784 results about "Speckle pattern" patented technology

New devices and methods are provided for noninvasive and noncontact real-time measurements of tissue blood velocity. The invention uses a digital imaging device such as a detector array that allows independent intensity measurements at each pixel to capture images of laser speckle patterns on any surfaces, such as tissue surfaces. The laser speckle is generated by illuminating the surface of interest with an expanded beam from a laser source such as a laser diode or a HeNe laser as long as the detector can detect that particular laser radiation. Digitized speckle images are analyzed using new algorithms for tissue optics and blood optics employing multiple scattering analysis and laser Doppler velocimetry analysis. The resultant two-dimensional images can be displayed on a color monitor and superimposed on images of the tissues.

A high-speed three-dimensional imaging system includes a single lens camera subsystem with an active imaging element and CCD element, and a correlation processing subsystem. The active imaging element can be a rotating aperture which allows adjustable non-equilateral spacing between defocused images to achieve greater depth of field and higher sub-pixel displacement accuracy. A speckle pattern is projected onto an object and images of the resulting pattern are acquired from multiple angles. The images are locally cross-correlated using a sparse array image correlation technique and the surface is resolved by using relative camera position information to calculate the three-dimensional coordinates of each locally correlated region. Increased resolution and accuracy are provided by recursively correlating the images down to the level of individual points of light and using the Gaussian nature of the projected speckle pattern to determine subpixel displacement between images. Processing is done at very high-speeds by compressing the images before they are correlated. Correlation errors are eliminated during processing by a technique based on the multiplication of correlation table elements from one or more adjacent regions.

An image projecting device and method are presented. The device comprises a light source system, a spatial light modulator (SLM) unit, and an image projection optics accommodated at the output side of the SLM unit. The SLM unit may be reflective or transmissive. The SLM unit comprises an SLM pixel arrangement enclosed between two glass substrates. The pixel array arrangement is formed by a pixel array assembly and at least one microlens assembly. The microlens assembly includes at least one microlens array accommodated proximate of the pixel array assembly. The light source system may comprise n light sources and a light converting means in optical path of light generated by the n light sources, to thereby produce m light beams of different wavelength ranges, wherein m>n. The light source system may comprise a multi-mode laser, thereby reducing a speckle effect in an integrated speckle pattern produced by the multiple modes, as compared to that of a single mode.

System and method for generating patterns P of aiming and treatment light on target eye tissue (e.g. the retina) of a patient's eye. The system includes light sources for treatment and aiming light, a scanner for generating patterns of spots of the generated light, a controller, and a graphic user interface that allows the user to select one of several possible spot patterns, adjust the spot density and / or spot size, and apply patterns with fixed or varied density. The patterns can be formed of interlaced sub-patterns and / or scanned without adjacent spots being consecutively formed to reduce localized heating. Partially or fully enclosed exclusion zones within the patterns protect sensitive target tissue from exposure to the light.

A system and method are presented for use in the object reconstruction. The system comprises an illuminating unit, and an imaging unit (see FIG. 1). The illuminating unit comprises a coherent light source and a generator of a random speckle pattern accommodated in the optical path of illuminating light propagating from the light source towards an object, thereby projecting onto the object a coherent random speckle pattern. The imaging unit is configured for detecting a light response of an illuminated region and generating image data. The image data is indicative of the object with the projected speckles pattern and thus indicative of a shift of the pattern in the image of the object relative to a reference image of said pattern. This enables real-time reconstruction of a three-dimensional map of the object.

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.

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.

The invention relates to a combined three-dimensional digital imaging method of digital speckle projection and phase measuring profilometry. The method comprises the following steps: (1), a random digital speckle pattern is projected onto an object and acquired through two cameras on left and right sides; (2), a sinusoidal fringe pattern is projected onto the object, and a corresponding sinusoidal fringe pattern is acquired; (3), the folded phase value of a coding fringe pattern is calculated; (4), a series of points (Pr1 to Prn) on the right camera corresponding to a point P1 on the left camera are searched according to the folded phase value; (5), the point Pr on the right camera corresponding to the point P1 is fixed in the position of P1 according to the acquired digital speckle pattern; (6), processes of the step (4) and (5) are performed to all points on the left and right cameras, to find all the corresponding point pairs; (7), the corresponding point pairs are re-established into three-dimensional point cloud data. The method has the advantages that the imaging speed is fast, small calculated amount, accurate result, and the method is suitable for the fields of on-line three-dimensional detection and dynamic three-dimensional data acquisition with higher accuracy and speed requirements.

