how to select region with longest length on segmented image ?

4 次查看（过去 30 天）
Thanh Vu
Thanh Vu 2022-3-21
编辑： Thanh Vu 2022-3-22
I have segmented the image like the following: and within the boundaries I want to select the boundary with the longest length from the boundaries extracted from the image like the image below: help me please.
% Initialization Steps.
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 = 15;
markerSize = 4;
%[filename, pathname] = uigetfile({'*.*'},'File Selector');
%if ~isequal(filename,0)
%fullname = strcat(pathname,filename);
I=imread('MH2.jpeg');
%else
% msgbox('Ban chua chon anh?')
%end
Id = size(I);
if length(Id) == 3
B0 = rgb2gray(I);
else
B0 = I;
end
B0 = imadjust(B0);
k1 = fspecial('gaussian', [5 5], 2.5);
Ic = imfilter(B0,k1);
figure(1),subplot(3,3,1), imshow(I);
title('anh goc');
figure(1), subplot(3,3,2), imshow(B0);
title('anh tang tuong phan');
figure(1), subplot(3,3,3), imshow(Ic);
title('anh loc gaussian');
%loc trung vi
I_m = medfilt2(B0,[3 3]);
figure(1),subplot(3,3,4), imshow(Ic);
title('anh loc trung vi');
%anh nhi phan
thresholdValue = 60;
bw = Ic > thresholdValue;
bw = bwareafilt(bw, 1);
figure(1),subplot(3,3,5), imshow(bw);
title('anh nhi phan');
%dong hinh thai
se = strel("disk",10);
C1 = imclose(bw, se);
figure(1),subplot(3,3,6), imshow(C1);
title('dong hinh thai');
%khai thac ranh gioi
[B,L,N] = bwboundaries(C1);
figure(2);
%subplot(3,3,7);
imshow(C1); hold on;
title('khai thac ranh gioi');
for k=1:length(B)
boundary = B{k};
if(k > N)
plot(boundary(:,2), boundary(:,1), 'g','LineWidth',1.5);
else
plot(boundary(:,2), boundary(:,1), 'r','LineWidth',1.5);
end
end
%

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yanqi liu
yanqi liu 2022-3-22
Ran in:
% Initialization Steps.
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 = 15;
markerSize = 4;
%[filename, pathname] = uigetfile({'*.*'},'File Selector');
%if ~isequal(filename,0)
%fullname = strcat(pathname,filename);
I=imread('https://ww2.mathworks.cn/matlabcentral/answers/uploaded_files/935629/MH2.jpeg');
%else
% msgbox('Ban chua chon anh?')
%end
Id = size(I);
if length(Id) == 3
B0 = rgb2gray(I);
else
B0 = I;
end
B0 = imadjust(B0);
k1 = fspecial('gaussian', [5 5], 2.5);
Ic = imfilter(B0,k1);
figure(1),subplot(3,3,1), imshow(I);
title('anh goc');
figure(1), subplot(3,3,2), imshow(B0);
title('anh tang tuong phan');
figure(1), subplot(3,3,3), imshow(Ic);
title('anh loc gaussian');
%loc trung vi
I_m = medfilt2(B0,[3 3]);
figure(1),subplot(3,3,4), imshow(Ic);
title('anh loc trung vi');
%anh nhi phan
thresholdValue = 60;
bw = Ic > thresholdValue;
bw = bwareafilt(bw, 1);
figure(1),subplot(3,3,5), imshow(bw);
title('anh nhi phan');
%dong hinh thai
se = strel("disk",10);
C1 = imclose(bw, se);
figure(1),subplot(3,3,6), imshow(C1);
title('dong hinh thai');
%khai thac ranh gioi
[B,L,N] = bwboundaries(C1);
figure(2);
%subplot(3,3,7);
imshow(C1); hold on;
title('khai thac ranh gioi');
len = [];
for k=1:length(B)
boundary = B{k};
% comput length
len(k) = (max(boundary(:,2))-min(boundary(:,2))).^2+(max(boundary(:,1))-min(boundary(:,1))).^2;
if(k > N)
plot(boundary(:,2), boundary(:,1), 'g','LineWidth',1.5);
else
plot(boundary(:,2), boundary(:,1), 'r','LineWidth',1.5);
end
end
% find
[~,ind] = max(len);
boundary = B{ind};
plot(boundary(:,2), boundary(:,1), 'm--','LineWidth',2);
  3 个评论
显示 1更早的评论
yanqi liu
yanqi liu 2022-3-22
Ran in:
yes，sir，let us check the follow method
% Initialization Steps.
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 = 15;
markerSize = 4;
%[filename, pathname] = uigetfile({'*.*'},'File Selector');
%if ~isequal(filename,0)
%fullname = strcat(pathname,filename);
I=imread('https://ww2.mathworks.cn/matlabcentral/answers/uploaded_files/935629/MH2.jpeg');
%else
% msgbox('Ban chua chon anh?')
%end
Id = size(I);
if length(Id) == 3
B0 = rgb2gray(I);
else
B0 = I;
end
B0 = imadjust(B0);
k1 = fspecial('gaussian', [5 5], 2.5);
Ic = imfilter(B0,k1);
figure(1),subplot(3,3,1), imshow(I);
title('anh goc');
figure(1), subplot(3,3,2), imshow(B0);
title('anh tang tuong phan');
figure(1), subplot(3,3,3), imshow(Ic);
title('anh loc gaussian');
%loc trung vi
I_m = medfilt2(B0,[3 3]);
figure(1),subplot(3,3,4), imshow(Ic);
title('anh loc trung vi');
%anh nhi phan
thresholdValue = 60;
bw = Ic > thresholdValue;
bw = bwareafilt(bw, 1);
figure(1),subplot(3,3,5), imshow(bw);
title('anh nhi phan');
%dong hinh thai
se = strel("disk",10);
C1 = imclose(bw, se);
figure(1),subplot(3,3,6), imshow(C1);
title('dong hinh thai');
%khai thac ranh gioi
b1 = bwperim(C1);
b1(:,[1:2 end-2:end]) = 0;
b1 = logical(b1);
[B,L,N] = bwboundaries(b1);
figure(2);
%subplot(3,3,7);
imshow(C1); hold on;
title('khai thac ranh gioi');
len = [];
for k=1:length(B)
boundary = B{k};
% comput length
len(k) = (max(boundary(:,2))-min(boundary(:,2))).^2+(max(boundary(:,1))-min(boundary(:,1))).^2;
if(k > N)
plot(boundary(:,2), boundary(:,1), 'g','LineWidth',1.5);
else
plot(boundary(:,2), boundary(:,1), 'r','LineWidth',1.5);
end
end
% find
[~,ind] = max(len);
boundary = B{ind};
figure;
%subplot(3,3,7);
imshow(C1); hold on;
plot(boundary(:,2), boundary(:,1), 'm--','LineWidth',2);
Thanh Vu
Thanh Vu 2022-3-22
编辑：Thanh Vu 2022-3-22
I'm really grateful to you yanqi liu. I still have one step to do is to extract the depth feature to classify the image by SVM method like the algorithm in figure below. But I don't understand what the edge pixels mentioned in the algorithm mean. so can you help me write this algorithm on matlab? I know I asked you too much, but I really don't understand the matlab code that I had to submit the report for the other day. help me please :((((((
I would appreciate it if you could help me. I'm really sorry if my requests bother you

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