A system for visualizing catheter irrigation, the system includes a fluid container, a pump, a schlieren imaging assembly and a processor. The fluid container is configured to: (i) contain a first fluid, which is at least partially transparent and has a first temperature, and (ii) receive into the first fluid a catheter having one or more irrigation holes. The pump is configured to inject, through the one or more irrigation holes, a second fluid, which is at least partially transparent and has a second different temperature. The schlieren imaging assembly is configured to acquire schlieren images of turbulence occurring in the first fluid when injecting the second fluid, and the processor is configured to visualize the irrigation using the schlieren images.

An optical scanning system including a radiating source that outputs a light beam, a time varying beam reflector that reflects the light beam through a scan lens towards a transparent sample at an incident angle of plus or minus ten degrees from Brewster's angle, a focusing lens configured to be irradiated by light scattered from the transparent sample, and a detector that is irradiated by the light scattered from the transparent sample. The detector outputs a signal that indicates an intensity of light measured by the detector. None of the light scattered from the transparent sample is blocked. The light scattered from the transparent sample is scattered from the top surface of the transparent sample, the bottom surface of the transparent sample, or any location in between the top surface of the transparent sample and the bottom surface of the transparent sample.

An optical scanning system including a radiating source that outputs a light beam, a time varying beam reflector that reflects the light beam through a scan lens towards a transparent sample at an incident angle of plus or minus ten degrees from Brewster's angle, a focusing lens configured to be irradiated by light scattered from the transparent sample, and a detector that is irradiated by the light scattered from the transparent sample. The detector outputs a signal that indicates an intensity of light measured by the detector. None of the light scattered from the transparent sample is blocked. The light scattered from the transparent sample is scattered from the top surface of the transparent sample, the bottom surface of the transparent sample, or any location in between the top surface of the transparent sample and the bottom surface of the transparent sample.

An optical apparatus, which illuminates a first area with light from a light source while the first area is longer in a second direction intersecting a first direction than in the first direction, includes a collector optical member which is arranged in an optical path between the light source and the first area, and condenses the light from the light source to form a second area in a predetermined plane, the second area being longer in a fourth direction intersecting a third direction than in the third direction; and a first fly's eye optical member which is provided within the predetermined plane including the second area, and has a plurality of first optical elements guiding the light of the collector optical member to the first area.

A system for measuring (200) a sample (2) by deflectometry comprising: a source (10) for generating a light beam in a source plane (105); an illumination module (19) for forming an illumination beam (9) comprising: a first converging optical element (18); a first selection optical element (16) with a first aperture (160); reflective matrix optical modulation means (30) to form a pattern (7), said first aperture (160) being configured to control the angles of said illumination beam (9) on said reflective matrix optical modulation means (30); a Schlieren lens (20) for obtaining an angle-intensity encoding of said pattern (7) on the sample (2); imaging (40) and detecting means (50) for detecting an image of said sample (2).

A system for measuring (200) a sample (2) by deflectometry comprising: a source (10) for generating a light beam in a source plane (105); an illumination module (19) for forming an illumination beam (9) comprising: a first converging optical element (18); a first selection optical element (16) with a first aperture (160); reflective matrix optical modulation means (30) to form a pattern (7), said first aperture (160) being configured to control the angles of said illumination beam (9) on said reflective matrix optical modulation means (30); a Schlieren lens (20) for obtaining an angle-intensity encoding of said pattern (7) on the sample (2); imaging (40) and detecting means (50) for detecting an image of said sample (2).

Provided are a Fourier lens, a method for designing a Fourier lens, and a schlieren apparatus. The Fourier lens includes a substrate and a plurality of cuboid waveguides. The plurality of waveguides are arranged on the substrate in parallel and spaced from each other at a preset interval. The material of the substrate and the material of the waveguides are all transparent to the working waveband of the Fourier lens. The preset interval is smaller than a quotient obtained by dividing a center wavelength of the working waveband by the refractive index of the substrate. The waveguide has a plurality of widths, and the waveguides of different widths correspond to different phase delays. The individual waveguides are arranged on the substrate according to phase delays required at different positions. According to the embodiments, the range of the working angle of the Fourier lens can be increased.

Provided are a Fourier lens, a method for designing a Fourier lens, and a schlieren apparatus. The Fourier lens includes a substrate and a plurality of cuboid waveguides. The plurality of waveguides are arranged on the substrate in parallel and spaced from each other at a preset interval. The material of the substrate and the material of the waveguides are all transparent to the working waveband of the Fourier lens. The preset interval is smaller than a quotient obtained by dividing a center wavelength of the working waveband by the refractive index of the substrate. The waveguide has a plurality of widths, and the waveguides of different widths correspond to different phase delays. The individual waveguides are arranged on the substrate according to phase delays required at different positions. According to the embodiments, the range of the working angle of the Fourier lens can be increased.

A digital projection and reflected glare reduction system according to various aspects of the present technology may include a digital display device capable of generating a one or two dimensional source grid pattern back-illuminated by a light source to project an image of a source grid onto a retroreflective background. The projected source grid image may then be re-imaged onto the original grid element at a slight offset eliminating the need to generate a separate cutoff grid thereby reducing the amount of time required to setup and adjust the system. The digital display device is also capable of switching between a schlieren visualization capability to some other visualization capability (such as particle tracking velocimetry (PTV), particle imaging velocimetry (NV), temperature sensitive paint measurements (TSP), pressure sensitive paint measurements (PSP), photogrammetry, etc.) allowing for the simultaneous use of two different imaging techniques.

A digital projection and reflected glare reduction system according to various aspects of the present technology may include a digital display device capable of generating a one or two dimensional source grid pattern back-illuminated by a light source to project an image of a source grid onto a retroreflective background. The projected source grid image may then be re-imaged onto the original grid element at a slight offset eliminating the need to generate a separate cutoff grid thereby reducing the amount of time required to setup and adjust the system. The digital display device is also capable of switching between a schlieren visualization capability to some other visualization capability (such as particle tracking velocimetry (PTV), particle imaging velocimetry (NV), temperature sensitive paint measurements (TSP), pressure sensitive paint measurements (PSP), photogrammetry, etc.) allowing for the simultaneous use of two different imaging techniques.