Investigation of Image Processing Steps for Reconstruction of Three-Dimensional Flow Visualization Images

The process of reconstructing and correcting three-dimensional flow visualization images created using a high-speed laser sheet scanning technique is explored. 3-D images are formed from a sequence of 2-D images obtained using laser sheet illumination with a MHz rate pulse burst laser system, a scanning mirror and a high-speed intensified camera capable of framing rates of 500,000 fps. Due to some unique properties of the high-speed camera, special image processing steps are required in order to form high quality 3-D images. Image processing steps described here include flat-field correction, dark field image subtraction, correction for non-uniform laser sheet intensity and image normalization. In addition, consideration is given to calibration of the 3-D image in 3-D physical space and correction of a ghosting phenomenon associated with the high-speed camera.Examples of visualizations compiled from sets of corrected image data are presented, the sources of remaining distortions are considered, and future system upgrades are described.

[1]  Brian S. Thurow,et al.  3-D POD Analysis of a Naturally Excited Jet , 2008 .

[2]  Brian S Thurow,et al.  Third-generation megahertz-rate pulse burst laser system. , 2009, Applied optics.

[3]  Brian S. Thurow,et al.  Three -Dimensional Flow Visualization Using a Pulse Burst Laser System , 2009 .

[4]  Walter R. Lempert,et al.  Pulse-burst laser system for high-speed flow diagnostics , 1996 .

[5]  Naibo Jiang,et al.  Narrow-linewidth megahertz-rate pulse-burst laser for high-speed flow diagnostics. , 2004, Applied optics.

[6]  Brian S. Thurow,et al.  Further Development of a High-Speed Three-Dimensional Flow Visualization System , 2007 .

[7]  Bryan J. Patrie,et al.  Instantaneous three-dimensional flow visualization by rapid acquisition of multiple planar flow images , 1994 .

[8]  Walter R. Lempert,et al.  A Burst Mode OPO System for MHz Frame Rate PLIF Imaging Diagnostics , 2004 .

[9]  Walter R. Lempert,et al.  A MHz rate imaging system for study of turbulent and time evolving high speed flows , 2001, ICIASF 2001 Record, 19th International Congress on Instrumentation in Aerospace Simulation Facilities (Cat. No.01CH37215).

[10]  Marshall B. Long,et al.  Measurement of three-dimensional concentrations in turbulent jets and flames , 1989 .

[11]  Walter R. Lempert,et al.  A Study of Convective Velocity in Supersonic Jets Using MHz Rate Imaging , 2006 .

[12]  Clemens F. Kaminski,et al.  Quantitative three-dimensional imaging of soot volume fraction in turbulent non-premixed flames , 2002 .

[13]  Richard B. Miles,et al.  Megahertz Pulse-Burst Laser and Visualization of Shock-Wave/Boundary-Layer Interaction , 2000 .