Collections > UNC Chapel Hill Undergraduate Honors Theses Collection > A Low-Cost, Non-Contact, Optical Imaging Pulse-Oximeter System

This thesis proposed the design and construction of a low-cost, non-contact, optical imaging system capable of data acquisition useful in calculating blood oxygenation and heart rate. This system essentially behaves the same way as traditional pulse-oximetry, with the modifications that it acts at a distance and calculates oxygenation over the pixels of an image rather than from a single photo-transducer. The system illuminates the human forearm with 660nm and 910nm wavelengths independently and acquires high frequency images at these two wavelengths. This allows for resolution of two distinct, wavelength-dependent absorption curves. The system is capable of measuring statistically significant changes in light absorption of biological tissue over time (p-value<0.05). By performing single and multi pixel analysis over images acquired at a high enough frequency to resolve pulsatile information the system is capable of perfusion mapping. The highly vascularized imaged area are highlighted by the system, illustrating vein location and increased blood flow. Issues with synchronizing the high frequency image acquisition with the illumination switching limited the system’s ability to produce measurements required for blood oxygen calibration techniques. Further research should be performed to analyze the depth capabilities of the system and whether it can be applied to areas other than the forearm.