霍夫直线图像校正Matlab实例

霍夫直线图像校正ceshi.m

clc; clear all; close all;

Img = imread('.\images\test.jpg');

I = rgb2gray(Img);

bw = im2bw(I, graythresh(I));

[Img1, theta] = HoughProcess(Img, bw);

HoughProcess.m

function [Img1, theta] = HoughProcess(Img, bw)

% 霍夫直线法

% 输入参数：

% Img——图像矩阵

% bw——二值图像矩阵

% 输出参数：

% Img1——倾斜校正结果

% theta——倾斜角度

[H, T, R] = hough(bw);

P = houghpeaks(H, 4, 'threshold', ceil(0.3*max(H(:))));

x = T(P(:,2)); y = R(P(:,1));

lines = houghlines(bw, T, R, P, 'FillGap', 50, 'MinLength', 7); max_len = 0;

for k = 1 : length(lines)

xy = [lines(k).point1; lines(k).point2];

len = norm(lines(k).point1-lines(k).point2);

Len(k) = len;

if (len > max_len)

max_len = len;

xy_long = xy;

end

end

% 强调最长的部分

[L1, Index1] = max(Len(:));

% 最长线段的起始和终止点

x1 = [lines(Index1).point1(1) lines(Index1).point2(1)];

y1 = [lines(Index1).point1(2) lines(Index1).point2(2)];

% 求得线段的斜率

K1 = -(lines(Index1).point1(2)-lines(Index1).point2(2))/...

(lines(Index1).point1(1)-lines(Index1).point2(1));

theta = atan(K1)*180/pi;

% imrotate是逆时针的所以取一个负号

Img1 = imrotate(Img, -theta, 'bilinear');

figure; imshow(Img); hold on;

plot(xy_long(:,1),xy_long(:,2),'LineWidth',2,'Color','blue'); hold off;

figure;

subplot(1, 2, 1); imshow(Img)

subplot(1, 2, 2); imshow(Img1)

hold off;