A B
C D E F G H I
J K L M N O P
Q R S T U V W
X Y Z
A
Achromatic : Light without
color. The quantity of light is the only attribute associated with
achromatic light. In physical terms this is the intensity or
luminance or in the psychological sense it is the perceived
intensity in which case the term brightness is used.
Additive Color Model : In an
additive color model, colors are defined as a sum of contributions
from primary colors. The most commonly used additive color model is
the Red-Green-Blue model and is used by computer monitors to
produce their display.
Additive
Primaries : Red, green, and blue (RGB). Lights of these
colors, when mixed together in varying intensities, produce any
other color in the additive color model.
Alpha Channel : The top byte of a 32-bit pixel
that is used for data other than color. The channel may hold mask
or transparency data.
Ambient
Light : A global (artificial) illumination level
representing infinite diffuse reflections from all surfaces within
a scene ensuring that all surfaces are visible (lit) particularly
those without direct illumination.
Animation : (1) A medium that provides the
illusion of a moving scene using a sequence of still images. (2)
Techniques used in the production of animated films. In computer
graphics this primarily concerns controlling the motion of computer
models and the camera.
Anti-aliasing : Antialiasing is a method of
reducing or preventing aliasing artifacts when rendering by using
color information to simulate higher screen resolutions. In one
technique, blurred pixels are introduced by filtering the image, or
individual elements. The blending of pixel colors on the perimeter
of hard-edged shapes, like type, to smooth out undesirable edges
(jaggies).
Artifacts/Artifact :
A classifiable visual error. E.g., a loss of resolution when
zooming into an image or incorrect depth sorting due to the
painter's algorithm.
ASCII :
(American Standard Code for Information Interchange) A standard
editable format for encoding data.
Aspect
Ratio : The ratio of the width of an image to its height
(x:y). For example, the aspect ratio of an image 640 x 480 pixels
is 4:3.
Atmospheric Effects :
Atmospheric conditions or phenomena that effect the clarity or mood
of a scene. Fog and smoke are examples of atmospheric effects.
Axis : The Hypothetical linear
path. The X, Y, and Z axes (width, height, and depth, respectively)
define directions of the 3D universe. The axis along which an
object is rotated is the axis of rotation.
B Backdrop : A picture that is automatically
composited behind a 3D scene. The matte paintings used in
traditional movie making are an example of backdrops.
Bezier Curve : (1) A spline curve that (in
the usual case of a cubic B�zier curve) is represented by four
control points defining a cubic polynomial. (2) A curved line
segment drawn using the Pen tool that can be reshaped by
manipulating its anchor points or direction lines.
Binary : In PhotoShop, it is a method for
encoding data. Binary encoding is more compact than ASCII encoding.
Binary Digit : A binary digit
is the smallest unit of information on a computer. Eight bits equal
one byte.
Bit Depth : The
number of bits used to define the shade or color of each pixel in
an image. A 1-bit image is black and white. An 8-bit grayscale
image provides 256 shades of gray. An 8-bit color image provides
256 colors. A 24-bit image provides over 16 million colors: 8 bits
are used for red, 8 are for blue, and 8 for green.
Bits per Pixel : The number of bits used to
describe the color or intensity of a pixel. For example, using 8
bits for to store a value from the RGB color model would permit 3
bits to be used for both red and green values and 2 bits for the
blue value. Blue gets a smaller range because the human eye
contains less blue cones and is thus is less sensitive to blue
variations.
Bitmap : Strictly a
one-bit-per-pixel representation for a defined area of a display.
In PhotoShop, Bitmap is also a one-channel mode consisting of only
black and white pixels.
Blur :
Reduces areas of high contrast to soften an image.
Boolean : An object created by combining
two objects using mathematical operators. The two object may be
subtracted from each other, merged, or intersected to form the new
object.
Bounding Box : The
smallest regular shaped box that encloses an object, usually
rectangular in shape.
Brightness : (1)The perceived intensity of
a radiating object. (2) The amount of light reflected by a surface.
(3) The intensity of a light source. (4) The luminance of a color.
