Fr.: plan d'image
The plane in which is formed an image produced by an → optical system.
Fr.: point image
One of the points constituting an extended image formed in an → optical system.
Fr.: traitement d'image
The use of techniques to produce, extract, identify, and display images for evaluation, interpretation, and further interaction with the data.
Fr.: qualité d'image
1) The degree of visibility of relevant → information
in an image.
Fr.: résolution d'image
The separation between two detached but adjacent points in an image.
bâzsâzi-ye tasvir (#)
Fr.: restauration d'image
The process by virtue of which the original image can be created by removing the blurring and the noise that occur during image formation.
Fr.: échelle de l'image
The quantity that relates the length on the image to the angular or physical separations on the sky.
Fr.: espace image
Fr.: tube imageur
A device for amplifying faint images by electronic means. Electrons, released when the incident radiation forms a pattern on a photocathode, are accelerated by a magnetic field so that they form a second, brighter image when they strike a phosphor screen.
adad-e pendâšti (#)
Fr.: nombre imaginaire
A number that is or can be expressed as the square root of a negative number; thus √ -1 is an imaginary number, denoted by i; i2 = - 1.
Adad, → number; pendâšti, adj. of pendâšt, pendâštan "to imagine, consider, think," from Mid.Pers. pad êd dâštan "to consider," from pad "to, at, in, on" + êd "this" + dâštan "to have, hold, keep" (Mod.Pers. dâštan); O.Pers./Av. root dar- "to hold, keep back, maintain, keep in mind;" Skt. dhar- "to hold, keep, preserve," dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE base *dher- "to hold, support."
The visual representation of an astronomical body using a two-dimensional detector and computerized techniques.
Tasvirgari, from tasvirgar agent noun from tasvir→ image + -gar from kar-, kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "makes;" cf. Skt. kr- "to do, to make;" krnoti "makes," karma "act, deed;" PIE base kwer- "to do, to make").
Imaging Atmospheric Cherenkov Technique (IACT)
tašnik-e tasvirgiri-ye Čerenkov-e javvi
Fr.: téchnique d'imagerie Čerenkov atmosphérique
The method used to detect very brief flashes of → Cherenkov radiation generated by the → cascade shower of → relativistic charged particles produced when a very high-energy → gamma ray (in the range 50 GeV to 50 TeV) strikes the atmosphere at a typical altitude of 10 km. Owing to this technique, it possible to discriminate cosmic gamma rays from the cosmic ray background and to determine their energy and source direction. More specifically, the incoming gamma-ray photon undergoes → pair production in the vicinity of the nucleus of an atmospheric molecule. The electron-positron pairs produced are of extremely high energy and immediately radiate in a → bremsstrahlung process. This radiation is itself extremely energetic, with many of the photons undergoing further pair production. A cascade of charged particles ensues which, due to its extreme energy, produces a flash of Cherenkov radiation lasting between 5 and 20 nano-seconds. The total area on the ground illuminated by this flash corresponds to many hundreds of square meters, which is why the effective area of IACT telescopes should be large.
Fr.: détecteur d'image
A detector with two-dimensional capability, such as a CCD.
1) âni, amadim; 2) amadim
1) Occurring or accomplished without delay; following or preceding without a lapse of
time. → instant.
M.E. immediat, from O.Fr. immediat, from L.L. immediatus "without anything between," from → in- "not, opposite of," + mediatus, p.p. of mediare "to be in the middle," from L. medius "middle," → medium.
To plunge into or place under a liquid; dip; sink (Dictionary.com).
To come to a country of which one is not a native, usually for permanent residence.
Fr.: impact, collision
A collision between two bodies. In the case of solar system objects, when one is much smaller than the other (like a meteoroid colliding with the Earth), a crater may be produced on the larger body.
From L. impactus, p.p. of impingere "to drive into, strike against," from → in- "in" + pangere "to fix, fasten."
Barxord, verbal noun of barxordan "to collide, clash, dash against each other," from bar- "on, upon, up" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + xordan "to hit, strike," originally "to eat, drink, devour," and by extension "to destroy," from Mid.Pers. xvardan "to eat, enjoy (food)," Av. xvar- "to consume, eat;" Laki dialect hovârden "to eat;" Proto-Iranian *huar- "to consume, eat."
Fr.: cratère d'impact
A depression produced by the collision of a meteorite, asteroid, or comet with the surface of a planet or a satellite. Impact craters are the most characteristic surface features of solar system rigid bodies. They range in size up to hundreds or thousands of kilometers (where the impacts create giant basins as on the Moon, Mars, and Mercury).
Fr.: impact cosmique
A collision between two celestial objects, specially solar system bodies, with considerable consequences. Impact events involve release of large amounts of energy. Some examples are the 1908 Siberian → Tunguska event by a → comet, the → Barringer Crater, and the collision of an → asteroid with Earth 65 million years ago, which is thought to have led to the extinction of the dinosaurs and other species of the → Cretaceous-Paleogene period.