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Speckle imaging and eye testing using speckle also use the speckle effect. Speckle is the chief limitation of coherent lidar and coherent imaging in optical heterodyne detection . In the case of near field speckles, the statistical properties depend on the light scattering distribution of a given sample.
Electronic speckle pattern interferometry (ESPI), [1] also known as TV holography, is a technique that uses laser light, together with video detection, recording and processing, to visualise static and dynamic displacements of components with optically rough surfaces. The visualisation is in the form of fringes on the image, where each fringe ...
The size of each speckle pattern should smaller than the photodetector's pixel size to avoid the decrease of contrast. The minimum speckle diameter for an LSCI system depends on the wavelength of light, imaging system magnification, and imaging system f-number: d min ≈ 1.2 ( 1 + M ) λ f / # {\displaystyle d_{\min }\thickapprox 1.2(1+M ...
When a surface is illuminated by a laser beam and is viewed by an observer, a speckle pattern is formed on the retina. [ 2 ] [ 3 ] If the observer has perfect vision, the image of the surface is also formed on the retina, and movement of the head will result in the speckle pattern and the surface moving together so that the speckle pattern ...
The optical transfer function (OTF) of an optical system such as a camera, microscope, human eye, or projector is a scale-dependent description of their imaging contrast.
Electro–optics is a branch of electrical engineering, electronic engineering, materials science, and material physics involving components, electronic devices such as lasers, laser diodes, LEDs, waveguides, etc. which operate by the propagation and interaction of light with various tailored materials.
The main challenge is to generate a flat-field illumination for short time exposures and wavelengths, to avoid speckle (in monochromatic light conditions) and statistical fluctuations of the light stream that become most obvious at short integration times. Many patents and methods exist to reduce or eliminate fixed-pattern noise in digital imagers.
In the optical regime the sum frequency will be too high to pass through the subsequent electronics. In many applications the signal is weaker than the LO, thus it can be seen that gain occurs because the energy flux in the difference frequency E L O E s i g {\displaystyle E_{\mathrm {LO} }E_{\mathrm {sig} }} is greater than the DC energy flux ...