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Topic: Optical depth

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optical depth Optical depth depends on the frequency of radiation, as well the type of medium. For example, blue light is strongly affected by interstellar dust, so dust clouds have a high blue-light optical depth; on the other hand radio waves are unaffected by dust so the radio optical depth of dust clouds is zero. A measure of how much light is absorbed in traveling through a medium, such as the atmosphere of a star, from the source of light to a given point. daviddarling.info /encyclopedia/O/optical_depth.html   (168 words)

Climate - Publications Barker, H., A. Marshak, W. yrmer, A. Trishchenko, and J. Blanchet, 2002: Inference of cloud optical properties from aircraft-based solar radiometric measurements. Chou, M.-D., K.-T. Lee, and P. Yang, 2002: Parameterization of shortwave cloud optical properties for a mixture of ice particles for use in atmospheric models. Smirnov, A., B. Holben, Y. Kaufman, O. Dubovik, T. Eck, I. Slutsker, C. Pietras, and R. Halthore, 2002: Optical properties of atmospheric aerosol in maritime environments. climate.gsfc.nasa.gov /publications.php?y=2002   (1259 words)

Martin Elvis - Home Page A brief guide to the optical, ultraviolet and X-ray features in quasar/AGN spectra. A revised version was published in August 1999 Sky & Telescope. hea-www.harvard.edu /~elvis   (341 words)

NSF UV Monitoring Network: References Cloud scattering optical depth and local surface albedo in the Antarctic: Simultaneous retrieval using ground-based radiometry. Biologically effective ultraviolet radiation, total ozone abundance, and cloud optical depth at McMurdo Station, Antarctica, September 15, 1988 through April 15, 1989. UV-B Radiation at common optical air masses: geographical comparison and model performance tests. www.biospherical.com /NSF/references.asp   (5001 words)

NASA: Code 614 - Publications Owe, M., R. de Jeu, and J. Walker, 2001: A methodology for surface soil moisture and vegetation optical depth retrieval using the microwave polarization difference index. Owe, M., and R.A.M de Jeu, 2001: Retrieving surface soil moisture and vegetation optical depth from satellite microwave observations. Krabill, 2001: Penetration depth of interferometric synthetic-aperture radar signals in snow and ice. neptune.gsfc.nasa.gov /publications/publications_2001.php   (5492 words)

ipedia.com: Timeline of solar system astronomy Article 1978 - Peter Goldreich and Scott Tremaine present a Boltzmann equation model of planetary-ring dynamics for indestructible spherical ring particles that do not self-gravitate and find a stability requirement relation between ring optical depth and particle normal restitution coefficient www.ipedia.com /timeline_of_solar_system_astronomy.html   (825 words)

Real Time Optical Flow See full image of optical flow field of moving hand. See full image of optical flow field magnitude and figure/ground separation. These coarse depth maps can be processed by generalized view integration algorithms to fuse the data into more detailed depth maps. www.cim.mcgill.ca /~apl/Research/OpticalFlow/benoits.html   (327 words)

Nikon MicroscopyU: Water Immersion Objectives Spherical aberration caused by the mismatch of refractive indices in the optical path is the primary cause of the image deterioration, and this aberration increases proportionally with imaging depth. Optical correction is optimized for the light distribution in a homogeneous medium adjacent to the cover glass, although in practice, the observation volume may be some distance away, and the distribution of light is dramatically affected by refractive index differences and by the distance of the focal plane from the glass. Imaging a specimen plane that is separated from the cover glass by a region of aqueous medium is representative of the optical conditions that prevail in thick biological specimen studies, and the image deterioration encountered is a primary incentive for the employment of water immersion objectives. www.microscopyu.com /articles/optics/waterimmersionobjectives.html   (4773 words)

Optical Depth / Skin Depth / Mean Optical Path Length While optical depth and skin depth are intimately (and mathematically) related, MOPL is a hypothetical construct best used to evaluate the relative importance of surface and volume scattering for a given set of surface conditions. Optical depth of a planetary atmosphere (from the surface to the top of the atmosphere): Skin Depth is the distance in a medium (usually a translucent slab) over which light will be attenuated by a factor of 1/e. wufs.wustl.edu /courses/epsc407_2005/notes/optical_terms.htm   (711 words)

