GRAPHICS ELEMENT Flashcards
is a spatial representation of an object,
a two-dimensional or three-dimensional scene or
another image.
image
images reflect the
____ of lights.
intensity
Most photographs are called _______ because the method used to develop the photograph creates the illusion of perfect continuous tone throughout the image
continuous-tone images
- Images stored and processed by computers,
displayed on computer screens, are called
digital
images
The smallest element on a digital image is known as a
pixel
is the number of bits used to represent
each pixel.
depth
black-and-white image, also called bitmap image
1-bit
can represent 16 colors, used in low resolution screens
(EGA/VGA)
4-bit
can have 256 colors. The 256 color images are often
known as indexed color images.
8-bit
256 grey-levels. The image contains only
brightness/intensity data without color information.
8-bit grey
can have 65,536 colors, also known
as hi
-color in Windows systems.
16-bit
2^24 = 16,777,216 colors, true color.
Each byte is used to represent the intensity
of a primary color, RED, GREEN and BLUE.
Each color can have 256 different levels.
24 -bit
2^32= 4,294,967,296 (4G). Usually, 3
bytes are used to represent the three
primary colors and the fourth byte is used
as the alpha channel.
32-bit
measures how much detail an image can have
Resolution
is the number of pixels in an image.
Image resolution
refers to number of dots per inch
(dpi) on a monitor
Display (Monitor) resolution
refers to number of dots per inch (dpi) on a
(hard copy) output device.
Output resolution
Instead of using pixels, objects can be
represented by their attributes, such as
size, color, location, and so on. This type
of graphics is known as
- This is an abstract representation of a 2-
dimensional or 3-dimensional scene.
* A __ file contains graphics
primitives, for example, rectangles,
circles, lines.
vector graphics,
or vector drawing.
There are many languages for describing vector graphics. Three of them are very popular. They are:
PostScript
Virtual Reality Markup
Language
Scalable Vector
Graphic.
was developed by Adobe as a page
description language
PostScript
It is for describing a
scene in a virtual
world.
Virtual Reality Markup
Language or VRML
It is a language for describing two dimensional graphics in XML.
SVG or Scalable Vector
Graphic
- contains an exact pixel-by pixel value of an image
- is easier to render
Bitmap
three types of graphic
objects
vector graphic shapes,
images and text.
- contains
mathematical description of objects - involves a large amount of
processing
Vector Graphic
- is a vital component of multimedia
- is a physical property of light,
Color
Color perception is a
human physiological
activity
Choosing a right color or color
combination involves many trials and
aesthetic judgment (true or false)
true
is the frequency/wave-length of a light wave within the narrow band
of the electromagnetic spectrum (380 – 760nm) to which the human eye
responds.
Color
This is probably the most popular color model
used in computer graphics.
RGB COLOR MODEL
system in which varying amount of the three primary colors, red, green and blue, are added to black to produce new colors.
additive
This model is based on the light absorbing quality of
inks printed on paper.
CMY COLOR MODEL
The three fundamental characteristics of
colors
Hue
Saturation
Brightness
the primary colors in RGB and CMY models are
complementary colors.
is the wavelength of the light
Hue
is the strength or purity of the
color
Saturation
— is the relative lightness or darkness
of the color.
Brightness
This model is widely used in encoding color
for use in television and video. The theory
behind this model is that human perception
is more sensitive to brightness than any
chrominance information, so a more
suitable coding distinguishes between
luminance and chrominance.
YUV COLOR MODEL
is the
range of colors that can be
displayed or printed
.
gamut
is an index table to
available colors in an indexed color
system.
color palette
Each program may have
its own palette. It may replace the system
palette with its own for the period it is
active. This may cause an annoying flash of
strange colors in your screen, known as
Palette flashing
is a technique to increase
the number of colors to be
perceived in an image.
Dithering
is caused by the
limited resolution of an output
device
Anti-Aliasing
is stored in a file conforming to certain format
digital image
Formats using compression will make the file size smaller (true or false)
true
sub-areas of DIGITAL IMAGE PROCESSING
Image analysis
Image recognition
Image enhancement
is concerned with techniques for extracting
descriptions from images that are necessary for higher-level scene
analysis methods.
Image analysis
is concerned with the techniques for recovering information about objects in the image.
Image recognition
is concerned with the technique to improve the image and to correct some defects, such as,
* color and tonal adjustment,
* Transformations, e.g., scale, rotate,
* Special effects, e.g., texture, stylize, blur, sharpen
- Image enhancement
Image editing and processing tools,
- Windows Paint— simple
- Adobe Photoshop
- MetaCreation Painter
- Corel PhotoPaint
- Paint Shop Pro— a low cost shareware
- The GIMP— an open source program with
excellent functions
Vector graphics tools
- Adobe Illustrator
- Corel Draw
- Format conversion tools
