flowToVectorImage.m
cfea8427fe6ccluster_pipeline

flowToVectorImage.m
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			function A = flowToVectorImage(w, n_sampling_points, resolution, frame_number, tmpdir)
			% flowToVectorImage(w, sampling_rate, resolution)
			% w is flow of form n x n x 2
			% n_sampling_points is the number of sampling point in x and y direction
			% resolution is an array of length 2 which specifies the resolution of the resulting vector image
			% frame_number is needed for parallel execution to separate tmp files
			sampling_rate_1 = round(size(w,1)/n_sampling_points(1));
			sampling_rate_2 = round(size(w,1)/n_sampling_points(2));
			u = w(1:sampling_rate_1:end,1:sampling_rate_1:end,1);
			v = w(1:sampling_rate_2:end,1:sampling_rate_2:end,2);
			[x,y] = meshgrid(1:sampling_rate_2:size(w,2),1:sampling_rate_1:size(w,1));
			figure;
			quiver(x,y,u,v,'color','k','AutoScale','off','LineWidth', 8);
			set(gca,'XTick',[]); % Remove the ticks in the x axis!
			set(gca,'YTick',[]); % Remove the ticks in the y axis
			set(gca,'XLim',[1,size(w,1)]);
			set(gca,'YLim',[1,size(w,2)]);
			set(gca,'Visible','off')
			set(gcf,'PaperUnits','inches','PaperPosition',[0 0 resolution(1) resolution(2)]);
			ax = gca;
			outerpos = ax.OuterPosition;
			ti = ax.TightInset;
			left = outerpos(1) + ti(1);
			bottom = outerpos(2) + ti(2);
			ax_width = outerpos(3) - ti(1) - ti(3);
			ax_height = outerpos(4) - ti(2) - ti(4);
			ax.Position = [left bottom ax_width ax_height];

			filename = fullfile(tmpdir,['tmpvector',num2str(frame_number),'.tiff']);
			print(filename,'-dtiff','-r1');
			im = imread(filename);
			A = imerode(imadjust(rgb2gray(im),[0.99, 1]), strel('square',1));

			delete(filename);