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Advanced Multimedia and Graphics Dr. Serhan Dagtas 12:15-1:30 pm Tue & Thu Introduction Introduction to the course Outline, objectives, material, etc. Introduction to multimedia Course Outline Introduction to various media types; still images, video, audio, speech, text, graphics

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advanced multimedia and graphics
Advanced Multimedia and Graphics
  • Dr. Serhan Dagtas
    • 12:15-1:30 pm Tue & Thu
introduction
Introduction
  • Introduction to the course
    • Outline, objectives, material, etc.
  • Introduction to multimedia
course outline
Course Outline
  • Introduction to various media types; still images, video, audio, speech, text, graphics
  • Acquisition
  • Compression techniques
  • Analysis and indexing of multimedia content
  • Multimedia retrieval
  • Storage
  • Applications
course objectives
Course Objectives
  • Understand the basics of multimedia systems
  • Store, process, and present multimedia data
  • Image, audio, and video indexing & retrieval
  • Work on research projects
  • Computer graphics and virtual reality
course materials
Course Materials
  • Textbooks
    • Mutimedia Fundementals Vol. I,
    • Multimedia Comm. Systems
    • Handouts and web material
exams and projects
Exams and projects
  • Exams
    • Midterm
    • Final
  • Projects
    • 3-5 assignments
    • Group project
policies
Policies
  • Reading
    • Read the chapters
    • Assignments may not be from lecture
  • Attendance is expected
multimedia
Multimedia
  • Media (plural of medium)
    • Virtually any means of conveying information
    • Mostly text, audio, images, video
    • Also music, raw data, graphic objects, etc.
  • Multimedia
    • More than one media type simultaneously manipulated
multimedia information systems
Multimedia Information Systems
  • Storage, Retrieval, Management and

Analysis of information in any form

    • Images
    • Video
    • Audio
    • Graphics, charts, etc.
    • Text
    • Data
multimedia what
multiMEDIA what?
  • Medium (media): A means by which information is perceived… Or: A means of affecting or conveying something (information)

“Multimedia” is an adjective!

multimedia information systems11
Multimedia Information Systems
  • The confluence of several technologies
  • Digital signal processing
  • Image processing
  • Computer graphics
  • Digital Video technology
  • Visual interactive languages
  • Advanced databases
  • Operating systems
  • Computer networks
some enabling factors
Some Enabling Factors
  • Optical disc technology
    • large volumes
    • preserve quality
  • Shift from analog to digital processing
    • high resolution image
    • high fidelity audio
slide13
Analog Video

Digital Video

  • loss of quality in copying
  • cannot be annotated
  • consumers cannot edit
  • duplication without loss
  • index, search, editing
  • fast random access
  • high quality playback
  • interactive
enabling factors cont d
Enabling Factors (cont’d)
  • Fiber optics technology
    • high bandwidth
    • accuracy
    • speed
  • Fast specialized processors
    • audio boards
    • video boards
  • Better software,
    • real-time OS
    • codec (software only)
properties of multimedia system
Properties of Multimedia System
  • Combination of Media
    • Is any combination of media a multimedia?
  • Independence
    • Tightly coupled media are not considered multimedia, e.g., a computer controlled video recorder stores audio and video but they are tightly connected
  • Computer supported integration
  • Communication systems
continuous vs discrete
Continuous vs. Discrete
  • Discrete media
    • time-independent: text and graphics
  • Continuous media
    • time-dependent: sound and full motion video
analog vs digital
Analog vs. Digital
  • Analog
    • Media represented using real values
  • Digital
    • Media represented using discrete values
      • (integers, quantized numbers, floating point representations)
sampled media
Sampled media
  • Sampled media
    • Represented by discrete points (which may be real valued)
  • Notice:
    • Sampled does not imply Digital
sampling
Sampling

Sampling - simply taking voltage readings at fixed points in time

Uniform sampling – sampling at regular intervals

digital conversion
Digital Conversion
  • Given voltage readings at points in time:
    • Convert the readings to digital
  • Options for digital representation:
    • Integers
    • Floating point values
we ll focus on
We’ll focus on...
  • Digital sampled media
  • But…
    • We have to understand the underlying continuous media...
an overview of media types
An Overview of Media Types

We will look at:

  • text
  • Image
  • Sound
  • Video
slide24
Text
  • Plain text:
    • alphanumeric characters
    • Most common representation is ASCII
  • Structured text
    • Text documents are structured (title, sections, …)
    • There are many standards and formats:
      • Word processor formats
      • LaTex, PDF
text compression
Text Compression
  • Compression is either lossy or lossless
  • Text compression is lossless
  • Text compression uses the fact that some characters and phrases appear more often than others
text compression huffman coding
Text compression: Huffman coding
  • Idea: assign fewer bits to symbols that appear more often and more bits to symbols that are less often
  • Example:
    • Assume a file with 1000 characters
    • Characters are e, t, x, and z
    • Probability of occurrence 0.8, 0.16, 0.02, and 0.02
    • In normal coding we need 2 bits for each symbol  2000 bits for the entire file
    • Using Huffman: 1 for e, 01 for t, 001 for x, and 000 for z
    • Total number of bits = 1000(1*.8+2*.16+3*.02+3*.02) = 1240
text compression run length coding
Text compression: run length coding
  • Directly reduce the number of repeating characters
  • A run of any length is represented by: Sc, X, C
    • Sc special character
    • X is the repeated character
    • C is the character count
text compression lampel ziv welch lzw
Represent the phrase by its token

Input

file

Yes

Phrase

No

add phrase to dictionary and

generate a token

Did it appear

before?

Text compression: Lampel-Ziv-Welch (LZW)
  • Idea: build a dictionary of phrases from the input file.
lzw example
LZW example
  • Assume a file with 10,000 characters
  • If we use 8 bits for each character, we need 80,000 bits for the file
  • Suppose the file has 2000 words or phrases out of which 500 are distinct
  • We can use 9 bit tokens for each word or phrase  total number of bits is 18,000 bits
image
Image
  • human and computer vision
  • Vision
    • to see an image and to understand its contents
    • capturing, analysis, and extracting features
  • Computer vision/image processing
    • intensity levels
    • resolution
    • distances and areas
    • the role of color
  • Images vs. Graphics
    • images are captured, graphics are created.
    • images are sequences of picture elements, graphics are a series of commands.
    • graphics may be converted into (synthetic) images
vision image processing and visualization
REAL

WORLD

IMAGE

Vision, Image Processing and Visualization

Photography

Image

Processing

Computer

Vision

Computer

Graphics/

Visualization

SCENE

DESCRIPTION

what kind of images
What kind of images…?
  • Face photos: Mug shots
  • Finger prints
  • CAT-scan data
  • News photos (general. Usually accompanied with explanatory text)
  • Surveillance (semi-specific domain,we may or may not know what to look for).
  • Video segments
    • Movies:general
    • surveillance
    • News broadcast
    • Sports
summary
Summary
  • Multimedia
  • Multimedia information systems
  • Enabling factors
  • Continuous vs. discrete
  • Analog vs. digital
  • Text
  • image
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