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When the speckle pattern changes in time, due to changes in the illuminated surface, the phenomenon is known as dynamic speckle, and it can be used to measure activity, as in ( for example ) an optical computer mouse.
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When and speckle
When we observe an illuminated surface, we detect the average energy of the light at the surface ; thus the brightness of a given point on a surface which has been illuminated by a set of random scatterers with a single frequency, is constant over time, but varies randomly from point to point, i. e. it is a speckle pattern.
When an image is formed of a rough surface which is illuminated by a coherent light ( e. g. a laser beam ), a speckle pattern is observed in the image plane ; this is called a “ subjective speckle pattern ” – see image above.
When laser light which has been scattered off a rough surface falls on another surface, it forms an “ objective speckle pattern ”.
When lasers were first invented, the speckle effect was considered to be a severe drawback in using lasers to illuminate objects, particularly in holographic imaging because of the grainy image produced.
When the particle concentration is so low that it is possible to follow an individual particle it is called Particle tracking velocimetry, while Laser speckle velocimetry is used for cases where the particle concentration is so high that it is difficult to observe individual particles in an image.
When and pattern
When a man recognizes a certain experience as the exact pattern of a previous dream, we have an instance of deja vue, except for the fact that he knows just why the experience seems familiar.
When reefs become environmentally stressed, this distribution of symbionts is related to the observed pattern of coral bleaching and recovery.
When the stone hits the surface of the water, a circular pattern of waves appears.
When physical chemist Richard Williams applied an electric field to a thin layer of a nematic liquid crystal at 125 ° C, he observed the formation of a regular pattern that he called domains ( now known as Williams Domains ).
When lifeforms take such giant leaps, they meet little to no competition and are able to exploit a plethora of available niches, following a pattern of adaptive radiation.
When these patterns occur in a patient, he or she is unable to move a limb segment in isolation of the pattern.
When they arrive in Precipice, the couple have to abandon their normal " urban pattern " to see the ways in which the town's unique design merges public and private space, along with natural and artificial structures.
When some effort at fulfilling some reparation condition fails, it must be repeated, usually by someone else after some intervening time-period ; history therefore exhibits a cyclic pattern.
When they land on a piece of film or other detector, these beams make a diffraction pattern of spots ; the strengths and angles of these beams are recorded as the crystal is gradually rotated.
When a crystal is mounted and exposed to an intense beam of X-rays, it scatters the X-rays into a pattern of spots or reflections that can be observed on a screen behind the crystal.
When in a normal solid state, the atoms of matter align themselves in a grid pattern, so that the spin of any electron is the opposite of the spin of all electrons touching it.
When software rescales an image ( the same process that creates the thumbnail shown in the lower image ) it, in effect, runs the image through a low-pass filter first and then downsamples the image to result in a smaller image that does not exhibit the moiré pattern.
When the wind is turned on the liquid quickly evaporates leaving behind the clay in a pattern characteristic of the air flow.
* When determining the pattern of a receiving antenna by computer simulation, it is not necessary to perform a calculation for every possible angle of incidence.
* When determining the pattern of an antenna by measurement, the antenna may be either receiving or transmitting, whichever is more convenient.
When the beams are manipulated correctly the target is drawn along with the interference pattern.
When a person has trouble getting to sleep, but has a normal sleep pattern once asleep, a circadian rhythm disorder is a likely cause.
( When Bugs Bunny was the closing character, he would break the pattern by simply saying, in his Brooklynese accent, " And Dat's De End !").
When used with a parabolic reflector or lens antenna, the phase center of the horn is usually placed at the focal point of the reflector, with the 3 dB points of the horn's radiation pattern set to be at the edge of the reflector.
When we do that, the interference pattern disappears.
When and changes
When lamb and mutton are irradiated at substerilization doses, the meat becomes dehydrated, the fat becomes chalky, and, again, unnatural changes in color occur.
When an APAF-1 gene trap is introduced into cells, many morphological changes occur, such as spina bifida, the persistence of interdigital webs, and open brain.
When this happens the distribution of lift changes dramatically, typically causing a powerful nose-down trim.
When the Church chooses to canonize new material, it is typically added to the Doctrine and Covenants ; the most recent changes were made in 1981.
When considering changes to halakha, Conservative Judaism's rabbinical authorities may rely on historical analysis as well as religious considerations.
When in estrus, the female's scent changes subtly and nearby males begin pursuit.
When the Industrial Revolution arrived, many changes occurred that brought about the food today in its modern form.
When crises arise, Clark quickly changes into Superman.
When W. Grant McMurray became Prophet – President, he declared that instruction specific to leadership changes would no longer be included, so that the focus of the work could be more doctrinal in nature, and less administrative.
When EM radiation interacts with matter, its behavior changes qualitatively as its frequency changes.
When the current changes, the magnetic field does too, inducing a voltage between the ends of the conductor.
When a user changes to pure darknet operation, Freenet becomes very difficult to detect from the outside.
When these revolutionary changes to the Church were implemented, it spawned a counter-revolutionary movement, particularly amongst women.
When an object changes, it always changes in some particular way.
When the current flowing through an inductor changes, creating a time-varying magnetic field inside the coil, a voltage is induced, according to Faraday's law of electromagnetic induction, which by Lenz's law opposes the change in current that created it.
When the blade of an ice skate passes over the ice, the ice undergoes two kinds of changes in its physical state and a change in temperature due to kinetic friction and the heat of melting.
When an object changes its color smoothly, the animation can be defined by keyframes — the first showing its original color, and the second showing its final color.
When cut, it possesses a silvery-white color that quickly changes to gray due to oxidation.
When a beam of light crosses the boundary between a vacuum and another medium, or between two different media, the wavelength of the light changes, but the frequency remains constant.
When airflow changes direction, a reaction force is generated opposite to the directional change.
When Hera, the most conservative of goddesses — for she had the most to lose in changes to the order of nature — discovered that Leto was pregnant and that Zeus was the father, she realized that the offspring would cement the new order.
When a substance undergoes a phase transition ( changes from one state of matter to another ) it usually either takes up or releases energy.
When making changes to the source code that programs are made up of, programmers need to make other programmers aware of the task that the routine is to perform.
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