Jbig2 dynamically pulls reference chunks out of the image, which makes it more likely to have insufficient separation between the target shapes.

It also gives a false sense of security when it displays dirty pixels that still clearly show a specific digit, since you think you're basically looking at the original.

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thaumasiotes 2 days ago | parent [-]

That's a description of Jbig2, not a description of OCR.

Jbig2 is an OCR algorithm that doesn't assume the document comes from a pre-existing alphabet.

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Dylan16807 2 days ago | parent [-]

You asked what the difference was, and I said the difference. Was it unclear that to fit the phrasing of your question, we add "OCR doesn't"? I would not personally call Jbig2 OCR.

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thaumasiotes 2 days ago | parent [-]

> You asked what the difference was, and I said the difference.

Take another look at my comment.

	▲	Dylan16807 2 days ago \| parent [-]
		Let me try rephrasing to make the response to your original comment as clear as possible. Question: "How can we describe OCR that wouldn't match this definition exactly?" Answer: This definition largely fits OCR, but "reference to a single instance" is a weird way to phrase it. A better definition of OCR would include how it uses builtin knowledge of glyphs and text structure, unlike JBIG2 which looks for examples dynamically. And that difference in technique gives you a significant difference in the end results. Is that better? The definition you quoted is not an "exact" fit to OCR, it's a mildly misleading fit to OCR, and clearing up the misleading part makes it no longer fit both.