Multi-Modal Infrared Thermography and Photoplethysmography for Characterizing Apparent Thermal Signal Variations Associated with Geometric Configuration Exposure: A Proof-of-Concept Study

This preprint presents a proof-of-concept experimental study investigating multi-modal physiological and infrared signal changes associated with exposure to a passive 58° geometric configuration. The study integrates three complementary measurement modalities: • Infrared thermography of a water sample before, during, and after controlled geometric exposure.• Photoplethysmography (PPG) measurements acquired before and after water consumption.• Facial infrared thermography acquired before and after water consumption. Thermal image processing included FFT-based frequency analysis, GLCM texture analysis, optical flow analysis, entropy estimation, fractal dimension, SSIM, and additional quantitative metrics. PPG analysis included heart rate, HRV parameters, spectral indices, and signal quality metrics. The work is intended as a methodological proof-of-concept and does not establish causal physical mechanisms. The presented workflow demonstrates an integrated multi-modal analytical framework for evaluating physiological and infrared imaging responses under controlled experimental conditions.