% EDGELIST2IMAGE - transfers edgelist data back into a 2D image array
%
% Usage: im = edgelist2image(edgelist, rowscols)
%
% edgelist - Cell array of edgelists in the form
% { [r1 c1 [r1 c1 etc }
% ...
% rN cN] ....]
% rowscols - Optional 2 element vector [rows cols] specifying the size
% of the image from which edges were detected (used to set
% size of plotted image). If omitted or specified as [] this
% defaults to the bounds of the linesegment points
%
% Note this function will only work effectively on 'dense' edgelist data
% obtained, say, directly from edgelink. If you have subsequently fitted
% line segments to the edgelist data this function will only mark the endpoints
% of the segments, use DRAWEDGELIST instead.
%
% See also: EDGELINK, DRAWEDGELIST
% Copyright (c) 2007 Peter Kovesi
%
% Permission is hereby granted, free of charge, to any person obtaining a copy
% of this software and associated documentation files (the "Software"), to deal
% in the Software without restriction, subject to the following conditions:
%
% The above copyright notice and this permission notice shall be included in
% all copies or substantial portions of the Software.
%
% The Software is provided "as is", without warranty of any kind.
% September 2007
function im = edgelist2image(edgelist, rowscols)
if nargin < 2, rowscols = [1 1]; end
Nedge = length(edgelist);
% Establish bounds of image
minx = 1; miny = 1;
maxx = rowscols(2); maxy = rowscols(1);
for I = 1:Nedge
minx = min(min(edgelist{I}(:,2)),minx);
miny = min(min(edgelist{I}(:,1)),miny);
maxx = max(max(edgelist{I}(:,2)),maxx);
maxy = max(max(edgelist{I}(:,1)),maxy);
end
% Draw the edgelist data into an image array
im = zeros(maxy,maxx);
for I = 1:Nedge
ind = sub2ind([maxy maxx], edgelist{I}(:,1), edgelist{I}(:,2));
im(ind) = 1;
end