aliasing

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Distortion caused by a low sampling rate, as Moire effect or stair-stepped edges
Present participle of alias
A spurious tidal frequency appearing in an analysis when there is an occurrence of a sea level variation with a periodicity smaller than the sampling period Usually presenting itself only when the observations are taken at intervals greater than one hour or when there is a seiche at the observation site
Where the sampling rate is less than twice the input signal's highest frequency content
Visibly jagged steps along angled or object edges, due to sharp tonal contrasts between pixels
Unwanted visual effects caused by insufficient sampling resolution or inadequate filtering to completely define an object; most commonly seen as a jagged or stepped edge along object boundaries or along lines
- A phenomenon, which can occur whenever a signal is not sampled at greater than twice the maximum bandwidth of the signal Causes high frequency signals to appear at low frequencies Filtering the signal to a bandwidth less than ½ the sample rate minimizes Aliasing When the signal starts at 0 Hz (baseband signals), bandwidth can be exchanged to maximum frequency in the definition above
Aliasing is what happens when a signal is sampled (converted to digital form) too slowly Specifically, if a signal contains frequencies above half the sampling rate, the sampled version of the signal will have frequencies (aliases) that aren't in the original signal This limit of half the sampling rate is known as the Nyquist limit For example, the CDP samples at 12288 Hz, so if the input signal contains frequencies higher than 6144 Hz the digital signal will not accurately represent the actual signal That is a rather incomplete description of aliasing If you'd like to learn more, the University of California at Santa Cruz has a general discussion of converting a signal to digital form
A phenomenon caused by sampling analogue data at too-low a frequency It results in a digital reconstruction of the original signal at a false, lower frequency This causes higher frequency signals to appear in a spectrum at lower frequencies (Aliasing terms) When analogue signals are digitised, the analogue input must be sampled at a rate at least twice the bandwidth of the signal to avoid loss of data (Nyquist Theorem)
(1) (n ) The jagged artifact in a line or in the silhouette of a curve that results from drawing on a raster grid It is especially noticeable in low-resolution monitors Also called jaggies See also antialiasing (2) (n ) See command aliasing
{i} (Computers) process through which curved lines appear to have a jagged edge due to low-end graphics capabilities; creation of a false frequency when sampling audio data (caused by a low sampling rate)
A set of problematic effects resulting from the usual method of displaying *scalable images on low-resolution screens When converting these images to *bitmaps for display, samples are taken from the theoretical mathematical image, usually at the pixel centres The influence of what is happening at these more or less arbitrary points is thereby greatly exaggerated, causing jagged edges, "pimples" and other undesirable effects (We should really be considering what is happening over the complete area covered by each pixel ) The approach to the problem that takes the generic term, *anti-aliasing, normally denotes careful shading of border pixels Another approach (distinct but complementary) is *hinting, a set of techniques that can in principle regularize features of any graphic, but in practice is confined to font technology
The erroneous interpretation of high-frequency signals as lower-frequency signals Such misinterpretations are an expected result of making discrete measurements with sampling devices such as analog-to-digital (A/D) converters See also anti-aliasing filters
In graphic design, aliasing occurs when a computer monitor, printer, or graphics file does not have a high enough resolution to represent a graphic image or text An aliased image is often said to have the "jaggies "
In audio sampling, a distortion-producing reflection caused by the fact that all frequency components higher than half the sampling frequency are reflected in the lower range Aliasing creates artifacts It can be avoided by processing the waveform to be sampled with a low-pass filter at half the sample rate before digitizing
The jagged edges (or staircasing) that result from drawing an image on a raster device such as a computer screen Compare antialiasing
