence incident light bar, and is used for at least penetrating the blue laser light and the red laser light sequentially and forming blue light and red light output. The double-color laser light source can effectively reduce speckle effect and improve display quality of projected images.

An ultrasound diagnosis apparatus of the present invention has: an image generator configured to execute transmission/reception of ultrasound waves to chronologically generate ultrasound image data of plural frames; a multiresolution decomposition part configured to hierarchically perform multiresolution decomposition on the ultrasound image data to acquire first-order to n^th-order (n represents a natural number of 2 or more) low-band decomposition image data and first-order to n^th-order high-band decomposition image data; a feature amount calculator configured to calculate a feature amount based on the acquired low-band decomposition image data; a filtering processor configured to perform a filtering operation on the calculated feature amount; and a multiresolution composition part configured to execute multiresolution composition using the low-band decomposition image data and high-band decomposition image data to generate a composite image. Thus, the apparatus can efficiently reduce change in speckle/noise in the temporal direction and perform a process without a time phase delay.

X-ray mammography has been the standard for breast cancer screening for three decades, but offers poor statistical reliability; it also requires a radiologist for interpretation, employs ionizing radiation, and is expensive. The combination of multiple independent tests, performed effectively at the same time and co-registered, can produce substantially more reliable detection performance than that of the individual tests. The multi-sensor approach offers greatly improved reliability for detection of early breast tumors, with few false positives, and also can be designed to support machine decision, thus enabling screening by general practitioners and clinicians; it avoids ionizing radiation, and can ultimately be relatively inexpensive.

An optical system (100) comprises a coherent light source (101) and optical elements for directing light from the source to a target (1001). The optical elements include at least one diffusing element (141, 161) arranged to reduce a coherence volume of light from the source and a variable optical property element (151). A control system (1021) controls the variable optical property element such that different speckle patterns are formed over time at the target (1001) with a temporal frequency greater than a temporal resolution of an illumination sensor or an eye (1011) of an observer so that speckle contrast ratio in the observed illumination is reduced. The variable optical property element (151) may be a deformable mirror with a vibrating thin plate or film.

For displaying a color image by recombination of several single color images, parasitic noise like speckles due to scattering within the system, in particular when laser light is involved, with the invention a significant improvement with a low number of parts can be realized by use of a color wheel that comprises in radially divided zones refractive elements for redirecting light beams incoming at different impinging angles and redistributing elements, e.g. a hologram, that provide for a defined output beam in an optical axis. The sequence of the individual light processing zones on the color wheel are synchronized with respective laser sources. The invention combines the functionality of plural elements, reduces speckles and avoids losses.

Methods and devices for producing cavitation in tissue are provided. In one embodiment, a low-frequency ultrasound pulse is transmitted into tissue, a high-frequency ultrasound pulse is transmitted into tissue, and a composite waveform is formed in the tissue that has a peak negative pressure value that exceeds an intrinsic threshold for cavitation in the tissue. In some embodiments, the peak negative pressures of the individual ultrasound pulses do not exceed the intrinsic threshold for cavitation. In another embodiment, a plurality of ultrasound pulses at various resonant frequencies are transmitted into tissue, and the time delays between these transmissions are adjusted to allow the ultrasound pulses to align temporally and form a monopolar pulse having a compound peak negative pressure that exceeds an intrinsic threshold for cavitation in the tissue. Systems for performing Histotripsy therapy are also discussed.

A method for detecting the positioning of an entity, comprising the steps of (a) using a projector, which comprises a laser and a MEMS micro mirror arranged to receive light from the laser and which can oscillate about at least one oscillation axis, to project light towards the entity to project an image which is composed of pixels onto the entity, wherein the image has a first density of pixels; (b) changing the density of pixels in the projected image; (c) sensing at least a portion of light of the projected image which is reflected from the entity; and (d) using the sensed portion of light to determine the position of the entity. There is also provided a corresponding device for detecting position. There is also provided a method and device for determining distance which involves using the sensed portion of light to determine the distance between the entity and projector.

An illumination apparatus forms, onto a linear array light modulator, a line of illumination that extends in a linear direction. The illumination apparatus has a first laser array with laser emitters for forming a first linear beam array and a second laser array with laser emitters for forming a second linear beam array. An array combiner aligns at least the first and second linear beam arrays in the linear direction and directs the first and second linear beam arrays along a propagation path to form a mixed illumination. At least first and second cylindrical lens elements having power in the linear direction relay the mixed illumination from the propagation path toward the linear array light modulator. At least third and fourth cylindrical lens elements having power in the cross-array direction that is orthogonal to the linear direction focus the mixed illumination onto the linear array light modulator.

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.

An optical signal generator is configured with an associated control system and driver configured to reduce speckle. Speckle reduction occurs by pulsing the drive signal between a first current level and a second current level. These pulses force the optical signal generator to introduce oscillations into the optical signal. The coherence of the emitted light is reduced during the period of oscillations in the optical signal, which reduces speckle. In one embodiment, the pulsing of the drive signal brings the drive signal down to a level near or below threshold, which in turn intermittently turns off the optical signal output. Returning the optical signal to a desired optical output intensity introduces the speckle reducing oscillation. The pulse frequency, and duty cycle is controlled by a duty cycle control signal to modulate overall optical power and adjust amount of despeckle.