Downsample

Downsample[array,n]

returns a downsampled version of the array by sampling every n^(th) element.

Downsample[array,n,offset]

starts sampling from the element at position offset.

Downsample[image,]

downsamples an image.

Details

  • In Downsample[array,], array can be an array of any rank.
  • Downsample works with arrays of any rank and 2D and 3D images.
  • Downsample[array,{n1,n2,}] samples every ni^(th) element in the i^(th) dimension.
  • Downsample[array,n] is equivalent to Downsample[array,n,1].
  • In Downsample[array,n,offset], the offset has to be an integer between 1 and n.

Examples

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Basic Examples  (4)

Downsample a list by a factor of 2:

Downsample a 2D array:

Downsample an image by a factor of 2:

Downsample a 3D image:

Scope  (4)

Downsample a list by a factor of 3:

Use an offset:

Use a different downsampling factor in each dimension:

Downsample a symbolic array:

Downsample an image:

Downsample using an offset of 2:

Applications  (2)

Create an image pyramid using iterative blurring and downsampling:

Use a smoothing filter to downsample a signal:

A faster implementation would add convolutions on the downsampled signal and downsampled filter:

Introduced in 2012
 (9.0)
 |
Updated in 2016
 (10.4)