Butterworth Lowpass Filter

The Butterworth Lowpass Filter (BLPF) does not have a sharp cutoff frequency as the ILPF, instead it lets all the frequencies
below Do pass and then the drop to the point where no frequencies pass is very gradual. The effect of order 'n' and cutoff
frequency 'Do' can be studied on the images below.


`The Original Image`	`Image after using the BLPF` `with Do = 30 & n = 1`	`Image after using the BLPF` `with Do = 30 & n = 2`

`Fourier Spectra of Original Image`	`Fourier Spectra after using the BLPF` `with Do = 30 & n = 1`	`Fourier Spectra after using the BLPF` `with Do = 30 & n = 2`


`Image after using the BLPF` `with Do = 60 & n = 1`	`Image after using the BLPF` `with Do = 60 & n = 2`

`Fourier Spectra after using the BLPF` `with Do = 60 & n = 1`	`Fourier Spectra after using the BLPF` `with Do = 60 & n = 2`

Page last updated on 28 January, 2004.	`AT cse.iitd.ac.in`	© Parag Chaudhuri , 2009