which is algorithm in this program?

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From the first image should get the last image. who has the ideas of algorithm in this program?
The first image - the original image
The second image - Binary image
The last image - the image brightness gradient boundary

http://xmages.net/i/3255828

Posted 12-Dec-11 20:43pm

OlegMoskva

Updated 12-Dec-11 21:21pm

v8

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Sergey Alexandrovich Kryukov 13-Dec-11 2:53am

Oleg, can you see "Improve question" above? Use it! But first think about correct inquiry itself.
--SA

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OriginalGriff · Accepted Answer · 2011-12-12T21:14:00

Solution 1

The best thing I can suggest is that you try Google: "image brightness gradient boundary"[^] - you do not give enough info to work it out from a couple of small pictures.

Posted 12-Dec-11 21:14pm

OriginalGriff

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OlegMoskva 13-Dec-11 3:27am

this is just edge detection. i need some thing more.

YvesDaoust · Accepted Answer · 2011-12-12T21:28:00

Solution 2

Funny but difficult quizz.

Even the middle image is hard to tell. Possibly edge detection filter (Canny) followed by thresholding (without non-maxima suppression).

The right one is really unexpected. Looks like anisotropic smoothing (edge flow) followed by edge detection followed by vectorization (looks like short line segments rather than free contours).

Anyway, the structures on the right image bear little resemblance with the original content and introduce many artifacts, as an overlay shows. http://xmages.net/i/3255881[^]

Other hypotheses:

- isophotes on the smoothed image, because the curves are bundled, followed by some postprocessing, because large portions are missing;

- postprocessing could be polylines fitted to isophotes in a snake-like fashion.

Posted 12-Dec-11 21:28pm

YvesDaoust

Updated 12-Dec-11 21:39pm

v2

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OlegMoskva 13-Dec-11 3:56am

The middle image - Binarization by medians, brightness gradient.
a on the right image show lineament structure in original images.

YvesDaoust 13-Dec-11 4:14am

What is binarization by medians ? Never heard of that. Median filter ?

I understand the intent to find lineaments. Anyway it seems to me that the method is very uneffective. May lineaments are detected where there are none in the source image, and conversely, many salients lineaments are ignored.

OlegMoskva 13-Dec-11 4:36am

Yes I mean binary image by Median filter. In my opinion this method very effective. we can see overall lineament structures in source image.

YvesDaoust 13-Dec-11 4:45am

The median filter does not produce a binary image by itself. Do you you mean binarization followed by binary median filter, or grayscale median filter followed by binarization, or something different ?

In my not-so-humble opinion, this algorithm is a poor lineament detector. Indeed it generates a lineament-like image, but that has little correspondence with the underlying image. Too many false positives and false negatives.

OlegMoskva 13-Dec-11 4:56am

its really binarization followed by binary median filter.

which of algorithm to detect lineament in your opinion effective more???
Not Hough transform?

YvesDaoust 13-Dec-11 5:40am

Actually, it is impossible to answer your question without knowing how you would define a good lineament detection. What would you really expect as a valid output of the algorithm. Subjectivity should be dealt with in the first place.

If I were to do it, I would first try a classical edge detector (Canny + non-maxima suppression + hysteresis thresholding), then filter on edges that go in pairs (this would be an ad-hoc algorithm to be created).

You can also get some inspiration from http://www.irisa.fr/vista/Papers/2000_mva_laptev.pdf, even though this is a fairly sophisticated solution.

OlegMoskva 14-Dec-11 4:29am

Thank you! But in this papers not same algorithm! do you have any idea more??

YvesDaoust 14-Dec-11 4:34am

No. What more do you know about these images ? [You seem to know how the middle one was obtained]
If yo don't tell me the context I cannot help you.

which is algorithm in this program?

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which is algorithm in this program?

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