Databases Reference
In-Depth Information
F I GU R E 10 . 15
Top left: codebook size 16; top right: codebook size 64; bottom
left: codebook size 256; bottom right: codebook size 1024.
In this example, we used codebooks trained on the image itself. Generally, this is not the
preferred approach because the receiver has to have the same codebook in order to reconstruct
the image. Either the codebook must be transmitted along with the image, or the receiver
T A B L E 10 . 7
Summary of compression measures for image
compression example.
Codebook Size
Bits Needed to
(# of codewords)
Select a Codeword
Bits per Pixel
Compression Ratio
16
4
0
.
25
32:1
64
6
0
.
375
21.33:1
256
8
0
.
50
16:1
1024
10
0
.
625
12.8:1
