OOF2: The Manual

OOF.PixelSelection.Despeckle
	6.2.189. OOF.PixelSelection Commands

Name

OOF.PixelSelection.Despeckle — Recursively select all pixels with a minimum number of selected neighbors. This fills in small holes in the selection.

Synopsis

OOF.PixelSelection.Despeckle(microstructure,neighbors)

Details

Parent Menu: OOF.PixelSelection
Callback: function doSelectionMod in module ooflib.common.pixelselectionmod
Parameters:

microstructure

Type: The path to an existing Microstructure object.

neighbors

Select pixels with at least this many selected neighbors Type: An integer in the range [4, 8].

Description

Some pixel selection tools such as OOF.Graphics_n.Toolbox.Pixel_Select.Burn or OOF.Graphics_n.Toolbox.Pixel_Select.Color tend to leave small holes in the selection due to imperfection of the micrograph or other reasons. With only a few holes, it's possible to fill them manually other tools in the Pixel Selection toolbox, but this quickly gets tedious. The Despeckle fills these holes efficiently.

	Note
	Note that it's the pixel selection that is being despeckled, not the `Image`. The term “despeckle” is also used to mean removing noise from an image, and OOF2 does include `Image` despeckling (OOF.Image.Modify.Despeckle.) OOF.PixelSelection.Despeckle selects pixels, but does not affect `Images`.

The end result of a despeckling is a solidification of the selecting region. Compare to Elkcepsed, which achieves a similar effect by deselecting pixels.

The microstructure parameter specifies the Microstructure where the selection resides.

The parameter neighbors controls the despeckling operation. Smaller values mean stronger filling power. The algorithm examines each unselected pixel, counts its selected neighbors (examining the 8 immediately adjacent pixels), and selects the target pixels if at least neighbors neighboring pixels were selected. The process repeats recursively until no more pixels are selected. The value of neighbors must be between 4 and 8 inclusive: values higher than 8 are meaningless, and values lower than 4 will cause all pixels to be selected. 4 itself is of dubious utility. See Figure 6.45 for examples.

Figure 6.45. Despeckling the Pixel Selection

A pixel selection (in red) containing some holes to be filled with Despeckle.

The result of despeckling with neighbors=8. Only single pixel holes have been filled.

The result of despeckling with neighbors=7. One and two pixel holes have been filled.

The result of despeckling with neighbors=6. Larger holes have been filled.

The result of despeckling with neighbors=5. Holes have been filled and the boundary has been smoothed.

The result of despeckling with neighbors=4. Almost everything has been obliterated.


OOF.PixelSelection.Copy		OOF.PixelSelection.Elkcepsed