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laser Doppler imaging of pulse waves on the surface of the hand by holographic photoplethysmography from on-axis digital interferometry. Principal component analysis of digital holograms [23] reconstructed from digitized interferograms acquired at rates beyond ~1000 frames per second reveals surface waves on the hand. This method is an ...
The PPGV was found to be useful in detecting blood loss by observing the spectral features of the PPGV. [3] [4] [5] LF power, together with other features derived from the PPG waveform, was used to classify patients into different ranges of systemic vascular resistance, which may be used as an indicator of critical illness. [6]
Venous translucence is the process of reflective image visualization of veins by light, which reaches up to the superficial venous system. It is a non-invasive method. It is a non-invasive method. Since it is a simple, low-cost technique it can be repeated as needed, which is useful in disease-process monitoring.
Clitoral photoplethysmography uses light to measure clitoral blood volume (CBV). A clitoral photoplethysmograph is a small clear acrylic device that contains a light source, and a light detector. The light source illuminates the capillary bed of the clitoral tissue and the blood circulating within it. As clitoral engorgement increases, more ...
Vaginal photoplethysmography (VPG, VPP) is a technique using light to measure the amount of blood in the walls of the vagina. The device that is used is called a vaginal photometer . Use
Quantum reflection, where very low kinetic energy atoms or molecules are diffracted (reflected) from surfaces. [11] Evanescent waves, which occur with all of the above and also photons where there is no flow of energy into the material. More details and citations on these can be found in the links provided above.
The overall reflection of a layer structure is the sum of an infinite number of reflections. The transfer-matrix method is based on the fact that, according to Maxwell's equations , there are simple continuity conditions for the electric field across boundaries from one medium to the next.
Multivariate (multiple variables) calibration techniques (e.g., principal components analysis, partial least squares, or artificial neural networks) are often employed to extract the desired chemical information. Careful development of a set of calibration samples and application of multivariate calibration techniques is essential for near ...