Disclosed herein are systems, methods, and devices for calibrating contrast measurements from laser speckle imaging systems to accurately determine unknown particle motion characteristics, such as flow rate. The calibration stores to memory calibration data, which may include a set of measurements from samples with known particle characteristics and/or estimates of noise, including the effects on contrast arising from undesired signals unrelated to the unknown particle motion characteristics. The calibration data may be accessed and used to correct an empirical measurement of contrast and/or interpolate a value of the unknown particle motion characteristic. The system may include a light source, photodetector, processor, and memory, which can be combined into a single device, such as a wearable device, for providing calibrated flow measurements. The device may be used, for example, to measure blood flow, cardiac output, and heart rate, and can be used to amplify the pulsatile signal.

A method and a system for photoacoustic inspection of a part are provided herein. The method may include the following steps: photo-acoustically exciting a predetermined position in a predetermined region on a part by pulsed laser illumination, to yield ultrasonic excitation of the part; coherently illuminating a predetermined location in the predetermined region on the part; detecting an illumination scattered from the predetermined location; determining, based on the scattered illumination, a plurality of sequence of two or more temporally-sequential de-focused speckle pattern images, wherein each of the sequences corresponds to one of the predetermined illuminated locations; and determining a set of translations, each determined based on the sequences, wherein each translation in the set is determined based on two temporally-sequential speckle patterns images in the respective sequence.

A digital speckle pattern interferometer (DSPI) is provided for long-range measurement of displacement of materials within a hazardous environments. A test arm of a portion of coherent beam from a laser is aimed at a selected angle to traverse a distance to a test surface. An input collimator has a lens wide enough to receive a reflected beam from the test surface and is focused at a corresponding distance. The reflected beam is combined with a reference beam split from the coherent radiation onto a camera for measuring displacement of the test surface based on an electronic speckle pattern interferometer (ESPI).

Translations of an object in a plurality of different spatial directions are measured using a plurality of interferometers to detect interference with light that has been reflected from a diffusively reflective surface, preferably using diffuse reflection from the same planar surface to measure in each of the different spatial directions. At least the interferometers that measure translation in directions that are not perpendicular to the surface each comprises a single mode fiber and a collimator configured to transmit the outgoing light to the object successively through the single mode fiber and the collimator, and to collect reflection into the single mode fiber with the collimator both along a same beam direction. It has been found that, when reflection of a beam with a beam direction at an oblique angle to a diffusively reflective surface is used, the interference resulting from translation of the object is due substantially only to translation in the beam direction.

In at least one embodiment, the optoelectronic semiconductor device comprises a carrier, a first semiconductor laser configured to emit a first laser radiation and applied on the carrier, and a multi-mode waveguide configured to guide the first laser radiation and also applied on the carrier, wherein the multi-mode waveguide comprises at least one furcation and a plurality of branches connected by the at least one furcation.

A method for measuring the surface topography of an object including the following steps: a) providing source radiation and dividing the source radiation into illumination radiation and reference radiation, b) illuminating the surface of the object with illumination radiation in a planar illumination field, the surface of the object being illuminated simultaneously with more than one spatial radiation mode and the radiation modes of the illumination being spatially and temporally coherent, but with a fixed phase difference from one another, and c) overlaying the reference radiation on illumination radiation back-scattered at the surface of the object, and detecting an interference signal of the overlaid radiation with a detector. Steps a) to c) are carried out for at least two different, fixed wavelengths. The surface topography of the object is determined by means of digital holography.

The present disclosure relates to systems and devices configured to determine the distance to objects within a field of view. Namely, at least a portion of the field of view may be illuminated with a coherent light source. Due to interactions between the laser light, the transmission medium, and the object, characteristic laser speckle patterns may be formed. These characteristic laser speckle patterns may be imaged with a camera. Using statistical image analysis, an estimated distance to the objects within the field of view may be obtained. For example, the image frame may be partitioned into a plurality of image segments. An autocorrelation for each image segment of the plurality of image segments may be obtained. A depth map may be obtained based on the autocorrelations.

Translations of an object in a plurality of different spatial directions are measured using a plurality of interferometers to detect interference with light that has been reflected from a diffusively reflective surface, preferably using diffuse reflection from the same planar surface to measure in each of the different spatial directions. At least the interferometers that measure translation in directions that are not perpendicular to the surface each comprises a single mode fiber and a collimator configured to transmit the outgoing light to the object successively through the single mode fiber and the collimator, and to collect reflection into the single mode fiber with the collimator both along a same beam direction. It has been found that, when reflection of a beam with a beam direction at an oblique angle to a diffusively reflective surface is used, the interference resulting from translation of the object is due substantially only to translation in the beam direction.

A defect detection device 10 is provided with: a laser light source 11 for irradiating laser light to a measurement region R of a surface of an inspection object S; a laser light source control unit 15 for controlling the laser light source so as to cause laser light to be outputted continuously or quasi-continuously for a time longer than a period of vibration generated in the inspection object; an interferometer (speckle shearing interferometer 14) for generating interference light in which reflected light of the laser light reflected in the measurement region and reference laser light emitted from the laser light source 11 interfere; a detector (image sensor 145) for detecting the intensity of the interference light for each point in the measurement region R; a phase shifter 143 for shifting the phase of the reflected laser light or the reference laser light; an integrated intensity pattern determination unit 16 for obtaining an integrated intensity obtained by integrating the intensity for each point over an integration time longer the period of the vibration in three or more phases, the phase being shifted by the phase shifter 143 into three or more different phases; an interference degree distribution generation unit 17 for obtaining the distribution of the degree of interference based on the integrated intensity obtained in each of the three or more phases for each point; and a defect detection unit 18 for detecting a defect in the measurement region R based on the distribution of the degree of interference in the measurement region R.

A digital speckle pattern interferometer (DSPI) is provided for long-range measurement of displacement of materials within a hazardous environments. A test arm of a portion of coherent beam from a laser is aimed at a selected angle to traverse a distance to a test surface. An input collimator has a lens wide enough to receive a reflected beam from the test surface and is focused at a corresponding distance. The reflected beam is combined with a reference beam split from the coherent radiation onto a camera for measuring displacement of the test surface based on an electronic speckle pattern interferometer (ESPI).