erosion_rectangle1 — Erode a region with a rectangular structuring element.
erosion_rectangle1(Region : RegionErosion : Width, Height : )
erosion_rectangle1 applies an erosion with a rectangular
structuring element to the input regions Region. The size
of the structuring rectangle is Width x
Height. The operator results in reduced regions, and the
areas smaller than the rectangular mask are eliminated.
erosion_rectangle1 is a very fast operation because the
height of the rectangle enters only logarithmically into the runtime
complexity, while the width does not enter at all. This leads to
excellent runtime efficiency, even in the case of very large
rectangles (edge length > 100).
Regions containing small connecting strips between large areas are separated only seemingly. They remain logically one region.
To reduce a region by the same amount in all directions,
Width and Height must be odd. If this is not the
case, the region is eroded by a larger amount at the right or at the
bottom, respectively, than at the left or at the top.
Region (input_object) region(-array) → object
Regions to be eroded.
RegionErosion (output_object) region(-array) → object
Eroded regions.
Width (input_control) extent.x → (integer)
Width of the structuring rectangle.
Default value: 11
Suggested values: 1, 2, 3, 4, 5, 11, 15, 21, 31, 51, 71, 101, 151, 201
Typical range of values: 1
≤
Width
≤
511 (lin)
Minimum increment: 1
Recommended increment: 1
Height (input_control) extent.y → (integer)
Height of the structuring rectangle.
Default value: 11
Suggested values: 1, 2, 3, 4, 5, 11, 15, 21, 31, 51, 71, 101, 151, 201
Typical range of values: 1
≤
Height
≤
511 (lin)
Minimum increment: 1
Recommended increment: 1
Let F1 be the area of an input region and H be the height of the rectangle. Then the runtime complexity for one region is:
erosion_rectangle1 returns TRUE if all parameters are
correct. The behavior in case of empty or no input region can be
set via:
empty region:
set_system('empty_region_result',<RegionResult>)
Otherwise, an exception is raised.
threshold,
regiongrowing,
watersheds,
class_ndim_norm
reduce_domain,
select_shape,
area_center,
connection
Foundation