%
% This program will output calibration coefficients for
% the three wave probes used in the 13.021 WAVES lab.
% 
% This is designed to work in MATLAB for windows -- It can be 
% adjusted to work in UNIX as well.
%
% 28 Nov 2000 -- Alex Techet
% MIT Towing Tank
%
% QUESTIONS? ahtechet@mit.edu
%

%open window to get calibration data file:
[filen, pathn] = uigetfile('*.i32','OPEN Calibration Data File');
filestub = [pathn '' filen];

%Load i32 format data and create array with channel 1,2,3 in columns:
cald = parsedl2(filestub,3);
caldata = cald';

figure(1);clf;
plot(caldata);
xlabel('time (s)');
ylabel('Probe reading in Volts');
legend('CH 1','CH 2','CH 3');

% INPUT 3 CALIBRATION HEIGHTS:

disp(sprintf('\n'));
h1 = input('ENTER THE HEIGHT OF THE FIRST CALIBRATION IN CM -->  [2.54] ');
if length(h1) == 0
   h1 = 2.54;
end;
h2 = input('ENTER THE HEIGHT OF THE SECOND CALIBRATION IN CM --> [5.08] ');
if length(h2) == 0
   h2 = 5.06;
end;
h3 = input('ENTER THE HEIGHT OF THE THIRD CALIBRATION IN CM -->  [8.62] ');
if length(h3) == 0
   h3 = 8.62;
end;

disp(sprintf('\n ~~~~~~~~~~~~~~CALIBRATION HEIGHTS~~~~~~~~~~~~~'));
disp(sprintf('  First calibration height was:  %4.2f cm',h1));
disp(sprintf('  Second calibration height was: %4.2f cm',h2));
disp(sprintf('  Third calibration height was:  %4.2f cm',h3));

%Calibrate Channels:
% FIRST FIND ZERO REGIONS!
%
%
figure(2);clf;

plot(caldata(:,1),'b');
title('Pick TWO ZERO regions for CHANNEL 1');
ctmp1 = ginput(2);
zero_off1 = mean(caldata(round(ctmp1(:,1)),1)); %this is the zero offset of channel 1!
plot(caldata(:,1)-zero_off1,'b');
title('press space to continue');
pause;

plot(caldata(:,2),'g');
title('Pick TWO ZERO regions for CHANNEL 2');
ctmp2 = ginput(2);
zero_off2 = mean(caldata(round(ctmp2(:,1)),2)); %this is the zero offset of channel 2!
plot(caldata(:,2)-zero_off2,'g'); 
title('press space to continue');
pause;

plot(caldata(:,3),'r');
title('Pick TWO ZERO regions for CHANNEL 3');
ctmp3 = ginput(2);
zero_off3 = mean(caldata(round(ctmp3(:,1)),3)); %this is the zero offset of channel 3!
plot(caldata(:,3)-zero_off3,'r'); 
title('press space to continue');
pause;

z_data = [caldata(:,1)-zero_off1 caldata(:,2)-zero_off2 caldata(:,3)-zero_off3];

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  NOW FIND VOLTS/CM for each channel
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
disp(' ');
disp('CALIBRATING CHANNEL 1...');

plot(z_data(:,1),'b');
title('PICK A POINT IN EACH CALIBRATION REGION 1,2,3 (DOWNWARD DISPLACEMENT)');
[xt,yt] = ginput(3);
xt = round(xt);

yt = z_data(xt,1)';

figure(3);clf;
hmat = [0 h1 h2 h3];
vmat = [0 yt];
plot(vmat, hmat,'b*');
ylabel('height in CM');
xlabel('voltage');

%Plot linear fit and get slope
hold on;
%p1 is the slope of a first order linear fit to the calibration...
p1 = polyfit(vmat,hmat,1); 
%PLOT a line with the slope p1
pv1 = polyval(p1,vmat);
plot(vmat,pv1,'b');
ccal1 = p1(1); %calibration coef for channel 1:



disp('CALIBRATING CHANNEL 2...');
figure(2);
plot(z_data(:,2),'g');
title('PICK A POINT IN EACH CALIBRATION REGION 1,2,3 (DOWNWARD DISPLACEMENT)');
[xt,yt] = ginput(3);
xt = round(xt);

yt = z_data(xt,2)';

figure(3);
hmat2 = [0 h1 h2 h3];
vmat2 = [0 yt];
plot(vmat2, hmat2,'g*');
ylabel('height in CM');
xlabel('voltage');

%Plot linear fit and get slope
hold on;
%p2 is the slope of a first order linear fit to the calibration...
p2 = polyfit(vmat2,hmat2,1); 
%PLOT a line with the slope p2
pv2 = polyval(p2,vmat2);
plot(vmat2,pv2,'g');
ccal2 = p2(1); %calibration coef for channel 2:


disp('CALIBRATING CHANNEL 3...');
figure(2);
plot(z_data(:,3),'r');
title('PICK A POINT IN EACH CALIBRATION REGION 1,2,3 (DOWNWARD DISPLACEMENT)');
[xt,yt] = ginput(3);
xt = round(xt);

yt = z_data(xt,3)';

figure(3);
hmat3 = [0 h1 h2 h3];
vmat3 = [0 yt];
plot(vmat3, hmat3,'r*');
ylabel('height in CM');
xlabel('voltage');

%Plot linear fit and get slope
hold on;
%p3 is the slope of a first order linear fit to the calibration...
p3 = polyfit(vmat3,hmat3,1); 
%PLOT a line with the slope p1
pv3 = polyval(p3,vmat3);
plot(vmat3,pv3,'r');
ccal3 = p3(1); %calibration coef for channel 1:


zero_off = [zero_off1 zero_off2 zero_off3];
ccoefs = [ccal1 ccal2 ccal3];

disp(sprintf('\n ~~~~~~~~~~~~~~CALIBRATION COEFFICIENTS~~~~~~~~~~~~~'));
disp(sprintf('CHANNEL 1: ZERO = %8.2f Volts; CalCoeff = %8.2f cm/Volts',zero_off1,ccal1));
disp(sprintf('CHANNEL 2: ZERO = %8.2f Volts; CalCoeff = %8.2f cm/Volts',zero_off2,ccal2));
disp(sprintf('CHANNEL 3: ZERO = %8.2f Volts; CalCoeff = %8.2f cm/Volts',zero_off3,ccal3));

disp(sprintf('\n SAVING DATA TO FILE cal.mat'));
save cal.mat zero_off ccoefs 
disp(sprintf('ALL DONE!! \n'));