画像からの座標の読み取り

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0 个投票

読み込んだ画像かからエッジを摘出し、その角の座標を取得したいのですが、エッジを摘出したあとにどうすれば良いのかわかりません。

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Chikako Kuriyama 2017-7-27

返信ありがとうございます。michioさんが添付していただいた図を最終的に得たいと考えています。

michio 2017-7-28

Image Analyst san, thanks for your offer :) If we see some hard-core image processing issues next time, I'll reach out to you!

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Answer 1

Tohru Kikawada 2017-7-27

在 MATLAB Online 中打开

3 个投票

画像処理でやりたいことがある場合には Image Processing Toolbox の例をまずは探されることをおすすめします。

たとえば、こちらのサンプルを活用することでやりたいことが実現できるかと思います。

ご参考まで。

%%Detect Lines in Images Using Hough
% This example shows how to detect lines in an image using the |hough| function.
%%Read an image into the workspace and binarize it
I = imread('https://jp.mathworks.com/matlabcentral/answers/uploaded_files/83898/%3F.png');
BW = imbinarize(rgb2gray(I));
BW = imclearborder(BW);
%%Compute the Hough transform of the binary image returned by |edge|.
[H,theta,rho] = hough(BW);
%%Display the transform, |H|, returned by the |hough| function.
figure
imshow(imadjust(mat2gray(H)),[],...
       'XData',theta,...
       'YData',rho,...
       'InitialMagnification','fit');
xlabel('\theta (degrees)')
ylabel('\rho')
axis on
axis normal 
hold on
colormap(gca,hot)
%%Find the peaks in the Hough transform matrix, |H|, using the |houghpeaks| 
% function.
P = houghpeaks(H,5,'threshold',ceil(0.3*max(H(:))));
%%Superimpose a plot on the image of the transform that identifies the peaks.
x = theta(P(:,2));
y = rho(P(:,1));
plot(x,y,'s','color','black');
%%Find lines in the image using the |houghlines| function. 
lines = houghlines(BW,theta,rho,P,'FillGap',30,'MinLength',50);
%%Create a plot that displays the original image with the lines superimposed 
figure, imshow(I), hold on
max_len = 0;
len = zeros(length(lines),1);
for k = 1:length(lines)
   xy = [lines(k).point1; lines(k).point2];
   plot(xy(:,1),xy(:,2),'LineWidth',1,'Color','green');
     % Presave line length
     len(k) = norm(lines(k).point1 - lines(k).point2);
  end
%%Connect lines
theta = [lines.theta];
theta(theta>0) = -Inf;
[~,min_angle] = max(theta);
theta = [lines.theta];
theta(theta<0) = Inf;
[~,max_angle] = min(theta);
pts = [lines(min_angle).point1; lines(min_angle).point2; lines(max_angle).point2;...
    lines(max_angle).point1; lines(min_angle).point1];
plot(pts(:,1),pts(:,2),'LineWidth',2,'Color','red');