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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]
Diagram showing vectors used to define the BRDF. All vectors are unit length. points toward the light source. points toward the viewer (camera). is the surface normal.. The bidirectional reflectance distribution function (BRDF), symbol (,), is a function of four real variables that defines how light from a source is reflected off an opaque surface. It is employed in the optics of real-world ...
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 ...
Notes Name Symbol [nb 2] Name Symbol Luminous energy: Q v [nb 3] lumen second: lm⋅s T⋅J: The lumen second is sometimes called the talbot. Luminous flux, luminous power Φ v [nb 3] lumen (= candela steradian) lm (= cd⋅sr) J: Luminous energy per unit time Luminous intensity: I v: candela (= lumen per steradian) cd (= lm/sr) J: Luminous flux ...
Depending on the sample, the spectrum can be measured in either reflection or transmission. Common incandescent or quartz halogen light bulbs are most often used as broadband sources of near-infrared radiation for analytical applications. Light-emitting diodes (LEDs) can also be used.
The Phong reflection model was developed by Bui Tuong Phong at the University of Utah, who published it in his 1975 Ph.D. dissertation. [1] [2] It was published in conjunction with a method for interpolating the calculation for each individual pixel that is rasterized from a polygonal surface model; the interpolation technique is known as Phong shading, even when it is used with a reflection ...
Diffuse reflection is the reflection of light or other waves or particles from a surface such that a ray incident on the surface is scattered at many angles rather than at just one angle as in the case of specular reflection.