FindRadonPeaks.m

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Finds the peak or trough of radon transform
%
% Arguments:
%   radout (struct): struct containing {txfm, theta, rp}
%   trough_mode (bool): optional flag for finding trough
%
% Returns:
%   peak.max_val (scalar): value of radon transform at peak/trough,
%     which equals the data averaged over the trajectory
%   peak.th_ind (scalar)
%   peak.rp_ind (scalar)
%   peak.angle (scalar)
%   peak.rad_pos (scalar)
%   peak.trough_mode (bool)
%   peak.hittingedgeflag (bool): if angle is at edge of theta range
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% TODO: Add optional restrictions to limit search space
function peak = FindRadonPeaks(radout, trough_mode)
if ~exist('trough_mode', 'var')
    trough_mode = false;
end
if trough_mode
    radout.txfm = -1 * radout.txfm;
end
[max_val, max_ind] = max(radout.txfm(:));
[rp_ind, th_ind] = ind2sub(size(radout.txfm), max_ind);
angle = radout.theta(th_ind);
rad_pos = radout.rp(rp_ind);

peak.max_val = max_val;
peak.th_ind = th_ind;
peak.rp_ind = rp_ind;
peak.angle = angle;
peak.rad_pos = rad_pos;
peak.trough_mode = trough_mode;
peak.hittingedgeflag = (th_ind==1 || th_ind==length(radout.theta));