Tool Name	Geodesic Morphological Reconstruction
Tool ID	12
Library ID	grid_filter
Version	1.0
Author(s)	HfT Stuttgart (c) 2013

Description

Geodesic morphological reconstruction according to Vincent (1993). Here we use the algorithm on p. 194: Computing of Regional Maxima and Breadth-first Scanning.

A marker is derived from the input grid by subtracting a constant shift value. Optionally, the shift value can be set to zero at the border of the grid ("Preserve 1px border Yes/No" parameter). The final result is a grid showing the difference between the input image and the morphological reconstruction of the marker under the input image. If the Option "Create a binary mask" is selected, the difference grid is thresholded with provided threshold value to create a binary image of maxima regions.

References

Arefi, H., Hahn, M. (2005): A Morphological Reconstruction Algorithm for Separating Off-Terrain Points from Terrain Points in Laser Scanning Data. Proceedings of the ISPRS Workshop Laser Scanning 2005, Enschede, the Netherlands, September 12-14, 2005. PDF

Vincent, L. (1993): Morphological Grayscale Reconstruction in Image Analysis: Applications and Efficient Algorithms. IEEE Transactions on Image Processing, Vol. 2, No 2. doi: 10.1109/83.217222

Parameters

Name	Type	Identifier	Description	Constraints
Input
Input Grid	grid, input	INPUT_GRID	Input for the morphological reconstruction
Output
Morphological Reconstruction	grid, output	DIFFERENCE_GRID	Reconstruction, difference to input grid.
Objects	grid, output, optional	OBJECT_GRID	Binary object mask
Options
Shift Value	floating point number	SHIFT_VALUE		Default: 5.000000
Preserve 1px border	boolean	BORDER_YES_NO		Default: 1
Threshold	floating point number	THRESHOLD	Threshold for object identification.	Minimum: 0.000000 Default: 1.000000