Module: Hysteresis Thresholding

Description:

Performs a hysteresis thresholding on the image, given a low and high threshold and a connectivity. In other words, if we call Sl the set of pixels with intensity greater than or equal to the low threshold and Sh the ones with with intensity greater than or equal to the high threshold, then this module extracts the connected components of Sl which contain pixels of Sh.

Illustration of the difference between a basic thresholding and a hysteresis thresholding. (a) is the original image, (b) is a thresholding, and (c) is a hysteresis thresholding.

Connections:

Image

[required]
The input image comes in through this port. For now, the only input type that has been implemented is HxUniformScalarField3.

Ports:

Low threshold

Specifies values of the lower threshold, which determines Sl.

High threshold

Specifies values of the higher threshold, which determines Sh.

Connectivity

Choice of the neighbourhood.

Illustration of the different connectivities. (a): 6-, (b): 18-, and (c): 26-connectivity (in case you didn't figure it out, n-connectivity means n pixels in the neighbourhood).

Action button

Push this button to start the computation.

Commands:

Additional options can be accessed when typing in the console Hysteresis_Thresholding COMMAND_NAME. Typing the command again usually reverts back to original settings.

`verbose`

Displays timing information after the computation. Retype to hide info.

`create`

Runs the computation. Returns the name of the output, so it can be used in a script, such as set RESULT [Hysteresis_Thresholding create].