High power LEDs in imaging flow diagnostics: Current status and future prospects

Abstract

The rapid progress in the light emitting diode (LED) manufacturing technology nowadays enables the application of high-power LEDs as light sources for both high-speed videography and flow velocimetry. These devices have a number of attractive advantages in comparison to lasers and xenon illumination. Aside from the dramatically reduced cost of procurement, relatively simple operation and considerably longer life time, LEDs are very stable in terms of intensity and their spatial distributions providing incoherent illumination free of speckle artefacts. The presentation describes newly designed pulsed LED-illuminators based on recently introduced high power LEDs which can be used for high-speed videography, Particle Image Velocimetry (PIV), Image Pattern Correlation Technique (IPCT), and Background Oriented Schlieren (BOS). Current developments suggest that LED devices with even higher light emission will be available in the future thereby further expanding the range of possible applications of LEDs in scientific imaging diagnostics.