machinevisiontoolbox.Image.dilate

Image.dilate(se, n=1, border='replicate', bordervalue=0, **kwargs)

Morphological dilation

Parameters:

• se (ndarray(N,M)) – structuring element

• n (int, optional) – number of times to apply the dilation, defaults to 1

• border (str, optional) – option for boundary handling, see convolve, defaults to ‘replicate’

• bordervalue (scalar, optional) – padding value, defaults to 0

• kwargs – addition options passed to opencv.dilate

Returns:

dilated image

Return type:

Image

Returns the image after morphological dilation with the structuring element se applied n times.

Example:

>>> from machinevisiontoolbox import Image
>>> import numpy as np
>>> pixels = np.zeros((7,7)); pixels[3,3] = 1
>>> img = Image(pixels)
>>> img.print()
 0.00 0.00 0.00 0.00 0.00 0.00 0.00
 0.00 0.00 0.00 0.00 0.00 0.00 0.00
 0.00 0.00 0.00 0.00 0.00 0.00 0.00
 0.00 0.00 0.00 1.00 0.00 0.00 0.00
 0.00 0.00 0.00 0.00 0.00 0.00 0.00
 0.00 0.00 0.00 0.00 0.00 0.00 0.00
 0.00 0.00 0.00 0.00 0.00 0.00 0.00
>>> img.dilate(np.ones((3,3))).print()
   0   0   0   0   0   0   0
   0   0   0   0   0   0   0
   0   0 255 255 255   0   0
   0   0 255 255 255   0   0
   0   0 255 255 255   0   0
   0   0   0   0   0   0   0
   0   0   0   0   0   0   0

Note:

• It is cheaper to apply a smaller structuring element multiple times than one large one, the effective structuing element is the Minkowski sum of the structuring element with itself N times.

• The structuring element typically has odd side lengths.

• For a greyscale image this is the minimum value over the structuring element.

References:

• Robotics, Vision & Control for Python, Section 11.6, P. Corke, Springer 2023.

Seealso:

erode opencv.dilate