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 high-speed three-dimensional imaging system includes a single lens camera subsystem with an active imaging element and CCD element, and a correlation processing subsystem. The active imaging element can be a rotating aperture which allows adjustable non-equilateral spacing between defocused images to achieve greater depth of field and higher sub-pixel displacement accuracy. A speckle pattern is projected onto an object and images of the resulting pattern are acquired from multiple angles. The images are locally cross-correlated using a sparse array image correlation technique and the surface is resolved by using relative camera position information to calculate the three-dimensional coordinates of each locally correlated region. Increased resolution and accuracy are provided by recursively correlating the images down to the level of individual points of light and using the Gaussian nature of the projected speckle pattern to determine subpixel displacement between images. Processing is done at very high-speeds by compressing the images before they are correlated. Correlation errors are eliminated during processing by a technique based on the multiplication of correlation table elements from one or more adjacent regions.

An apparatus for measuring at least one parameter associated with a fluid flowing within a pipe comprises an optical measurement device and a signal processor. The optical measurement device provides output signals indicative of unsteady pressures within the fluid at two or more axial locations along the pipe in response to light reflected from an outer surface of the pipe. The signal processor provides an output signal indicative of at least one parameter associated with the fluid in response to the output signals. The optical measurement device may include, for example, an electronic speckle pattern interferometer, a Fabry-Perot device, and / or a laser vibrometer. The at least one parameter may include at least one of: density of the fluid, volumetric flow rate of the fluid, mass flow rate of the fluid, composition of the fluid, entrained air in the fluid, consistency of the fluid, size of particles in the fluid, and health of a device causing the unsteady pressures to be generated in the pipe.

A method and system for estimating the volume of blood ejected from a cardiac ventricle or atrium uses ultrasound to track speckle patterns in the heart. The process utilizes the M-mode to estimate volume differences in a view of the ventricle or atrium over time using speckle pattern motion to estimate volume differences between systole and diastole. Alternatively, the ultrasound speckle tracking method may be used in combination with Doppler processing techniques or to obtain temporal flow profiles across flow cross-sectional areas, from which the flow volume is computed. The method can also measure the phase delay of motion of sites on the cardiac wall relative to each other or relative to an ECG signal.

An optical device and methods thereof are described. The device includes a first light source adapted to emit light onto a surface, and a detector adapted to receive light reflected from the surface. The reflected light produces a speckle pattern. The distance between the optical device and the surface can be measured using a quantifiable attribute associated with the speckle pattern.

A fibre optic sensing method and apparatus for determining location and direction information of disturbances occurring in the environment of a sensor optical fibre are provided. The method comprises launching optical pulses into at least one polarisation eigenmode of a polarisation maintaining fibre as the sensor optical fibre, detecting temporal speckle patterns of light backscattered from the at least one polarisation eigenmode of the fibre, comparing the temporal speckle patterns to determine the location and direction information of a disturbance in the environment of the sensor optical fibre. The location information may be a distance along the fibre, and the direction information may be a direction radially from the axis of the fibre. The apparatus or instrument may be used to detect disturbance over long distances such as pipes, pipelines, or wells. Other applications include detecting intruders entering a controlled area.

The invention relates to a system 100 for verifying the authenticity of medicament entitlement tokens, such as prescriptions 102, used to control the dispensing of medicaments. The system comprises a network 104 connecting at least one token provider terminal 106, a system server 120 and a verification terminal 130. The token provider terminal 106 is operable to provide a signature from a speckle pattern derived from a medicament entitlement token that can be stored by the server system 120. The verification terminal 130 can then be operated remotely to recreate the signature in order to verify the authenticity of the medicament entitlement token by comparing it to stored signatures. The system 100 relies upon the intrinsic physical properties of the medicament entitlement token to generate a unique signature for each token that is produced. This makes the medicament entitlement tokens themselves very difficult to forge. Moreover, the signatures transmitted over the network do not need to contain any details relating to the content of the medicament entitlement tokens, such as patient data, hence signature data stored by the system can be made privacy neutral so that even if it were to be intercepted or copied this would not compromise confidentiality.

