Transcript Multimedia Systems Design

Multimedia Systems Design
Introduction
Introduction
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“A Picture is worth a thousand words”
There have been ongoing attempts to improve
productivity of knowledge workers.
Reducing paper flow (reports, memos) has been
one important area where electronic mail and
groupware technologies are beginning to have
impact.
As the demands of business increased, the 1980s
were distinguished by overnight mail and fax as
the
means
of
communicating
important
information that did not require face to face
meeting.
Introduction
Electronic Mail
 Electronic Meetings
 Video Conferencing
 ISDN
 HDTV
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Introduction
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The technologies at the core of the
computing revolution have reached a
point where one can envision a
computing system composed of a
number of elements together by
various communication methods, all
striving to serve user.
Introduction
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The machine user interaction will be at
conversational level rather that through the typed
cryptic commands of yesterday or the mouse
movements still in use.
As screens become larger and feature increasingly
higher resolutions, the demand to see higherresolution images is increasing.
New technologies especially developed for GUI
allows
multiple
applications
to
operate
simultaneously using multiple windows, thereby
placing increasing demands on screen estates.
Introduction
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The main challenge for the designers of
multimedia systems will be to pack large volumes
of information in compact packets.
Local area network provides bandwidth ranging
from 10mbits/sec to several gigabits per second.
WAN depends on land, sea or satellite based
communication channels that carry a large number
of conversations.
With
such
bandwidths
compression
and
decompression of data is important.
The size of compressed data is important because
it determines the bandwidth necessary to meet
acceptable performance requirements.
What constitutes Multimedia?
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Multimedia meant a combination of text with
images.
Document image management was an outgrowth
of facsimile technology.
Facsimile provided a means of scanning and
converting a document into coded information that
described each pixel as white or black.
When the number of pixel per inch was low, the
information was easily manageable.
When the pixel densities increased as better fax
machines were developed, the information
became very large.
What Constitutes Multimedia?
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Wide variety of multimedia applications are in use
or under development like:
1. Video Conferencing
2. Medical applications, such as analysis of
surgical procedures and high resolution.
3. Real estates on-line video clips with property
descriptors
4. Multimedia help and training material
5. Security systems for employee identification
Multimedia Elements
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Multimedia applications require dynamic
handling of data consisting of a mix of text,
voice,
audio
components,
video
components, and image animation.
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Integrated multimedia application allows
user to cut sections of all or any of these
components and paste them in a new
document or in another application.
There
are
several
components
of
Multimedia:
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Facsimile
Fax. A process by which fixed graphic material
including pictures, text, or images is scanned and the
information converted into electrical signals which
are transmitted via telephone to produce a paper
copy of the graphics on the receiving fax machine.
 Facsimile transmissions were the first practical
means of transmitting document images over a
telephone line.
 It uses group3 compression standards.
 Typical pixel densities used for facsimile are in the
100 to 200 dpi range.
 The higher resolution are used to enhance the
clarity of documents.
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Document Images
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Document images are used for storing business
documents that must be retained for long periods
of time or may need to be accessed by a large
number of people.
Providing multimedia access to such documents
removes the need for making several copies of the
original for storage or distribution.
For storage of such documents minimum dpi
required is 300 dpi.
An uncompressed A-size(8 -½ inch x 11 -½ inch
image) is over 1 Mbyte.
Even with group 3 compression this size reduces
to approximately 75kbytes.
Document Images
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For images that are gray scaled or color, the sizes
are much larger to accommodate the pixel color
information.
Scanning of document images at that a high
resolution requires very efficient compression and
decompression technologies.
Photographic Image
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Photographic images are used for wide range of
applications such as employee records for instant
identification at a security desk, real estate
systems with photographs of house in the
database containing the descriptions of house.
For bank signature cards, patient medical history,
fingerprint cards.
To create photographic image with laser printer
resolution of 600 dpi is considered essential .
Geographic information system
maps
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Maps created in GIS are widely used for natural
resource and wild life management as well as
urban planning.
These systems store the graphical information of
the map along with a database containing
information relating high lighted map elements.
Two kinds of technologies are used for storage
and display of geographic maps.
Raster technology to display natural resources.
Another application combines raster image and
vector overlay showing railroads or highways and
other human made structure.
Voice Commands
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Voice commands allow the user to direct computer
operation by spoken commands.
Voice commands allow hands free usage of
computer applications by allowing command via
short voice commands rather than a keyboard or
pointing device.
Recognition of commands requires specialized
techniques and powerful processing capabilities to
compensate for differences in pitch, accents, and
voice modulation techniques of users.
