How to extract region of Interest of gray Image?

Hi, I'd like to extract right half and left half of breast and i found borders of left( red line)and right (yellow line)of breast and middle line. Also I seperated image from middle but i couldn't extract both right and left half of image.

Second Image (c) is what i want.

clc;    % Clear the command window.
fprintf('Beginning to run %s.m ...\n', mfilename);
close all;  % Close all figures (except those of imtool.)
clearvars;
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
grayImage = rgb2gray(imread('DINAMIC-FRONTAL1.jpg'));
en = imsharpen(grayImage,'Radius',2,'Amount',1);
B = double(imgaussfilt(en,1.4));

% filtered_image = zeros(size(B));
% Mx = [-1 0 1; -1 0 1; -1 0 1];
% My = [-1 -1 -1; 0 0 0; 1 1 1];
% for i = 1:size(B, 1) - 2
%     for j = 1:size(B, 2) - 2
%   
%         % Gradient approximations
%         Gx = sum(sum(Mx.*B(i:i+2, j:j+2)));
%         Gy = sum(sum(My.*B(i:i+2, j:j+2)));
%                  
%         % Calculate magnitude of vector
%         filtered_image(i+1, j+1) = sqrt(Gx.^2 + Gy.^2);
%          
%     end
% end
% filtered_image = uint8(filtered_image);
% figure(); imshow(filtered_image); title('Filtered Image');
% thresholdValue = 100; % varies between [0 255]
% output_image = max(filtered_image, thresholdValue);
% output_image(output_image == round(thresholdValue)) = 0;
ed=edge(B,'canny',0.3,0.5);
figure();
imshow(ed);
title('Initial Canny Edge', 'FontSize', fontSize);

bw1=bwareaopen(ed,10);
se = strel('disk',4);
bw=imdilate(bw1,se);
subplot(2, 2, 2);
imshow(bw);
title('Next Mask', 'FontSize', fontSize);
% Take largest 2 blobs.
bw = bwareafilt(bw, 2);
% Erase top half
[rows, columns] = size(bw);
bw(1:round(rows/2), :) = false;
% Skeletonize
bw = bwskel(bw);
% Find branchpoints.
[bpRows, bpColumns] = find(bwmorph(bw, 'branchpoints'))
% Erase branchpoints.
hold on;
for k = 1 : length(bpRows)
	bw(bpRows(k), bpColumns(k)) = false;
	plot(bpColumns(k), bpRows(k), 'r.', 'MarkerSize', 50);
end
% Erase any blobs with a centroid below 400.
props = regionprops(bw, 'Centroid');
xy = vertcat(props.Centroid)
% Don't keep the two with the highest centroid.
indexesToKeep = find(xy(:, 2) < 405);
% Extract all but the lowest two.
labeledImage = bwlabel(bw);
bw = ismember(labeledImage, indexesToKeep);
subplot(2, 2, 3);
imshow(bw);
axis('on', 'image');
title('Final Mask', 'FontSize', fontSize);
% Put the branchpoints back in to make each breast just one curve.
for k = 1 : length(bpRows)
	bw(bpRows(k), bpColumns(k)) = true;
end
labeledImage = bwlabel(bw);
% Find the left breast curve
[yr, xr] = find(labeledImage == 1);
% Find the right breast curve
[yl, xl] = find(labeledImage == 2);
subplot(2, 2, 4);
imshow(grayImage, 'border', 'tight' );
hold all
 plot(xr, yr, 'r.', 'MarkerSize', 14);
plot(xl, yl, 'y.', 'MarkerSize', 14);
% Find the midline
xMiddle = mean([max(xl), min(xr)]);
xline(xMiddle, 'Color', 'm', 'LineWidth', 4);
title('Breast Outlines Overlaid on Original Image', 'FontSize', fontSize);


leftHalf = grayImage(:, 1:xMiddle, :);
rightHalf=grayImage(:, xMiddle+1:end, :);
figure(); imshow(leftHalf);
figure(); imshow(rightHalf);

Answer 1

[Image Analyst]

I already answered this here:

https://www.mathworks.com/matlabcentral/answers/892157-how-i-could-detect-the-bottom-breast-boundaries-by-using-a-2nd-order-polynomial-curve-fitting-algori#answer_760857

[Beren Ac]

But i can’t seperate the left half and right half of breast from the total image. I need 2 pics and just include halves of breast without body. Could you please help me how to get each half of breast same as (c)section of 2nd pic.

[Image Analyst]

In the code I find "xMiddle" so to crop out each half into it's own picture, you can use indexing:

leftHalfImage = grayImage(:, 1 : xMiddle);
rightHalfImage = grayImage(:, xMiddle+1 : end);

[Beren Ac]

Thanks but i have already had this code. That’s for serapating middle of image. I need code to seperate left half of breast and right half of brest of which boundaries are yellow and red lines.

[Image Analyst]

The purple line is the midline. It will let you separate the image there, which may not be exactly in the middle of the image but is in the middle of the leftmost point of the left curve and the leftmost point of the right curve.

[Beren Ac]

I used purple line to seperate left and right half part of body or image but i need to extract left half and right half of breast but it don’t now how to extract region of left and right half of breast by using red and yellow lines which detects boundaries of breast along with purple. Thank you to try to help me but that’s not what i need. Maybe you didn’t get what i meant.

[Beren Ac]

I need just breast and i’d like to get rid off other parts of body.

[Image Analyst]

xl are the left breast coordinates and xr are the right breast coordinates. If you want to cut out the right breast, so

x1 = min(xr);
x2 = max(xr);
xrMiddle = mean([x1, x2]);
% Get the left half of the right breast.
leftOfRightBreast = grayImage(:, x1:xrMiddle);
% Get the right half of the right breast.
rightOfRightBreast = grayImage(:, xrMiddle+1 : x2);

Do a similar thing for the halves of the left breast:

x1 = min(xl);
x2 = max(xl);
xlMiddle = mean([x1, x2]);
% Get the left half of the right breast.
leftOfLeftBreast = grayImage(:, x1:mrMiddle);
% Get the right half of the right breast.
rightOfLeftBreast = grayImage(:, xlMiddle+1 : x2);

[Beren Ac]

Thank you again you spent too time for me but all i need is just breast organ i meant i don't want other part of body. In other words I need left curve(red line and its inner part) and right curve(yellow line and its inner part)of breast . So i want to extract breast region and remove other part of image. You can see it in image below. As you see there is no other parts of body just breast. There is Final Mask Above That's what i want as gray image.

[Image Analyst]

I don't know why you need that. Anyway, how do you decide on the radius of curvature of the circle that's atop the breast? You could draw a straight line (using poly2mask) but your stuff includes pixels above the straight line connecting the left top and right top of the curve. How do you decide on the radius of curvature to put between those two points? Do you just want to hard code in some radius?

[Beren Ac]

I’ll use it for asymmetry analysis.Those pics are from an article I’d like to get that result. But the article used polynomial curve fitting to detect curves of breast and circle fitting so as not to lose some part of breast. But I can just detect outher border of breast curve but can’t seperate it from total pic.

[Beren Ac]

Can we use circle fitting by using xr-yr and middle line for right half of breast and xl-yl and middle line for left half. If yes, could you please help me for it? There is as picture(section b)red circles below;

[Image Analyst]

Code for fitting a circle is given in the FAQ:

https://matlab.fandom.com/wiki/FAQ#How_can_I_fit_a_circle_to_a_set_of_XY_data.3F