machinevisiontoolbox.Image.decimate

Image.decimate(m=2, sigma=None)

Decimate an image

Parameters:

  • m (int) – decimation factor

  • sigma (float, optional) – standard deviation for Gaussian kernel smoothing, defaults to None

Raises:

ValueError – decimation factor m must be an integer

Returns:

decimated image

Return type:

Image

Return a decimated version of the image whose size is reduced by subsampling every m (an integer) pixels in both dimensions.

The image is smoothed with a Gaussian kernel with standard deviation sigma. If

  • sigma is None then a value of m/2 is used,

  • sigma is zero then no smoothing is performed.

Note:

  • If the image has multiple planes, each plane is decimated.

  • Smoothing is used to eliminate aliasing artifacts and the standard deviation should be chosen as a function of the maximum spatial frequency in the image.

Example:

>>> from machinevisiontoolbox import Image
>>> img = Image.Random(6)
>>> img.print()
 133 171  65 148 154  83
  34  89 193  88 173 155
 176 118 221   1 202 243
  90 198 239 191  83 182
 156  89  75   4 179 186
  77 120  45 221 159 132
>>> img.decimate(2, sigma=0).print()
 133  65 154
 176 221 202
 156  75 179
References:

  • Robotics, Vision & Control for Python, Section 11.7.2, P. Corke, Springer 2023.

Seealso:

replicate scale