My code so far:
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);
My conclusion on the image on the Canny-Deriche Wikipedia page 
I cannot find the error because I followed the instructions there and on the Canny edge detector to the letter. I just implemented the algorithm as it is, and it still cannot seem that it produces the same output. Features are thick and sharp, and not smooth, as on Wikipedia pages.
EDIT: Dropbox link to code / image, so you don’t need to copy and paste it.