Brush : Traditionally in art, a
brush is an implement that has hairs or bristles firmly set into a
handle and used to paint with. In Photoshop, Painter and other
computer graphics applications the brush is a virtual tool
replicating the functions of its real world counterpart. Virtual
brushes (depending on the program used) can emulate anything from a
hard edge pencil, to soft edge airbrush effects, to crayons, oils,
watercolour or even impasto style strokes. In most programs you
usually have control over the characteristics of the brush stroke
and you can also create custom brushes. When using pressure
sensitive devices such as a graphics tablet, different
characteristics of your brush stroke such as width and opacity can
be controlled by factors such as pressure and pen tilt (depending
on the device).
Bump Mapping :
A technique used to increase the realism of a surface by changing
how light reflects from that surface. Usually, the surface normal
at a given point on a surface is used in the calculation of the
brightness of the surface at that point. Part of what gives this
techniques its appeal is that the original surface maintains its
original (usually smooth) shape, and the bump-mapping distortion is
specified by a compact function of shape. This is usually much
simpler and more compact than specifying the surface texture by
explicitly representing the textured surface.
Burn : A PhotoShop tool that is used to
darken an area of an image.
C CAD :
Abbreviation of Computer Aided Design. In the context of graphics,
CAD refers to the use of computer based models of objects for
visualization or testing as an aid in the design process.
Calibration : The process of
setting a device to known color conditions. Calibration must be
performed externally for devices whose color characteristics change
frequently. For example, calibration must be performed on monitors
because phosphors lose brightness over time, and on printers
because proofers and other digital printing devices can change
output when colorant or paper stock is changed. Calibration is not
required for most input devices (e.g., scanners and cameras) since
these devices are generally self-calibrating.
Camera : A virtual viewpoint in world space
with position and view direction to provide a view of a scene in
the same way as a photographer would position a camera.
Canvas : A two-dimensional
region of graphics information. The canvas may be displayed on
screen or be recorded in off-screen display memory.
Canvas Size : The full editable area of an
image.
Caustics : The
concentrated light reflections caused by refraction through a
transparent surface.
Channel :
An image component that contains the pixel information for an
individual color. A grayscale image has one color channel, an RGB
image has three color channels, and a CMYK image has four color
channels.
Chroma : (1) A
characterization of how much a color differs from both the pure
color and the grey of the same intensity. Also called saturation.
(2) The color component of a composite video signal. (3) The
quality of a color that is the combination of hue and brightness.
In the Munsell system of color notation, chroma indicates the
purity of a color as measured along an axis; the farther from the
axis, the purer the color.
Clipboard : An area of memory used to
temporarily store selection pixels. The Clipboard is accessed via
the Cut, Copy, and Paste commands.
Clipping : (1) The selective removal of an
object disjoint with the display area or the non-visible parts of
an object that does intersect the display area. Parts of an object
intersecting the display area may lie outside of the display area
or be partially or fully obscured by another intersecting object.
(2) Color shift caused by the inability of one color space to
reproduce all the colors of another color space. (3) In PhotoShop,
the automatic adjustment of colors to bring them into printable
gamut.
CMYK : (Cyan, Magenta,
Yellow, and Black) The four-ink colors used in process printing.
Cyan, magenta, and yellow are the three subtractive primaries. CMYK
colors are simulated on a computer monitor using additive red,
green, and blue light. To color separate an image from PhotoShop,
convert it to CMYK Color mode.
CODEC : Algorithms used in multimedia.
Stands for Compression/Decompression.
Color Correction : The adjustment of color
in an image to match original artwork or a photograph. Color
correction is usually done in CMYK Color mode in preparation for
process printing.
Color Keying/Chroma
Keying : Using the pixel color of one image to designate
that pixel data from another image should replace the first pixel's
color. The first image might be a binary image, which would select
regions of interest from the second image. Another use is in
blue-screening, where an actor works against a blue background. In
the output image, the blue pixels get replaced by another image.
For example, a weather map can be placed behind the weather
presenter who is actually standing in front of a blue screen.
Color Models : A color model is
a method of specifying a color (position) in color space, often
using a co-ordinate system. Examples include RGB and the Munsell
Color System.
