s_HumanOptics

Make a mesh plot of the human optical transfer function. Note that some values are negative, which indicates that some of the harmonics are imaged in the wrong (negative) phase. This is called spurious resolution.

This function is also used in teaching to illustrate the OTF at different wavelengths.

See also: plotOTF, plotOI, s_HumanLSF

Copyright ImagEval Consultants, LLC, 2011.

Contents

OTF

wave = 400:10:700;       % nanometer
sampleSF = 0:0.5:50;     % cyc/deg
p  = 0.0015;  % Pupil radius (m)
D0 = 60;      % Dioptric power of human lens

otf = humanCore(wave,sampleSF,p,D0);

Plot the amplitude of the optical transfer function.

vcNewGraphWin;

mesh(sampleSF,wave,otf)
view(32.5,14);
xlabel('Spatial freq cy/deg');
ylabel('Wavelength (nm)');
zlabel('OTF')

Plot graphs of a few sample wavelengths

The effect of chromatic aberration (defocus in the short) is quite apparent in these graphs.

vcNewGraphWin;
waveList = [420 550 670];
cList = {'b-','g-','r-'};
for ii=1:length(waveList)
    plot(sampleSF,otf(ieFindWaveIndex(wave,waveList(ii)),:),cList{ii});
    hold on
end
grid on

xlabel('Spatial freq cy/deg');
ylabel('OTF value');
legend({'420 nm','550 nm','670 nm'})