Blur

Blur[image]

gives a blurred version of image.

Blur[image,r]

gives a version of image blurred over pixel radius r.

Details

  • Blur is a filter function typically used for blurring an image. It is commonly used to suppress noise or to defocus an image.
  • Blur[image] is equivalent to Blur[image,2].
  • Blur works with 2D and 3D images. For multichannel images, it operates separately on each channel.
  • Blur[image,{r1,r2}] uses radius r1 in height and r2 in width.
  • Blur[image,{r1,r2,r3}] uses radius r1 in height, r2 in depth and r3 in width.
  • Blur[image] gives an image with the same underlying data type as image, except for "Bit" images. »

Background & Context

  • Blur is a filter function typically used for blurring (or smoothing) of an image. It can be used to suppress noise and local pixel variation or as an effect to de-focus an image.
  • Finer control over the amount and shape of blurring to be applied can be obtained using other filter functions such as GaussianFilter and ImageConvolve.
  • The converse of blurring is known as sharpening, which can be performed by functions such as Sharpen and ImageDeconvolve.

Examples

open allclose all

Basic Examples  (2)

Blur a photo:

Specify the amount of blurring:

Scope  (5)

Data  (2)

Blur a binary image:

Blur a 3D volume:

Parameters  (3)

Vary the pixel radius to achieve different degrees of blurring:

Blur in the horizontal direction only:

Blur vertically:

Blur a 3D image in the vertical direction only:

Blur the horizontal planes only:

Applications  (7)

Reduce noise in a color image:

Remove Moiré patterns and high spatial frequencies:

Background equilibration:

Subtract the blurred background:

Sharpen an image using Blur:

Subtract the unsharp mask from a version of the original image:

Create soft shadows:

Find and anonymize faces in an image:

Create a mask that covers each face by a disk:

Compose the original image and a blurred version using the mask:

Emphasize faces in an image by blurring the background:

Display a motion pattern by blurring an animation in the temporal dimension:

Convert the animation frames into an Image3D object and blur along the slices:

Properties & Relations  (2)

Blur is equivalent to GaussianFilter with radius r, width σ=r/2, and "Fixed" padding:

Blur preserves the ImageType, except for "Bit" images:

Neat Examples  (1)

Blur an image outside an artificial focal plane, as in digital tilt-shift photography:

Find the in-focus area:

Wolfram Research (2008), Blur, Wolfram Language function, https://reference.wolfram.com/language/ref/Blur.html (updated 2012).

Text

Wolfram Research (2008), Blur, Wolfram Language function, https://reference.wolfram.com/language/ref/Blur.html (updated 2012).

CMS

Wolfram Language. 2008. "Blur." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2012. https://reference.wolfram.com/language/ref/Blur.html.

APA

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

BibTeX

@misc{reference.wolfram_2021_blur, author="Wolfram Research", title="{Blur}", year="2012", howpublished="\url{https://reference.wolfram.com/language/ref/Blur.html}", note=[Accessed: 21-January-2022 ]}

BibLaTeX

@online{reference.wolfram_2021_blur, organization={Wolfram Research}, title={Blur}, year={2012}, url={https://reference.wolfram.com/language/ref/Blur.html}, note=[Accessed: 21-January-2022 ]}