利用hough变换，matlab编程实现DM二维码的转正，定位，及01矩阵

以下是利用hough变换，matlab编程实现DM二维码的转正，定位，及01矩阵的步骤：

1. 读取图像并提取二维码区域。

img = imread('dmcode.png');
I = rgb2gray(img);
BW = imbinarize(I);
BW = ~BW;
BW = bwareaopen(BW, 50);
BW = imclearborder(BW);
stats = regionprops(BW, 'BoundingBox');
bbox = stats.BoundingBox;
cropped = imcrop(BW, bbox);

2. 利用hough变换进行直线检测，找到二维码的边缘。

[H,theta,rho] = hough(cropped);
P = houghpeaks(H,4);
lines = houghlines(cropped,theta,rho,P);
figure, imshow(cropped), 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

3. 计算二维码的旋转角度，并进行旋转。

angle = atan2(xy_long(2,2)-xy_long(1,2), xy_long(2,1)-xy_long(1,1));
angle = rad2deg(angle);

rotated = imrotate(cropped, angle, 'bilinear', 'crop');

4. 利用二维码的定位图案，找到二维码的位置。

loc = locateQRCode(rotated);
rect = [loc(1), loc(2), loc(3)-loc(1), loc(4)-loc(2)];
cropped = imcrop(rotated, rect);

5. 利用二维码的数据区域，提取01矩阵。

numrows = 10;
numcols = 10;
rowstep = size(cropped,1)/numrows;
colstep = size(cropped,2)/numcols;
code = zeros(numrows, numcols);
for row=1:numrows
    for col=1:numcols
        xstart = round((col-1)*colstep + 1);
        xend = round(col*colstep);
        ystart = round((row-1)*rowstep + 1);
        yend = round(row*rowstep);
        subimg = cropped(ystart:yend, xstart:xend);
        code(row, col) = mean(subimg(:)) > 128;
    end
end

至此，我们完成了利用hough变换，matlab编程实现DM二维码的转正，定位，及01矩阵的过程。