How to outline a defect in an image?

Question

The images given below are a result of fruit defect detection algorithm i have made myself...

Just wanted to know is there a way of outlining these defects?

Original image 1:

enter image description here

1st Image:

enter image description here

Original image 2:

enter image description here 2nd Image:

enter image description here

What i want to achieve is this :

You should add more detail, such as, what are the original two images, what operations have you executed on them to obtain this end result, and what is the defect you are talking about? — Geerten, Commented Feb 8, 2012 at 14:09
Yes, original images would help. Also, what qualifies as a defect? — Phonon, Commented Feb 8, 2012 at 14:18
@vini Hmm, would it be correct to say that (so far) a defect is defined as simply a discoloration? That seems to be the only feature here ya? — Spacey, Commented Feb 8, 2012 at 20:34

Martin Thompson · Accepted Answer · 2012-02-09 17:27:38Z

4

As far as I understand what you call defects are detcted by changes in color of the fruit.

I would proceed as follow:

edge detection algorithm, (as you did), to detect the fruit region in the image.
In this region, compute the median color, that is the color that matches the most pixels (for example, it would be some kind of yellow for a banana)
For each pixel in the fruit region, check the distant between the median computed at step 2 and the color of the pixel. If the distance is high, mark the pixel as defect
At the end, apply some morphological operator to remove outliers

Hope this helps.

Martin Thompson

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answered Feb 9, 2012 at 11:30

Stocastico

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$\begingroup$ Maybe add a connected component step in between to evaluate blobs further (on area size, mean distance of that blob to the mean color of the fruit, etc). $\endgroup$
– Geerten
Commented Feb 9, 2012 at 12:17

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