Straight Lines module behaviour
Frank Steinke from Australia  [3 posts]
14 year

Still fiddling with RoboRealm, and getting inconsistent behaviour with the Straight Lines module in  The basic symptom is that in certain circumstances it will only detect vertical lines, ignoring all horizontal ones.

With the uploaded file, doing a Canny it's fine, but use a Sobel (All), or leave raw, and run Straight Lines, then only verticals are picked up. Insert a Rotate 90 deg. between the Sobel and Straight Lines, and completely different parts of the image are detected!

Also, while playing with this I noted that the edge artifacts which disappear with zooming -- that you just looked at, appear in all their glory...

Thanks for listening,

Anonymous 14 year

The sobel edge detection was generating much thicker lines that the straight_lines module was expecting. We've tweaked that a little to improve the results which are better but now include a lot of little spots in them. But these can be filtered out using the min line length in the straight_lines module. Should be fixed in

Or try using Border and then Straight_Lines on your image ... that seems to work reasonably well.


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