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 ImageEn Library for Delphi, C++ and .Net
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 How you get outline (raster tracing)
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AlexS

USA
9 Posts

Posted - Feb 21 2024 :  11:52:55  Show Profile  Reply
Hello Everyone,

Maybe somebody can give a hint, or point to right direction. I am searching for a way to trace raster image and get sequence of vectors (outline). OpenCV does it and has corresponding function. If ImageEn can do this - it would be awesome.

Please let me know if you have any information about this.

Thank you!

Alex

xequte

38231 Posts

Posted - Feb 21 2024 :  16:26:21  Show Profile  Reply
Hi Alex

Which OpenCV methods are you referring to? IEVision supports:
- HoughLines: http://www.imageen.com/help/TIEVisionImage.houghLines.html
- Canny: http://www.imageen.com/help/TIEVisionImage.canny.html

Nigel
Xequte Software
www.imageen.com
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AlexS

USA
9 Posts

Posted - Feb 22 2024 :  11:07:46  Show Profile  Reply
Hi Nigel,

Thank you for response, much appreciated. You are right, the talk about Canny. I also found findContours function in your API. If memory serve, OpenCV also has some functions for processing of point array after findContours(), mostly clean-ups, conversion to curves, etc.

Once again - thank you for quick answer, I see where to start.

Thanks!
Alex
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xequte

38231 Posts

Posted - Feb 22 2024 :  13:14:32  Show Profile  Reply
Hi Alex

Let us know if you find any OpenCV features that are missing.

Nigel
Xequte Software
www.imageen.com
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AlexS

USA
9 Posts

Posted - Feb 22 2024 :  13:28:56  Show Profile  Reply
Hi Nigel,

Thanks for response. I just started, may I ask a question, just for getting some initial expectation. What do you think, how many OpenCV functions exposed in your API? Just approximate percentage. I was trying to find a way how to use OpenCV from Delphi apps, tons of attempts without real success. I see what you did, and much appreciate your hard work. Just interesting how far you guys did go.

Technically, I dont need all OpenCV, as soon as will get raster/video to vector conversion done will become supper happy and thankful customer :)

Thanks again!
Alex.


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xequte

38231 Posts

Posted - Feb 22 2024 :  19:29:31  Show Profile  Reply
Hi Alex

That's very hard to say. We try to implement all of the functionality that we consider useful. We also look to add those features that customers request. Coming next month we will add support for Neural Networks too.

Nigel
Xequte Software
www.imageen.com
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AlexS

USA
9 Posts

Posted - Feb 22 2024 :  19:47:11  Show Profile  Reply
Thanks for answer Nigel!

That is perfect strategy. Absolutely reasonable.

Best Regards,
Alex

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AlexS

USA
9 Posts

Posted - Apr 05 2024 :  21:05:14  Show Profile  Reply
Hi Nigel,

I made simple test app for findContours(). The only detail which I cannot find explanation in help file is - how to detect is sequence of points is closed contour or no. I mean, last point question.





Please pay attention to white big rectangle. Left side is input raster. The right side s painted contours in standard bitmap. White pixels - points from contour. Lines has random colors to separate them easily. So, the square/rect in left/top area. It visualized as moveto() and then sequence of lineto(). Similar situation in outer and inner rectangle. Outer has 4 points which explain missing side of the square.

Probably I explain too complicated. As example - we have perfect square. How many points I should expect - 4 or 5? if 4, then how should I know that last and first point form a visible line? there might be situations where 4 points form 3 visible lines.

Let me know if the question formulated not well enough.

Thank you,
Alex.






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xequte

38231 Posts

Posted - Apr 06 2024 :  18:32:51  Show Profile  Reply
Hi Alex

findContours() is an OpenCV method, so it is difficult to say specifically what will be returned. Can you post your test image and code (or email it to me), I'd like to test it more in-depth.


Nigel
Xequte Software
www.imageen.com
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