Color Separation
: The production of a separate printing plate for each ink color
that will be used to print an image. Four plates are used in
process color separation, one each for Cyan, Magenta, Yellow, and
Black. An addition plate is used for each spot color.
Color Space : A mathematical space defining
a range and encoding of colors. E.g. see RGB, LUV, HSV, HSL, YIQ,
YUV and XYZ.
Color Table : The
color palette of up to 256 colors of an image in Indexed Color
mode.
Composite Printer : The
printer used to make a composite color image of a file. This
printer can be used for proofing or for final output.
Compositing : The process of combining
multiple images into a single image. Usually this is performed in
films to make a computer graphics generated character appear on a
previously filmed background. The term is also used in traditional
photographic manipulation to refer to the process by which cel
animation is recorded onto film under a rostrum camera. In film the
'mechanical' process is usually called matte photography (see color
keying), and the process, when used in film sequences is
ambiguously called traveling matte.
Compression : The process by which some of
an image's data is either stored in patterns or eliminated in order
to reduce the images file size.
Continuous-Tone Image : An image, such as a
photograph, in which there are gradual transitions between shades
or colors.
Contract Proof : The
proof (e.g., Dupont WaterProof or Imation MatchPrint) of a color
printing job that is the basis of a contract between a printer and
a client. The appearance of the contract proof should represent the
appearance of final printed piece.
Contrast : The range of colors in an image.
Increasing the contrast of a color palette makes different colors
easier to distinguish, while reducing the contrast makes them
appear washed out.
Crop : A
tool used to trim away part of an image.
Crop Marks : Short, fine lines that are
placed around the edges of a page to designate where the paper is
to be trimmed at a print shop.
D Data
Rate : Transfer speed of a specific device.
DCS 2.0 : (Desktop Color Separation) A file
format for saving a CMYK image for color separation, with the
option for saving spot color channels and alpha channels, and an
optional low resolution file for previewing and laser printing.
Depth of Field : The distance
between the closest and farthest objects in focus within a scene as
viewed by a lens at a particular focus.
Diffuse : Light that is reflected from an
object's surface, regardless of the angle from witch its viewed.
Dissolve : An animation effect
that is a transition between two sequences involving a fade from
one directly to the other.
Dither : The mixing of adjacent pixels to
simulate additional colors when available colors are limited, such
as on an 8-bit monitor or an 8-bit palette.
Dithering : One of many processes for
reducing the total number of colors present in an image while
retaining visual fidelity. Dithering can be done by interleaving
pixels of selected colors to locally approximate the desired color.
Dithering can be applied to either a color or a grayscale color
space and may be necessary due to a limited number of colors
available on the display device.
Dodge : To bleach (lighten) an area of an
image.
Dot Gain : Measured by
the increase in size of a midtone dot, the spreading of dots during
platemaking or on a printing press as wet ink is pushed into the
paper and possibly absorbed by it, which causes colors or shades to
look darker.
DPI : (Dots per
inch) A unit that is used to measure the resolution of a printer or
image setter. Dpi is sometimes used to describe the input
resolution of a scanner, but "ppi" is the more accurate term.
Duotone : A grayscale image
that is printed using two plates to enhance its tonal depth.
DXF : A standard 3D file format
that was originally developed by Autodesk to exchange CAD data
between various software applications. This format only offers
support for basic geometric information.
Dye Sublimation : A continuous-tone
printing process in which a solid printing medium is converted into
a gas before it hits paper.
E EPS :
Encapsulated PostScript, the file format based on Adobe PostScript.
Primarily used to define vector graphics (i.e., geometrical
shapes), it can also be used to contain and provide instructions
for rendering image (i.e., pixel-based) data. In the case of
PhotoShop, an optional PICT or TIFF image for screen display is
included too. EPS is a commonly used format for moving files from
one application to another and also for color separation.
F
Feather : Fades an area over a
specified number of pixels.
Fill/Flood
Fill : These are techniques for coloring areas bounded
by line edges. The algorithms that fill interior-defined regions
(the largest connected region of pixels whose values are the same
as a given starting pixel) are called flood fill algorithms.
