MATLAB: Plotting dots on the edges of an object uniformly

digital image processingdistance along curvedistance along lineimageimage analysisimage processingimage segmentationMATLAB

Hello, everyone. I wonder is it possible to distribute a specific number of dots on the edges of the acquired image. Think of a circle for instance, is it possible to distribute,like, 8 dots uniformly on the circle ? Note: As in the image i have uploaded. Red circles are the dots etc.(sorry for paint level image :3)

Best Answer

See http://www.mathworks.com/matlabcentral/answers/317921-distances-along-a-plotted-line#answer_248275

You would probably want to set marker_dist to dist_from_start(end)/N where N is the number of dots you want around the edge.

Note that that code does not try to put the markers at corners: it is code for placing the markers at equal distances along the path, where-ever that comes out to be.

Related Solutions

MATLAB: Distances along a plotted line

   marker_dist = 1;
   x = [0 5 10];
   y = [2 4 1];
   dist_from_start = cumsum( [0, sqrt((x(2:end)-x(1:end-1)).^2 + (y(2:end)-y(1:end-1)).^2)] );
   marker_locs = marker_dist : marker_dist : dist_from_start(end);   %replace with specific distances if desired
   marker_indices = interp1( dist_from_start, 1 : length(dist_from_start), marker_locs);
   marker_base_pos = floor(marker_indices);
   weight_second = marker_indices - marker_base_pos;
   marker_x = x(marker_base_pos) .* (1-weight_second) + x(marker_base_pos+1) .* weight_second;
   marker_y = y(marker_base_pos) .* (1-weight_second) + y(marker_base_pos+1) .* weight_second;
   plot(x, y);
   hold on;
   plot(marker_x, marker_y, 'r+');
   hold off

MATLAB: Gca.XLimMode does not work

If you check the xLimMode after running your code, you will see that it has changed back to auto after the plot() statement. You need to hold() the axis to stop it from changing automatically.

fig = figure;
ha1 = axes;
ha1.Position = [0.5 0.5 0.3 0.3]
ha1.XLim = [-10 -5];
ha1.YLim  = [-5 -1];
set(ha1,'xlimMode','manual');
set(ha1,'ylimMode','manual');
[x,y] = ginput;
hold(ha1);  %<--- this line will prevent automatic changes.
plot(x,y);

Best Answer

Related Solutions

MATLAB: Distances along a plotted line

MATLAB: Gca.XLimMode does not work

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