🚀 go-pugleaf

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In article <1993Jan21.192619.10241@pinet.aip.org>, scotj@pinet.aip.org (scot_shinderman) writes:
[...]
|>   While reading the standard image processing books I have noticed one
|>algorithm that seems to be glossed over: contour tracing.  In the
|>pictures that I am scanning, a filter is run across the pixels and a
|>threshold is applied to produce either white or black pixels for the
|>grey-scale.  At this point there is usually a rather disconnected set of
|>dots due to noise in the picture but also some strong edges from the
|>filter.  What is the "pratical" method of moveing along the detected
|>pixels to find lines (or curves).  If I try to step from one pixel to
|>the next by looking in a neighborhood, then the path almost always gets
|>caught up in the noise off to one side or another.  Is there a way to
|>"nudge" the search in a particular direction based on previous motions.
[...]

1)	You can try to fix some "small gaps" in your lines by morphological 
	operations ( n times dilate and afterwards n times erode, where 0<n<6 ).
2)	You can use a Hough-Transform to get clues, where to find lines (or curves)
	in the image.
3)	You can use a sort of relaxation method to extract the lines, but to do
	this you can not simply threshold your filter output.
4)	You can extract line parts as a symbolic description of the connected
	components of your binary image and join line parts to lines (or curves)
	by symbolic methods
	
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Torsten Ihle, cand. inf., TU-Dresden
EMail: ihle@iki101.inf.tu-dresden.de

Es ist deutsch in Kaltland !
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