Filter : 1) An optical device
that selectively attenuates the intensity of light passing through
it according to the light's properties. Common filters attenuate
light according to either wavelength or polarization state. 2) An
algorithm that selectively modifies the intensity or color of image
data according to the image's properties. 3) An element (software
or hardware) which takes in a stream of data and produces a stream
of results, on average one output for each input.
Foreground Color : The color that is
applied when a painting tool is used, type is created, or the
stroke command is applied.
Four-color
Process : The printing process that reproduces colors by
combining, cyan (C), magenta (M), yellow (Y), and black (K) inks.
This process is alternately called four-color printing, CMYK
printing, or process printing.
FPS : Frames Per Second. The rate at which
animations are displayed.
Frame
: A still two-dimensional image. Often a frame is a raster image as
used in the frame buffer of a graphics display system. In computer
animation frames per second is a measurement of the number of still
frames displayed in one second to give the impression of a moving
image.
Frame Rate : The frame
rate of a video source is determined by the speed at which it
completes the rendering of a new image. This is limited by both the
speed at which image data can be created and the rate at which
video images can be presented on a display. For example the NTSC
system redraws at 30Hz, PAL is 25Hz and computer displays are now
usually 72-75Hz.
Frame Size : A
term used to refer to the dimensions of the array of pixels forming
a frame of an animation, or alternatively the memory requirement
and hence indirectly the resolution and dimensions.
G Gamma : The values produced by a monitor
from black to white are nonlinear. If you graph the values, they
form a curve, not a straight line. Gamma defines the slope of that
curve at halfway between black and white. Gamma adjustment
compensates for the nonlinear tonal reproduction of output devices
such as monitor tubes.
Gamut :
The total range of colors produced by a device. A color is said to
be "out of gamut" when its position in one device's color space
cannot be directly translated into another device's color space.
GIF : Graphic Interchange
Format. This file format is commonly used on the internet.
Gradient Fill : In PhotoShop, a
graduated blend between the Foreground and Background colors that
is produced using the Gradient tool.
Grayscale : A color space where colors are
represented by their luminance values only, i.e. saturation and hue
are zero. An image that contains black, white, and up to 256 shades
of gray, but no color In PhotoShop, Grayscale is a one-channel
image mode.
H Halftone
Screen : A pattern of tiny dots that is used for
printing an image to simulate continuous tones.
Hard Proof : The printed proof of a
document created to preview how colors will look when reproduced on
a specific output device, usually a commercial printing press. A
hard proof may be produced using a laminate contract proofing
system (e.g., Imation MatchPrint) or a tightly calibrated digital
printer designed for proof creation.
Highlight : The area of a glossy object
over which specular reflection can be viewed. It is normally the
color of the light source, not of the object.
Histogram : A graph showing the number of
pixels at each level of brightness in an image.
HSB : A three-coordinate,
device-independent color model. The HSB coordinates define colors
in terms of Hue, Saturation, and Brightness.
HSL/Hue-Saturation-Lightness : HSL, also
known as HSI (Hue-Saturation-Intensity) is a color space used to
represent images. HSL is based on polar coordinates, while the RGB
color space is based on a three-dimensional Cartesian coordinate
system. Intensity is the vertical axis of the polar system, hue is
the relative angle and saturation is the planar distance from the
axis. HSL is thought to be more intuitive to manipulate than RGB
space. For example, in the HSI space, to change red to pink
requires only changing the saturation parameter. <
HSV/Hue-Saturation-Value : A
color space that describes color using three basis components: hue,
saturation and brightness.
Hue
: The wavelength of light of a pure color that gives a color its
name--such as red or blue--independent of its saturation or
brightness.
I Illuminance : The amount of light falling
into a patch of unit surface area. It is measured in lux.
Imagesetter : A high-resolution
printer (usually between 1,270 and 4,000 dpi) that generates paper
or film output from a computer file.
Image
File Format : A representation (usually binary) used by
a computer system as an agreed format to store an image. Examples
of image file formats include the Graphics Interchange Format (GIF)
and Tagged Image File Format (TIFF).
