A flow velocity determining apparatus (10) includes an irradiating unit (20) that emits irradiation light (L1) toward a liquid mixture (BL) which contains a non-spherical solid (BC) and a liquid (BP) and flows through a flow path (TB), a detecting unit (30) that detects reflected light (L2) emitted by the irradiating unit (20) and reflected by the liquid mixture (BL) flowing through the flow path (TB), the detecting unit (32) being disposed on at least one side of an optical axis (L2A) of the reflected light (L2) when seen in a plan view of an imaginary plane including an optical axis (L1A) of the irradiation light (L1) and the optical axis (L2A) of the reflected light (L2), and a determining unit (40) that determines a flow velocity of the liquid mixture (BL) by using a light amount of the reflected light (L2) detected by the detecting unit (32).

A froth bubble moving speed measuring device includes a light source configured to illuminate an upper surface of a flotation tank, an imaging unit configured to capture at least a part of the upper surface of the flotation tank, and an arithmetic processing unit configured to calculate a moving speed of a froth bubble by calculating a moving distance of the froth bubble based on the image processed by the image processing unit.

A froth bubble moving speed measuring device includes a light source configured to illuminate an upper surface of a flotation tank, an imaging unit configured to capture at least a part of the upper surface of the flotation tank, and an arithmetic processing unit configured to calculate a moving speed of a froth bubble by calculating a moving distance of the froth bubble based on the image processed by the image processing unit.

A method includes irradiating a target droplet in an extreme ultraviolet light source of an extreme ultraviolet lithography tool with light from a droplet illumination module. Light reflected and/or scattered by the target droplet is detected. Particle image velocimetry is performed to monitor one or more flow parameters inside the extreme ultraviolet light source.

Systems and methods are provided for making in-situ measurements of the sea bed 3 component fluid velocity field and sediment motion across a range of real ocean conditions using particle image velocimetry (PIV). A PIV system in accordance with an embodiment of the present disclosure can include a camera to capture images of the particles in motion, a laser to generate a laser sheet for illuminating the particles, and a synchronizer to act as an external trigger for the laser and the camera.

Systems and methods are provided for making in-situ measurements of the sea bed 3 component fluid velocity field and sediment motion across a range of real ocean conditions using particle image velocimetry (PIV). A PIV system in accordance with an embodiment of the present disclosure can include a camera to capture images of the particles in motion, a laser to generate a laser sheet for illuminating the particles, and a synchronizer to act as an external trigger for the laser and the camera.

A portable electronic device is operable in a particulate matter concentration mode where the portable electronic device uses a self-mixing interferometry sensor to emit a beam of coherent light from an optical resonant cavity, receive a reflection or backscatter of the beam into the optical resonant cavity, produce a self-mixing signal resulting from a reflection or backscatter of the beam of coherent light, and determine a particle velocity and/or particulate matter concentration using the self-mixing signal. The portable electronic device is also operable in an absolute distance mode where the portable electronic device determines whether or not an absolute distance determined using the self-mixing signal is outside or within a particulate sensing volume associated with the beam of coherent light. If not, the portable electronic device may determine a contamination and/or obstruction is present that may result in inaccurate particle velocity and/or particulate matter concentration determination.

A method for tracking moving particles in a fluid. The method includes illuminating the moving particles with an illumination sequence of patterns generated by a light projector; measuring with a single camera light intensities reflected by the moving particles; calculating, based on the measured light intensity, digital coordinates (x′, y′, z′) of the moving particles; determining a mapping function f that maps the digital coordinates (x′, y′, z′) of the moving particles to physical coordinates (x, y, z) of the moving particles; and calculating the physical coordinates (x, y, z) of the moving particles based on the mapping function f. The illumination sequence of patterns is generated with a single wavelength, and light emitted by the projector is perpendicular to light received by the single camera.

There is provided a scattered light signal measurement apparatus and an information processing apparatus that are capable of performing accurate measurement while preventing noise due to changes in relative velocity and relative position caused between a sensor and an observation target. The scattered light signal measurement apparatus includes a light receiving element and an incident angle limiting unit. The light receiving element receives scattered light obtained when coherent light emitted to a measurement target is scattered by the measurement target. The incident angle limiting unit limits an incident angle of the scattered light that is incident on a single point of the light receiving element to be equal to or smaller than a predetermined angle and controls the single light receiving element to increase an aperture ratio.

A method includes irradiating a target droplet in an extreme ultraviolet light source of an extreme ultraviolet lithography tool with light from a droplet illumination module. Light reflected and/or scattered by the target droplet is detected. Particle image velocimetry is performed to monitor one or more flow parameters inside the extreme ultraviolet light source.