1
Q
What is lossless compression
A
Reversible data compression
PNG
2
Q
Where is lossless used
A
Magical images. Court of law images
3
Q
What is lossy compression
A
Irreversible compression
JPG
4
Q
Where is lossy compression used
A
Non essential perceptual data
5
Q
What is Huffman coding
A
Minimal length variable code
6
Q
What type of code does Huffman generate
A
Variable length codes
7
Q
Typical reduction from Huffman
A
10%-50%
8
Q
First step of Huffman coding
A
Sort symbols by probability
9
Q
What are the steps of converting an image to JPEG
A
1 - transform an image into an intensity based colour system
2 - break into small blocks
3 - shift values around zero
4 - Apply DCT
5 - quantisation
6 - Huffman encoding
