Course: CIS451/651  Data Compression in Multimedia
Professor: Paul D. Amer
Semester: Spring 2009
Title:  Homework Chapter 4 - Arithmetic Coding
Due Date:

Tasks

Read Sections 4.1 - 4.4.2, and 4.5-4.7, inclusive.  (You are not responsible for Section 4.4.3, nor the details within Section 4.6).  For all problems where the answer requests any value within an interval, choose the midpoint or a greater value that is easy to convert to binary.  For all answers, show all work.
  1. (2 pts) Chapter 4 Projects and Problems: 5
  2. (2 pts) Chapter 4 Projects and Problems: 6
  3. (4 pts) Assume a 2 symbol input alphabet (a1, a2} with probabilities {.6, .4}, respectively.  Use arithmetic encoding (without scaling) to derive a binary encoding of  the following two strings:
    1. a1 a1 a2
    2. a2 a2 a2
  4. (2 pts) Given an alphabet {a,b,c,d} with respective expected probabilities {.1,.3,.4.,.2}, decode the value .75 as a 8 symbol string.
  5. (2 pts) Encoding without scaling.  Redo Example 4.3.5 (which is based on Example 3.2.3), but with underlying probabilites for {a1, a2, a3} of {.7, .1, .2} instead of {.8, .02, .18}.  Submit your answer in binary.
  6. (2 pts) Decoding without scaling. Redo Example 4.3.6 with your previous answer (and revised probabilities {.7,.1,.2}).
  7. (2 pts) Encoding with scaling.  Redo Examples 4.4.2 also with the revised probabilites of {.7, .1, .2}.
  8. (2 pts) Decoding with scaling. Redo Example 4.4.3 with your previous answer (and revised probabilities of {.7, .1, .2}).

Notes