Machine Vision

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Hello all.


I am new to NI Vision and am in the middle of a college project. I am using Labview 2010 and a usb webcam. The camera is working fine and I can acquire an image no problem but do not know how to use the necessary tools within labview to process it. I was using NI Vision Assistant also to help me along in the process but am hitting a brick wall. I am attempting to find a line in a region of interest. Once found I want to get the lenght of the line and the angle of the line with respect to an origin. I have attached a VI that I have been working on so far.


Thank you in advance

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Message 1 of 9

Can you attach one of the images you're working with? That would hlelp getting you advice.


Best regards,



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Message 2 of 9
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Message 3 of 9

My initial thought is to use Concentric Rake to find the line.  You can define an annulus that goes around the spot in the center and covers the range you need.  This will help you locate the line and figure out its orientation.


Once you know where the line is, you can measure the length.  Concentric Rake may output all the edge points on the line, which would give you a pretty good estimate of the length.  If not, you could generate a rectangle around the area of the line and locate the first edge going from the outside toward the center.


Good luck.



Bruce Ammons
Ammons Engineering
Message 4 of 9

Thank you for that .


I am already attempting to use concentric rake but when I try to connect the image that I have captured is tells me that it is not an image. Maybe I have to convert it to an 8 bit image.

You would hardly have any examples of how to input the correct parameters to the VI. I have included an example that i am working on.



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Message 5 of 9

Yes, a color image would need to be converted to grayscale (8 bit) before using the rake function.



Bruce Ammons
Ammons Engineering
Message 6 of 9


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Message 7 of 9

I and I need help for a project

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Message 8 of 9

Hello Matchpattern,


If you need help, please open a new forum post and specify your issue.


Andrew George @ NI UK
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