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The Projected BOS imaging system provides a significant advancement over other BOS flow visualization techniques. Specifically, the present BOS imaging method removes the need for a physically patterned retroreflective background within the flow of interest and is therefore insensitive to the changing conditions due to the flow. For example, in a wind tunnel used for aerodynamics testing, there are vibrations and temperature changes that can affect the entire tunnel and anything inside it. Any patterned background within the wind tunnel will be subject to these changing conditions and those effects must be accounted for in the post-processing of the BOS image. This post-processing is not necessary in the Projected BOS process here. In the Projected BOS system, a pattern is projected onto a retroreflective background across the flow of interest. The imaged pattern in this configuration can be made physically (a pattern on a transparent slide) or can be digitally produced on an LCD screen. In this projection scheme, a reference image can be taken at the same time as the signal image, facilitating real-time BOS imaging and allowing the pattern to be changed or optimized during measurements. The Projected BOS imaging technology has been proven to work by visualizing the air flow out of a compressed air canister taken with this new system. The Projected BOS is available for patent licensing.

NASA’s digital projection focusing Schlieren system is attached to a commercial-off-the-shelf camera. For focusing Schlieren measurements, it directs light from the light source through a condenser lens and linear polarizer towards a beam-splitter where linear, vertically-polarized component of light is reflected onto the optical axis of the instrument. The light passes through the patterned LCD element, a polarizing prism, and a quarter-wave plate prior to projection from the assembly as left- or right-circularly polarized light. The grid-patterned light (having passed through the LCD element) is directed past the density object onto a retroreflective background (RBG) that serves as the source grid. Upon reflection off the RBG, the polarization state of light is mirrored. It passes the density object a second time and is then reimaged by the system. Upon encountering the polarizing prism the second time, the light is slightly offset. This refracted light passes through the LCD element, now serving as the cutoff grid, for a second time before being imaged by the camera. The LCD element can be programmed to display a variety of grid patterns to enable sensitivity to different density gradients. The color properties of the LCD can be leveraged in combination with multiple colored light sources to enable simultaneous multi-color, multi-technique data collection. This system is ready for integration into commercial flow visualization and diagnostic equipment, offering manufacturers and research facilities an efficient, cost-effective solution for multi-technique imaging. The Schlieren system is currently available for patent licensing.

The robotic system is comprised of six main components: the orb that performs the reconnaissance, an orb injector housing that attaches to a piping network, a tether and reel subsystem that attaches to the back of the injector housing, a fluid injection subsystem that attaches toward the front of the injector housing, an external power and data subsystem, and associated control and monitoring software. Usage of the system begins with an operator attaching the injector housing, with the orb stowed inside, to a flanged gate valve belonging to the piping network of concern. Requisite power, data, and fluid subsystems are attached, and the system is energized for usage. The orb is released via the tether and reel, and a controlled fluid force is imparted on the orb to help guide it along its mission. The tether supplies power and guidance to the orb, and relays real-time data back to the operator. The orb’s interior features a modular plug-and-play architecture which may comprise COTS instrumentation for reconnaissance or investiga-tion, LIDAR, and inertial measuring and motion sensors. This instru-mentation could be used in combination with other sub-systems such as lighting, and core and sample retrieving mechanisms. These com-ponents are supported by other onboard devices such as a CPU, power source and controller, and data transmission encoders and multiplexers. The Robotic System for Infrastructure Reconnaissance is at TRL 8 (actual system completed and "flight qualified" through test and demonstration), and is now available for licensing. Please note that NASA does not manufacture products itself for commercial sale.