Skip to main content

Performance evaluation of an overdriven LED for high-speed schlieren imaging


A quantitative comparison of an overdriven light-emitting diode (LED) and a high-intensity discharge (HID) lamp as illumination sources for high-speed schlieren imaging is presented. A custom pulser circuit utilizing a new and improved driver circuit was developed to overdrive the LED by a factor of ten while simultaneously reducing pulse widths to sub-microsecond durations. The LED system has been developed as a simple and inexpensive alternative light source to discharge lamps and pulsed laser systems, which are typical for high-speed schlieren imaging. Image quality of a decaying spherical shock wave, produced from the unsteady release of an under-expanded helium jet, is analyzed to assess comparative performance. The effects of framing rate, camera exposure time, and pulse duration on image quality were assessed and compared for the novel LED and an HID. Framing rates of 10,000 and 50,000 fps and exposure times of 1 and 10 µs were tested. Image quality was assessed qualitatively through side-by-side comparisons of fluid dynamic features such as the resolution of shock waves, compression waves, and shear layers. Quantitative analysis was performed through the comparison of the signal-to-noise ratio at the various conditions. LED performance was found to be superior when imaging fast events and inferior when imaging slower events. Results and potential system improvements indicate that the LED system is ideal for low-cost, high-speed flow imaging.

Graphical Abstract

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11


  • Ben-Yakar A, Hanson RK (2002) Ultra-fast-framing schlieren system for studies of the time evolution of jets in supersonic crossflows. Exp Fluids 32:652–666

    Article  Google Scholar 

  • Bespalko R (2012), June 2012 (personal communication)

  • Biss M, Settles G, Hargather M, Dodson L, Miller J (2009) High-speed digital shadowgraphy of shock. In: Hannemann K, Seiler F (eds) Shock waves. Springer, Berlin, pp 91–96

  • Blumel D (2012) XeVision, May 7, 2012 (personal communication)

  • Buchmann N, Willert C, Soria J (2012) Pulsed, high-power LED illumination for tomographic particle image velocimetry. Exp Fluids 53(5):1545–1560

    Article  Google Scholar 

  • Ciccarelli G, Johansen C, Kellenberger M (2013) High-speed flames and DDT in very rough-walled channels. Combust Flame 160(1):204–211

    Article  Google Scholar 

  • Digi-Key Corporation (2012) Electronic components distributor, DigiKey Corp. Accessed May 2012

  • Gregg J (2013) High speed imaging (HSI), November 25, 2013 (personal communication)

  • International Organization for Standardization (2006) ISO 12232:2006—photography—digital still cameras—determination of exposure index, ISO speed ratings, standard output sensitivity, and recommended exposure index

  • Jonassen D, Settles G, Tronosky M (2006) Schlieren “PIV” for turbulent flows. Opt Lasers Eng 44:190–207

    Article  Google Scholar 

  • Misiewicz C, Myrabo L, Shneider M, Raizer Y (2004) Combined experimental and numerical investigation of electric-arc airspikes for blunt body at Mach 3. In: 35th AIAA plasmadynamics and lasers conference, Portland, OR

  • Mizukaki T, Wakabayashi K, Matsumura T, Nakayama K (2013) Background-oriented schlieren with natural background for quantitative visualization of open-air explosions. Shock Waves. doi:10.1007/s00193-013-0465-4

    Google Scholar 

  • Mouser Electronics, Inc. (2012) Mouser electronics—electronic components distributor. Accessed May 2012

  • Rainbow P (2012) Laser components USA, Inc., May 1, 2012 (personal communication)

  • Saravanan S, Nagashetty K, Hedge G, Jagadeesh G, Reddy K (2011) Schlieren visualization of shock wave phenomena over a missile-shaped body at hypersonic Mach numbers. In: Proceedings of the Institution of Mechanical Engineers, part G., journal of aerospace engineering

  • Settles G (2001) Schlieren and shadowgraph techniques. Springer, Berlin

    Book  MATH  Google Scholar 

  • Settles G, Grumstrup T, Miller J, Hargather M, Dodson L, Gatto J (2005) Full-scale high-speed ‘Edgerton’ retroflective shadowgraphy of explosions and gunshots. In: Proceedings of PSFVIP-5 5th Pacific symposium flow visualization and image processing, Australia

  • Shepherd J (2009) Detonation in gases. Proc Combust Inst 32:83–98

    Article  Google Scholar 

  • Texas Instruments (2004) Single 9-A high speed low-side MOSFET driver with enable datasheet, Dallas

  • Willert C (2012) Deutsches Zentrum für Luft- und Raumfahrt (DLR), July 16, 2012 (personal communication)

  • Willert C, Stasicki B, Klinner J, Moessner S (2010) Pulsed operation of high-power light emitting diodes for imaging flow velocimetry. Meas Sci Technol 21(7):075402

  • Willert C, Mitchell D, Soria J (2012) An assessment of high-power light-emitting diodes for high frame rate schlieren imaging. Exp Fluids 53(2):413–421

    Article  Google Scholar 

  • Zakharin B, Stricker J, Toker G (1999) Laser-induced spark schlieren imaging. AIAA J 37(9):1133–1135

    Article  Google Scholar 

Download references


The private communications with Dr. Christian Willert, Dr. Ryan Bespalko and Dr. Gary Settles are gratefully acknowledged. Financial support for this work is from Dr. Johansen’s Alberta Innovates Technology Futures (AITF) Strategic Chair position and equipment support from CMC Microsystems to Dr. Murari via the emSYSCAN program.

Author information

Authors and Affiliations


Corresponding author

Correspondence to S. Wilson.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wilson, S., Gustafson, G., Lincoln, D. et al. Performance evaluation of an overdriven LED for high-speed schlieren imaging. J Vis 18, 35–45 (2015).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Schlieren imaging
  • Light-emitting diode (LED)
  • High-intensity discharge (HID) lamp
  • Shock propagation