Use of high dynamic range imaging for quantitative combustion diagnostics

Area of Science:

• Combustion Science
• Optical Diagnostics
• Image Processing

Background:

• Quantitative combustion diagnostics require high signal-to-noise ratio (SNR) for accurate measurements.
• Traditional imaging techniques can be limited by detector dynamic range, affecting sensitivity and precision.

Purpose of the Study:

• To evaluate the effectiveness of high dynamic range (HDR) imaging for quantitative combustion diagnostics.
• To improve SNR and measurement sensitivity in two-color ratio pyrometry using HDR techniques.

Main Methods:

• Applied HDR imaging to coflow laminar diffusion flames.
• Determined camera response functions and analyzed detector linearity and reciprocity.
• Implemented a simplified HDR reconstruction algorithm.
• Calculated soot and flame temperatures using color-ratio pyrometry.

Main Results:

• HDR imaging significantly increased SNR, leading to more precise temperature measurements.
• The HDR approach extended the measurable temperature range to lower regions.
• Pixel cross talk was identified as a limiting factor for detector HDR capabilities.

Conclusions:

• HDR imaging offers a significant advantage over low dynamic range methods for combustion temperature measurements.
• The improved SNR results in smoother temperature distributions and enhanced sensitivity.
• HDR imaging is a valuable tool for advancing quantitative combustion diagnostics.