The invention discloses a laser source comprising a laser device, a fluorescent wheel, a color filter wheel. The fluorescent wheel is excited by laser to emit fluorescence. The laser emitted from the laser device passes through a first diffusion slice before reaching the fluorescent wheel. The first diffusion slice is fixedly arranged. After being combined, the laser and the fluorescence pass through a second diffusion slice before being subjected to color filtering of the color filter wheel. The second diffusion slice is controlled to rotate. The cooperation of the first diffusion slice and the second diffusion slice effectively increases the spatial random phase of the laser, forms multiple independent speckle patterns, effectively weakens a speckle effect, and improves projection image display quality.

In a lens sheet, a lens portion (3) made of activation energy curing resin such as ultraviolet curing resin has a plurality of lens units, the lens portion (3) is disposed on at least one side of a transparent substrate (2) such as plastic sheet, a relaxation layer (1) is disposed between the transparent substrate (2) and the lens portion (3), and the thickness of the relaxation layer (1) is within a range of 1% to 30% of the height (H) of the lens units. The relaxation layer (1) is made of activation energy curing resin and formed integrally with the lens portion (3). The refractive index of the transparent substrate (2) is lower than that of the lens portion (3). The lens units are elongated prisms each having a substantially triangular cross section. The thickness of the relaxation layer is within a range of 1 mum to 10 mum, for example. The prisms have the vertical angle of 50° to 75° and are arranged with a pitch of 10 mum to 150 mum. The lens sheet having the relaxation layer (1) is obtained by providing activation energy curing composition to an area between a lens portion transferring pattern surface of a lens forming mold and one side of the transparent substrate to form a composition layer between the lens forming mold and the transparent substrate, and making the thickness of the composition layer uniform with use of a nip roll disposed so as to confront the other side of said transparent substrate while nip pressure of the nip roll is regulated by pressure regulating means. Due to the relaxation layer (1), the deformation of the surface of the lens portion caused by polymerization shrinkage of the activation energy curing composition is suppressed so as to prevent occurrence of the optical defect in the lens sheet such as spot pattern, glare, etc.

The present invention provides a structured light projection module based on VCSEL array light sources, comprising: a VCSEL array light source including a semiconductor substrate and at least two sets of VCSEL sub-arrays arranged on the semiconductor substrate, wherein the VCSEL sub-arrays consist of VCSEL light sources; and a diffractive optical component comprising: at least two diffractive optical component sub-units corresponding to the VCSEL sub-arrays respectively and used for multiplying the light beams emitted by the light sources of the VCSEL sub-arrays by a certain multiple and then projecting them outward. According to the invention, sparse and dense speckle patterns can be projected into the space to form a variety of structured light patterns and through the matching algorithm featuring the large window prior to small window, both high-precision and high-frame rate depth images can be obtained so that the depth camera using the module can be applied to a variety of applications.

The invention discloses a structured light projection module group, a depth camera and a method for manufacturing the structured light projection module group. The structured light projection module group comprises a light source which comprises multiple child light sources which are arranged into a two-dimensional array and used for transmitting two-dimensional patterned beams corresponding to the two-dimensional array; a lens which receives and converges the two-dimensional patterned beams; and a diffractive optical element which receives the two-dimensional patterned beams which are emergent through convergence of the lens and projects speckle patterned beams, wherein the speckle patterns include multiple image patterns corresponding to the two-dimensional patterns, and the relationshipbetween the adjacent image patterns of multiple image patterns at least includes two relationship of overlapping, adjoining and spacing. The structured light projection module group can project the speckle patterns having high degree of non-correlation.

A method for the elimination of image speckles in a scanning laser projection is suggested, in which a phase hologram is used for dividing the illumination beam of the projector into partial beams. The partial beams are heterodyned again on the image screen within the image element (pixels) to be projected in such a way that differing speckle patterns are formed which average each other out in the eye of the viewer over time and / or space. Thus, a device is provided especially for the laser projection which substantially eliminates or reduces the speckles at the viewer. However, the beam form and the beam density are hardly or not changed.

A method of characterizing the coagulation or sedimentation dynamics of a fluid such as whole blood, a blood fraction, or blood plasma, the method comprising: illuminating a sample of said fluid with a beam of coherent light; acquiring a time series of images of a speckle pattern generated by interaction between said sample and said spatially coherent light beam; and processing said time series of images; wherein said processing step includes calculating a function representative of the variation in said speckle pattern between two or more images of the series. The invention also provides a device for implementing such a method.

