Question

matlab实现hough变换检测直线

matlab实现hough变换检测直线，提示错误Function HOUGH expected its second input, PARAM,
to be one of these types:har Instead its type was double.具体代码如下：
clear all;
clc;
f = imread('C:\Users\lenovo\Desktop\canny.jpg');
figure
imshow(f, []);
[H, theta, rho] = hough(f, 0.5);
figure
imshow(H, [],'Xdata', theta, 'Ydata', rho, 'InitialMagnification','fit');
axis on, axis normal

[r, c] = houghpeaks(H, 5);
hold on;
plot(theta(c), rho(r), 'linestyle', 'none', 'marker', 's', 'color', 'w')

lines = houghlines(f, theta, rho, r, c)
figure, imshow(f, []), hold on
for k = 1: length(lines)
xy = [lines(k).point1; lines(k).point2];
plot(xy(:, 2), xy(:, 1), 'LineWidth', 4, 'Color', [.6, .6, .6]);
end
错误提示具体如下：
Warning: Image is too big to fit on screen; displaying at 67%
> In imuitools\private\initSize at 73
In imshow at 262
In kljh at 3
??? Error using ==> iptcheckinput
Function HOUGH expected its second input, PARAM,
to be one of these types:

char

Instead its type was double.

Error in ==> iptcheckstrs at 43
iptcheckinput(in, {'char'}, {'row'}, function_name, variable_name, ...

Error in ==> hough>parseInputs at 126
inputStr = iptcheckstrs(input, validStrings,mfilename,'PARAM',idx);

Error in ==> hough at 93
[bw, rho, theta] = parseInputs(varargin{:});

Error in ==> kljh at 4
[H, theta, rho] = hough(f, 0.5);
求大神讲解。
我附带的图已经经过灰度化，滤波，二值分割，canny边缘检测。

Answer 1

clear all;
clc;
r = imread('C:\Users\lenovo\Desktop\canny.jpg');
t=rgb2gray(r);
figure,imshow(t)
f=edge(t,'canny');
figure,imshow(f)
[H, theta, rho] = hough(f,'RhoResolution',0.5,'Theta',-90:0.5:89.5);
figure
imshow(imadjust(H),'Xdata', theta, 'Ydata', rho, 'InitialMagnification','fit');
axis on, axis normal
p= houghpeaks(H, 5);
%[r,c] = houghpeaks(H, 5);
hold on;
%plot(theta(r), rho(c), 'linestyle', 'none', 'marker', 's', 'color', 'w')
plot(p, 'linestyle', 'none', 'marker', 's', 'color', 'r')
lines = houghlines(f, theta, rho,p);
%lines = houghlines(f, theta, rho, r, c);
figure,
imshow(t)
hold on
for k = 1: length(lines)
xy = [lines(k).point1; lines(k).point2];
plot(xy(:, 2), xy(:, 1), 'LineWidth', 4, 'Color', [.6, .2, .1]);
end
hold off

按上面语句试试

追问

不行，还有我的图已经灰度，滤波，二值分割，边缘检测过了。运行后出现
Error using ==> rgb2gray>parse_inputs at 82
MAP must be a m x 3 array.
Error in ==> rgb2gray at 35
X = parse_inputs(varargin{:});
Error in ==> shiyan1 at 4
t=rgb2gray(r);

追答

如果你的图已经是灰度图了，就用%把t=rgb2gray(r);注释掉

追问

追答

你对hough的用法不理解。hough作用于二值图，不对rgb图。扩展名为.jpg的图不是bw二值图，须t=rgb2gray(r);转换，不可注释掉