Walter Scott, Jr. College of Engineering

Graduate Exam Abstract

Cameron Kleinkort
M.S. Final
May 25, 2016, 3:00 pm - 4:30 pm
ECE Conference Room
Visual Hull Method for Realistic 3D Particle Shape Reconstruction Based on High-Resolution Photographs of Snowflakes in Freefall from Multiple Views
Abstract: A visual hull method for reconstruction of realistic 3D shapes of snowflakes and other hydrometeors
based on high-resolution photographs of particles in freefall from multiple views captured by a multi-angle
snowflake camera (MASC), or another similar instrument, is proposed and presented. The visual hull of
an object is the maximal domain that gives the same silhouettes as the object from a certain set of
viewpoints. From the measured fall speed and the particle shape reconstruction, the particle density and
dielectric constant are estimated. This is the first time accurate realistic shape reconstructions based on
high-resolution photographs of real (measured) snowflakes are performed. The results are clearly much
better than any similar data in the literature. They demonstrate – in experiments involved in real snow
storm observations and those with simulated and fake 3D printed snowflakes – sufficient silhouette
information from the five cameras of the expanded MASC system and excellent performance of the
implemented mechanical calibration and software self-calibration of the system. In addition to enabling
realistic “particle-by-particle” computations of polarimetric radar measurables for winter precipitation, the
visual hull 3D shape reconstructions of hydrometeors can be used for microphysical characteristics
analyses, hydrometeor classification, and improvement of radar-based estimations of liquid equivalent
snow rates.
Adviser: Branislav Notaros
Co-Adviser: N/A
Non-ECE Member: Steven Rutledge, Atmospheric Sciences
Member 3: V. N. Bringi, ECE
Addional Members: Ali Pezeshki, ECE
Program of Study: