在我的Canny-Deriche的MATLAB实现中无法获得干净的输出

Question

到目前为止我的代码是：

function imgg = derichefilter1(x, k, a, b, c)
osize = size(x);
x = double(x);
a = double(a);
b = double(b);
c = double(c);
k = double(k);
y1 = zeros(osize(1),osize(2));
y2 = zeros(osize(1),osize(2));
y1(:,1) = a(1)*x(:,1);
y1(:,2) = a(1)*x(:,2) + a(2)*x(:,1) + b(1)*y1(:,1);
for ii=3:osize(2)
    y1(:,ii) = a(1)*x(:,ii) + a(2)*x(:,ii-1) + b(1)*y1(:,ii-1) + b(2)*y1(:,ii-2);
end

y2(:,osize(2)-1) = a(3)*x(osize(2));
for ii=(osize(2)-2):-1:1
    y2(:,ii) = a(3)*x(:,ii+1) + a(4)*x(:,ii+2) + b(1)*y2(:,ii+1) + b(2)*y2(:,ii+2);
end
imgg = c*(y1+y2);

function imgg = derichefilter2(x, k, a, b, c)
imgg = derichefilter1(x,k,a(1:4),b,c(1));
imgg = (derichefilter1(imgg',k,a(5:8),b,c(2)))';

function [mask magn] = nonmaxsupp(x, y)
magn = sqrt(x.^2 + y.^2);
argu = atan2(y,x);
argu = argu/pi*4;
argu = int32(round(argu));
argu(argu == 4) = 0;
argu(argu < 0) = argu(argu < 0) + 4;
mask = boolean(zeros(size(x)));
for ii = 2:(size(x,1)-1)
    for jj = 2:(size(x,2)-1)
        switch argu(ii,jj)
            case 0
                mask(ii,jj) = (max(magn(ii,jj+1),magn(ii,jj-1)) <= magn(ii,jj));
            case 1
                mask(ii,jj) = (max(magn(ii-1,jj+1),magn(ii+1,jj-1)) <= magn(ii,jj));
            case 2
                mask(ii,jj) = (max(magn(ii-1,jj),magn(ii+1,jj)) <= magn(ii,jj));
            case 3
                mask(ii,jj) = (max(magn(ii+1,jj+1),magn(ii-1,jj-1)) <= magn(ii,jj));
        end
    end
end

function imgg = hystthres(x,Tl,Th)
imgg = (x>Th);
limg = (x>=Tl);
osize = size(x);
nTh = 0;
for ii = 1:osize(1)
    for jj = 1:osize(2)
        if imgg(ii,jj)
            nTh = nTh + 1;
        end
    end
end
c = zeros(1,nTh); r = zeros(1,nTh); nTh=0;
for ii = 1:osize(1)
    for jj = 1:osize(2)
        if imgg(ii,jj)
            nTh = nTh + 1;
            c(nTh) = ii; r(nTh) = jj;
        end
    end
end
imgg = bwselect(limg,r,c,8);

function imgg = derichecomplete(x, alph, Tl, Th)
k = (1 - exp(-alph))^2/(1 + 2*alph*exp(-alph) - exp(-2*alph));
as = zeros(1,8);
as(1) = k;
as(2) = k*exp(-alph)*(alph-1);
as(3) = k*exp(-alph)*(alph+1);
as(4) = -k*exp(-2*alph);
as(5:8)=as(1:4);
b = zeros(1,2);
b(1) = 2*exp(-alph);
b(2) = -exp(-2*alph);
cs = [1,1];
ax = [0,1,-1,0,as(5:8)];
cx = [-(1 - exp(-alph))^2,1];
ay = [ax(5:8),ax(1:4)];
cy = [cx(2) cx(1)];

deriches = derichefilter2(x, k, as, b, cs);
derichex = derichefilter2(deriches, k, ax, b, cx);
derichey = derichefilter2(deriches, k, ay, b, cy);
[mask mag] = nonmaxsupp(derichex, derichey);
mag(~mask) = 0;
imgg = hystthres(mag,Tl,Th);

clc; clear all; close all;
imagepath = input('Enter the image path in single quotes: ');
alph = input('Enter the value of alpha to be used: ');
Tl = input('Enter the value of Tl to be used: ');
Th = input('Enter the value of Th to be used: ');
imgg = imread(imagepath);
szzz = size(size(imgg));
if szzz(2) == 3
    osize = size(imgg);
    hystf = boolean(zeros(osize(1:2)));
    for ii=1:3
        hystf = hystf | derichecomplete(imgg(:,:,ii),alph,Tl,Th);
    end
else    
    hystf = derichecomplete(imgg,alph,Tl,Th);
end
imshow(hystf);

我在Canny-Deriche Wikipedia page

上的图片上的输出

我似乎无法找到错误，因为我按照那里的说明并在Canny edge detector页面上写了这封信。我刚刚实现了算法，但仍然无法产生相同的输出。这些功能很厚而且前卫，而不是维基百科页面上的光滑。

编辑：Dropbox link代码/图片，这样您就不必复制/粘贴它。

Answer 1

我认为您没有处理正确的文件。我将您的函数应用于全分辨率图像http://upload.wikimedia.org/wikipedia/commons/5/5e/Sunflowers_in_July.jpg，结果看起来很好

如果我将您的功能应用于50K预览文件，我会得到您在上面显示的结果。