Imaging

Use of photoplethysmographic processes in order to determine blood pulsing is known. By providing illumination over a range of excitation frequencies or wavelengths and using a multi time gating technique with regard to returned light, images are created which provide a spectral depth due to the varying scatter and absorption effects at the different excitation wavelengths. These images can be consolidated in order to provide a substantially real time view of pulsing action dependent upon blood oxygen saturation within the blood circulation system.