Sharpening is basically done by adding a signal proportional to a high-pass filtered version of the image to the original one.
sharhar
Yeah, if you look closely at the sky in the sharpened image, it is very noisy. This is because the high frequency noise in the image also gets amplified (along with the image details themselves)
patrickrz
I was curious about why the low frequency parts of the image get more noisy. It makes sense as the high pass filter that others have talked about is applied to the entire image. Thus, even small bits of noise in the original image will be amplified in the sharpened version.
How does sharpening actually work?
Sharpening is basically done by adding a signal proportional to a high-pass filtered version of the image to the original one.
Yeah, if you look closely at the sky in the sharpened image, it is very noisy. This is because the high frequency noise in the image also gets amplified (along with the image details themselves)
I was curious about why the low frequency parts of the image get more noisy. It makes sense as the high pass filter that others have talked about is applied to the entire image. Thus, even small bits of noise in the original image will be amplified in the sharpened version.