# How to estimate the noise of an image?

I want to know how to estimate the noise of an image?

Also is this represent the camera's noise?

Does anyone know how to estimate the noise of an image or camera?

# Update:

Especially, I want to know about the A, B, C from as following. How Can I plot these A, B,C curve? Also I want to know what is C. What does C mean? ## 1 Answer

There are various methods to estimate the noise of a signal (or adapt a threshold to be used later in PCA for example).

There are adaptive methods and statistical methods. Statistical methods employ a statistical model of the noise and estimate from the data, while adaptive methods iteratively filter the data until a certain threshold of (reduced signal) accuracy is reached. These are just generalities of the most used approaches.

The following references deal (mostly) with images from cameras:

• Thanks for letting me But especially, If you can would please let me know how to plot like above A,B,C? – gmotree May 2 '15 at 8:07
• @gmotree, where do these plots come from? i suspect these use some algorithm to draw these data. So use the same algorithm. There is not one fixed algorithm for this problem, but various approaches as explained in the answer some work better for some data while worse for other data'. – Nikos M. May 2 '15 at 8:16
• that plot come from your references – gmotree May 2 '15 at 8:18
• @gmotree, oh ok,, then use this algorithm. i'm not sure if these are open-source somewhere, if not implement the algorithm yourself (in matlab or scilab for example) – Nikos M. May 2 '15 at 8:19
• Thanks. But if I can got a algorithm from the references, I did not ask to here. – gmotree May 2 '15 at 8:23