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f_uniform_interp.m
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f_uniform_interp.m
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function [XIs,YIs] = f_uniform_interp(Xs,Ys,n_samp)
% % test
% Xs = (1:10)';
% Ys = [3 4 12 4 3 5 6 12 2 9]';
% n_samp = 11;
XIs = zeros(n_samp,1);
YIs = zeros(n_samp,1);
len_all = 0;
difXs = diff(Xs);
difYs = diff(Ys);
seg_lens = [0; sqrt(difXs.^2+difYs.^2)];
len_all = sum(seg_lens);
d_len = len_all/(n_samp+1);
% interpolate to get each point
n_pt = length(Xs);
for(ii=2:n_pt)
seg_lens(ii) = seg_lens(ii)+seg_lens(ii-1);
end
i_fill = 0;
cur_len = d_len;
for(ii=2:n_pt)
while cur_len <= seg_lens(ii) && i_fill<n_samp
% interpolate a point
r = (cur_len-seg_lens(ii-1)) / (seg_lens(ii)-seg_lens(ii-1));
x = Xs(ii-1)+r*(Xs(ii)-Xs(ii-1));
y = Ys(ii-1)+r*(Ys(ii)-Ys(ii-1));
i_fill = i_fill+1;
XIs(i_fill) = x;
YIs(i_fill) = y;
cur_len = cur_len+d_len;
end
end
% test
if 1
figure(97); clf; hold on;
plot(Xs,Ys,'r.-');
plot(XIs,YIs,'b+');
title(['n_samp=' i2s(n_samp) ', len=' i2s(length(XIs))]);
keyboard;
end