calc_inner_IR.m

% Copyright 2018 
% Open University (Katrine Rogers - k.s.rogers@open.ac.uk)
% University of Southampton (Edward Rogers - etr@orc.soton.ac.uk)

% A function which calculates the IR inside the FoV

function IR_in = calc_inner_IR(fn,ind_red)

diff_fn = diff(fn);
diff2pos_ind = find(diff_fn > 0,1,'first'); % position where function starts increasing
if isempty(diff2pos_ind)    % i.e. function is decreasing evenrywhere
    IR_in = 0;
elseif diff2pos_ind >= ind_red    % i.e. function is decreasing inside whole considered FoV
    IR_in = 0;
else
    IR_in = max(fn(diff2pos_ind:ind_red))/fn(1);
end