A method for determining the velocity of a moving fluid surface, which comprises the following steps S1 to S5: S1) taking a sequence of images of the moving fluid surface by at least one camera; S2) comparing a first image from the sequence with a second image from the sequence in order to distinguish moving patterns of the fluid surface from non-moving parts and to obtain a first processed image (im_1f) comprising the moving patterns; S3) comparing a third image from the sequence with a fourth image from the sequence in order to distinguish moving patterns of the fluid surface from non-moving parts and to obtain a second processed image (im_2f) comprising the moving patterns; S4) comparing the first and second processed images in order to determine the spatial displacements of the moving patterns; and S5) determining from the spatial displacements the velocity.

An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes.

An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes.

A method includes: receiving, from a plurality of sensors, detection signals indicative of fluid flow, the fluid flow having a direction and a speed, the plurality of sensors having respective mutual positions and distances between pairs of sensors in the plurality of sensors; determining, as a function of the detection signals, a first detection sensor in the plurality of sensors detecting the fluid flow prior to other sensors in the plurality of sensors; determining time delays between detection of the fluid flow by a first sensor and by a second sensor in each pair of sensors in the plurality of sensors; and determining a fluid flow velocity vector indicative of the direction and the speed of the fluid flow as a function of the mutual positions and distances between the pairs of sensors in the plurality of sensors and the time delays.

The present invention provides an online measuring method of particle (such as bubbles, droplets and solid particles) velocity in multiphase reactor. The method based on an online multiphase measuring instrument includes the following steps: (1) the online multiphase measuring instrument is placed into the multiphase reactor, and then a particle image produced by two or more exposures are obtained; (2) the actual size of individual pixel in the particle image is determined; (3) valid particles are determined in the depth of field; (4) then the centroid coordinates are conversed to the actual length of the coordinates (x.sub.t,i, y.sub.t,i) and (x.sub.t+t,i, y.sub.t+t,i) using the actual size of individual pixel. Thus, the instantaneous velocity of particles can be calculated by $V_i=\sqrt{\frac{{\left(x_{t+t,i}-x_{t,i}\right)}^2+{(y_{t+t,i}}^{}}{}}$

The present invention provides an online measuring method of particle (such as bubbles, droplets and solid particles) velocity in multiphase reactor. The method based on an online multiphase measuring instrument includes the following steps: (1) the online multiphase measuring instrument is placed into the multiphase reactor, and then a particle image produced by two or more exposures are obtained; (2) the actual size of individual pixel in the particle image is determined; (3) valid particles are determined in the depth of field; (4) then the centroid coordinates are conversed to the actual length of the coordinates (x.sub.t,i, y.sub.t,i) and (x.sub.t+t,i, y.sub.t+t,i) using the actual size of individual pixel. Thus, the instantaneous velocity of particles can be calculated by $V_i=\sqrt{\frac{{\left(x_{t+t,i}-x_{t,i}\right)}^2+{(y_{t+t,i}}^{}}{}}$

There is provided a speckle measurement apparatus to improve accuracy of flow velocity measurement or the like of particulates such as erythrocytes, the speckle measurement apparatus including an imager that captures scattered light images returned from an object to be measured when the object to be measured is irradiated with coherent light as speckle images, and a controller that determines a measurement area that is the same site of the object to be measured in a plurality of the speckle images captured continuously in time series by the imager by incorporating a displacement amount of a relative positional relationship between the object to be measured and the imager.

There is provided a speckle measurement apparatus to improve accuracy of flow velocity measurement or the like of particulates such as erythrocytes, the speckle measurement apparatus including an imager that captures scattered light images returned from an object to be measured when the object to be measured is irradiated with coherent light as speckle images, and a controller that determines a measurement area that is the same site of the object to be measured in a plurality of the speckle images captured continuously in time series by the imager by incorporating a displacement amount of a relative positional relationship between the object to be measured and the imager.

Techniques are provided for determining a moving body's position and velocity in the presence of motion of a measuring device relative to the body. For example, a swimmer's position and velocity may be determined by compensating for bias that may result from a swimmer's arm swing. This may help avoid over-estimating a swimmer's velocity that results in inaccurate position estimation along the swimmer's path. To compensate for the swimmer's arm swing, an estimate of translational velocity due to arm rotation may be removed, e.g., from pseudo-range rates (PRRs) from satellite positioning system measurements, to reduce the systematic bias errors. A scale factor is applied to an estimated velocity of the swimmer's body to estimate the velocity of a mobile device on the swimmer's wrist, e.g., while above water.

Techniques are provided for determining a moving body's position and velocity in the presence of motion of a measuring device relative to the body. For example, a swimmer's position and velocity may be determined by compensating for bias that may result from a swimmer's arm swing. This may help avoid over-estimating a swimmer's velocity that results in inaccurate position estimation along the swimmer's path. To compensate for the swimmer's arm swing, an estimate of translational velocity due to arm rotation may be removed, e.g., from pseudo-range rates (PRRs) from satellite positioning system measurements, to reduce the systematic bias errors. A scale factor is applied to an estimated velocity of the swimmer's body to estimate the velocity of a mobile device on the swimmer's wrist, e.g., while above water.