how can i follow canny output?

I segment a mammography breast image but the border of it is not accurate. I also have canny output of the image. now, I want to expand breast region to outer border of canny, but I do not know how to do it? I insert the output of breast segmentation and canny output below. I want to expand segmentation to outer border of canny. can you help me?

[nadia]

no one has any suggestion?

Answer 1

[Image Analyst]

Why did you use canny anyway? Why not just threshold? Or maybe you can use activecontour() for a smoother outline.

[nadia]

Dear Image Analyst, I use different threshold but the background is very noisy or very similar to foreground and using threshold can not solve the problem. In this attached demo a threshold should be specified that I do not know how to compute it based on each image? suppose one of my main image is below and I want to extract breast region using activecontour. how can I do it?

[nadia]

I use my segmented image as mask and main image before segmentation as grayImage in this demo. but it move into image and can not follow outer border.

[Image Analyst]

Why do you need to "remove" the background anyway? The signal is very low. If you need to mask it off, I'd probably just use a triangle threshold (attached) and erase it.

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;

filename = 'D:\Matlab\work\Tests\mdb00.png';
grayImage = imread(filename);
subplot(2, 2, 1);
imshow(grayImage);
title('Original Image', 'FontSize', fontSize);

% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off') 

pixelCounts = imhist(grayImage);
thresholdLevel = triangle_threshold(pixelCounts, 'R', true)
mask = grayImage > thresholdLevel;
subplot(2, 2, 2);
imshow(mask);
title('Initial Mask', 'FontSize', fontSize);

mask = bwareafilt(mask, 1); % Take largest blob only
mask = ~imfill(mask, 'holes');
subplot(2, 2, 3);
imshow(mask);
title('Final Mask', 'FontSize', fontSize);

grayImage(mask) = 0;
subplot(2, 2, 4);
imshow(grayImage);
title('Final, Masked Image', 'FontSize', fontSize);

[nadia]

that's very good but when I use triangle_threshold it produce this error and dose not work?! Undefined function or variable 'WarnUser'

[Image Analyst]

is just this:

function WarnUser(warningMessage)
fprintf('%s\n', warningMessage);
uiwait(warndlg(warningMessage));

[nadia]

I solve the error but in some images like below it dose not work. do you have any idea? I appreciate your help.

[Image Analyst]

Zero out the pixelCount(1). There's something weird about the histogram so it's not finding the right threshold. It's because the second bin is zero and the first bin is real high. Zeroing out the first bin will fix that.

[nadia]

no, this solution dose not work. because in some other images by zero out the pixelCount(1),threshold become very big and only some white part remain.