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RemoveBackground
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RemoveBackground

Updated in 14.1

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returns an image with an alpha channel where the background is transparent.

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RemoveBackground[image,model]

uses foreground or background model specification.

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RemoveBackground[video,…]

performs background removal on frames of video.

Details and Options

  • RemoveBackground is also known as foreground-background segmentation. It is typically used to analyze the foreground or background or replace the background.
  • RemoveBackground works with arbitrary 2D and 3D images.
  • The model specification is used to indicate the foreground that is kept in the image or the background that is removed from the image.
  • Possible settings for the model specification are:
  • specforeground or background specification spec
    {"Background",spec}background specification spec
    {"Foreground",spec}foreground specification spec
  • By default, these models are used as foreground specifications:
  • "Salient"saliency object detection based on neural networks
    "Object"semantic segmentation of foreground and background
    {"Object",params}position or bounding box specification
    "People"people segmentation
    Rectangle[…]segment indicated by a bounding box
  • By default, these models are used as background specifications:
  • colregion of almost uniform color col
    markerimageregion of almost uniform colors specified by an image
    possegment containing the position pos
    {pos1,pos2,…}segment containing all posi
    "Blurred"blurred region
    {"Blurred",r}assume blur factor of r
    "Bright"brighter foreground or background
    "Dark"darker foreground or background
    "Uniform"region of almost uniform color
    {"Uniform",params}color, position and color distance specification
  • Positions posi are assumed to be in the standard image coordinate system.
  • The following options can be given:
  • BatchSize Automatichow many examples to process in a batch
    PerformanceGoalAutomaticwhether to optimize for speed or quality
    TargetDevice "CPU"the target device on which to perform training
  • If an image already has an alpha channel, the result will have an alpha channel equal to the computed foreground map multiplied with the original alpha channel.
  • RemoveBackground for some models uses machine learning. Its methods, training sets and biases included therein may change and yield varied results in different versions of the Wolfram Language.
  • RemoveBackground may download resources that will be stored in your local object store at $LocalBase, and can be listed using LocalObjects[] and removed using ResourceRemove.

Examples

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Basic Examples  (4)Summary of the most common use cases

Remove the background of an image:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-h63rr0
Direct link to example
Out[1]=1

Remove the background of a given color:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-1t1qzq
Direct link to example
Out[1]=1

Remove the background using saliency object detection:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-byrd11
Direct link to example
Out[1]=1

Remove the background from a picture of a person:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-p458c
Direct link to example
Out[1]=1

Scope  (16)Survey of the scope of standard use cases

Basic Uses  (5)

Remove the background from an image:

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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-hz6vtt
Direct link to example
Out[2]=2

Remove the background using a background specification:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-t3k8p1
Direct link to example
Out[1]=1

Remove the background using a foreground specification:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-qlgp9n
Direct link to example
Out[1]=1

Remove the background from a video:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-wl7apo
Direct link to example
Out[1]=1
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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-thykwo
Direct link to example
Out[2]=2

Remove the background from a 3D image:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-jtb49m
Direct link to example
Out[1]=1

Background Specification  (5)

Separate an almost uniformly colored background:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-r6gmvh
Direct link to example
Out[1]=1

Specify the color and threshold for uniform background detection:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-ek3fm7
Direct link to example
Out[1]=1

Specify a marker for detecting the uniform background:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-m0dwl1
Direct link to example
Out[1]=1

Markers can also be specified by a list of coordinates:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-gg90ax
Direct link to example
Out[1]=1

Remove a blurred background:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-0i2kwc
Direct link to example
Out[1]=1

Removing the background using background model specification is equivalent:

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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-5exs1b
Direct link to example
Out[2]=2

Foreground Specification  (6)

Separate the background from a salient foreground segmentation:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-831001
Direct link to example
Out[1]=1

This is equivalent to:

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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-oxzc1b
Direct link to example
Out[2]=2

Segment the foreground using the "Object" model:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-y9xgfi
Direct link to example
Out[1]=1

Remove the background using a point marker as the object specification:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-bnk8mm
Direct link to example
Out[1]=1

This is equivalent to:

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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-bd7qh9
Direct link to example
Out[2]=2

Remove the background using a rectangle marker as the object foreground specification:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-lye0n4
Direct link to example
Out[1]=1
Copy to clipboard.
In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-5rgqn
Direct link to example
Out[2]=2

Separate an almost uniformly colored foreground:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-sfy1au
Direct link to example
Out[1]=1

Specify the color for uniform foreground detection:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-j67g4s
Direct link to example
Out[1]=1

Generalizations & Extensions  (1)Generalized and extended use cases

Background and foreground may be completely separated at multiple steps:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-0u1og4
Direct link to example

Remove the light yellow background:

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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-oehwu9
Direct link to example
Out[2]=2

Remove the yellow background from the temporary image:

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In[3]:=3
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https://wolfram.com/xid/05ftvcq0uu-pdewwz
Direct link to example
Out[3]=3
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In[4]:=4
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https://wolfram.com/xid/05ftvcq0uu-hipa3g
Direct link to example
Out[4]=4

Options  (2)Common values & functionality for each option

BatchSize  (1)

Compare evaluation times using various batch sizes:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-fitfir
Direct link to example
Out[1]=1
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In[7]:=7
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https://wolfram.com/xid/05ftvcq0uu-d5bv65
Direct link to example
Out[7]=7

TargetDevice  (1)

Compare evaluation times using "CPU" and "GPU" devices:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-bq32bj
Direct link to example
Out[1]=1
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In[3]:=3
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https://wolfram.com/xid/05ftvcq0uu-c1620f
Direct link to example
Out[3]=3