A data input device for use with a tracking surface having light-scattering properties. The device comprises a coherent light source for projecting a coherent light beam onto the tracking surface to reflect a speckle pattern. A detector having a field of view detects and images the speckle pattern. The detector operates in a tracking mode when the field of view intersects the coherent light beam. The intersection of the coherent light beam and the field of view comprise a detection zone. Relative movement between the coherent light beam and the tracking surface within the detection zone between is detected in the tracking mode, based on the reflected speckle pattern. Relative movement between the coherent light beam and the tracking surface outside the detection zone is not detected. A controller responsive to the detector operates in the tracking mode for correlating the imaged laser speckle pattern to track the relative movement within the detection zone.

Packaged integrated circuits (ICs) of some types, such as processors, are graded and sold according to a performance scale, such as maximum specified clock speed, set by the manufacturer as a result of testing. As a record of this grading some part of the package, usually the upper surface, is marked with the specified performance attribute. However, criminal activity has developed where the packaging is relabelled to show a higher specification so the ICs can be fraudulently resold at a higher price. To address this problem, the invention envisages that manufacturers maintaining a product database for each packaged IC which logs not only the performance specification, but also a digital signature derived from a speckle pattern obtained from the packaging. Subsequently, any packaged IC can be rescanned to interrogate its speckle pattern and recompute the signature. The signature is then used to find the product in the database, whereby the originally specified performance attribute is retrieved. The fraud is then detectable. This method can be used to test products returned under a warranty claim, for example.

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.

The invention provides a structured light projection module. The projection module comprises a VCSEL array, an irregular pattern generator, a lens and a structured light pattern generator. The VCSEL array comprises vertical cavity surface emitting lasers (VCSELs) which are arranged on a semiconductor substrate in a manner of two-dimensional regular patterns and is used for emitting first light beams with the two-dimensional regular patterns. The irregular pattern generator is used for receiving the first light beams and emitting second light beams with irregular patterns. The lens is used for receiving and gathering the second light beams. The structured light pattern generator is used for receiving the second light beams gathered through the lens and outwards emitting multiple second light beams which are partially mutually overlapped. Compared with the prior art, the regularly arranged VCSEL arrays are used as light sources, irregular patterns are generated through the irregular pattern generator and random structured light speckle patterns are projected, so difficulty level and cost for customization of the VCSEL arrays are reduced.

A system and method are provided for reshaping the surface of a resilient transparent material such as a cornea. In the system, a laser unit generates a femto-second laser beam to deliver focused energy inside the material. Specifically, the energy is focused over a defined spot pattern to weaken the material. Further, the system includes a contact element that forms a contour surface. In order to reshape the material, the system provides for holding the contour surface of the contact element against the surface of the weakened material. After holding the contour surface against the material for a pre-determined time duration, the surface of the material is reshaped with a desired configuration that substantially mimics the contour surface of the contact element.

A data input device for use with an optically rough tracking surface comprising a substantially coherent light source for projecting a substantially coherent light beam onto the tracking surface for scattering the substantially coherent light beam. An optic guides the projected substantially coherent light beam toward the tracking surface and comprises a first boundary facing the substantially coherent light source and a second boundary opposite the first boundary. A detector detects at least a portion of the scattered light beam comprising a speckle pattern. The optic is arranged such that the tracking surface is spaced from the second boundary by a distance sufficient to inhibit any substantial retro-reflection of the substantially coherent light beam striking the second boundary from striking the detector. A controller responsive to the detector operates the device in a tracking mode for utilizing the detected speckle pattern to track relative movement between the device and the tracking surface. The device is particularly useful in handheld and laptop devices, such as personal digital assistants, cellular phones, laptop computers, etc., where it is desirable to interact with a tracking surface comprising human skin, such as a fingertip.

A data input device for use with a tracking surface having light-scattering properties with respect to the device is disclosed. The device comprises a coherent light source for projecting a coherent light beam onto the tracking surface. The tracking surface scatters the coherent light beam striking the tracking surface. The device further comprises a detector associated with the coherent light source for detecting at least a portion of the scattered light. The detected portion of the scattered light comprising a speckle pattern. The device further comprises a controller configured to respond to the detected speckle pattern and operate the device in one of a tracking mode and a non-tracking mode, depending upon a speckle size characteristic of the detected speckle pattern as determined by the controller.