Inbetweening : Inbetweening is the
generation of intermediate transition positions from a given start
and end point or keyframes. This technique is often used in
animation, where a lead artist generates the beginning and end
keyframes of a sequence (typically 1 second apart), a breakdown
artist does the breakdowns (typically 4 frames apart), and an
�inbetweener� completes the rest.
Indexed Color : In PhotoShop, an image mode
in which there is only one channel and a color table that can
contain up to 256 colors. All the colors in an Indexed Color image
are displayed on its table.
Indexed 16 and
256 Color Images : An indexed color image consists of a
set of references to values stored in a color table or palette. The
palette, which is often contiguous in an image file, lists all the
colors as sets of coordinates in color space. An indexed 16-color
image contains a palette with 16 color entries (4 bits), whereas in
an indexed 256 color image 256 colors are listed (8 bits).
Interpolation : A process that
occurs automatically when an image's dimensions or resolution are
changed which results in re-coloring the pixels. Interpolation may
cause an image to look blurry when it's printed. You can choose an
interpolation method in PhotoShop from slower, but better, to
faster but lower quality.
Interlaced
Display : A technique for displaying images at a higher
resolution than the monitor. Two images consisting of every second
row of pixels are alternately displayed during every screen refresh
(e.g. every fiftieth of a second). There is hence a flickering
artifact.
International Color Consortium
(ICC) : The group established by eight industry vendors
(including Adobe Systems) for the purpose of creating, promoting,
and encouraging the standardization and evolution of an open,
vendor-neutral, cross-platform color management system
architecture.
Inverse Kinematics
(IK) : The study of how movement of a body part affects
other attached body parts.
Invert : To reverse an image's light and
dark values and/or colors.
J JPEG :
Acronym for Joint Photographic Experts Group. Commonly used to
indicate a pixel-based graphic file format, JPEG is actually a
compression method used mostly for continuous tone images.
JPG : An image format commonly
used on the internet. It does not support layers, transparency or
alpha channel data.
K Kern :
To adjust the horizontal spacing between a pair of characters.
Keyframe : An image that is
stored in some way to be used as a reference point. Key frames are
often used in animation.
L LAB
Model : The color model is based on the model proposed
by the Commission Internationale d'Eclairage (CIE). LAB color is
designed to be device-independent and perceptually uniform. LAB
color consists of a luminance or lightness component (L*) and two
chromatic components: the A* component (from green to red) and the
B* component (from blue to yellow).
Layer : A level of an image that can be
edited independently from the rest of the image.
Leading : The spacing between lines of
type, measured from baseline to baseline.
Lightness : The lightness (or brightness)
of a color, independent of its hue and saturation.
Luminosity : The distribution of an image's
light and dark values.
Line
Drawing : An image created only from points connected by
lines. It can be described using a series of end-point coordinate
information. This can be combined with a weight which denotes the
thickness of the connecting line.
Local
Light Source : Light source that directly (i.e., not by
reflection or transmission) illuminates a point on a surface.
LPI : (Lines per inch/halftone
frequency/screen frequency) The unit that is used to measure the
frequency of rows of dots on a halftone screen.
Luminance : The absolute quantity of
radiation emitted from a given light source or the brightness of a
surface determined by the amount of light it emits or reflects.
Luminosity : The relative
quantity of radiation emitted by a light source.
LUV Space : A color space similar to the
XYZ model, except that the components are scaled to be perceptually
linear. The human eye perceives brightness on a logarithmic scale,
and hence LUV components are logs of the corresponding XYZ values.
M
Mask : An area that can be
protexted and isolated from changes applied to the rest of the
image.
N
Noise : Random recoloring of
pixels to create a grainy pattern.
NURBS : Non-Uniform Rational B-Splines, are
mathematical representations of 3-D geometry that can accurately
describe any shape from a simple 2-D line, circle, arc, or curve to
the most complex 3-D organic free-form surface or solid. Because of
their flexibility and accuracy, NURBS models can be used in any
process from illustration and animation to manufacturing.
O
Opacity : The density of a
layer or color.
P Parallel
Light : A light that casts rays that are perfectly
parallel to one another.