Voice Synthesis
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Transforming computer output to voice or audio
output.
It is easier to achieve in compare to voice
recognition.
The cadence(the consistency with which the
spoken words are stung together) of the output
should be good for message to be clear.
Digital signal processors designed for such an
application have the processing power to perform
the computations and maintain correct cadence.
Audio Messages
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Audio messages are substitute of text messages.
Computers having microphone can record audio
message and can embed it into electronic mail.
Audio messages also require large volumes of
storage.
Compression techniques are required to manage
the storage efficiently.
With image speed of decompression and display is
important, speed of decompression and playback
of audio message with proper cadence is
important for audio message.
Video Messages
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Similar to audio messages, video messages can be
embedded into electronic mail messages.
The storage and playback requirements are even
more complex with video messages because of
storage of each video shots.
Full motion stored and live
video
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Full motion video act as very useful idea for online
training manuals.
Full motion video can be used for video
conferencing, live video presentations.
Full motion video requires high bandwidth for
communication, massive storage requirements and
high compression techniques.
High-definition television (or HDTV) is a digital
television broadcasting system with higher
resolution than traditional television systems
Again digital HDTV(High definition TV) places
another major demand on the design- that of
special effects such as zoom, freeze frame, image
merging and image reconstruction.
Holographic Images
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Holographic images extend the concept of virtual
reality by allowing the user to get inside a part,
such as, an engine and view its operation from the
inside.
Multimedia Applications
Document Imaging
 Image Processing and Image
Recognition
 Full Motion Digital Video Applications
 Electronic Messaging
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Document Imaging
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Organizations such as insurance agencies, law
offices, state governments, and the federal
government, including the department of defense,
manage large volumes of documents.
Document imaging makes it possible to store,
retrieve, and manipulate very large volumes of
drawings, documents, and other graphical
representations.
Ex: Sending large volumes of engineering data
about complex systems in electronic form rather
than on paper.
Document Imaging
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Almost all document image systems use below
work flow:
1. Scanning images
2. Performing Quality checks
3. Performing data entry based on the contents
of the images.
4. Indexing them
5. Storing them on optical media
Image Processing and Image Recognition
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Image
Image
Image
Image
Image
processing involves:
Recognition
Enhancement
Synthesis
Reconstruction
Image Processing and Image Recognition
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The original image is not altered in document
image workflow.
Image processing system actually alter the
contents of the image itself.
Ex: Recognition of images: in factory floor
quality assurance systems,
Image Enhancement: Satellite reconnaissance
systems
Image Synthesis: Law enforcement suspect
identification
Image Reconstruction: In Plastic surgery design
systems
Image Enhancement
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Image enhancement improves the quality of
images for human viewing.
Removing blurring and Noise, increasing
contrast .
For example an image might be taken of any
cell of body which might be of low contrast
range could enhance the image.
Increasing sensitivity and contrast makes picture
darker by making borderline pixels black or
increasing the gray scale level of pixels.
Image Animation
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Computer created or scanned images can be
displayed sequentially at controlled display
speeds to provide image animation.
Image animation is a technology developed by
Walt Disney and brought into every home in the
form of cartoons.
Optical Character recognition
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OCR technology is used for data entry by
scanning typed or printed words in a form.
OCR technology used as a means for data entry
may be used for as simple a task as reading the
number of an invoice, or for capturing entire
paragraphs of text.
Handwriting Recognition
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Handwriting Recognition has been subject of
intensive research now a days.
Pen based systems are designed to allow user to
write commands on an electronic tablet.
Key Design Constraint: Ability to recognize
writer
independent
continuous
cursive
handwriting accurately in real time.
Two factors are important: Strokes or shapes
being inputted and velocity of input.
Parse recognizer will identify topology of
strokes.
Handwriting Recognition
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The stroke is compared with the prototype
character set until a match is found or all
predefined prototypes are checked.
Full Motion Digital Video
Applications
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Full Motion video is the most complex and the most
demanding component of multimedia applications.
Full Motion Video Applications:
1. Training and Manuals:
On-Line Reference
CD-Rom
Training
2. Business Applications;
E-Mail
Video Conferencing
Presentations
Demos
Full Motion Digital Video
Applications
3.
Games and Entertainment
Interactive TV
CD-ROM Interactive Games
Full Motion Digital Video
Requirements
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It should be possible to attach full motion video clips
to other documents such as memos, presentations.
Users should be able to take sections of a video clip
and combine the sections with sections from other
video clips to form their own new video clip.
Features such as rewind, fast-forward, play, and
search should be available.
