Upsample

✖
`Upsample`

Upsample[array,n]

returns an upsampled version of the array by inserting zeros between array elements.

Upsample[array,n,offset]

shifts array so that its first element moves to the position offset in the resulting array.

Upsample[array,n,offset,val]

inserts elements of value val between array elements.

Upsample[image,…]

upsamples an image.

Details

In Upsample[array,…], array can be an array of any rank.
Upsample works with arrays of any rank and 2D and 3D images.
Upsample[array,{n₁,n₂,…}] inserts n_i zeros between elements in the i dimension.
Upsample[array,n] is equivalent to Upsample[array,n,1].
In Upsample[array,n,offset], the offset has to be an integer between 1 and n.

Examples

open allclose all

Basic Examples (3)Summary of the most common use cases

Upsample a list by a factor of 3:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-mwupo5

Out[1]=1

Use an offset:

In[2]:=2

✖

https://wolfram.com/xid/0h2re4c6ey-vlhdtg

Out[2]=2

Specify the value to be inserted:

In[3]:=3

✖

https://wolfram.com/xid/0h2re4c6ey-dxqdjn

Out[3]=3

Upsample a 2D array:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-ipuo5m

Upsample an image by a factor of 2:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-zia02h

Out[1]=1

Scope (3)Survey of the scope of standard use cases

Use a different upsampling factor in each dimension:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-qtomuu

Upsample a symbolic array:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-els2ut

Out[1]=1

Upsample an image by a factor of 2:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-0ged7c

Out[1]=1

By default, using offset equal to 1, no shifting is performed:

In[2]:=2

✖

https://wolfram.com/xid/0h2re4c6ey-fypcq9

Out[2]=2

Use a larger offset:

In[3]:=3

✖

https://wolfram.com/xid/0h2re4c6ey-lzhw3s

Out[3]=3

Use a different offset in each dimension:

In[4]:=4

✖

https://wolfram.com/xid/0h2re4c6ey-fzt4dj

Out[4]=4

Specify the insertion value:

In[5]:=5

✖

https://wolfram.com/xid/0h2re4c6ey-gsu80j

Out[5]=5

Applications (3)Sample problems that can be solved with this function

Create a Nyquist filter of length 7:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-cxpvus

Out[1]=1

Upsample by a factor of 2 using the smoothing filter:

In[2]:=2

✖

https://wolfram.com/xid/0h2re4c6ey-4a89no

Out[2]=2

In[3]:=3

✖

https://wolfram.com/xid/0h2re4c6ey-oxbmfd

Out[3]=3

In[4]:=4

✖

https://wolfram.com/xid/0h2re4c6ey-ue3mc

Out[4]=4

Linear interpolation using upsampling and convolution:

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-47uvql

In[2]:=2

✖

https://wolfram.com/xid/0h2re4c6ey-msz9qb

Out[2]=2

This implementation is not very efficient:

In[3]:=3

✖

https://wolfram.com/xid/0h2re4c6ey-gop2is

Out[3]=3

A faster implementation would merge convolutions of the signal with odd and even samples of the filter:

In[4]:=4

✖

https://wolfram.com/xid/0h2re4c6ey-q8l3kk

Out[4]=4

In[5]:=5

✖

https://wolfram.com/xid/0h2re4c6ey-tpffne

Out[5]=5

Linear interpolation by a factor :

In[1]:=1

✖

https://wolfram.com/xid/0h2re4c6ey-2yrdzx

In[2]:=2

✖

https://wolfram.com/xid/0h2re4c6ey-ptf48

In[3]:=3

✖

https://wolfram.com/xid/0h2re4c6ey-8v50ae

Out[3]=3

Top