% plotf.m
%
% loads response function from picture of test chart and plots it
%
% plots   [black and 11 step greyvalues] 

k=115; % frame number
% k=116 returns last f value closer than 3 sigma to 255, so may be distorted
% k=115 seems to be brightest image that's not at risk of distortion
%function plotf(k)
if ((k<100) | (k>118))
  error('must load one of frame 100 to 118')
end%if

f=loadf(k);

q0=.011; % true black
% true black then 11 values of steps:
q=[.011; .021; .048; .079; .126; .185; .264; .358; .472; .622; .733; .893];

subplot(211)
plot(q,f);
Q=log(q);
subplot(212)
plot(Q,f);