Question

In MATLAB’s Image Processing Toolbox there’s the improfile function that returns the intensity profile of an image from underneath a line defined by two points.

Is there a writing equivalent of this function? That is, I would like to pass two points (to specify a line) and a vector of pixel values to replace a bunch of pixels underneath the line.

Answer 1

I’ve done basically what Ghaul suggested, but replaced imline() with manually finding underlying pixels. The advantage is that a figure is not shown which brings some speed benefits (~0.5s in my tests);

dist_euc = norm(p1 - p2);
n_pix = round(dist_euc*2);
step = (p1 - p2)/n_pix;
pix_coords = zeros(n_pix, 2);
for cp = 0:n_pix
    pix_coords(cp+1, :) = round(p2 + cp*step);
end
pix_inds = sub2ind(size(im), pix_coords(:,2), pix_coords(:,1));
pix_inds = unique(pix_inds);
im(pix_inds) = interpft(prof, length(pix_inds));