It should be possible to view the same clip on a
variety of display terminal types with varying
resolution capabilities without storing multiple copies
in different formats.
It should be possible for users to move and resize the
window displaying the video clip.
Full Motion Digital Video
Requirements
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The users should be able to adjust the contrast and
brightness of the video clip and also adjust the
volume of the associated sound.
Evolving Technologies for multimedia
systems
Hypermedia documents
Hypertext
Hyper speech
 HDTV and UDTV
 3-D Technologies and Holography
 Fuzzy Logic
 Digital Signal Processing
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Hypermedia documents
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Technical and business documents in
electronic form.
It contains text, embedded or linked
multimedia objects such as image, audio or
full motion video.
Hypermedia has its roots in hypertext.
Hypertext
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Hypertext allows authors to
Link information together,
 Create information paths through a large
volume of related text in documents
 Explicit connections or links allow readers
to move from one location to another in a
document or to other documents.
 Hypermedia is an extension of hypertext in
that these electronic documents, in addition
to containing text will also include any kind of
information that can be stored electronically.
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Hypertext
An important issue arise with Hypermedia
document is storage.
 It does not make sense to embed full copies of
each component of a hypermedia document within
document file.
 Rather, since the embedded components may
also be included in other documents.
 Hypermedia document only store references to
the documents.
 The user sees a single document, but the
locations of the various components that are in
document are transparent.
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HDTV and UDTV
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The electronics industry is attempting to raise the resolution levels
of commercial television broadcasting.
Among the better-known television broadcasting standards are
NTSC, PAL, SECAM, NHK, and others.
These standards range in resolution from 525 lines for NTSC to
819 lines for the French standard.
A hot debate has been in progress for bringing the world together
on a single high-definition television (HDTV) broadcasting
standard.
A 1125-line digital HDTV has been developed and is being
commercialized.
NHK of Japan is trying to leapfrog the digital technology to
develop ultra definition television (digital UDTV) featuring
approximately 3000 lines. Figure 1-5 shows the progression in the
resolution of television pictures..
HDTV and UDTV
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There are some key technologies necessary to make
the jump to a 3000-line UDTV standard.
It requires the development of ultra- resolution
displays at a commercially viable price, high-speed
video-processing ICs, and ultra broadband
communications bandwidths for WAN services such
as ISDN.
Fuzzy Logic
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It
includes
graphics
rendering,
data
compression for images, voice and video, voice
recognition and synthesis, as well as signal
processing for video, high resolution facsimile.
Graphics rendering involves the painting of
three dimensional objects onto a twodimensional display
Any application that is computationally
intensive can benefit from the mathematical
principles behind fuzzy logic.
Types of images
Visible Images
Visible Images include
Drawings such as
Blueprints, Engineering Drawings, Space maps for Offices,
n Town Layouts, Paintings, Photographs, Documents,
Still Frames
 Non-visible Images:
Non-visible Images are not stored as images but it is displayed
as images. The examples include
Pressure Gauges
Temperature Gauges
Other metering displays
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Abstract Images
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Abstract Images are not really images. They exist
as real world objects or representations.
They are computer generated images based on
some arithmetic calculations. The examples are
Kaleidoscope – Shows different patterns due to
relative positions of glass beads when it is rotated
The mathematical used for generating Abstract
Images:
Discrete Functions – It results in still images that
remain constant.
Continuous Functions – It is used to show
animated images and operations such as image
fading or dissolving into another image
Multimedia data interface Standards
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Video Processing Standards:
Intel’s DVI
Apple’s Quick Time
Microsoft’s AVI
Intel’s DVI
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DVI is actually both the name of the Digital Video
Interactive hardware system sold by Intel and the file
format associated with that system. DVI technology
is essentially a PC-based interactive audio/video
system used for multimedia applications
Apple’s Quick time
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QuickTime (sometimes called QTM) is the native
method of storing audio and motion video
information on the Apple Macintosh platform.
It is used to record and play back multimedia
information and store the data on magnetic or optical
media.
QuickTime, however, is not only a data-storage
format. It is also a collection of tools (the Movie
Toolbox) that allows QuickTime movies to be
modified (edit, cut, copy, paste, and so on), just as a
word processor is capable of modifying an ordinary
text file.
Apple’s Quick time
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Quick time includes:
System Software
File formats
Compression/Decompression
algorithms
Human interface standards
Microsoft’s AVI
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Microsoft’s Audio video interleave standard, similar
to apple’s quick time offers low cost, low resolution
video processing.
It allows users to set parameters such as window size,
quality, compression algorithm