WOLFRAM

Wolfram Language & System Documentation Center
Wolfram Language Home Page »

CommonestFilter
✖
CommonestFilter

✖
CommonestFilter[data,r]

filters data by replacing every value with the most common value in its range-r neighborhood.

✖
CommonestFilter[data,{r1,r2,…}]

uses ri for filtering the ^(th)dimension in data.

Details

  • CommonestFilter, also known as majority filter, is used to filter data by returning the commonest local value, where the extent of the effect is dependent on the value of r.
  • The function applied to each range-r neighborhood is Commonest.
  • If more than one commonest pixel exists and the center pixel is one of them, the center pixel is used. Otherwise, the pixel is replaced with a random commonest.
  • The data can be any of the following:
  • listarbitrary-rank numerical array
    tseriestemporal data such as TimeSeries, TemporalData, …
    imagearbitrary Image or Image3D object
    audioan Audio object
  • For multichannel images, CommonestFilter replaces each pixel by the commonest pixel vector in the neighborhood.
  • CommonestFilter[data,{r1,r2,…}] computes the commonest value in blocks centered on each sample.
  • CommonestFilter assumes the index coordinate system for lists and images.
  • At the data boundaries, CommonestFilter uses smaller neighborhoods.

Examples

open allclose all

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

Apply a majority filter to a vector of numbers:

In[45]:=45
✖
https://wolfram.com/xid/0v5mspv2e197e-nepdk7
Out[45]=45

Filter a TimeSeries:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-fx6jf7
In[2]:=2
✖
https://wolfram.com/xid/0v5mspv2e197e-g9fo2
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0v5mspv2e197e-dulvtd
Out[3]=3

Commonest filtering of a color image:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-lhc1w0
Out[1]=1

Scope  (11)Survey of the scope of standard use cases

Data  (7)

Commonest filtering applied to arbitrary expressions:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-8fkivw
Out[1]=1

Majority filtering of a 2D array:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-cxywqj

Filter a quantity array:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-jopin9
In[2]:=2
✖
https://wolfram.com/xid/0v5mspv2e197e-coijx0
Out[2]=2

Filter an EventSeries:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-62t833
In[2]:=2
✖
https://wolfram.com/xid/0v5mspv2e197e-77v7p5
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0v5mspv2e197e-18tdm0
Out[3]=3

Filter an Audio signal:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-p90slf
In[2]:=2
✖
https://wolfram.com/xid/0v5mspv2e197e-em7h2s
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0v5mspv2e197e-j5yrn4
Out[3]=3

Filtering a 2D grayscale image:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-dc0gtv
Out[1]=1

Apply commonest filtering to a 3D volume:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-dauq0o
Out[1]=1

Parameters  (4)

Specify one radius to be used in all directions:

In[101]:=101
✖
https://wolfram.com/xid/0v5mspv2e197e-tlzgi7
Out[101]=101

Increasing the radius will increase the regions of uniform value in images:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-ibus74
Out[1]=1

Majority filtering just in the first direction:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-gdx3zh
Out[1]=1

Second direction:

In[2]:=2
✖
https://wolfram.com/xid/0v5mspv2e197e-hzoyls
Out[2]=2

Commonest filtering of a 3D image in the vertical direction only:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-37xttb
Out[1]=1

Filtering of the horizontal planes only:

In[2]:=2
✖
https://wolfram.com/xid/0v5mspv2e197e-5u7xo
Out[2]=2

Applications  (2)Sample problems that can be solved with this function

Replacing each pixel with the most common color in its neighborhood creates a posterization effect:

In[20]:=20
✖
https://wolfram.com/xid/0v5mspv2e197e-0ie9os
Out[20]=20

Majority filtering removes noise from a binary image:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-u3epfo
Out[1]=1

Properties & Relations  (1)Properties of the function, and connections to other functions

Commonest filter gives the same result as MedianFilter on binary images:

In[11]:=11
✖
https://wolfram.com/xid/0v5mspv2e197e-cdiszd
Out[12]=12

Possible Issues  (1)Common pitfalls and unexpected behavior

Majority filtering may not have the desired effect when applied to real-valued data, since all sample values may be unique:

In[86]:=86
✖
https://wolfram.com/xid/0v5mspv2e197e-chqy32
Out[86]=86
In[87]:=87
✖
https://wolfram.com/xid/0v5mspv2e197e-d9bpl5
Out[87]=87

Quantize the sample values to overcome this problem:

In[93]:=93
✖
https://wolfram.com/xid/0v5mspv2e197e-fgy9kv
Out[93]=93

Neat Examples  (1)Surprising or curious use cases

Commonest filtering applied to random noise:

In[1]:=1
✖
https://wolfram.com/xid/0v5mspv2e197e-jtx4ai
Out[1]=1
Wolfram Research (2008), CommonestFilter, Wolfram Language function, https://reference.wolfram.com/language/ref/CommonestFilter.html (updated 2016).
✖
Wolfram Research (2008), CommonestFilter, Wolfram Language function, https://reference.wolfram.com/language/ref/CommonestFilter.html (updated 2016).

Text

Wolfram Research (2008), CommonestFilter, Wolfram Language function, https://reference.wolfram.com/language/ref/CommonestFilter.html (updated 2016).

✖
Wolfram Research (2008), CommonestFilter, Wolfram Language function, https://reference.wolfram.com/language/ref/CommonestFilter.html (updated 2016).

CMS

Wolfram Language. 2008. "CommonestFilter." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/CommonestFilter.html.

✖
Wolfram Language. 2008. "CommonestFilter." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/CommonestFilter.html.

APA

Wolfram Language. (2008). CommonestFilter. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/CommonestFilter.html

✖
Wolfram Language. (2008). CommonestFilter. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/CommonestFilter.html

BibTeX

@misc{reference.wolfram_2025_commonestfilter, author="Wolfram Research", title="{CommonestFilter}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/CommonestFilter.html}", note=[Accessed: 19-June-2025 ]}

✖
@misc{reference.wolfram_2025_commonestfilter, author="Wolfram Research", title="{CommonestFilter}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/CommonestFilter.html}", note=[Accessed: 19-June-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_commonestfilter, organization={Wolfram Research}, title={CommonestFilter}, year={2016}, url={https://reference.wolfram.com/language/ref/CommonestFilter.html}, note=[Accessed: 19-June-2025 ]}

✖
@online{reference.wolfram_2025_commonestfilter, organization={Wolfram Research}, title={CommonestFilter}, year={2016}, url={https://reference.wolfram.com/language/ref/CommonestFilter.html}, note=[Accessed: 19-June-2025 ]}