Compression
Data compression, source coding,
or bit-rate reduction
-Lossless compression
--Reduces bits by identifying and
eliminating statistical redundancy
-Lossy compression
--Dropping nonessential detail
RLE in Text and image
-Run-length encoding
-
stored as a single data value and count, rather than as the original run
-eg:
12W1B12W3B24
- lossless data
compression
- used by bitmap and jpeg.
Lempel–Ziv–Welch (LZW)
- universal lossless data
compression algorithm
- gif, tiff, pdf
- Encoding
--A high level view of the encoding
algorithm is shown here:
1.Intlize the
dictnry 2 contain al strngs f lngth 1. 2.Fnd
d lngst strng W in the dctinry tht matchs d current i/p.
3.Emit the dictnry
index for W to o/p & remove W from the i/p. 4.Add W folowd by d next symbl in d i/p 2 d dictnry. 5.Go 2 Step 2.
Huffman's Coding
-
is an entropy encoding algorithm usd 4 lossless data compression
- The technique works by creating a binary tree of nodes. These can be stored in a
regular array, the size of which depends on the
number of symbols. A node can be
either a leaf node or an internal node. Initially, all nodes are leaf
nodes, which contain the symbol itself, the weight of the symbol and optionally, a link
to a parent node which makes it easy to read the
code starting from a leaf node. Internal nodes contain symbol weight, links to two child nodes and the optional link to a parent node. As a common convention, bit '0'
represents following the left child and bit '1' represents following the right
child. A finished tree has up to leaf nodes and internal nodes. A Huffman tree that omits unused symbols produces the
most optimal code lengths.
Graphics Interchange Format
-widespread usage World Wide Web due to its wide support and portability.
- upport up to 8 bits per pixel
- 256 distinct
colors chosen from the 24-bit RGB color space
-LZW Lossless compression
-usg ,anim, ow-color sprite data for games
JPEG
-JPEG uses a lossy form of compression based on the discrete cosine transform (DCT).
-extension .jpg and .jpeg, though .jpe, .jfif and .jif
Software for animation : Presentation , Application(), Authoring, Animation, Web browser, Html
editors.
MORPHING
Morphing is a special technique that
creates a smooth, controlled transformation of one image into another. The
morphing effect is widely used for various tasks ranging from generation of
fancy special effects, smoothing transitions between video frames to funny
warping of faces and mixing parent's photos for prediction of how their child
will look like . A classic example of this sort of transformation is shown in
the well-known Black Or White video clip by Michael Jackson, where the faces of
different people change one into another.
Explore Different Types of Animation
-2D, 3D and Stop Motion
-Any way to manipulate a sequence of
images, frame by frame, is considered a Type of Animation. All animations falls into one of these three categories.
-2D animation
The term "2D" refers to
animation that is created using two dimensional drawings.
-3D animation
"3D" refers to Computer
Generated Images (CGI) that create the illusion of three dimensional space with
great accuracy.
-Stop Motion Types of animation
Everything that is shot live, frame by
frame, in front or under a camera is called Stop Motion or "Stop
Frame" Animation. Clay animations are usually the first thing that comes
to mind in this category.
Pre-Production
Stage
1: planning
•poor planning results in a loss
of money, •with poor planning an
inferior video is created
•Deliverables:, •Proposal
-explains the content and identifies the target audience, •Storyboard -graphic
organizer of main scenes, •Script -dialogue, narration, audio instructions and
visual instructions
Production
Stage 2: set your stage and
shoot the footage
•Consider:
•framing
and composition
•lighting
requirements
•audio,
•camera techniques
•lead in and lead out
Post-Production
•Stage
3: edit and enhance your footage
•select
and trim clips
•add:, •transitions,
•audio(music,
voice over, sound effects), •titles and credits,
•text,credits,
graphics and animation
•special effects (filters, green
screen)
•render
your video, •publish it
Raster-Scan Displays
The most common type of graphics
monitor employing a CRT is the raster-scan display, based on television
technology. In a raster-scan system, the electron beam is swept across the
screen, one row at a time from top to bottom. As the electron beam moves across
each row, the beam intensity is turned on and off to create a pattern of
illuminated spots. Picture definition is stored in a memory area called the
refresh buffer or frame buffer. Each screen point is referred to as a pixel. The
capability of a raster-scan system to store intensity information for each
screen point makes it well suited for the realistic display of scenes
containing subtle shading and color patterns.
