An imaging method and corresponding apparatus according to an embodiment of the present invention enables measurement and visualization of fluid flow. An embodiment method includes obtaining video captured by a video camera with an imaging plane. Representations of motions in the video are correlated. A textured background of the scene can be modeled as stationary, with a refractive field translating between background and video camera. This approach offers multiple advantages over conventional fluid flow visualization, including an ability to use ordinary video equipment outside a laboratory without particle injection. Even natural backgrounds can be used, and fluid motion can be distinguished from refraction changes. Depth and three-dimensional information can be recovered using stereo video, and uncertainty methods can enhance measurement robustness where backgrounds are less textured. Example applications can include avionics and hydrocarbon leak detection.

An imaging method and corresponding apparatus according to an embodiment of the present invention enables measurement and visualization of fluid flow. An embodiment method includes obtaining video captured by a video camera with an imaging plane. Representations of motions in the video are correlated. A textured background of the scene can be modeled as stationary, with a refractive field translating between background and video camera. This approach offers multiple advantages over conventional fluid flow visualization, including an ability to use ordinary video equipment outside a laboratory without particle injection. Even natural backgrounds can be used, and fluid motion can be distinguished from refraction changes. Depth and three-dimensional information can be recovered using stereo video, and uncertainty methods can enhance measurement robustness where backgrounds are less textured. Example applications can include avionics and hydrocarbon leak detection.

An EUV collector is rotated between or during operations of an EUV photolithography system. Rotating the EUV collector causes contamination to distribute more evenly over the collector's surface. This reduces the rate at which the EUV photolithography system loses image fidelity with increasing contamination and thereby increases the collector lifetime. Rotating the collector during operation of the EUV photolithography system can induce convection and reduce the contamination rate. By rotating the collector at sufficient speed, some contaminating debris can be removed through the action of centrifugal force.

The present invention is a system and method of visualizing fluid flow around an object, such as an aircraft or wind turbine, by aligning the object between an imaging system and a celestial object having a speckled background, taking images, and comparing those images to obtain fluid flow visualization.

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 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 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.

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.

A schlieren system for in-situ/online monitoring of spatter in a large-area melt pool is provided, including a parallel light generation part, a parallel light deflection part, and an image acquisition part. The system can monitor spatter and other physical phenomena in the melt pool in a process of multi-layer printing and adjust a monitored area during an experiment to expand a monitored range. A reflector group composed of a plurality of plane mirrors is arranged, such that an optical path can be kept away from powder and dust areas, avoiding interference between the schlieren system and inherent devices inside a build chamber. Communication between a laser path controller and an optical path deflecting mirror galvanometer motor controller is established to automatically control the plane mirrors to change the monitored area, automatically track the melt pool, and realize online monitoring.

A schlieren system for in-situ/online monitoring of spatter in a large-area melt pool is provided, including a parallel light generation part, a parallel light deflection part, and an image acquisition part. The system can monitor spatter and other physical phenomena in the melt pool in a process of multi-layer printing and adjust a monitored area during an experiment to expand a monitored range. A reflector group composed of a plurality of plane mirrors is arranged, such that an optical path can be kept away from powder and dust areas, avoiding interference between the schlieren system and inherent devices inside a build chamber. Communication between a laser path controller and an optical path deflecting mirror galvanometer motor controller is established to automatically control the plane mirrors to change the monitored area, automatically track the melt pool, and realize online monitoring.