## 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} =} supermatte (@var{input1}, @var{input2})
##
## @seealso{}
## @end deftypefn

## Author: Jens <jens@orion>
## Created: 2020-10-04

function [matte, dev, conf] = supermatte (im_rgb, ref_rgb, k_e)

im_minus_ref = im_rgb - ref_rgb;
var_im_minus_ref = var(im_minus_ref, 0, 3);

# The base matte
matte = 1-exp(-k_e*var_im_minus_ref);

# Deviation from reference color
dev = vecnorm(im_minus_ref, 2, 3);

# Deviation from gray
conf =  mean(abs(im_minus_ref), 3);
endfunction