A Pixel Is Not A Little Square

TL;DR — Microsoft Technical Memo 6 — the correction of a misconception that still generates bugs thirty years on.

⬇ Download the archived copy — kept here so the document survives its source going dark. Explicitly free / author-released / CC.

Technical Memo 6, 17 July 1995, by one of the founders of Pixar. The title is repeated three times on the cover, which tells you how tired he was of the point.

A pixel is a point sample, not a little geometric square, and a voxel is not a little cube. Treating samples as squares is what produces the aliasing, resampling and filtering errors that follow.

Eleven pages that still describe live bugs in image pipelines, and a good example of a correction that is easy to state and hard to internalise.

Where this came from

• Brendan Sheehan’s public are.na channel

11 pages. A copy is archived locally against link rot; the header links the original source.