Investigating the Effect of Color Mask on Sensitivity for the Color Schlieren Imaging

  • Chien-Chih Chen
  • Chen-Ching Ting
Keywords: color schlieren technique, color mask, LCD projector


This work aims to investigate influence of the color mask for color schlieren technique. To demonstrate the effect, a series of experiments by changing the color mask shape are carried out. The applied color mask is a round mask with three RGB (red, green, and blue) colors gaps which is first presented by Settles, G. S. in 1980. In this work, experiments used a digital color mask instead of a film mask. The applied digital color mask is prepared in computer and projected by an LCD projector. The major discussed parameter is ratio of the outside and inside mask diameters. With the new technique, the digital color mask can be easily varied in computer directly and projected conveniently. In this work, the best color mask with outside diameter ca. 10 mm and inside diameter ca. 8 mm that has the highest sensitivity for color schlieren imaging has been successfully found. In general, the larger inside diameter, the higher sensitivity. The inside diameter has the limitation while the passing light intensity is too weak.


H. Hecht, Optics, Addison-Wesley Publishing Company, 2002.

H. Oertel, Optische Strömungsmesstechnik, G. Braun Karlsruhe, 1989.

G. S. Settles, “Color schlieren optics-A review of techniques and applications,” Bochum, W. Merzkirch(Ed) Hemisphere, 1982.

D. Kastell, M. Carl, and G. Eitelberg, “Phase Step Holographic Interferometry applied to Hypervelocity, Non-equilibrium Cylinder Flow,” Experiments in Fluids, vol. 22, pp. 57-66, 1996.

H. Kleine, “Application and limitation of a schlieren system,” RWTH-Aachen Germany, Report, 1994.

C. C. Ting, S. J. Wu, J. S. Huang, H. D. Lin, and Y. B. Luo, “Investigation to influence of color mask for color schlieren technique,” AASRC/CCAS Joint Conference, 2004.

C. C. Ting, “Wechselwirkung von Stoßwellen und Expansion eines Freistrahls unter Berücksichtigung der Dissoziation in Hochenthalpiestrümungen,” Interner Bericht, Germany, 1997.

W. Merzkirch, Flow visualization, Academic Press, pp. 115-218, 1989.

C.C. Ting, “Strömungs und Wärmeübergangsmessung für das zweistufige Raumtransportsystem ELAC,” Verlag Mainz, Wissenschaftsverlag, Aachen, Germany, 2003.

C. C. Chen, Y. C. Hung, S. C. Wang, and C. C. Ting, “Developing the color full-scale schlieren technique for flow visualization,” Proceedings of ASME 2011 International Mechanical Engineering Congress & Exposition, IMECE2011, pp. 1-6, November 2011.

Y. C. Hung, C. C. Chen, S. C. Wang, and C. C. Ting, “Developing the modular background-oriented full-scale schlieren technique,” Proceedings of ASME 2011 International Mechanical Engineering Congress & Exposition, IMECE2011, November 2011.

J. W. Tang and G. S. Settles, “Coughing and aerosols,” New Engl. J. Med., vol. 359, pp. e18, 2008.

J. W. Tang, T. J. Liebner, B. A. Craven, and G. S. Settles, “A schlieren optical study of the human cough with and without wearing masks for aerosol infection control,” J. R. Soc. Interface, vol. 6, pp. S727-S736, 2009.

J. W. Tang and G.S. Settles, “Coughing and masks,” New Engl. J. Med., vol. 361, pp. e62, 2009.

G. S. Settles, “Imaging gas leaks by using schlieren optics,” Pipeline Gas J., vol. 226, pp. 28-30, 1999.

C. C. Ting and C. C. Chen, “Detection of gas leakage using micro color schlieren technique,” Measurement, Accepted, 2013.

A. Cwik, and H. Ermert, “A quantitative schlieren method for the investigation of axisymmetrical shock waves,” IEEE Conference, Ultrasonics Symposium, 1993.

How to Cite
C.-C. Chen and C.-C. Ting, “Investigating the Effect of Color Mask on Sensitivity for the Color Schlieren Imaging”, Int. j. eng. technol. innov., vol. 3, no. 2, pp. 114-122, Apr. 2013.