1 In spectral analysis, error which is due to undersampling One may wish to sample a signal that is known to be band-limited, but whose bandwidth is not known a priori The Fourier transform of Shannon's series is periodic; aliasing is of the form of an overlapping, or superposition of these "replicated" spectra See also Nyquist sampling rate and aliased response 2 In computer graphics, the jagged artifact in a line or curve that results from drawing on a raster grid 3 In computer programming languages, giving access to a region of memory through more than one language entity (e g , pointers in C or C++) Aliasing makes it harder for compilers to optimize code, as they may not understand all the ways in which a given memory location might be modified
Visibly jagged steps along angled lines, or object edges due to sharp tonal contrast between pixels
Defects or distortion in a television picture or audio Defects are typically seen as jagged edges on diagonal lines and twinkling or brightening In digital video, aliasing is caused by insufficient sampling or poor filtering of the digital video
A phenomenon which can occur whenever a signal is not sampled at greater than twice the maximum frequency component Causes high frequency signals to appear at low frequencies Aliasing is avoided by filtering out signals greater than 1/2 the sample rate
Undesired frequencies that are produced when harmonic components within the audio signal being sampled by a digital recording device or generated within a digital sound source lie above the Nyquist frequency Aliasing differs from some other types of noise in that its pitch changes radically when the pitch of the intended sound changes See Nyquist frequency
In sampling theory, when an input signal frequency component exceeds the Nyquist limit, the signal is "aliased" or "folded back" or replicated at other frequencies in the frequency spectrum above and below Nyquist Normally, aliasing is due to unwanted signals beyond the Nyquist limit To prevent aliasing, all undesired signals must be filtered adequately so that they are not digitized by the analog-to-digital converter (ADC) Aliasing can be used advantageously when undersampling See also Nyquist and undersampling
A type of signal distortion that occurs during A/D conversion if the sampling frequency is less than twice that of the highest audio frequency A/D converters employ aliasing filters to filter out audio frequencies higher than half the sampling frequency See also Nyquist Sampling Theorem
A type of distortion caused by sampling at too low a sample rate To avoid aliasing, the sample rate must be at least twice the highest frequency in the sound
The misrepresentation of high frequencies from the original signal as low frequencies in the sampled result, due to undersampling Aliasing distorts the letterforms and letter spacing
In computer graphics, the jagged appearance of curves or diagonal lines on a display screen This appearance is caused by low screen resolution
In a sampled data system, the analog input must be sampled at a rate of at least twice the bandwidth of the signal in order to avoid loss of data (Nyquist Theorem) Adhering to the Nyquist Theorem prevents in-band "alias" signals, which are beat frequencies between the analog signal and the sampling clock that inherently occur
A spectrum analysis problem resulting from sampling data at too low a frequency It causes high-frequency signals to appear in a spectrum at low frequencies In a sampled data system, the analog input must be sampled at a rate at least twice the bandwidth of the signal to avoid loss of data (Nyquist Theorem)
alias
to become indistinguishable
alias
An spurious signal generated as a technological artifact
alias
An abbreviation that replaces a string of in-game commands and thereby reduces typing when performing routine actions or tasks
alias
Otherwise; at another time; in other circumstances; otherwise called
alias
Used to connect the different names of a person who has gone by two or more, and whose true name is for any cause doubtful; as, Smith, alias Simpson
alias
an assumed name
alias
{n} a second writ
alias
{a} otherwise, or else
Alias
A hostname that replaces another hostname, such as an alias which is another name for the same Internet address For example, www company com could be an alias for server03 company com
Alias
A lightweight reference to files and folders in Mac OS Standard (HFS) and Mac OS Extended (HFS+) file systems An alias allows multiple references to files and folders without requiring multiple copies of these items Aliases are not as fragile as symbolic links because they identify the volume and location on disk of a referenced file or folder; the referenced file or folder can be moved around without breaking the alias See also symbolic link
Alias
An alternative name for a command
Alias
1) An alternative name or names assigned to a program or to an electronic mail address 2) Mailer: A named electronic mail address for mailing to a group of users By creating an alias for a group of users, you can type one name instead of each individual name to send electronic mail messages to the group
Alias
