Digital Schlieren System for Flow Diagnostics

This is an SBIR proposal to develop a revolutionary digital schlieren imaging system that will greatly improve a widely used aerodynamics tool and render it so robust, user friendly, and productive that it will be useable in test facilities and environments that have been prohibitive before. Also, by incorporating recent advances in consumer camera and display technologies we can produce a new class of digital focusing schlieren (DFS) systems that drastically reduce the manufacturing costs as well as the size and weight, while maintaining sensitivity, improving robustness, making it more user friendly, and over all a much more powerful instrument. The digital schlieren concept represents the first major improvement in schlieren imaging in over 150 years, a true quantum jump in the technology. Conversion to digital obviates many of the long-standing problems with focusing schlieren systems that are associated with precisely matching the cutoff grid to the background light pattern. Because the system is digital, the control software can perform real-time image enhancement as well. Consequently, the most severe hardware production and alignment restrictions are now software problems that are solvable continuously, quickly, and inexpensively in real time. This capability enables the system to compute and compensate for imperfect windows and optics, optical aberrations, misalignments, and temporal changes in the system and subject.