Synergistic event-SVE imaging for quantitative propellant combustion diagnostics.

Area of Science:

• Combustion Science
• Optical Diagnostics
• Imaging Systems

Background:

• Real-time monitoring of high-energy propellant combustion is challenging due to extreme high dynamic range (HDR), microsecond particle motion, and dense smoke.
• Conventional imaging techniques suffer from saturation, motion blur, and unstable particle extraction under these conditions.

Purpose of the Study:

• To develop a novel measurement system for microsecond-resolved 3D combustion analysis under challenging, smoke-obscured, high dynamic range conditions.
• To enable accurate characterization of particle dynamics, including separation height and equivalent particle size.

Main Methods:

• A closed-loop Event-SVE system was developed, coupling a spatially variant exposure (SVE) camera with stereo neuromorphic event cameras.
• An explicit smoke-aware fusion strategy was implemented for HDR map generation, separating particle emission from smoke scattering.
• A stereo event-based 3D pipeline was used for feature extraction and triangulation to estimate particle parameters.

Main Results:

• The system successfully generated calibrated HDR intensity maps by fusing SVE and event camera data, providing absolute intensity reference.
• The method effectively suppressed smoke-driven artifacts and improved particle-state discrimination, achieving a maximum calibration error of 0.56%.
• Experiments on boron-based propellants revealed multimodal equivalent-radius statistics and captured fast separation transients.

Conclusions:

• The proposed Event-SVE framework offers a practical and calibration-consistent approach for microsecond-resolved 3D combustion measurements.
• This system addresses limitations of conventional sensors in high-energy combustion environments with significant smoke and HDR.
• The findings provide valuable insights into propellant combustion dynamics previously difficult to observe.