comparison nonExposed/adjustScaleForEBR.m @ 14:b1901e8d8f5f

initial commit

+function scale = adjustScaleForEBR (fg, bg, offset, targetEBR, snrType, eps)
+% Computes the value of 'scale' such that fg*scale has a given EBR
+% relatively to bg at position 'offset'.
+% ebrType is used to select what kind of EBR should be considered:
+% 1 - standard temporal ebr over whole length of sample
+% 2 - max of standard temporal ebr over 1/4s windows
+% 3 - more to come ?
+% eps is the epsilon used to check for convergence; optional, defaults to
+% 0.01
+
+% This program was written by Mathias Rossignol & Grégoire Lafay
+% is Copyright (C) 2015 IRCAM <http://www.ircam.fr>
+%
+% 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 <http://www.gnu.org/licenses/>.
+
+if (nargin == 5) eps = 0.01; end
+%if (targetSNR <= 0) targetSNR = exp(targetSNR); end
+prevScale = 1;
+scale = 1;
+ebrFunc=@ebr;
+if (snrType==2) ebrFunc=@maxWindowEBR; end
+count = 0;
+while (ebrFunc(fg, bg, offset, scale) > targetEBR && count < 100)
+    prevScale = scale;
+    scale = scale/2;
+    count = count+1;
+end
+if (count == 100)
+    msg = ['Max count, stage 1, scale = ', num2str(scale), ' - ', num2str(ebrFunc(fg, bg, offset, scale)), ' - ', num2str(ebrFunc(fg, bg, offset, prevScale)), ' - ', num2str(ebrFunc(fg, bg, offset, 1))];
+    error(msg)
+end
+count=0;
+while (ebrFunc(fg, bg, offset, scale) < targetEBR && count < 100)
+    prevScale = scale;
+    scale = scale*2;
+    count = count+1;
+end
+if (count == 100)
+    msg = ['Max count, stage 2, scale = ', num2str(scale)];
+    error(msg)
+end
+count=0;
+if (scale<prevScale)
+    a = scale;
+    b = prevScale;
+else
+    a=prevScale;
+    b=scale;
+end
+delta = ebrFunc(fg, bg, offset, (a+b)/2) - targetEBR;
+while (abs(delta) > eps && count < 100)
+    if (delta>0)
+        b = (a+b)/2;
+    else
+        a = (a+b)/2;
+    end
+    delta = ebrFunc(fg, bg, offset, (a+b)/2) - targetEBR;
+    count = count+1;
+end
+if (count == 100)
+    msg = ['Max count, stage 3, scale = ', num2str(a)];
+    error(msg)
+end
+scale = (a+b)/2;
+end