Posted by
Kenneth Sloan-2 on
Jan 20, 2018; 1:39am
URL: http://imagej.273.s1.nabble.com/question-on-edge-detection-tp5019908p5019915.html
yes - that's pretty simple, as vasculature goes. Herbie seems to be on track to help you
on your plan to find and trace boundaries, so I won't intrude there.
But...it might be helpful to make available a complete stack of images - because I think your *real* question is "how are the boundaries moving" and not so much "where are the boundaries in each individual frame".
If I may, I suggest first converting to 8-bit, and perhaps apply some smoothing to get rid of the speckle. And then, find a way to share an entire stack. If all else fails, I can create a "Box" folder where you can upload a sequence of images.
Personally, I'm a bit interested in whether it will work to concentrate on identifying MOTION without actually tracing the boundaries.
On the other hand, Herbie has demonstrated that *he* can easily find your boundaries in your images, and if that works for you there's no need to look further.
As you can probably appreciate, there is a mountain of literature on solving this problem. The question is: does someone here have something you can use, more or less "off the shelf". I suspect that Herbie does. I don't.
--
Kenneth Sloan
[hidden email]
Vision is the art of seeing what is invisible to others.
> On 19 Jan 2018, at 16:16 , David Schaffer <
[hidden email]> wrote:
>
> Thanks, Kenneth.
> Actually, our problem may be simpler that I gave the impression.
> We choose our images so that there is one big artery in the image plane.
> No worries about branching (at least for now).
>
> What I have in mind is, starting from an edge segment (from Canny, or
> some such), I expect to have to write code that tries to "follow the
> edge" into the unknown.
> Something like ridge-following in the derivative of the intensities,
> even if they get pretty noisy.
> We'll have to fiddle with criteria for choosing the best next-point, and so on.
>
> OK, I don't even know how to write low-level ImageJ code.
> Could someone send me an example or two of such a thing?
> Perhaps someone has already written such an edge-extender before.
> Or, failing that, some code that accesses the same image info I need,
> given an xy pixel location, how to get the neighbors in a particular
> direction and compute intensity gradients, ...
>
> Hoping I can learn the art of ImageJ programming from a few examples.
>
> Thanks,
> Dave
>
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