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Erode and Dilate

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Erode and Dilate Guanglei Xiong 04 Jan 06:51
  Erode and Dilate Sven Neumann 07 Jan 15:47
Erode and Dilate Brannon King 04 Jan 07:29
  Erode and Dilate John Cupitt 04 Jan 09:47
Guanglei Xiong
2006-01-04 06:51:12 UTC (over 18 years ago)

Erode and Dilate

hi gimp-developers,

The erode and dilate filters in Gimp seem to be reversed to the common sense. I try to erode a binary image in which the foreground is white and the background is black. The resulting object is wider and thicker than the original. The dilate filter outputs the opposite. Why?

bear

Brannon King
2006-01-04 07:29:09 UTC (over 18 years ago)

Erode and Dilate

I feel the same way. It applies to color and greyscale images as well. Traditionally, I've always thought that eroding would end up with less of the light and more of the dark.

John Cupitt
2006-01-04 09:47:42 UTC (over 18 years ago)

Erode and Dilate

Image processing has usually used 0 for object and 1 for background for the morphological operators. Imagine an image taken down a transmission microscope: the background will be the microscope light and objects will always be darker.

On 1/4/06, Brannon King wrote:

I feel the same way. It applies to color and greyscale images as well. Traditionally, I've always thought that eroding would end up with less of the light and more of the dark.

Sven Neumann
2006-01-07 15:47:38 UTC (over 18 years ago)

Erode and Dilate

Hi,

Guanglei Xiong writes:

The erode and dilate filters in Gimp seem to be reversed to the common sense. I try to erode a binary image in which the foreground is white and the background is black. The resulting object is wider and thicker than the original. The dilate filter outputs the opposite.

Can we please keep that discussion in http://bugzilla.gnome.org/show_bug.cgi?id=156545?

Sven