- added matlab scripts

chromakey/to_param.m

@@ -0,0 +1,59 @@
+## 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} =} to_param (@var{input1}, @var{input2})
+##
+## @seealso{}
+## @end deftypefn
+
+## Author: Jens <jens@orion>
+## Created: 2020-10-07
+
+function p = to_param(x, pmin, pmax, B, k, pcenter, scenter)
+
+	if (pmin == pmax)
+		pmax += 1E-9;
+	end
+
+	if (k == 0)
+		k = 1E-9;
+	end
+
+	if ((pcenter < pmin) || (pcenter > pmax))
+	    pcenter = pmax*scenter + pmin*(1-scenter);
+	end
+
+	x = min(1, max(0, x));
+	kc = 1/(B^k-1);
+	p = [];
+	for n=1:length(x);
+		s = x(n);
+		if (s < scenter)
+			s = (scenter-s)/scenter;
+			ks = -(pcenter-pmin);
+		else
+			s = (-scenter+s)/(1-scenter);
+			ks = (pmax-pcenter);
+		end
+		if (B == 1)
+			p = [p pcenter + ks*kc*s];
+		else
+			p = [p pcenter + ks*kc*(B.^(k*s)-1)];
+		end
+	end	
+endfunction
+