Image compression

1. IMAGE COMPRESSION & TRANSMISSION
THROUGH DIGITAL COMMUNICATION SYSTEM

2.  Shaik Babu
 Chenamsetty Suresh
 Gadde Jhansi
 Guda Madhusudhan Reddy
Under the guidance
Of
Prof. M.Venu Gopala Rao

3. The main aim of the project is to reduce the
amount of data required to represent the
digital image,using DCT or DWT, and the
transmission of the compressed image
through digital communication system.

4.  Huffman and shannon coding,which remove
coding redundancies ,when combined with
the techniques like DCT & DWT helps in
compressing the image data to a very good
extent.

5.  Source coding in the form of image
compression at transmitter side and image
recovery at the reciever side are the integral
process involved in any digital
communication system

7.  A DCT expresses a sequence of finite data
points in terms of sum of cosine functions
oscillating of different frequencies.
 A DWT is any wavelet transform for which the
wavelets are discretely sampled.

9.  A wavelet is a wave-like oscillation with
an amplitude that start out at zero,increases,
and then decreases back to zero.
 It can typically be visualized as a "brief
oscillation" like one might see recorded by
a seismograph or heart monitor.
A simple wavelet.

10. 2-Dimension analysis

11. LL2 HL2
LH2 HH2
LH
HL
HH
LH
HL
HH
HL2
LH2 HH2
LL3 HL3
HH3
LH3

12. Huffman Coding Example

13. Shannon coding Example

15.  Signal modulation is achieved by using the
‘Binary phase shift keying’[BPSK].
 BPSK as amodulation technique ,where the
two phases of a signal are used to double the
data rate and hence it’s also known as 2-PSK
modulation.

17.  A channel is used to convey an information
from one or more senders to one or more
recievers.
 A channel has a certain capacity for
transmitting information,measured in Hz or
data rate in bits/sec.

18.  Generally,channel refers to a physical
transmission medium like wire or logical
connection over multiplexed medium such as
radio channel.

19.  In information theory,channel coding refers
to,”however the channel is contaminated
noise interference”,it is possible to
communicate digital data nearly error free up
to given maximum rate through the channel.

20.  And the channel coding can be achieved by
adding some redundancies in the transmitted
data stream in a controlled manner.

24.  We see that SNR & compressed ratio are
directly affected by changes in quantization
level & number of diagnols.
 As expected the SNR increases &compression
ratio decreases by increasing the number of
diagnols number of quantization levels and it
can also be noticed that SNR decreases and
compression ratio increases with the increase in block
size.

25.  Digital image processing using matlab
- Rafael C.Gonzalez
 Digital signal processing
-G.Proakis
 Information theory and coding
-Ranjan bose
 Getting started with matlab
-Rudra pratap