Catheter systems and methods for determining blood flow rates based on light reflection measurements. The catheter may include a lumen extending between a proximal end of the catheter and a distal end of the catheter. The catheter may include fluid infusion openings at the distal end region of the catheter that are configured to permit the indicator fluid to exit the catheter from the lumen. The catheter system may include an optical fiber having one or more sensors thereon for sensing light reflected by blood particles in a body vessel lumen. A blood flow rate may be determined based on the sensed light reflected by blood particles in the body vessel lumen.

The present disclosure relates to methods for determining a liquid front position of a liquid on a surface of an assay test strip placing a liquid on the surface of the test strip; and acquiring one or more signals from the surface of the test strip at one or more times, comparing the one or more acquired signals to a threshold, wherein the liquid front position is a position on the surface of the test strip where a signal is greater than or less than a threshold (e.g., fixed or dynamic threshold). Such methods may be used to determine the liquid front velocity of a liquid on a surface of an assay test strip and the transit time of a liquid sample to traverse the one or more positions on the surface of the assay test strip.

The present disclosure relates to methods for determining a liquid front position of a liquid on a surface of an assay test strip placing a liquid on the surface of the test strip; and acquiring one or more signals from the surface of the test strip at one or more times, comparing the one or more acquired signals to a threshold, wherein the liquid front position is a position on the surface of the test strip where a signal is greater than or less than a threshold (e.g., fixed or dynamic threshold). Such methods may be used to determine the liquid front velocity of a liquid on a surface of an assay test strip and the transit time of a liquid sample to traverse the one or more positions on the surface of the assay test strip.

First to N-th (N is an integer of three or more) sensor elements each including a light source unit and a light reception unit are arranged around a tube that allows a fluid containing scatterers to flow at equiangular intervals, and coherent light which is emitted from the light source unit of any one sensor element of the first to N-th sensor elements and is transmitted through the fluid flowing through the tube is received by the light reception unit of another predetermined sensor element of the first to N-th sensor elements. At this time, when a distance between the light source unit and the light reception unit of any one sensor element is d and an outer radius of the tube is r, a distance between any one sensor element and another predetermined sensor element is set to πd/2 or more and √3r or less.

An apparatus for measuring fluid speed by using the refraction of light is disclosed. The apparatus includes: a channel in which a passage is formed to allow the flow of a fluid; a first and a second light source that are located in any one region of an upper part and a lower part of the channel; a sensor installed in an opposite region of the region where the first and second light sources are located with respect to the channel, to receive the light emitted from the first and second light sources; a speed calculation unit configured to calculate a speed of the fluid by using the intensity of the light received at the sensor.

An apparatus for measuring fluid speed by using the refraction of light is disclosed. The apparatus includes: a channel in which a passage is formed to allow the flow of a fluid; a first and a second light source that are located in any one region of an upper part and a lower part of the channel; a sensor installed in an opposite region of the region where the first and second light sources are located with respect to the channel, to receive the light emitted from the first and second light sources; a speed calculation unit that calculates the speed of the fluid by using a time point at which the intensity of the light received at the sensor changes; and an adjustment unit that is connected to the channel and configured to adjust the flow speed of the fluid based on the calculated speed of the fluid.

The present invention provides an immersion-type online multiphase measuring instrument and method. The instrument comprises a package tube; a viewport; LED lamps and a brightness-adjustable light source system including a power supply, a signal generator and an oscilloscope; a telecentric lens and an image sensor; a controller; a signal processing and outputting system; and a display system. The LED lamps, the telecentric lens and the image sensor are located in the package tube. The exposure period of the image sensor is less than the pulse period of the signal generator. The photographic probe used in this measuring instrument has the advantages of online quantitative measurement, small size, portability, less-impact of fluid temperature and the surrounding environment, adaptability to transparent and opaque reactors with two-phase, three-phase and more than three-phase. It can capture the high contrast images of local fluid flow in multiphase reactor. And then the local characteristics such as concentration, particle size and velocity distribution of bubble, liquid droplets or solid particles can be obtained using corresponding measuring method and professional image processing software.

The invention relates to a method for measuring a flow velocity (v) of a gas stream (14) featuring the steps: (a) time-resolved measurement of an IR radiation parameter (E) of IR radiation of the gas stream (14) at a first measurement point (P1) outside of the gas stream (14), thereby obtaining a first IR radiation parameter curve (E.sub.g1,1(t)), (b)time-resolved measurement of an IR radiation parameter (E) at a second measurement point (P2) outside of the gas stream (14), thereby obtaining a second IR radiation parameter curve (E.sub.g1,2(t)), (c) calculation of a transit time (τ1) from the first IR radiation parameter curve (E.sub.g1,1(t)) and the second IR radiation parameter curve (E.sub.g1,2(t)), in particular by means of cross-correlation, and (d) calculation of the flow velocity (vG) from the transit time (τ1), (e) wherein the IR radiation parameter (E.sub.g1) is measured photoelectrically at a wavelength (g1) of at least 780 nm, and (f) a measurement frequency (f) is at least 1 kilohertz.

A processor analyzes an image obtained by imaging a subject including a tubular structure in which a fluid flows, thereby deriving fluid information regarding flow of the fluid at each of pixel positions in the tubular structure. The processor derives, within the tubular structure included in the image, a matching degree between the fluid information at a plurality of pixel-of-interest positions set at a first sampling interval and the fluid information at a plurality of pixel positions within a predetermined region based on the pixel-of-interest positions. The processor sets a second sampling interval for displaying the fluid information in accordance with the matching degree. The processor samples the fluid information at the set second sampling interval and causes a display to display the fluid information.

A processor analyzes an image obtained by imaging a subject including a tubular structure in which a fluid flows, thereby deriving fluid information regarding flow of the fluid at each of pixel positions in the tubular structure. The processor derives, within the tubular structure included in the image, a matching degree between the fluid information at a plurality of pixel-of-interest positions set at a first sampling interval and the fluid information at a plurality of pixel positions within a predetermined region based on the pixel-of-interest positions. The processor sets a second sampling interval for displaying the fluid information in accordance with the matching degree. The processor samples the fluid information at the set second sampling interval and causes a display to display the fluid information.