Am I right to think that the expression "noise cancellation" is used for sound noise and "noise reduction" for image noise?
3 Answers
noise cancellation and noise reduction have technical definitions and both can refer to any electronic signal, whether audio, image or otherwise.
noise reduction is any technique used to filter out noise, while noise cancellation is the active electronic process of determining the part of the signal that is noise, then adding the opposite noise signal back into the original signal, thereby subtracting out the original noise.
(I'm a software engineer)
No. Noise cancellation and noise reduction can be used for sound and image. I presume by image noise you mean a noise made by an image on something like a tv screen?