Pitch
: The rotation of an object. Usually forward and back.
Pixels : (Basic image elements) The
individual dots that are used to display an image on a computer
monitor. Image size and resolution are defined in terms of number
of pixels.
Pixel Depth : The
number of bits used to generate a color at each pixel. For instance
a pixel depth equal to one means that only black and white colors
could be displayed; with a pixel depth equal to four, sixteen
different colors could be displayed.
Plug-in Module : Third-party software that
is loaded into the PhotoShop Plug-ins folder which enables it to be
accessed from a PhotoShop menu. Or, a plug-in module that comes
with PhotoShop that is used to facilitate Import, Export, file
format conversion, or other operations.
PNG : Portable Network Graphics. A web
based format that supports one alpha channel and transparency.
Point : A unit of measure that
is used to describe type size (measured from ascender to
descender), leading (measured from baseline, to baseline) and line
width.
Posterize : Produces a
special effect in an image by reducing the number of shades of gray
or colors to a specified (usually low) number.
PostScript : The page description language
created and licensed by Adobe Systems Inc. that is used to display
and print fonts and images.
POV
: (Point of View) The position and angle used when viewing a scene.
PPI : (Pixels per inch) The
unit that is used to measure the resolution of a bitmapped image.
Primary Colors : Colors,
usually three, which are combined to produce the full range of
other colors within a color model. All non-primary colors are
mixtures of two or more primary colors. Red, green, and blue are
the primary colors of the additive color model. Cyan, magenta, and
yellow are the primary colors of the subtractive color model.
Process Color : Inks that are
used to print an image from four separate plates, one each for Cyan
(C), Magenta (M), Yellow (Y), and Black (K). In combination, they
produce an illusion of an even wider range of colors.
Process Colors : The subtractive primary
colors, cyan, magenta, and yellow (CMY), used in process printing.
Purity : The degree to which a
color is saturated.
Q QuickTime : Developed by Apple Computer. A
type of video file format.
R Radiosity : The level of light reflected
off of or scattered by light falling across surfaces. It is a
natural occurence that object's surfaces do not absorb all light
rays and so reflect some back into the surrounding area.
Render : The process of
building a 2D image from the data contained in a 3D scene.
Resolution : This indicates the
number of pixels per image. It is often represented in this format:
where N and M are the number of pixels per column and row
respectively.
RGB Color Model :
The RGB (red, green, blue) color model describes a color as a
positive combination of three appropriately defined red, green and
blue primaries. They represents the additive color model, where 0%
of each component yields black and 100% of each component yields
white. Red, green and blue are the additive complements of cyan,
magenta, and yellow respectively.
RGB True
Color : An RGB color system with 24 bits per pixel color
resolution. This gives a choice of over 16 million colors per
pixel. Such a system is generally known as a true color or full
color system.
Roll : The
rotation of an object. Usually Left to right (tilting). Gives the
illusion that your horizon is tilted.
S Saturation : A perceptual term referring to
the colorimetry quantity 'excitation purity' of a color. Hue can be
used together with saturation and luminance to define a HSL color
space.
Scaling : The process in
which the size of an image or geometric representation is modified
by multiplying each component of the representation's coordinates
by constant factors. Scaling and many other simple transformations
can be done simultaneously if positions and directions are
represented in homogeneous coordinates.
Screen Capture : The process of capturing
what is currently displayed on your monitor.
Separations Color : Any color in a document
that needs to print as a separate plate on a printing press.
Shading : Coloring a surface
according to its incident light. The color depends on the position,
orientation and attributes of both the surface and the sources of
the illumination.
Snap To : The
process of moving a point to a specific grid location.
Specular : The highlight of an object that
has a shiny surface.
Soft Proof
: In a color-managed workflow, the use of ICC device profiles to
preview document colors directly on your monitor as they will be
reproduced by a specific device.
Spot
Color : Also called pre-mixed inks, the inks used for
printing a specific color. Spot color inks are cost-effective for
two- or three-color printing and may also be used for colors that
process printing cannot adequately produce. Use spot color inks
when: you need three or fewer colors and you will not be
reproducing process-color photographs; or you want to print logos
or other graphic elements that require precise color matching.
