Phasor-based hyperspectral thermal imaging for contactless vital sign detection

Begin thermal imaging has a broad range of applications, including night vision navigation, industrial processes monitoring, and medical diagnostics, with the merits of privacy respect and no need for illumination. However, it can cause ambiguity due to overlapping spectra from multiple heat sources, i.e., the ghost effect. To address this challenge and broaden biomedical applications of thermography, we developed a phasor-based hyperspectral thermal imaging framework, phasor thermography (PTG). Phasor thermography provides a rapid and accurate approach for texture extraction and material classification based on unique thermal fingerprints in the phasor do-main, significantly enhancing feature identification capability. Accurate temperature measurement is achieved by incorporating emissivity variations arising from material classification and texture variations into our innovative phasor-enabled multiparametric thermal unmixing algorithm. Vivid and insightful phasor thermographic vision (PTG-vision) is generated by integrating material, texture, and temperature information. Through a functional study, PTG is demonstrated to accurately capture variations in respiration rate following intense exercise, highlighting its superior flexibility and robustness. We present a novel image-based approach for contactless vital sign detection using phasor thermography, offering transformative potential for health monitoring and medical thermography.