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doetoe | 1 year ago

A real image not, but a digital image built up from pixels certainly is band limited. A sharp edge will require contributions from components across the whole spectrum that can be supported on a matrix the size of the image, the highest of which is actually called the Nyquist frequency

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astrange|1 year ago

Not quite. You can tell this isn't true because there are many common images (game graphics, text, pixel art) where upscaling them with a sinc filter obviously produces a visually "wrong" image (blurry or ringing etc), whereas you can reconstruct them at a higher resolution "as intended" with something nonlinear (nearest neighbor interpolation, OCR, emulator filters like scale2x). That means the image contains information that doesn't work like a bandlimited signal does.

You could say MIDI is sort of like that for audio but it's used a lot less often.