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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
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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:

Wolfram Research (2012), Downsample, Wolfram Language function, https://reference.wolfram.com/language/ref/Downsample.html (updated 2016).

Text

Wolfram Research (2012), Downsample, Wolfram Language function, https://reference.wolfram.com/language/ref/Downsample.html (updated 2016).

CMS

Wolfram Language. 2012. "Downsample." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/Downsample.html.

APA

Wolfram Language. (2012). Downsample. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Downsample.html

BibTeX

@misc{reference.wolfram_2025_downsample, author="Wolfram Research", title="{Downsample}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/Downsample.html}", note=[Accessed: 13-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_downsample, organization={Wolfram Research}, title={Downsample}, year={2016}, url={https://reference.wolfram.com/language/ref/Downsample.html}, note=[Accessed: 13-August-2025]}