# java profram hi bob

Document Sample

```					                                                Image Processing

Q1-Dennis Gabor, a Hungarian-born British electrical engineer who won a Nobel Prize in
Physics for the invention of optical holography, was also interested in Image Processing. In
his paper published 45 years ago, Gabor suggested interesting modifications of a standard
image enhancement procedure.

A common way to enhance a given monochrome (grey-scale) image I  x, y  is to amplify
linearly the high frequencies of the image
 0           I enhanced  x, y   I  x, y   C I  x, y 
where  is the Laplacian and C is a constant to be determined empirically.

Gabor suggested two non-linear modifications of (0):
2I
1              I enhanced  x, y   I  x, y   C 2
n
 2I 1 2I 
 2              I enhanced  x, y   I  x, y   C  2      2 
 n 3 s 

where n is the coordinate in the direction of the gradient of I  x, y  and s is the coordinate
in the direction orthogonal to n . It is not difficult to show that
2                         2
 2 I  I       2 I I I  2 I  I                      2 I  I       2 I I I  2 I  I 
2                                                                                            2

     2                                                          2                    
2 I     x 2  x      xy x y y 2  y 
               2 I     x 2  y 
        xy x y y 2  x 
                                                            
n 2                      I   I 
2          2
s 2                    I   I 
2          2

                                                         
 x   y                                                x   y 

Your task is to implement and compare image enhancement methods (1), (2), and (3|).

Reference:

M. Lindenbaum, M. Fischer, and A. Bruckstein, “On Gabor’s Contribution to Image

Enhancement”, Pattern Recognition, Vol. 27, No. 1, pp. 1-8, 1994.

Q2 -Given an grey-scale image I(x,y), consider the following non-linear iterative process:

I 0  x, y   I  x, y 

wij  exp  k I n x, y   I n x  i, y  j  
1                         1
I n1 x, y        w I  x  i, y  j   w
ij n                      ij
i , j  1                i , j  1
where k is a positive constant. Note that the weights {wij} depend on the pixel positions (x,y)
and the iteration number n. After a certain number of iterations you should get results similar
to those shown in the picture below: small-scale image details are removed while salient
image edges are sharpened. Your task is to implement the above non-linear iterative
procedure, perform a number of experiments (with different images, various numbers of
iterations and k).

 Is the proposed non-linear averaging procedure good for generating cartoon-like
images?
 Is it difficult to find an appropriate number of iterations and K for a given image?
 Is your implementation of the procedure time-consuming?
 Can similar results be achieved using simpler tools?
 Propose possible applications for the procedure.
 Try to suggest some improvements.

```
DOCUMENT INFO
Shared By:
Categories:
Stats:
 views: 17 posted: 2/13/2010 language: English pages: 2