as known or named at another time or place; "Mr Smith, alias Mr Lafayette"
Alias
A name, usually short and easy to remember, that is translated into another name that is usually long and difficult to remember An alias may also be used where the 'real' name is subject to change and the users do not want to keep track of the changes In Telstra, email address aliases shield external senders from the need to know about changes to MS-Mail Post Offices [Telstra]
Alias
A unique and usually shorter URL (link) that can be distinguished from other links even if they ultimately go to the same Web page This makes it possible to track which message led viewers to click on the link
Alias
A short, easy to remember name created for use in place of a longer, more complicated name; commonly used in e-mail applications Also referred to as a "nickname"
Alias
A URL that points to another website Many websites use aliases to differentiate traffic Fastclick allows approved aliases to be used with the same ad code as the main website
Alias
A name, usually short and easy to remember, that is translated into another name, usually long and difficult to remember DNS does aliasing It is a lot easier to remember www airmail net than 206 66 12 43
Alias
A naming convention has been applied to Web Servers at Murdoch University This convention uses the assignment of aliases in a preferred format For organisation units or resource areas the format is www orgunitname murdoch edu au The name of the organisation unit or resource area therefore appears to be a sub-domain of the murdoch edu au domain For functions, services, application systems and publications, aliases assigned use a preferred format of title murdoch edu au The Web Server aliases associated with computer hosts have been entered into the Domain Name Server (DNS) Aliases using the previous naming convention of wwworgunitname murdoch edu au and wwwtitle murdoch edu au are still used
Alias
An object that consists of a reference to another object An alias saves space, since the alias object is small, and can be used to reference very large objects Resolving an alias refers to retrieving the object that the alias references See also Entry Alias Source: NPG
Alias
(I) A name that an entity uses in place of its real name, usually for the purpose of either anonymity or deception [RFC2828] (see also anonymous, masquerade)
Alias
The alias is an unique, abbreviated identifier for the unique Project, Task, and Award (PTA) combination Certain sites on campus use business software that cannot accommodate the use of the PTA As a workaround, a table has been created that will use a number that can be entered into the peripheral systems and translate into PTA in order to feed the charges to Oracle The only sites using only the alias are the Mail Services and the Athenaeum
Alias
Alias refers to the non-standard names for a locus Sometimes a locus gets published with different names and SGD decides (following the Gene naming guidelines) the standard name for the locus and keeps the other published names under 'Alias'
Alias
A nickname that refers to a person or group of people on a network For example the address webmaster@waitinglist co uk is an alias for the person responsible for maintaining the waiting list site All e-mail sent to this address will be routed to the person who owns the alias
Alias
In RGD, an alternative symbol or name for one of the objects stored in the database Typically these are names and symbols which were in use in earlier publications but that have since been updated as the result of nomenclature events They are listed to allow users to related older publications to the current database information
Alias
a convenient way of short-cutting to an application, folder, or e-mail address; an icon on the desktop or under the Apple menu, linked to some other place or entity Double-clicking on the alias launches the application, even though the application icon itself may be buried deep in some folder Alias labels appear in italic type to distinguish them from their actual referents In the context of electronic mail, an alias is a short nickname electronically linked to look up a longer e-mail address or set of addresses; for example, sending a message to a class alias allows an instructor to put only a short alias name in the "to" field, but reach everyone on the address list
Alias
In MGI, an alternative symbol or name for part of the sequence of a known gene that resembles names for other anonymous DNA segments For example, D6Mit236 is an alias for Cftr
Alias
In System 7, a file that "points to" another file, folder, or disk, and may generally be used in place of the original item In network usage, alias usually refers to a simple name, location, or command that you can use in place of a more complex name, location, or command Aliases are commonly used for email addresses, directories, or commands
