# Can I simultaneously remove salt and pepper noise and improve the image resolution?

What should my approach be towards designing a filter that can simultaneously remove salt & pepper noise and improve the resolution?

• Your question needs some more details. "Resolution" is a somewhat vague term; do you mean you want to remove speckle noise while sharpening the image at the same time? Commented Dec 10, 2011 at 17:31
• yes that would be it
– vini
Commented Dec 11, 2011 at 9:27
• Why does it need to be done simultaneously ? Why not use two filters ? Commented Dec 11, 2011 at 12:27
• am sorry for giving you such a hard time i am new to MATLAB and image processing.. Yes two or more filters that would get the job done is what i want to undertake
– vini
Commented Dec 11, 2011 at 15:51

If you use two linear filters, they could be combined (because of linearity, the convolution with the convolution of the two filters equals to the consecutive convolution with the two filters).

$(I*a)*b=I*(a*b)$

Nevertheless the simplest way to deal with salt & pepper noise is median filtering, which is non-linear. If you use linear filters it is possible.

• One issue with using linear filters is that removing salt and pepper noise is a lowpass operation, which will reduce image sharpness. A linear filter used for sharpening would be highpass, which would pass the undesired noise. I'm guessing a nonlinear approach would be required to effectively achieve both goals. Commented Dec 11, 2011 at 14:30
• Yes thanks a lot will keep your post in mind
– vini
Commented Dec 11, 2011 at 15:52
• Which is the best filter by the way to reduce noise?
– vini
Commented Dec 11, 2011 at 15:54
• That's, again, a very vague question. It's like asking "what is the best car?" It all depends upon the problem at hand. You might try posting some examples of what you'd like to process. Commented Dec 11, 2011 at 22:11
• There are several different types of noise. en.wikipedia.org/wiki/Image_noise As @jason-r said, you need to choose the best tool for the task at hand. Usually what people refer generically to as "noise" is Gaussian. Commented Dec 15, 2011 at 13:55