`scipy.ndimage._morphology:grey_opening`

source: /scipy/ndimage/_morphology.py :1449

Signature

   def     grey_opening (    input    ,    size    =  None   ,    footprint    =  None   ,    structure    =  None   ,    output    =  None   ,    mode    =  reflect   ,    cval    =  0.0   ,    origin    =  0   ,  * ,     axes    =  None     )

Summary

Multidimensional grayscale opening.

Extended Summary

A grayscale opening consists in the succession of a grayscale erosion, and a grayscale dilation.

Parameters

input : array_like: Array over which the grayscale opening is to be computed.
size : tuple of ints: Shape of a flat and full structuring element used for the grayscale opening. Optional if footprint or structure is provided.
footprint : array of ints, optional: Positions of non-infinite elements of a flat structuring element used for the grayscale opening.
structure : array of ints, optional: Structuring element used for the grayscale opening. structure may be a non-flat structuring element. The structure array applies offsets to the pixels in a neighborhood (the offset is additive during dilation and subtractive during erosion).
output : array, optional: An array used for storing the output of the opening may be provided.
mode : {'reflect', 'constant', 'nearest', 'mirror', 'wrap'}, optional: The mode parameter determines how the array borders are handled, where cval is the value when mode is equal to 'constant'. Default is 'reflect'
cval : scalar, optional: Value to fill past edges of input if mode is 'constant'. Default is 0.0.
origin : scalar, optional: The origin parameter controls the placement of the filter. Default 0
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

grey_opening : ndarray: Result of the grayscale opening of input with structure.

Notes

The action of a grayscale opening with a flat structuring element amounts to smoothen high local maxima, whereas binary opening erases small objects.

Array API Standard Support

grey_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.arange(36).reshape((6,6))
a[3, 3] = 50
a
ndimage.grey_opening(a, size=(3,3))

✓

Aliases

scipy.ndimage.grey_opening