How to Automatically remove noise using Image historgram based?

How to Automatically remove noise using Image historgram based?

[KALYAN ACHARJYA]

Can you elaborate the question with sample image?

[voxey]

Hi KALYAN ACHARJYA,

Check this image. From this image, can we automatically remove noise?

Answer 1

[Image Analyst]

I don't believe so, at least not via a global operation, since the noise is likely very close to the local means. So you can't just look at the histogram and say all bright stuff is noise. Perhaps you can use a scanning method where you're looking at the histogram just in a local area and looking for outliers, like a sigma filter or something. There are some very good noise filters out there. For example, you might want to check out imnlmfilt() to do a non-local means noise reduction.

[KALYAN ACHARJYA]

Yes sir, but how do we distinct between noise and information in such images?

[Image Analyst]

The filter makes that distinction, like the median filter assumes that the "signal" will be the median of values in the scanning window. If you have your own knowledge of what is signal and what is noise (even if it's probability distributions), then you can design a custom filter to take that into account.

I'm sure there are probably CT-specific papers on noise removal in medical images here in vision bibliography

Answer 2

[Ranjith veeran]

https://de.mathworks.com/help/images/noise-removal.html

Check the above link

[voxey]

Ranjith, i am asking auto noise removal? your answer not related to my question ?