Alias
a name that an entity uses in place of its real name, in computing usually for purposes of convenience or brevity, but in security often for the purpose of either anonymity or deception
Alias
a name that has been assumed temporarily
Alias
A feature of UNIX shells that enables users to define program names (and parameters) and commands with abbreviations When an alias is used in a command line, the system substitutes the alias definition for the abbreviation (the alias) For example, the following command creates an alias called ls: % alias ls `ls -l` Whenever you use the ls command, the operating system interprets the command as ls -l, That is, instead of just listing the files in a directory, it lists the files with additional attributes such as owner, date, and protections For more information, see "Using Aliases" in the "For Advanced Users" section of Chapter 3, Using Programs
Alias
A type of nickname (usually short and easy to remember) that refers to a type of network resource Aliases are used so you won't have to remember the long and difficult names typical of network resources
Alias
A name, usually short and easy to remember, that is translated into another name, usually long and difficult to remember [Source: RFC1392]
Alias
An alternate name or address for an existing account (see "e-mail alias")
alias
also-known-as
alias
An alias is a false name, especially one used by a criminal. Using an alias, he had rented a house in Fleet, Hampshire
alias
You use alias when you are mentioning another name that someone, especially a criminal or an actor, is known by. the defendant Pericles Pericleous, alias Peter Smith. a false name, usually used by a criminal
alias
Otherwise; otherwise called; a term used in legal proceedings to connect the different names of any one who has gone by two or more, and whose true name is for any cause doubtful; as, Smith, alias Simpson
alias
a name that has been assumed temporarily as known or named at another time or place; "Mr
alias
At another time
alias
To assign an additional name to an entity, often a more user-friendly one
alias
A second or further writ which is issued after a first writ has expired without effect
alias
Lafayette
alias
{i} assumed name, pseudonym, nickname
alias
Smith, alias Mr
alias
Another name; an assumed name
alias
Otherwise; at another time; in other circumstances; otherwise called. (Used in legal proceedings to connect the different names of a person who has gone by two or more, and whose true name is for any cause doubtful; as, Smith, alias Simpson.)
anti aliasing
removal of jagged edges in digital images by averaging adjoining pixels to create a smooth blend of colour
anti aliasing
The method in which jagged lines in 3d environments (easily seen in the horizon of games) are removed and smoothed out for a picture that is easier on the eyes
anti aliasing
A method of reducing jagged edges
anti aliasing
A technique used to make diagonal or curved edges appear smoother by setting pixels near the edge to intermediate colors according to where the edge crosses the underlying color
anti-aliasing
Anti-aliasing is a technology used to resize bitmaps which you may have noticed as "fuzziness" on an image Imagine you are resizing a graphic of black text on a white backgroundas you resize it up and down the software has to decide whether to make the new pixels black or white, which can produce a jagged appearance What anti-aliasing does instead is put in a gray pixel, which produces a smoother transition, even though it does add a little fuzziness
anti-aliasing
In computer imaging, a blending effect that smoothes sharp contrasts between two regions-e g , jagged lines or different colors This reduces the jagged edges of text or objects In voice signal processing, it refers to the process of remov-ing or smoothing out spurious frequencies from waveforms produced by convert-ing digital signals back to analog
anti-aliasing
A method to remove the jagged edges of objects It looks very good, but is not supported in FS98, because so few cards do anti-aliasing without a performance decrease Can be done with brute force by rendering a scene at 1600x1200 then downsampling to 800x600 (at the cost of performance), or cleverly by antialiasing each edge (at the cost of developing hardware that does this fast) Here is a very-nicely anti-aliased scene, using the PixelSquirt chipset
anti-aliasing
In computer graphics, the smoothing of the jagged, "stairstep" appearance of graphical elements See also jaggies
anti-aliasing
Removing alias frequencies from the sampled signal In letterfoms, jaggedness can be minimized during reconstruction by using various grey levels at the edges of stokes
anti-aliasing
Smoothing the jaggy edges of selection or paint tools in digital imaging applications
anti-aliasing