Op Art - Op Art Art Optical Art is a mathematically-oriented form of (usually) Abstract art, which uses repetition of simple forms and colors to create vibrating effects, moiré patterns, an exaggerated sense of depth, foreground-background confusion, and other visual effects. Optical art, or Op art as it is better known, is an abbreviation for Optical Art, a modern art movement that developed in the United States and Europe in the mid-1960s... The aim of Op Art was to produce illusions of depth, relief and motion; it would blur or stir the eye, but never by resorting to actual movement (as in Kinetic Art). www.huntfor.com /arthistory/C20th/opart.htm   (711 words)

www.herts.ac.uk/natsci/astro_ub/aO_ub.html A medium of high optical depth may also be referred to as being optically thick and one of low optical depth may be referred to as optically thin. Low optical depths mean that photons can pass through the medium relatively unhindered. Optical binaries are also known as visual binaries. www.herts.ac.uk /astro_ub/aO_ub.html   (756 words)

Numerical dispersion compensation for Partial Coherence Interferometry and Optical Coherence Tomography Here we present a numerical dispersion compensation technique for Partial Coherence Interferometry (PCI) and Optical Coherence Tomography (OCT) based on numerical correlation of the depth scan signal with a depth variant kernel. Schmitt and G. Kumar, "Optical scattering properties of soft tissue: a discrete particle model," Appl. Fercher, C. Hitzenberger, M. Sticker, R. Zawadzki, B. Karamata, T. Lasser, "A new dispersion compensation technique for Partial Coherence Interferometry (PCI) and Optical Coherence Tomography (OCT)," Proc SPIE 4431 (to be published). www.opticsexpress.org /abstract.cfm?URI=OPEX-9-12-610   (434 words)

Grayfield Optical Now you can monitor live tissue under the microscope with magnifications in excess of 25,000 times with a resolution of better than 100nm with variable depth of field, with sharp contours. Grayfield technology is like Scanning Electron Microscope (SEM), but in color and with variable depth of field, without the need for coatings or vacuums. While other microscopes at such high resolutions deliver images in an unnatural, black and white, Grayfield technology provides the researcher: www.grayfieldoptical.com   (197 words)

Optical Art: Artists and their Works Optical Art is a mathematically-themed form of Abstract art, which uses repetition of simple forms and colors to create vibrating effects, moiré patterns, foreground-background confusion, an exaggerated sense of depth, and other visual effects. With Optical Art, the rules that the viewer's eye uses to try to make sense of a visual image are themselves the "subject" of the artwork. In the mid-20th century, artists such as Victor Vasarely, Josef Albers and M.C. Escher experimented with Optical Art. www.artcyclopedia.com /history/optical.html   (197 words)

Optical Illusions and Visual Phenomena Stereokinetic Phenomenon – an optical illusion of 3D from motion (aka »kinetic depth effect«) »Optical illusion« sounds pejorative, as if exposing a malfunction of the visual system. Note: most of the demonstrations require the free players for Apple’s Quicktime (4 or higher) and Macromedia’s Flash (6 or higher), both available for several platforms; some graphics are in PNG format. www.michaelbach.de /ot   (197 words)

Microscope - Wikipedia, the free encyclopedia Compound optical microscopes can magnify an image up to 1000× and are used to study thin specimens as they have a very limited depth of field. Van Leeuwenhoek's microscopes consisted of a single, small, convex lens mounted on a plate with a mechanism to hold the material to be examined (the sample or specimen). The stereo microscope is often used to study the surfaces of solid specimens or to carry out close work such as sorting, dissection, microsurgery, watch-making, small circuit board manufacture or inspection, and the like. en.wikipedia.org /wiki/Optical_microscope   (1208 words)

Depth - Wikipedia, the free encyclopedia In photography/optical physics the depth of field describes a range, the distance in front of and behind the subject, which appears to be in focus. Depth may describe any of a number of different concepts both abstract and concrete, and such concepts can be either qualitative or quantitative in nature. In physiology, depth perception is the ability of an animal to see objects in three dimensions. en.wikipedia.org /wiki/Depth   (369 words)

Reading on Optical vs Electron Microscopy As the magnification increases in the optical microscope the depth of focus decreases. The wavelength of the visible light used in optical microscopes is between 400 and 700 nanometers (nm). The attractive feature of optical microscopy is that it is so easy: samples can be analyzed in air or water, the images are in natural color with magnifications of up to one hundred to one thousand times, and modern semiconductor electronics with charge-coupled devices (CCD) allow image processing. acept.la.asu.edu /PiN/rdg/elmicr/versus.shtml   (528 words)

Doppler Shift of Self-Reflected Optical Pulses at an Interface: The Dynamic Nonlinear Optical Skin Effect In the linear optical skin effect a pulse incident from air is reflected from a highly absorbing interface after penetrating only a fraction of a wavelength into the absorbing medium, this distance being the skin depth [1, 2]. This new basic effect for the electrodynamics of interfaces combines the concepts of self-r eflected waves [4] and front propagation, and is also a prime example of a nonlinear optical phenomenon where the SVEA fails and the full Maxwell equations must be employed. We introduce the dynamic nonlinear optical skin effect in which a pulse incident on a saturable absorbing interface is self-reflected from a moving absorption front. www.acms.arizona.edu /publication/pub_by_year/journals/wlad-flesch/doppler.html   (2272 words)

