Feasibility of pulse oxigraphy is examined using an in- vitro phantom, perfused with human blood by a heart- lung machine. 29 different oxygen saturation levels, measured with our experimental camera and a clinical pulse oximeter, were matched against laboratory blood gas analysis. Discrete transfer functions between measurements & laboratory values were derived for camera (f CAM-LAB) & pulse oximeter f Pulse-lab). 87 additional independent pulse oximeter & camera measurements were subjected to these functions to check reproducibility (R 2 = 0.99). To demonstrate imaging capacities, a dual reservoir was applied to image venous and arterial samples from 2 patients. Camera-derived vs laboratory arterial values were: 97.0% vs 99.5% (pat. 1, pH=7.41) & 97.5% vs 99.5% (pat. 2, pH=7.37). Venous resulst were: 86.5% vs 74.4% (pat. 1, pH=7.39) & 89.1% vs 86.2% (pat. 2, pH=7.34). In vitro pulse oxigraphy can visualize regions with different blood oxygenation.