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bundles / scipy 1.17.1 / scipy / ndimage / _morphology / binary_opening

function

scipy.ndimage._morphology:binary_opening

source: /scipy/ndimage/_morphology.py :546

Signature

def   binary_opening ( input structure = None iterations = 1 output = None origin = 0 mask = None border_value = 0 brute_force = False * axes = None )

Summary

Multidimensional binary opening with the given structuring element.

Extended Summary

The opening of an input image by a structuring element is the dilation of the erosion of the image by the structuring element.

Parameters

input : array_like

Binary array_like to be opened. Non-zero (True) elements form the subset to be opened.

structure : array_like, optional

Structuring element used for the opening. Non-zero elements are considered True. If no structuring element is provided an element is generated with a square connectivity equal to one (i.e., only nearest neighbors are connected to the center, diagonally-connected elements are not considered neighbors).

iterations : int, optional

The erosion step of the opening, then the dilation step are each repeated iterations times (one, by default). If iterations is less than 1, each operation is repeated until the result does not change anymore. Only an integer of iterations is accepted.

output : ndarray, optional

Array of the same shape as input, into which the output is placed. By default, a new array is created.

origin : int or tuple of ints, optional

Placement of the filter, by default 0.

mask : array_like, optional

If a mask is given, only those elements with a True value at the corresponding mask element are modified at each iteration.

border_value : int (cast to 0 or 1), optional

Value at the border in the output array.

brute_force : boolean, optional

Memory condition: if False, only the pixels whose value was changed in the last iteration are tracked as candidates to be updated in the current iteration; if true all pixels are considered as candidates for update, regardless of what happened in the previous iteration. False by default.

axes : tuple of int or None

The axes over which to apply the filter. If None, input is filtered along all axes. If an origin tuple is provided, its length must match the number of axes.

Returns

binary_opening : ndarray of bools

Opening of the input by the structuring element.

Notes

Opening [1] is a mathematical morphology operation [2] that consists in the succession of an erosion and a dilation of the input with the same structuring element. Opening, therefore, removes objects smaller than the structuring element.

Together with closing (binary_closing), opening can be used for noise removal.

Array API Standard Support

binary_opening has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable SCIPY_ARRAY_API=1 and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.

====================  ====================  ====================
Library               CPU                   GPU
====================  ====================  ====================
NumPy                 ✅                     n/a                 
CuPy                  n/a                   ✅                   
PyTorch               ✅                     ⛔                   
JAX                   ⚠️ no JIT
Dask                  ⚠️ computes graph     n/a                 
====================  ====================  ====================

See dev-arrayapi for more information.

Examples

from scipy import ndimage
import numpy as np
a = np.zeros((5,5), dtype=int)
a[1:4, 1:4] = 1; a[4, 4] = 1
a
ndimage.binary_opening(a, structure=np.ones((3,3))).astype(int)
ndimage.binary_opening(a).astype(int)
ndimage.binary_erosion(a).astype(int)
ndimage.binary_dilation(ndimage.binary_erosion(a)).astype(int)

See also

binary_closing
binary_dilation
binary_erosion
generate_binary_structure
grey_opening

Aliases

  • scipy.ndimage.binary_opening

Referenced by

This package