Applications  (6)Sample problems that can be solved with this function

Remove the background of a video with people in the foreground:

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https://wolfram.com/xid/05ftvcq0uu-jca9qe
Direct link to example
Copy to clipboard.
In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-xul9hx
Direct link to example
Out[1]=1

Highlight bacteria:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-js1sz1
Direct link to example
Out[1]=1

Segment an object specified by a marker:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-rb6q9r
Direct link to example
Out[1]=1

Count birds in a picture by first removing the uniform background:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-uvhlcy
Direct link to example
Out[1]=1
Copy to clipboard.
In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-1mqz6l
Direct link to example
Out[2]=2

Extract the shape of each component:

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In[3]:=3
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https://wolfram.com/xid/05ftvcq0uu-js9mxj
Direct link to example
Out[3]=3

Detect the background in an image and replace it with fully transparent pixels:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-rbvam6
Direct link to example
Copy to clipboard.
In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-0hbceb
Direct link to example
Out[2]=2

Compose the foreground on top of a different background:

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In[3]:=3
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https://wolfram.com/xid/05ftvcq0uu-hvynr0
Direct link to example
Out[3]=3

Chroma key compositing or chroma keying is a common technique to remove the background (typically green) from an image or video:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-rmv6yl
Direct link to example

Find the shade of the green used in the background:

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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-xuqzap
Direct link to example
Out[2]=2

RemoveBackground replaces green pixels of the image with fully transparent pixels:

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In[3]:=3
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https://wolfram.com/xid/05ftvcq0uu-3bbd2a
Direct link to example
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In[4]:=4
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https://wolfram.com/xid/05ftvcq0uu-io0ek7
Direct link to example
Out[4]=4

Compose the foreground over a slightly blurred background to also get an out-of-focus effect:

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In[5]:=5
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https://wolfram.com/xid/05ftvcq0uu-nsm96o
Direct link to example
Copy to clipboard.
In[6]:=6
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https://wolfram.com/xid/05ftvcq0uu-m1m689
Direct link to example
Out[6]=6

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

The foreground mask is stored as the alpha channel:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-tzd8yk
Direct link to example
Out[1]=1

Use AlphaChannel to extract it:

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In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-sb2qqf
Direct link to example
Out[2]=2

Replace the background with a different color:

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In[3]:=3
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https://wolfram.com/xid/05ftvcq0uu-pfgr4v
Direct link to example
Out[3]=3

Use a background image to fill the background:

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In[4]:=4
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https://wolfram.com/xid/05ftvcq0uu-ers5fd
Direct link to example
Out[4]=4

Possible Issues  (2)Common pitfalls and unexpected behavior

When using the object method, specifying a point or a region can improve the result significantly:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-iaaqxw
Direct link to example
Copy to clipboard.
In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-kmotue
Direct link to example
Out[2]=2
Copy to clipboard.
In[4]:=4
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https://wolfram.com/xid/05ftvcq0uu-nxxf91
Direct link to example
Out[4]=4

Different methods may provide better results depending on the image content and the region of interest:

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In[1]:=1
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https://wolfram.com/xid/05ftvcq0uu-dl00a3
Direct link to example
Copy to clipboard.
In[2]:=2
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https://wolfram.com/xid/05ftvcq0uu-il9x3i
Direct link to example
Out[2]=2

Compare to the "Object" model:

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In[3]:=3
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https://wolfram.com/xid/05ftvcq0uu-o30y9j
Direct link to example
Out[3]=3
Wolfram Research (2014), RemoveBackground, Wolfram Language function, https://reference.wolfram.com/language/ref/RemoveBackground.html (updated 2024).
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Wolfram Research (2014), RemoveBackground, Wolfram Language function, https://reference.wolfram.com/language/ref/RemoveBackground.html (updated 2024).

Text

Wolfram Research (2014), RemoveBackground, Wolfram Language function, https://reference.wolfram.com/language/ref/RemoveBackground.html (updated 2024).

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Wolfram Research (2014), RemoveBackground, Wolfram Language function, https://reference.wolfram.com/language/ref/RemoveBackground.html (updated 2024).

CMS

Wolfram Language. 2014. "RemoveBackground." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/RemoveBackground.html.

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Wolfram Language. 2014. "RemoveBackground." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/RemoveBackground.html.

APA

Wolfram Language. (2014). RemoveBackground. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/RemoveBackground.html

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Wolfram Language. (2014). RemoveBackground. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/RemoveBackground.html

BibTeX

@misc{reference.wolfram_2025_removebackground, author="Wolfram Research", title="{RemoveBackground}", year="2024", howpublished="\url{https://reference.wolfram.com/language/ref/RemoveBackground.html}", note=[Accessed: 27-March-2025 ]}

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@misc{reference.wolfram_2025_removebackground, author="Wolfram Research", title="{RemoveBackground}", year="2024", howpublished="\url{https://reference.wolfram.com/language/ref/RemoveBackground.html}", note=[Accessed: 27-March-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_removebackground, organization={Wolfram Research}, title={RemoveBackground}, year={2024}, url={https://reference.wolfram.com/language/ref/RemoveBackground.html}, note=[Accessed: 27-March-2025 ]}

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@online{reference.wolfram_2025_removebackground, organization={Wolfram Research}, title={RemoveBackground}, year={2024}, url={https://reference.wolfram.com/language/ref/RemoveBackground.html}, note=[Accessed: 27-March-2025 ]}