scipy.ndimage.binary_hit_or_miss

scipy.ndimage.binary_hit_or_miss(input, structure1=None, structure2=None, output=None, origin1=0, origin2=None)

Multi-dimensional binary hit-or-miss transform.

The hit-or-miss transform finds the locations of a given pattern inside the input image.

Parameters

inputarray_like (cast to booleans)

Binary image where a pattern is to be detected.

structure1array_like (cast to booleans), optional

Part of the structuring element to be fitted to the foreground (non-zero elements) of input. If no value is provided, a structure of square connectivity 1 is chosen.

structure2array_like (cast to booleans), optional

Second part of the structuring element that has to miss completely the foreground. If no value is provided, the complementary of structure1 is taken.

outputndarray, optional

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

origin1int or tuple of ints, optional

Placement of the first part of the structuring element structure1, by default 0 for a centered structure.

origin2int or tuple of ints, optional

Placement of the second part of the structuring element structure2, by default 0 for a centered structure. If a value is provided for origin1 and not for origin2, then origin2 is set to origin1.

Returns

binary_hit_or_missndarray

Hit-or-miss transform of input with the given structuring element (structure1, structure2).

See also

binary_erosion

References

1

https://en.wikipedia.org/wiki/Hit-or-miss_transform

Examples

>>> from scipy import ndimage
>>> a = np.zeros((7,7), dtype=int)
>>> a[1, 1] = 1; a[2:4, 2:4] = 1; a[4:6, 4:6] = 1
>>> a
array([[0, 0, 0, 0, 0, 0, 0],
       [0, 1, 0, 0, 0, 0, 0],
       [0, 0, 1, 1, 0, 0, 0],
       [0, 0, 1, 1, 0, 0, 0],
       [0, 0, 0, 0, 1, 1, 0],
       [0, 0, 0, 0, 1, 1, 0],
       [0, 0, 0, 0, 0, 0, 0]])
>>> structure1 = np.array([[1, 0, 0], [0, 1, 1], [0, 1, 1]])
>>> structure1
array([[1, 0, 0],
       [0, 1, 1],
       [0, 1, 1]])
>>> # Find the matches of structure1 in the array a
>>> ndimage.binary_hit_or_miss(a, structure1=structure1).astype(int)
array([[0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0],
       [0, 0, 1, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 1, 0, 0],
       [0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0]])
>>> # Change the origin of the filter
>>> # origin1=1 is equivalent to origin1=(1,1) here
>>> ndimage.binary_hit_or_miss(a, structure1=structure1,\
... origin1=1).astype(int)
array([[0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 1, 0, 0, 0],
       [0, 0, 0, 0, 0, 0, 0],
       [0, 0, 0, 0, 0, 1, 0],
       [0, 0, 0, 0, 0, 0, 0]])