相似的像素保持在同一组中的梯度的函数的应用。

I = imread('circuit.tif');
rotI = imrotate(I, 33, 'crop');
BW = edge(rotI, 'canny');
[H, T, R] = hough(BW);
imshow(H, [], 'XData', T, 'YData', R, 'InitialMagnification', 'fit');
xlabel('\theta'), ylabel('\rho');
axis on, axis normal, hold on;
P = houghpeaks(H, 5, 'threshold', ceil(0.3 * max(H(:))));
x = T(P(:, 2));
y = R(P(:, 1));
plot(x, y, 's', 'color', 'white');
%Find lines and plot them
lines = houghlines(BW, T, R, P, 'FillGap', 5, 'MinLength', 7);
figure, imshow(rotI), hold on;
max_len = 0;
for k = 1:length(lines)
    xy = [lines(k).point1; lines(k).point2];
    plot(xy(:,1), xy(:,2), 'LineWidth', 2, 'Color', 'green');
    %plot beginnings and ends of lines
    plot(xy(1,1), xy(1,2), 'x', 'LineWidth', 2, 'Color', 'yellow');
    plot(xy(2,1), xy(2,2), 'x', 'LineWidth', 2, 'Color', 'red');
    %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;
    end
end

I = imread('circuit.tif');
rotI = imrotate(I, 33, 'crop');
BW = edge(rotI, 'canny');
[H, T, R] = hough(BW);
imshow(H, [], 'XData', T, 'YData', R, 'InitialMagnification', 'fit');
xlabel('\theta'), ylabel('\rho');
axis on, axis normal, hold on;
P = houghpeaks(H, 5, 'threshold', ceil(0.3 * max(H(:))));
x = T(P(:, 2));
y = R(P(:, 1));
plot(x, y, 's', 'color', 'white');
%Find lines and plot them
lines = houghlines(BW, T, R, P, 'FillGap', 5, 'MinLength', 7);
figure, imshow(rotI), hold on;
max_len = 0;
for k = 1:length(lines)
    xy = [lines(k).point1; lines(k).point2];
    plot(xy(:,1), xy(:,2), 'LineWidth', 2, 'Color', 'green');
    %plot beginnings and ends of lines
    plot(xy(1,1), xy(1,2), 'x', 'LineWidth', 2, 'Color', 'yellow');
    plot(xy(2,1), xy(2,2), 'x', 'LineWidth', 2, 'Color', 'red');
    %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;
    end
end

I = imread('coins.png');
level = graythresh(I);
BW = im2bw(I, level);
figure, imshow(I), figure, imshow(BW), figure, imhist(I);