Removing impulse noise from the Lenna image using the median filter. Peak signal-to-noise ratio calculated using provided MATLAB function psnr .m, which is based on formula given in the text, (a) Original image, (b) Lenna with 40% additive impulse noise, (c) Processed image using 3x3 median filter, (d) Processed image using 5x5 median filter.
The fastest way to clean backgrounds in Photoshop is by using Photoshop's Filters. We found that the Median filter works very well and saves a ton of time. Go to Filter -> Noise -> Median and choose a radius that will make all the dirt vanish.