Machine Vision

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Need some help

Hi
 
Please help me to build an algorithm to find horizontal lines in seat pictures is attached.I tried various filter but not able to get all lines properly
 
Warm Regards
Orooj Ahmed
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Message 1 of 16
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Well you dont need the filter all the time. Please see the attachment. The cluster of 3 edges represent one horizontal line.Got it?
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Message 2 of 16
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Hi...

I have to check the parellelity of lines ...i tried edge detection also....some time due to cotrast difference it is not able to locate lower line..

 

Warm Regards

Orooj ahmed

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Message 3 of 16
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Well there is no rule that u need to use a single edge dection line.Use multiple lines and vary the contrast accordingly(If u r not able to acheive uniform illumination).

What is the illumination u r using?

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Hi..

I am using high frequency CFL....

Warm Regards

Orooj Ahmed

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Message 5 of 16
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Hi..

I am using high frequency CFL....

Warm Regards

Orooj Ahmed

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Message 6 of 16
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Try filtering with a differencing filter.  It would be a vertical array that looks like -1 -1 -1 -1 0 1 1 1 1.  You could adjust the number of elements.  This should give you a fairly bright line where the edge of each line is.  You may have to reverse the signs to get the highlighting.

After that, peak detection would work well to find the center of each bright line.

Bruce

Bruce Ammons
Ammons Engineering
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Message 7 of 16
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One efficent way to simultaneously test for the presence and orientation of lines in an image is called the hough line transform. You'll likely want to run an edge detector over the image first, then use the hough transform. You can find good information on it through google. here is a decent one: http://en.wikipedia.org/wiki/Hough_transform. It might seem confusing at first, but it is actually very simple and it is easy to implement, and it works like a charm. Just reply if you need additional help.


global variables make robots angry


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Message 8 of 16
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 Hi...

As far as i know hough transform takes too much of time.............also in Imaq we dont have hough transform...if possible please give me hough.vi..

Warm Regards
Oroj Ahmed

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Message 9 of 16
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Alas u dont have the hough transform in LabVIEW.I had mentioned this in " What are your dreams about IMAQ?" thread.
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Message 10 of 16
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