Spotlight : A light that casts
its rays in a cone shaped pattern.
Subtractive Color Model : The color model
in which colors are produced by combining various percentages of
the subtractive primaries, cyan, magenta, and yellow. Four color
printing uses cyan, yellow, and magenta (CMY) inks. In theory,
combining 100% of each cyan, magenta, and yellow should produce a
pure black. In practice, however, the combining of cyan, magenta,
and yellow inks does not produce a pure black due to impurities in
inks. For this reason, black ink (K) is used in addition to the
cyan, magenta, and yellow inks in four-color printing.
T Tesselation : A technique to construct a
surface by a small set of figures which fit together. They are
drawn repeatedly over the entire plane leaving no gaps.
Texture Map : A bitmap used to
texture a 3D polygon model, including adjustments for perspective
correction, where vertices of the object model are mapped onto the
2D texture bitmap. In addition to color and brightness, textures
may also be encoded with the properties of transparency and
specular reflectivity. This kind of texture may also be procedural
in nature. A possible side-effect of texture mapping occurs unless
the renderer can apply texture maps with correct perspective.
Perspective-corrected texture mapping involves an algorithm that
translates texels, or pixels from the bitmap texture image, into
display pixels in accordance with the spatial orientation of the
surface.
TGA : (Targa) A
photorealistic graphics file format originally designed for systems
with a Truevision display adapter. It supports 1 to 32 bit images,
and professional features like an alpha (mask) channel, gamma
settings and a built-in thumbnail image.
Thumbnail : A smaller representation of a
larger image.
TIFF : Acronym
for Tag Image File Format; the graphics file format first released
by Aldus Corporation in 1986. TIFF is the standard file format used
for most digital imaging programs. TIFF is a highly extensible
format that allows image data to be tagged with additional
information through an image file directory (IFD) which contains
header-type information without actually being a part of the file's
header. TIFF can be used for black-and-white, grayscale, RGB, and
CMYK images. TIFF can be uncompressed or may use any of a variety
of compression methods, though TIFF most commonly uses LZW
compression.
Torus : A
primitive that looks like a donut.
Transparency : The ratio of the amount of
light passing through a material to the amount of light incident on
the material.
True Color : The
common name for 24-bit color.
TWAIN : An industry wide standard for
devices such as scanner and digital cameras to interface with
software programs.
U V Value
: The relative lightness or darkness of a color.
Vanishing Point : A point in a perspective
projection where parallel lines not parallel to the projection
plane converge. A finite 2D projection of a point at infinity in
3D.
Vector : A list of numbers,
typically Cartesian coordinates or a direction in 2D or 3D.
Vector Graphic : The earliest
computer graphics displays were drawn on so-called vector displays,
because the electron beam which produced the image was under
software control. The beam followed a chain of vectors (i.e. a
polyline) from one point to another. Vector graphics is sometimes
referred to as line-drawing graphics.
VRML : Virtual Reality Modeling Language. A
3D model description format suited to transfer on the WWW.
W
Watermark : Information
embedded in an image that is invisible to the human eye. Can be
used for copyrighting images.
Wireframe : A wire mesh representation of a
3D object.
X XYZ Color
Space : A color model in which X specifies the red
component and Y the green component. The blue component is 1-X-Y
(the color components are scaled so that R+G+B=1). Z specifies the
brightness.
Y Yaw :
The rotation of an object. Usually turning left to right.
YIQ Color Space : A
chrominance/luminance color space model used in the American NTSC
television standard, Y specifies luminance, I and Q specify
chrominance. I specifies the red-orange/cyan (or blue-green)
component, and Q specifies the green/magenta (or purple) component.
YUV Color Palette : A
chrominance/luminance color space model used in the British PAL
television standard, Y specifies luminance, U and V specify
chrominance. U specifies the blue/yellow component, and U specifies
the red/cyan (or blue-green) component.
Z Zooming : Viewing an image at different
sizes. Zooming in creates an enlarged view of a portion of the
scene in the image frame. Zooming out does the reverse.
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