direction of flow lines in an image
6 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Abhishek Saini
am 12 Okt. 2021
Kommentiert: yanqi liu
am 12 Okt. 2021
Hi,
I have a 2D image or image data. I want to find the average direction of flow lines with respect to horizontal. how can i do that.
Attached is the iamge I generated by using
imgradient
red lines I draw to show the approximate flow of lines in the image and \theta is the average angle , which I want to determine.
0 Kommentare
Akzeptierte Antwort
yanqi liu
am 12 Okt. 2021
sir,please check the follow code to get some information
clc; clear all; close all;
im = imread('https://ww2.mathworks.cn/matlabcentral/answers/uploaded_files/764756/untitled.jpg');
jm = rgb2lab(im);
s = mat2gray(jm(:,:,2));
bw = im2bw(s);
bw = bwareafilt(bw,1);
bw2 = imopen(bw, strel('line', 19, 0));
bw(bw2) = 0;
bw = bwareafilt(bw,1);
[H,T,R] = hough(bw);
P = houghpeaks(H,5,'threshold',ceil(0.3*max(H(:))));
lines = houghlines(bw,T,R,P,'FillGap',5,'MinLength',7);
max_len = 0;
line_r = [];
for k = 1:length(lines)
xy = [lines(k).point1; lines(k).point2];
% Determine the endpoints of the longest line segment
len = norm(lines(k).point1 - lines(k).point2);
if ( len > max_len)
max_len = len;
xy_long = xy;
line_r = lines(k);
end
end
figure; imshow(im); hold on;
plot(xy_long(:,1),xy_long(:,2),'LineWidth',2,'Color','cyan');
title(sprintf('theta=%.1f°', 90-line_r.theta));
6 Kommentare
Weitere Antworten (1)
yanqi liu
am 12 Okt. 2021
sir,please check the follow code to get some information
clc; clear all; close all;
img = imread('cameraman.tif');
[Gx,Gy] = imgradientxy(img);
[Gmag,Gdir] = imgradient(Gx,Gy);
mk = zeros(16,16);
mk(8:9,:) = 1;
mk = logical(mk);
ms = mk;
% rotae theta
mk = imrotate(mk, 30);
mk = bwmorph(mk,'thin',inf);
% find direction
res = imfilter(double(Gdir), double(mk), 'replicate');
res = res > max(res(:))*0.5;
figure;
subplot(2, 2, 1); imshow(mat2gray(Gdir)); title('origin image');
subplot(2, 2, 2); imshow(mat2gray(ms)); title('h base filter');
subplot(2, 2, 3); imshow(mat2gray(mk)); title('theta filter');
subplot(2, 2, 4); imshow(mat2gray(res)); title('result');
2 Kommentare
Siehe auch
Kategorien
Mehr zu Geometric Transformation and Image Registration finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!