Finding Edges with IMAQ Vision

[amila]

QUOTE (crelf @ Jan 22 2009, 06:04 PM)

Check out the VIs in the "Vision and Motion" > "Machine Vision" > "Locate Edges" functions palette.

Hi.. I tried to use 'find horizontal edge' in the functions palette. But I don't know exactly how to wire the 'rectangle' and how to display the edge coordinates. Could you tell me how to do this?

Many thanks.

[crelf]

RTFM.

[OlivierL]

Amila,

I had to do something similar not so long ago and one of the tools I found useful was (from memory) "pattern matching". One example in NI Vision set is a rotating part (that is with Vision 6 though...) that is located, with its angle with respect to it's original position. Take a look at the examples coming with Vision to learn how to use pattern matching but it could really well offer you a good alternative and an easier way of finding your object. One of the only constraints is that the object should be the same shape, always.

Hope this helps.

[amila]

Hi..

I've managed to improve my LabView program. I've already can detect edges that I want but using the clamp vi. But this vi will give result in term of distance measured between two points (in red color), please refer to my 'image result' file. What I want is the distance measured between horizontal edges (yellow points). My result should have the coordinates of every yellow points so that I can calculate the mid point for these edges.

How can I do this? Please help me.. Many thanks.

Amila

[Neville D]

Use the Edge Finder to get the "1st and last" edges. They will be in arrays. Subtract the two arrays to get the distance between the edges.

N.

[amila]

QUOTE (Neville D @ Feb 5 2009, 11:15 PM)

Use the Edge Finder to get the "1st and last" edges. They will be in arrays. Subtract the two arrays to get the distance between the edges.

N.

I've used Edge Detector and basically, I draw a line over the image and it give only 2 points (the first and last edges). How can I get a series of edges from top to bottom of the strip (all in one time)? Is it possible to detect automatically all this edges and display all the coordinates?

Many thanks.

[Neville D]

QUOTE (amila @ Feb 6 2009, 03:31 AM)

I've used Edge Detector and basically, I draw a line over the image and it give only 2 points (the first and last edges). How can I get a series of edges from top to bottom of the strip (all in one time)? Is it possible to detect automatically all this edges and display all the coordinates?

Yes, everything is possible.

Look at the LV examples for edge detection. You will learn a lot.

You need to define a ROI that encompasses the feature. Use this ROI for the edge detection.

N.

[amila]

QUOTE (Neville D @ Feb 6 2009, 06:09 PM)

Yes, everything is possible.

Look at the LV examples for edge detection. You will learn a lot.

You need to define a ROI that encompasses the feature. Use this ROI for the edge detection.

N.

I'm using the IMAQ Rake to get multiple parallel edges. But I don't know what's wrong with my program. There is no coordinates been displayed. And if I want to see the rake's lines, how can I do this? I've attached my VI here.

[Neville D]

Look at the Straight Edge Detection Example.vi and Edge Detection Example.vi

Try to follow what they're doing, and repeat for your case.

N.

[amila]

Hi All..

I want to express a very very very deep appreciation and thank you to all of you that have help me.. I manage to run my VI and it did the job.

Just another question, I run my VI which capture live video and did the image processing real time. The image been displayed was flickered very frequent. How this can be solved? Is it related to the webcam setting?

I attached my VI here..