A technique that smooths the roughness in images or sound caused by aliasing During frequency sampling, aliasing generates a false (alias) frequency along with the correct one With images this produces a stair-step effect Anti-aliasing corrects this by adjusting pixel positions or setting pixel intensities so that there is a more gradual transition between pixels
anti-aliasing
In computer graphics, the smoothing of the jagged, "stairstep" appearance, known as aliasing, in graphical elements such as diagonal lines, curves, and circles Aliasing occurs when the resolution of an image is too coarse to achieve the appearance of a smooth line or curve Anti-aliasing software routines can blur the roughness of a jagged edge by shading or coloring neighboring pixels to make the transition between light and dark (or between two colors) less distinct and therefore less immediately visible
anti-aliasing
One solution to the *aliasing problem The pixels of the graphic being displayed are shaded by analysing them as areas (not dimensionless points) on a theoretical infinite *resolution output surface In practice it's adequate to resample on a grid 2 to 16 times as fine as the original device grid - meaning 5 to 257 grey levels respectively See the TrueType Anti-Aliasing page
anti-aliasing
A method of smoothing out pixels' jagged edges using software
anti-aliasing
Technique used in imaging applications to alleviate the jagged appearance of graphics produced on low-resolution devices such as computer monitors Neutral colour is interpolated between two colour planes
anti-aliasing
AA Hides the jagged effect of image diagonals by modulating the intensity on either side of the diagonal boundaries This creates a local blurring along these edges and reduces the appearance of stepping The result is a smoother, far more realistic image Also see: Real-Time Full-Scene HW Anti-Aliasing
anti-aliasing
In audio applications, the smoothing of steps between discrete samples to reduce the undesirable effects of low bit-rate capture
anti-aliasing
Smoothing or blending the transition of pixels in an image Anti-aliasing the edges on a graphic image makes the edges appear smooth, not jagged
anti-aliasing
The process of reducing stair-stepping by smoothing edges where individual pixels are visible
anti-aliasing
A technique for smoothing out jaggiesthe jagged edges on diagonal lines and curves on-screen To compensate, graphics cards blur the edges by adding various shades of gray or color to surrounding pixels (this is called dithering)
anti-aliasing
A form of interpolation used in graphics display technology when combining images; pixels along the transitions between images are averaged to provide a smooth transition
anti-aliasing
Anti-aliasing is the process of making diagonal or curved lines appear smooth and continuous in computer-generated images Images on a computer screen are made up of tiny squares, or pixels When these are in a straight line, they have straight smooth edges, but when they are placed at an angle or curve to each other they can appear jagged Anti-aliasing fills in data between the pixels by adding pixels of intermediate color values to to blend the edge, improving its appearance Anti-aliasing also adds more colors to the image making it less compressible and therefore larger
anti-aliasing
[ed: this is an 'off-the-cuff' definition, feel free to clarify it for me ;-) ] On low-resolution bitmap devices (where ragged, ugly characters are the norm) which support more than two colors, it is possible to provide the appearance of higher resolution with anti-aliasing Anti-aliasing uses shaded pixels around the edges of the bitmap to give the appearance of partial-pixels which improves the apparent resolution
anti-aliasing
A software process to smooth out the jagged appearance of lines in a bit-mapped image
anti-aliasing
A remarkable Acorn invention to improve display of outline fonts, where the edges are made fuzzy, blending to the background This process can also be applied to vector graphics, whereby lines and curves are smoothed, rather than having the classic computer staircase effect The logo above is fully anti-aliased The following images, using the same font, illustrate the poor text display of a Windows™ PC, despite being in a 32-bit screen mode, when compared to the RISC OS display - which matches the printed document as closely as possible: PC: Acorn
anti-aliasing
Smooths out the step-like rough edges of a line by blending the colours of the pixels that make up that line with surrounding colours
anti-aliasing
A technique that is used to smooth curves and diagonal lines by adding pixels of intermediate shades or colors around the line
anti-aliasing
When combining images in graphics-display technology, AA is a form of interpolation The combination averages the pixels along the transitions between images to provide a smooth transition