---
# System prepended metadata

title: A non-local algorithm for image denoising (NL-means)
tags: [paper]

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{%hackmd SybccZ6XD %}
###### tags: `paper`

# A non-local algorithm for image denoising (NL-means)

Goal
> Denoising algorithms
> Recover the original image from a noisy measurement

Algorithm
> W: similarity between two pixels i and j depends on the similarity of the intensity gray level vectors
> ![](https://hackmd.io/_uploads/BJsyp1tE3.png)
> ![](https://hackmd.io/_uploads/B10X6yKEn.png)
> normalizing constant
> ![](https://hackmd.io/_uploads/SJCEpJtE3.png)

Note
> The NL-means not only compares the grey level in a single point but the the geometrical configuration **in a whole neighborhood**
> 也就是說可以去找相似的texture