Data compression

An alphabet consist of the letters A, B, C and D. The probability of occurence of A=0.4, B=0. 1,C=0.2 and D=0.3 The Huffman code is

• A0

  B111

  C110

  D10

• A0

  B111

  C11

  D101

• A01

  B111

  C110

  D10

• 0

  11

  10

  111

The basic idea behind Huffman coding is to

• Fever bits to encode fewer frequently occuring character

• Expand data by using fewer bits to encode more frequently occuring character

• Compress data by using more bit to encode more frequently occuring character

• Compress data by using fewer bits to encode more frequently occuring character

Huffman coding is an encoding algorithm used for

• Broadband system

• Lossy data compression

• Lossless data compression

• Files greater than 1 Mbit

Huffman encoder takes a set of characters with fixed length and produces a set of characters of

• Constant length

• Random length

• Fixed length

• Variable length

Huffman code A1, B000, C001, D01. probability of A=0.4, B=0.1, C=0.2and D=0.3.

The average number of bits per letter is

• 1.9

• 2

• 2.1

• 8

The idea with wavelets is to represent a complicated function by

• Lines

• Sinus function

• Simple basic function

• Square function

Down sampling is to make a digital image file smaller by

• Adding noise

• Adding pixels

• Removing pixels

• Removing noise

In a typical picture most pixels will be

• Bright

• Equal

• Very similar to their neighbours

• Very different to their neighbours

Without losing quality JPEG2000 can achieve compression ratio of

• 2:1

• 200:1

• 20:1

• 2000:1

The best visual compression quality is achieved using

• Fourier transform

• DCT

• Wavelets

• Dolby