Mahotas – Hit & Miss transform

In this article we will see how we can perform hit and miss transform in mahotas. In mathematical morphology, hit-or-miss transform is an operation that detects a given configuration in a binary image, using the morphological erosion operator and a pair of disjoint structuring elements.

In order to do this we will use mahotas.hitmiss method

Syntax : mahotas.hitmiss(img, template)

Argument : It takes two numpy ndarray as argument

Return : It returns ndarray

Below is the implementation

# importing required libraries
import mahotas as mh
import numpy as np
from pylab import imshow, show

# creating region
# numpy.ndarray
regions = np.zeros((10, 10), bool)

# setting 1 value to the region
regions[1, :2] = 1
regions[5:8, 6: 8] = 1
regions[8, 0] = 1

# showing the image with interpolation = 'nearest'
print("Image")
imshow(regions, interpolation ='nearest')
show()

# template for hit miss
template = np.array([
            [0, 1, 1],
            [0, 1, 1],
            [0, 1, 1]])

# hit miss transform
img = mahotas.hitmiss(regions, template)

# showing image
print("Image after hit miss transform")
imshow(img)
show()

Output :

Image

Image after hit miss transform

Another example

# importing required libraries
import mahotas as mh
import numpy as np
from pylab import imshow, show

# creating region
# numpy.ndarray
regions = np.zeros((10, 10), bool)

# setting 1 value to the region
regions[2:3, :3] = 1
regions[7:, 7:] = 1

# showing the image with interpolation = 'nearest'
print("Image")
imshow(regions, interpolation ='nearest')
show()

# template for hit miss
template = np.array([
            [0, 1, 1],
            [0, 1, 1],
            [0, 1, 1]])

# hit miss transform
img = mahotas.hitmiss(regions, template)

# showing image
print("Image after hit miss transform")
imshow(img)
show()

Output :

Image

Image after hit miss transform