How to remove the noise in this image??

Hi, I am new to matlab and I have an assignment to segment the iris region of this image. Here is the code I have done so far.

clc;

clear all;

img = im2double(imread('1_L.jpg'));

subplot(3,3,1);imshow(img);title('Original image');

imgBW = edge(img, 'canny');

subplot(3,3,2);imshow(imgBW);title('Canny edge detection');

Thresh1 = 0.4;

Thresh2 = 0.7;

R1 = img < Thresh1;

R2 = img >= Thresh1 & img <= Thresh2;

R3 = img > Thresh2;

%//Zero-pad the regions so we can check the borders

R1 = padarray(R1, [1 1], 'replicate');

R2 = padarray(R2, [1 1], 'replicate');

%//Transform into columns

B1 = im2col(R1, [3 3]);

B2 = im2col(R2, [3 3]);

%//Extract size for later

[rows,cols] = size(R1);

%// Extract centre of each neighbourhood

middleB2 = B2(5,:);

% // Find the indices of those neighbourhoods that have 1 in the centre

windowsHaving1 = find(middleB2 == 1);

% // Access the corresponding neighbourhoods in R1

% // If ANY of them have a pixel of 1, then we know

% // these locations from R2 need to go back to R1

% // In that case, all you really have to do is take whichever

% // pixels are true, and set them to true in R1

% // See which neighbourhoods in `R1` have any pixels that are 1

% // given the corresponding region in R2

finalColumns = any(B1(:,windowsHaving1), 1);

% // Grab the indices of these columns

finalColumnsIndex = windowsHaving1(finalColumns);

% // Reasign those pixels that are neighbours to R1

B1(5, finalColumnsIndex) = 1;

B2(5, finalColumnsIndex) = 0;

%// Restructure back - Recall this image is padded

%// We took the rows and columns of the padded image

%// and so we need to subtract each dimension by 2

R1 = reshape(B1(5,:), rows-2, cols-2);

R2 = reshape(B2(5,:), rows-2, cols-2);

R3 = R2 | R3;

subplot(3,3,3);imshow(R2);title('Wanted region');

The problem is, I cannot fully turn the wanted region of the iris as the lower part has some darkness and I do not know how to remove the noise in the image. What am I doing wrong?? Is there a step I skipped??

[shreevi vijayan]

yes u skipped a step called denoising.that is u have to remove noise in your image before using canny edge detector

[Mohd Zulhelmi Muhamud Naim]

Thank you shreevi, for pointing that out. Would care to point on how to do it??

EDIT: Ok, here is the image result of the above code

[Image Analyst]

And you forgot to attach your image (so we can't try your code) or show any intermediate images.

Answer 1

[shreevi vijayan]

yes u skipped a step called denoising.that is u have to remove noise in your image before using canny edge detector

Answer 2

[shreevi vijayan]

chech this link for denoising :

http://in.mathworks.com/help/wavelet/examples/de-noising-signals-and-images.html