diff --git a/chromakey/alpha.png b/chromakey/alpha.png
index 3c2bf66..0237a3e 100644
Binary files a/chromakey/alpha.png and b/chromakey/alpha.png differ
diff --git a/chromakey/bluescreen.m b/chromakey/bluescreen.m
index d0827c1..eae3ec6 100644
--- a/chromakey/bluescreen.m
+++ b/chromakey/bluescreen.m
@@ -23,6 +23,7 @@
 ## Author: Jens <jens@orion>
 ## Created: 2020-10-03
 
+# bluescreen('adventure_rose.jpg', 0.4, 0.4, 4)
 function retval = bluescreen (img_name, k_sb, k_ds, k_cw)
 im = im2double(imread(img_name));
 im_rgb = imresize(im, 1);
diff --git a/chromakey/chromakey.m b/chromakey/chromakey.m
new file mode 100644
index 0000000..8d1b82a
--- /dev/null
+++ b/chromakey/chromakey.m
@@ -0,0 +1,90 @@
+## Copyright (C) 2020 Jens
+## 
+## This program is free software: you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <https://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{retval} =} bluescreen (@var{input1}, @var{input2})
+##
+## @seealso{}
+## @end deftypefn
+
+## Author: Jens <jens@orion>
+## Created: 2020-10-03
+
+function chromakey (img_name)
+im = im2double(imread(img_name));
+im_rgb = imresize(im, 1);
+se = strel('square',3)
+
+#ref_rgb = toRef([0.3 0.4 0.65], size(im_rgb));
+ref_rgb = toRef([0.2 0.6 0.95], size(im_rgb));
+
+k_ds = 0.2;
+k_c_matte = 1.0
+k_e_matte = 3
+
+k_c_edge = 3.0
+k_e_edge = 3.0
+
+close all;
+
+figure;
+imshow(ref_rgb);
+
+figure;
+matte = min(1, k_c_matte*similarity_rgb(im_rgb, ref_rgb, k_e_matte));
+#matte = mask_clip_below(matte, 0.5);
+imshow(matte); title("matte")
+
+figure;
+final = max(0, im_rgb - k_ds*matte.*ref_rgb).*matte;
+imshow(final); title("final")
+
+figure;
+edges = k_c_edge*coloredges(final, ref_rgb, k_e_edge);
+#edges = mask_clip_below(edges, 0.25);
+imshow(edges); title("edges")
+
+figure;
+final_cc = im_rgb - edges.*ref_rgb;
+imshow(final_cc); title("final_cc")
+
+imwrite(final, 'final.png','png','alpha', matte);
+imwrite(final_cc, 'final_cc.png','png','alpha', matte);
+imwrite(matte, 'alpha.png','png');
+
+function r = toRef(ref, d)
+	r = repmat(reshape(ref,1, 1, 3), d(1), d(2));
+endfunction
+
+function s = similarity_rgb(im, ref, k)
+	s = 1-exp(-k*vecnorm (im - ref, 2, 3));
+endfunction
+
+function s = coloredges(im, ref, k)
+	s = exp(-k*vecnorm (im - ref, 2, 3));
+endfunction
+
+function mask = mask_clip_above(mask_in, thresh)
+		k = mask_in < thresh;
+		mask = k .* mask_in + kn;
+endfunction
+
+function mask = mask_clip_below(mask_in, thresh)
+		k = mask_in > thresh;
+		mask = k .* mask_in  + 0;
+endfunction
+
+endfunction
diff --git a/chromakey/final.png b/chromakey/final.png
index 1aab552..e31638d 100644
Binary files a/chromakey/final.png and b/chromakey/final.png differ