Embodiments of the present application are directed toward a focusing Schlieren technique that is capable of adding color-coded directional information to the visualization of density gradients. Other advantages of the technique can include that it does not require manual calibration, has a simple design and is sensitive enough to be used in compact experimental setups. Certain embodiments include the use of a color-coded source image that replaces the conventional source grid. The technique may benefit from a computer-controlled digital background, which is used for both illumination and display of color-coded source images.

An optical test apparatus includes a light convergence element, an optical filter, and an image sensor. The light convergence element converges light from a subject. The optical filter is arranged on an optical axis of the light convergence element. The image sensor is arranged in an effective region not crossing the optical axis of the light convergence element, and receives light passing through the light convergence element and the optical filter.

According to one embodiment, an optical test apparatus includes a first aperture, a second aperture, an image sensor, and a first lens. The first aperture includes a first aperture plane provided with a first wavelength selecting region. The second aperture includes a second aperture plane provided with a second wavelength selecting region different from the first wavelength selecting region. The image sensor is configured to image a light beam passing through the first aperture plane and the second aperture plane and reaching an imaging plane. The first lens is configured to make a light beam passing through the first aperture plane and the second aperture plane be incident on the imaging plane.

A method is provided for detecting primary gas flows (18) in flow chambers (10). The primary gas (18) flowing in a flow chamber (10) is locally seeded with a seed substance and the movement of the seed substance, representative of the flow of the primary gas (18), is detected by imaging by an image detector (28) and an imaging optics (30) arranged in front of said image detector (28). A gas mixture (34) that moves along with the primary gas (18) without relative motion and that has a refractive index distinguishable from that of the primary gas (18) is used as the seed substance, and imaging detection is carried out by a background schlieren measurement method.

A phase gradient calculation unit calculates a phase gradient on a plane intersecting an irradiation direction of light corresponding to an optical coherence tomography signal indicating a state of a sample for each of sample points arranged on the plane. A bulk phase error calculation unit integrates, for each of plurality of paths from an origin that is a sample point where a bulk phase error is determined to a destination that is a sample point where the bulk phase error is not determined, the phase gradient for each of the sample points along each of the plurality of corresponding paths to calculate a path specific phase error at the destination, and combines the path specific phase errors among the plurality of corresponding paths to determine the bulk phase error at the destination.

According to one embodiment, an optical test apparatus includes a first aperture, a second aperture, an image sensor, and a first lens. The first aperture includes a first aperture plane provided with a first wavelength selecting region. The second aperture includes a second aperture plane provided with a second wavelength selecting region different from the first wavelength selecting region. The image sensor is configured to image a light beam passing through the first aperture plane and the second aperture plane and reaching an imaging plane. The first lens is configured to make a light beam passing through the first aperture plane and the second aperture plane be incident on the imaging plane.

A system for visualizing one or more bubbles formed by a catheter, the system includes a fluid container, a pulse generator, a schlieren imaging assembly, and a processor. The fluid container is configured to: (i) contain a fluid, and (ii) receive into the fluid the catheter having one or more electrodes. The pulse generator is configured to apply one or more pulses to at least one of the electrodes. The schlieren imaging assembly is configured to acquire schlieren images of the bubbles occurring in the fluid when applying the one or more pulses, and the processor is configured to visualize the bubbles using the schlieren images.

According to the embodiment, a processing apparatus includes an arithmetic section. The arithmetic section is configured to calculate a refractive index distribution forming a light beam path based on an estimated output calculated by inputting light beam data indicating the light beam path to an estimation model, an updated output calculated based on the light beam data and the estimated output, and an evaluation index of the estimation model calculated from a ray equation independent of a time which the light beam path follows.

A system includes a light source, a first lens, a second lens, a third lens, a beam splitter, a first image collection device, and a second image collection device. The first lens is configured to collimate a light beam and to direct the collimated light beam through a test sample. The beam splitter is configured to split the light beam from the test sample and to transmit a first portion of the light beam toward the second lens and reflect a second portion of the light beam toward the third lens. The first image collection device is positioned adjacent to a first obstruction and configured to record an obstructed first image formed by the first portion of the light beam. The second image collection device is positioned adjacent to a second obstruction and configured to record an obstructed second image formed by the second portion of the light beam.

A method of analyzing a spray generated by a spray device for spraying pharmaceutical fluid, including providing a spray head of a spray device for spraying pharmaceutical fluid, the spray head including a spray orifice; causing a test fluid to pass through the spray head towards the spray orifice, the test fluid being air at a temperature that is different from ambient temperature; displaying, by strioscopy, the flow of test fluid leaving the spray orifice; and analyzing the display of the test-fluid flow so as to determine whether or not the test-fluid spray coming from the spray head complies with predetermined specifications. The cycle time for analyzing one spray head is less than 1.5 seconds, advantageously less than 1 second.