Optical Data Storage Systems For the current optical storage systems, the depth of focus is about 1 mm. Optical drives of all kinds operate on the same principle of detecting variations in the optical properties of the media surface. It is usually desired in optical recording to achieve the smallest laser beam spot possible, since the spot size is a measure of the bit size, which defines the areal density of the storage system. www.usbyte.com /common/optical_data_storage_systems.htm   (699 words)

Condon Report, Sec VI, Chapter 4: Optical Mirage The quantity Sigma·R is often called the optical depth of an atmospheric layer, although it is a dimensionless quantity. An optical mirage is a phenomenon associated with the refraction of light in the gaseous (cloud-free) atmosphere. The optical refractive index (n) is defined as the ratio of the velocity (v) at which monochromatic (single wavelength) light is propagated in a homogeneous, isotropic, non-conductive medium, to the velocity (c) of light in free space, i.e., n = c/v. www.project1947.com /shg/condon/s6chap04.html   (14997 words)

Optical Physics of Microcavity Surface Emitting Lasers - Storming Media Abstract: This dissertation consists of an in-depth theoretical analysis of the optical impact of transverse index confinement on the lasing modes of microcavity surface emitting lasers. These are: (1) the transverse confinement of the optical mode, the degree of tilt of the mode propagation vector away from normal to the mirror surfaces, and (2) the density of parasitic modes in the spectral vicinity of the lasing mode. Two different variational techniques were employed to calculate the relevant optical laser parameters: (1) modal resonance, field profile, (2) confinement factor, and (3) threshold gain. www.stormingmedia.us /65/6524/A652443.html   (14997 words)

O Mundo de Claudia: Optical Art Optical Art is a mathematically-oriented form of art, which uses repetition of simple forms and colors to create vibrating effects, moiré patterns, an exaggerated sense of depth, foreground-background confusion, and other visual effects. Victor Vasarely is the "father" of Op' Art. Victor Vasarely is the "father" of Op' Art. claudia.weblog.com.pt /arquivo/2003/10/13/optical_art.html   (14997 words)

Artcyclopedia: Monthly Spotlight: Op Art, or Optical Art Optical Art is a mathematically-oriented form of (usually) abstract art, which uses repetition of simple forms and colors to create vibrating effects, moiré patterns, an exaggerated sense of depth, foreground-background confusion, and other visual effects. Op Art is the term everyone uses; however in its narrowest sense that refers to a specific artistic movement in the 1960's, and by that time two of the best-known 20th-century artists working with perception and optical illusion, M.C. Escher and Victor Vasarely, had been experimenting in this area for decades. With Optical Art, the rules that the eye applies to makes sense of a visual image are themselves the "subject" of the artwork. www.artcyclopedia.com /feature-sep99.html   (14997 words)

Optical Art / Op Art [encyclopedia] Optical Art is generally characterized by hard-edged black and white patterns or geometric shapes which use repetition of simple forms and colors to create vibrating effects, moiré patterns, an exaggerated sense of depth, foreground-background confusion, impressions of movement, flashing and vibration, or alternatively of swelling or warping. Optical art, or Op art as it is better known, is an abbreviation for Optical Art, a modern art movement that developed in the United States and Europe in the mid-1960s. Op art paintings exploit the fallibility of the eye through the use of optical illusions induced by abstract spiral or wavy patterns, stripes, spots, etc. Hungarian-born French painter Victor Vasarely (1908-) and British painter Bridget Riley (1931-) were leading exponents. eluzions.com /Illusions/Art/Optical   (540 words)

PERRET OPTICIANS The optical nerve is the cable that transmits optical information to the brain. They also perceive colors: rom red to blue, with 100 nuances and 750 levels of luminosity, information is transmitted to the brain by the optical nerve. This information is then analysed by the brain, the two images from the two eyes being fused into one image with depth perception, colors, shades, shadows, eye movements, a marvellous process. www.perret-optic.ch /optometrie/anatomie_oeil/opto_anato_oeil_2_gb.htm   (540 words)

Mechanical and Manufacturing Engineering at Loughborough University The optical Engineering Research Group is multi-disciplinary and is unique in the UK for the breadth and depth of its research in the applications of modern optics and laser technology to engineering problems. This includes Laser cutting, drilling, welding etc. and development and application of diffractive optical elements. This includes both digital and optical image signal processing techniques and fringe analysis research www.lboro.ac.uk /departments/mm/research-groups/optical   (186 words)

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