[Insight-users] A Few Questions and Problems

[Amitesh Agarwal]

Hi Jens,

Well if you refer to the book "Digital Image Processing" by Rafeal C.
Gonzalez & Richard E. Woods Section 9.2 & 9.3 specifically 9.3 It says
"Dilation expands an image and erosion shrinks it ........ Opening
Generally Smoothes the contour of an object, breaks narrow isthumuses
and eliminates thin protrusion. Closing also tends to smooth sections
of countour, as opposed to opening, it generally fuses narrow breaks
and long thin gulfs, eliminates small holes, and fills gaps in the
countour"

Moreover in certain situtations, as I have experienced while working
with binary image of skull and brain,  a combination of BinaryErode
and BinaryDilate doesn't completly solve the problem of opening and
closing in some regions. Some regions actually start merging with each
other if I use a bigger BinaryStructuralBallBearingElement (5x5x5) for
better removal of undesirable noise in the data in the order first
BinaryErode and then BinaryDilate with minimum erosion and maximum
dilation for best results.

I hope this clarifies my point.

Amitesh


On Wed, 5 Jan 2005 08:47:04 +0100, Jens Eickmeyer <eickmeyer at gmail.com> wrote:
> Hi!
> 
> On Tue, 4 Jan 2005 15:40:43 -0600, Amitesh Agarwal
> <amiteshagarwal at gmail.com> wrote:
> > 4) Opening and closing operation in a binary image
> >
> > I just wanted to know if there is any filter present in ITK for
> > performing opening and closing operation in a given Binary Image. It
> > is my understanding that BinaryErode and BinaryDilate do similar
> > operation in effect but not exactly the same.
> I haven't found such a filter, too. I use BinaryDilate and BinaryErode
> to apply closing to a binary image. But why are you thinking that this
> hasn't the same effect? Closing is just a dilation followed by am
> erosion and opening is just an erosion followed by a dilation. If
> BinaryErode and BinaryDilate work correctly - and I think we can
> assume this - the combined execution should lead to the right results.
> 
> Jens
>