Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Diff between discrete cosine and wavelet

Status
Not open for further replies.

Resistance

Member level 4
Joined
Dec 24, 2005
Messages
74
Helped
5
Reputation
10
Reaction score
2
Trophy points
1,288
Activity points
2,034
signal denoising discrete cosine transform

hi

Diff between discrete cosine and wavelet

wat makes the former more stronger..

appications where they are used specifically..

regards
 

sehablavhdl

Junior Member level 2
Joined
Nov 22, 2001
Messages
21
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
46
Hi
DCT is the type of Fourier transform, in this transform cosines are basis functions,where as in wavelet transform wavelet is the basis funtion.that means in DCT your signal is represented in terms of cos functions where as in wavelet transform signal is represented with shifted and scled version of mother wavelet.

Beauty of wavelet transform is time -frequency representation and basis choice.

Added after 2 minutes:

Hi
Sorry i forgot to mention about applications of DCT and wavelet transform(WT)
mostly DCT is used in Image compression, where as wavelet transform is also useful in image compression, Image denoising,signal denoising,Transient signal processing,time-freq representation.
 

Robinenemy

Advanced Member level 4
Joined
Jul 10, 2006
Messages
110
Helped
26
Reputation
52
Reaction score
11
Trophy points
1,298
Activity points
1,916
A discrete cosine transform (DCT) is a Fourier-related transform similar to the discrete Fourier transform (DFT), but using only real numbers. DCTs are equivalent to DFTs of roughly twice the length

DCT is used in JPEG image compression, MJPEG, MPEG, and DV video compression

DCTs are also widely employed in solving partial differential equations by spectral methods

Wavlet is time-freq representation of signal.
Wavelets are used in numerous applications including
They can do multiresolution analysis of a signal which is not possible in DCT as it has only one resolution that of the frequency.
Compression
Feature Extraction
and other engg applications as well.
Numerous type of Wavelets are available includind Haar,Gabor,Mexican Hat you can even create your own wavelet functions

Regards

Robin
 

yuna

Newbie level 6
Joined
Sep 27, 2006
Messages
12
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,371
Hello,
Now i am doing palm print recognition, may i ask Discrete Cosine and wavelet which is better?
How am i develop it in my project after i extract the palm line from the palm?

Thanks in advance.:cry:
 

yok

Member level 3
Joined
Jul 27, 2006
Messages
59
Helped
11
Reputation
22
Reaction score
3
Trophy points
1,288
Activity points
1,639
Use wavelets. Wavelets is able to generate better image feature (I assume you will capture palm print using imaging system) compared to DCT. As given in the first two reply, wavelets has the ability to represent signal/image in time-freq localisation which Fourier basis are only well represented in freq domain. So, why you are needed good time-freq representation for your palm features? That is to ensure the captured palm feature has spatial geamentry invariant properties. Thus, the recognition performance will be improved.

Added after 2 minutes:

For the palm lines, you can refer to some papers on the topics of wavelet singularities detection. From there you should be able to construct a good wavelet represntation of your palm features. Search for Mallat's papers for the topics, he is the Guru of that.
 

yuna

Newbie level 6
Joined
Sep 27, 2006
Messages
12
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,371
Hello Yok,

Actually i already extracted the palm lines from the palm by using sobel operator...
But now i am in stuck....i don't know how to implement the wavelet in the palm print feature extraction for classification?
Hope you can guide me....

Thanks in advance.:|
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top