%?23/02/2011
%?IFSTTAR?copyright
%
%?The?approach?is?described?in?details?in?
%
%?“Blind?Contrast?Restoration?Assessment?by?Gradient?Ratioing?at?Visible?Edges“
%?by?N.?Hautiere?J.-P.?Tarel?D.?Aubert?and?E.?Dumont
%?in?proceedings?of?International?Congress?for?Stereology?（ICS‘07）?
%?Saint?Etienne?France?August?30-September?7?2007.
%?http://perso.lcpc.fr/tarel.jean-philippe/publis/ics07.html
%

%%%%?Cleaning
clc
clear?all
close?all

%%%%?Images?reading:?the?input?2?images?must?be?grayscale

NameOri=‘Original.pgm‘;
NameResto=‘Restored.pgm‘;
%NameResto=‘Restored2.pgm‘;
%NameResto=‘Restored3.pgm‘;
%NameResto=‘Restored4.pgm‘;
%NameResto=‘Restored5.pgm‘;

I1=Imread（NameOri）;
I1=double（I1）;
%?if?the?input?image?is?a?color?image?use?following?line
%?I1=double（rgb2gray（uint8（I1）））;

[nlnc]=size（I1）;

R1=Imread（NameResto）;
R1=double（R1）;
%?if?the?input?image?is?a?color?image?use?following?line
%?R1=double（rgb2gray（uint8（R1）））;

%%%%?Figure?1
figure（1）
colormap?gray
subplot（121）
imagesc（I1）
axis?image
title（‘Original‘）
subplot（122）
imagesc（R1）
axis?image
title（‘Restored‘）

%%%%?Sobel?Gradient
Sy?=?double（[1?2?1;0?0?0;-1?-2?-1]）;
GIy?=?imfilter（I1Sy‘symmetric‘）;
GRy1?=?imfilter（R1Sy‘symmetric‘）;

Sx?=?double（[1?0?-1;?2?0?-2;?1?0?-1]）;
GIx?=?imfilter（I1Sx‘symmetric‘）;
GRx1?=?imfilter（R1Sx‘symmetric‘）;

GI=sqrt（（GIx.^2）+（GIy.^2））;
GR1=sqrt（（GRx1.^2）+（GRy1.^2））;

minGI=min（GI（:））;
maxGI=max（GI（:））;

%%%%?Figure?2
figure（2）
colormap?gray
subplot（121）
imagesc（GI[minGI?maxGI]）;
title（[‘Gradients?of?the?original?image‘]）;?
axis?image
colorbar
subplot（122）
imagesc（GR1[minGI?maxGI]）;
title（[‘Gradients?of?the?restored?image‘]）;?
axis?image
colorbar

%%%%?Contrast?Computation?at?5%
tic
[C1?Crr1]=functionContrastAt5PerCent（R1）;
[Ci?Crri]=functionContrastAt5PerCent（I1）;
toc

minCrri=min（Crri（:））;
maxCrri=max（Crri（:））;

%%%%?Figure?3
figure（3）
colormap?gray
subplot（121）
imagesc（Crri[minCrri??maxCrri]）;
axis?image
title（[‘Visible?edge?in?the?original?image‘]）;
colorbar
subplot（122）
imagesc（Crr1[minCrri??maxCrri]）;
axis?image
title（[‘Visible?edge?in?the?restored?image‘]）;
colorbar

%%%%?Visible?Gradients?Ratio
Cratio1=zeros（nlnc）;
Cratio1（Crr1>0）=GR1（Crr1>0）./GI（Crr1>0）;

rmin=1;
rmax=10;

%%%%?Figure?4
figure（4）
imagesc（Cratio1[rmin?rmax]）;
axis?image
title（[‘Visible?gradients?ratio?between?‘num2str（rmin）?‘?and?‘num2str（rmax）]）;?
colormap?jet
colorbar

%%%%?Descriptor?computation

%?Rate?of?new?visible?edges
whitePixels1=sum（C1（:））;
whitePixelsi=sum（Ci（:））;
e1=（whitePixels1-whitePixelsi）/whitePixelsi;

%?Number?of?saturated?pixels?after?restoration
ns1=sum（R1（:）==256?|R1（:）==0）;
ns1=ns1/（nl*nc）;

%?Restoration?quality?（geometric?mean?ratios?of?visibility?level）
XX=log（Cratio1）;
r1=exp（（1/（whitePixels1））*nansum（XX（isfinite（XX））））;

%%%%?Figure?5:?Final?result?with?the?visible?edges?at?5%?and?descriptors
figure（5）
subplot（12

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件????????3413??2011-02-23?15:10??EvaluationDescriptor\EvaluationDescriptorCalculation.m
?????文件????????5335??2011-02-23?15:11??EvaluationDescriptor\functionContrastAt5PerCent.m
?????文件??????437775??2010-02-11?14:58??EvaluationDescriptor\Original.pgm
?????文件??????437775??2010-03-04?16:43??EvaluationDescriptor\Restored2.pgm
?????文件??????437775??2010-03-04?16:44??EvaluationDescriptor\Restored3.pgm
?????文件??????437775??2010-03-04?16:44??EvaluationDescriptor\Restored4.pgm
?????文件??????437775??2010-03-04?16:44??EvaluationDescriptor\Restored5.pgm
?????文件??????437775??2010-03-07?22:29??EvaluationDescriptor\Restored.pgm