# What is the different between boxBlur and kernelBlur in Blur ESM?

**URL:** <https://forum.babylonjs.com/t/what-is-the-different-between-boxblur-and-kernelblur-in-blur-esm/33327>\
**Category:** Questions\
**Tags:** shadows\
**Created:** [August 24, 2022, 8:15am UTC](https://forum.babylonjs.com/t/what-is-the-different-between-boxblur-and-kernelblur-in-blur-esm/33327 "2022-08-24T08:15:17Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Aze](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/aze/32/23050_2.png) [@Aze](https://forum.babylonjs.com/u/Aze)\
**Post date:** [August 24, 2022, 8:15am UTC](https://forum.babylonjs.com/t/what-is-the-different-between-boxblur-and-kernelblur-in-blur-esm/33327/1 "2022-08-24T08:15:17Z")

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I don’t know what is the box means?If it means that the bounds texel?

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**Author:** ![carolhmj](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/carolhmj/32/25918_2.png) [@carolhmj](https://forum.babylonjs.com/u/carolhmj)\
**Post date:** [August 24, 2022, 11:55am UTC](https://forum.babylonjs.com/t/what-is-the-different-between-boxblur-and-kernelblur-in-blur-esm/33327/2 "2022-08-24T11:55:33Z")

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Hello! boxBlur and kernelBlur are different post-processes applied to the shadow map. Kernel blur refers to the technique of using image kernels to transform images:

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/b/1/b1ed3029848e11aaa719ad1c293a2d13dda91b7b.png)  
(source: [Image Kernels explained visually (setosa.io)](https://setosa.io/ev/image-kernels/))

While the box blur is kind like a special kernel blur where all pixels have the same weight: [Amrita Mazumdar - Understanding Box Blur](http://amritamaz.net/blog/understanding-box-blur)

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<div class="post-metadata">

**Author:** ![Aze](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/aze/32/23050_2.png) [@Aze](https://forum.babylonjs.com/u/Aze)\
**Post date:** [August 25, 2022, 3:11am UTC](https://forum.babylonjs.com/t/what-is-the-different-between-boxblur-and-kernelblur-in-blur-esm/33327/4 "2022-08-25T03:11:49Z")

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Thanks~