8,617 terms
Photonics Dictionary
edge detectionIn image processing, the location of edges by employing templates that respond to the first or second derivative of gray-scale intensity in the neighborhood of each pixel.
edge enhancementIn image processing, any operation that strengthens information about the edges of objects displayed. Three types of spatial filtering are used: shift and difference, gradient and Laplacian.
edge filter -> bandpass filterA filter with a transmission that is high for a particular band of frequencies, but that falls to low values above and below this band.
edge followingIn image processing, a segmentation algorithm for isolating a region in an image by following its edge.
edge responseIntensity distribution in the image of an edge. The gradient of the edge-response curve is a measure of the image quality of the optical system under test.
edge sensing, second derivativeTechnique for the precision evaluation of coincidence of a laser beam's center with the edge of the object under study and exact location of that edge by means of a double electronic differentiation...
edge thickness differenceThe maximum variation in thickness of a lens as measured around a diameter centered on the optical axis. The ETD divided by that diameter yields the wedge of the lens.
edge-defined film-fed growthProcess for growth of solar cells that results in rectangular shapes consisting of many interconnected cells in a series or series-parallel arrangement. EFG cells show increased efficiency with...
edge-emitting LEDAn edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the semiconductor chip rather than from the surface. Edge-emitting LEDs are...
edgingThe finishing of the edge of an optical element by grinding.
EDMelectron discharge machining
EDPelectronic data processing
EDRequivalent direct radiation; effective data rate
EDTelectrodeless discharge tube
EDTAethylenediaminetetraacetic acid
EDWAerbium-doped waveguide amplifier
EDXRFenergy-dispersive x-ray fluorescence
EECEuropean Economic Community
EELSelectron-energy-loss spectroscopy
EETexcitation energy transfer
effefficiency
effect filterA color filter, generally used in photography, to emphasize certain color tones and to modify others in a picture for a more dramatic image. A blue effect filter, for example, darkens red and yellow,...
effective f numberFor a lens with an obscured or noncircular aperture, the focal length divided by the effective aperture.
effective aperture1. That portion of the aperture that functions to collect energy and deliver it to the final system detector. 2. For an obscured or noncircular aperture, the equivalent nonobscured, circular aperture.
effective beamIn photoelectric sensing, the portion of the transmitted beam that actually functions in the system; the diameter of the beam that determines the presence or absence of an object by being blocked or...
effective colorThe color of an object when it is illuminated by a nonisophotic source.
effective data rateA characterization of the throughput performance of data storage systems; the EDR is the total of data retrieved divided by the total time it takes to retrieve it, expressed as megabytes per second.
effective focal length -> focal lengthThe focal length of a lens is the distance between the lens's optical center (or principal point) and the image sensor or film when the lens is focused at infinity. In simple terms, it is the...
effective numerical apertureThe real numerical aperture (NA) of a fiber when the computed NA is not valid because of change in the glass indices during drawing and fusion.
efficiencyAs applied to a device or machine, the ratio of total power input to the usable power output of the device.
EFGedge-defined film-fed growth
EFLeffective focal length; equivalent focal length
EFPelectronic field production
EFPIextrinsic Fabry-Perot interferometer
EFSextrafield sensitivity
EFTAEuropean Free Trade Area
EGAenhanced graphic adapter
EGDelectrogas dynamics
egg-cratingA weight reducing method whereby material from the rear of a reflector is removed leaving a pattern of ribs normal to the surface in an egg-crate pattern.
EGMerbium gain module
EHDelectrohydrodynamics
EHFextremely high frequency
EHPelectron-hole pair
EIexposure index
EIAElectronic Industries Alliance
eikonometerA scale attached to a microscope eyepiece that is seen superimposed on the image and that is used to measure the dimensions of the viewed object.
EILelectron injection laser
einsteinA unit of energy equal to the amount of energy absorbed by one molecule of material undergoing a photochemical reaction, as determined by the Stark-Einstein law.
Einstein coefficientsThree proportional coefficients labeled Am, Bmn, and Bnm, that respectively characterize the rate of spontaneous emission, induced emission, and absorption of radiation by an atom, ion or molecule.
Einstein shiftA shift in the direction of the red in the spectral lines of light which, defined by the relativity theory, will have decreased frequencies upon emerging from a highly gravitational field.
Photonics Dictionary