Software to analyse noise in dark images

[luka]

Hi

I will be finishing my cold-finger cooled DSLR soon and would like to profile image noise vs sensor temperature. What (free) software can analyse images and calculate noise from them?

Thanks
Luka

[Shiraz]

Iris is great. http://www.astrosurf.com/buil/us/iris/iris.htm

1. load an image.
2. manually select a small region in an image where there is no structure and no obvious hot pixels, right click on it and select "statistics" - "mean" gives you signal and "sigma" the noise power. The main idea is to get a large enough region that the SD is meaningful, but you need to ensure that you don't include abnormal outliers (hot/warm pixels etc) that could distort the result.

[luka]

Thank you, works wonderfully!!!