Macroscopic three-dimensional particle location using stereoscopic imaging and astigmatic aberrations.

Area of Science:

• Fluid dynamics
• Optical measurement techniques
• Particle imaging velocimetry

Background:

• Astigmatism particle tracking velocimetry (APTV) accurately determines 2D particle positions but has limitations in precise 3D localization.
• Measuring three velocity components with similar accuracy is crucial for analyzing highly three-dimensional flows.

Purpose of the Study:

• To present a stereoscopic imaging concept for enhanced 3D particle localization.
• To improve the accuracy of three-dimensional flow measurements using APTV.

Main Methods:

• The stereoscopic APTV approach utilizes APTV for initial particle location estimation.
• Corresponding particle images from a stereoscopic system are matched.
• Particle locations are then mapped to physical space using sensor data.

Main Results:

• The stereoscopic APTV method achieves measurement errors of less than 0.012 mm for xy and 0.025 mm for z.
• High accuracy was demonstrated using 1-μm DEHS particles in a defined measurement volume.
• The technique proved effective for macroscopic domain measurements.

Conclusions:

• Stereoscopic APTV significantly enhances the accuracy of 3D particle localization.
• This technique is highly suitable for precise measurements in three-dimensional flows.
• The method overcomes previous limitations in determining particle z-coordinates with APTV.