Image.medianfilter#

Image.medianfilter(h: int = 1, **kwargs: Any) → Any[source]#

Median filter

Parameters:

  • h (int, optional) – half width of structuring element, defaults to 1

  • kwargs – options passed to rankfilter

Returns:

median filtered image

Return type:

Image instance

Return the median filtered image. For every \(w \times w, w=2h+1\) window take the median value as the output pixel value.

Example:

>>> from machinevisiontoolbox import Image
>>> import numpy as np
>>> array = np.arange(25).reshape((5,5))
>>> array[2, 2] = 0
>>> img = Image(array)
>>> img.print()
    0  1  2  3  4
    5  6  7  8  9
   10 11  0 13 14
   15 16 17 18 19
   20 21 22 23 24
>>> img.medianfilter(h=1).print()  # median filter
    1  2  3  4  4
    5  5  6  7  9
   10 10 11 13 14
   15 16 17 18 19
   20 20 21 22 23
>>> img = Image.Read('monalisa.png')
>>> img.medianfilter(h=5).disp()  # ameliorate background cracking
<matplotlib.image.AxesImage object at 0x7f076e0046e0>

Note

This filter is effective for removing impulse (aka salt and pepper) noise.

References:
Seealso:

rankfilter