Random-Scan Displays
a CRT has the electron beam directed only to
the parts of the screen where a picture is to be drawn. These monitors draw a
picture one line at a time and for this reason are also referred
to as vector displays.
Random-scan systems are designed for line drawing applications and cannot
display realistic shaded scenes.
DDA Algorithm
The digital differential analyzer (DDA) is a
scan-conversion line algorithm. This algorithm is summarized in the following
procedure, which accepts as
input the two endpoint pixel positions.
Horizontal and vertical differences between the endpoint positions are assigned
to parameters dx and dy. The difference with the greater magnitude determines
the value of parameter steps. Starting with pixel position (xa, ya),
we determine the offset needed at each step to generate the next pixel position
along the line path. We loop through this process steps times. If the magnitude
of dx is greater than the magnitude of dy and xa is less than xb, the values of
the increments in the x and y directions are 1 and m, respectively. If the
greater change is in the x direction, but xa is greater than xb, then the
decrements - 1 and -m are used to generate each new point on the line. Otherwise,
we use a unit increment (or decrement) in they direction and an x increment
(or decrement) of l / m .
Bresenham's
Line Algorithm
An accurate and efficient raster
line-generating algorithm, developed by Bresenham, scan converts lines using
only incrementa1 integer calculations that can be adapted to display circles
and other curves.
LINE ATTRIBUTES
Basic attributes of a straight line segment are its type, its width, and
its color. Various attribute specifications.
-Line Type
Possible selections for the line-type attribute include solid lines,
dashed lines, and dotted lines.
-Line Width
Implementation of line- width options depends on the capabilities of the
output device.
-Pen and Brush Options
With some packages, lines can be displayed with pen or brush selections.
Options in this category include shape, size, and pattern.
-Line Color
When a system provides color (or intensity) options, a parameter giving
the current color index is included in the list of system-attribute values.
AREA-FILL ATTRIBUTES
Options for filling a defined region include a choice between a solid
color or a patterned fill.
-Fill Styles
Areas are displayed with three basic fill styles: hollow with a color
border, filled
with a solid color, or Wed with a specified pattern or design.
-Pattern fill
-Soft fill : Modified
boundary-fill and flood-filI procedures that are applied to repaint areas so
that the fill color is combined with the background colors are referred to as soft-fill
or tint-fill algorithms.
CHARACTER TEXT ATTRIBUTES
-Font, size, color, and orientation
- bold face, italics, underline
Transformations
applying translation, rotation, and scaling parameters to reposition and
resize two-dimensional objects.
-Translation
A translation is applied to an object by repositioning it along a
straight-line path from one coordinate location to another.
-Rotation
A two-dimensional rotation is applied to an object by repositioning it
along a circular path in the xy plane.
-Scaling
A scaling transformation alters the size of an object.
LOGICAL CLASSIFICATION OF INPUT DEVICES
LOCATOR - a
device for specifying coordinate position ( x , y)
STROKE- a
device for specifying a series of coordinate positions
STRING- a
device for specifying text input( Physical Keyboard)
VALUATOR-a
device for specifying scalar value:
CHOICE-a device
for selecting menu options(with mouse)
PICK-a device
for selecting picture components(pick widow)
-LOCATOR:
mouse, joystick, trackball, space ball, thumbwheels, dials, a digitizer
stylus or hand cursor, or some other cursor-positioning
device.
-STROKE:
This class of logical devices is used to input a sequence of coordinate
positions. Stroke-device input is equivalent to multiple calls to a locator
device. The set of input points is often used to display line sections.
---VALUATOR -
scalar values are stores. such rotation angle.
