%Chapter 7,  Fig 7.2
%Eric Dubois, updated 2018-12-12
%Plot spectral absorption and reflection curves
%Data files should be placed in a data directory on the MATLAB path.
clear all, close all;
%read and interpolate the spectral absorption curve
filterName = 'f807_darkLemon.txt';
absorp_in = dlmread(filterName,' ');
%interpolate the absorption curve
lami = 400:2:700;
absorp = interp1(absorp_in(:,1),absorp_in(:,2),lami,'spline')';
figure;

plot(lami,absorp,'k')
xlabel('wavelength (nm)')
axis([400 700 0 1])
xlabel('Wavelength (nm)');
ylabel('Normalized power');
title('Spectral transmission of dark lemon plastic filter');
set(gcf,'Color',[1 1 1]);
set(gca,'fontname','times')          %set the plot font to Times

%Read the Macbeth data
macbeth_spect = dlmread('specref.txt');
macsize = size(macbeth_spect);
lam_mac = macbeth_spect(:,1);
macbeth_yellow = interp1(lam_mac,macbeth_spect(:,17),lami,'spline');
figure;

plot(lami,macbeth_yellow,'k');
xlabel('wavelength (nm)')
axis([400 700 0 1])
xlabel('Wavelength (nm)');
ylabel('Normalized power');
title('Spectral reflectance of yellow square on a Macbeth Color Checker chart');
set(gcf,'Color',[1 1 1]);
set(gca,'fontname','times')          %set the plot font to Times