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You are supposed to deskew (and de-warp if the image isn't flat) images before running through tesseract. There are other tools for doing that.

Tesseract is last gen. Multimodal is SOTA, and can handle even heavily distorted or destroyed text.

Am I overlooking something, or is automating page rotation no more work than just a 2d FFT?

Mind ELI5ing this? it seems neat

The Fourier transforms map plane waves to points. Blocks of regularly-spaced text have a periodic character, with the period length of their line spacing; their Fourier transform (I think??) would, in 2d frequency space, have amplitude peaks on vectors that have the same angle as the rotation of the lines.

thanks!

I think it's more typical to low-pass (i.e. blur) the image and then use a line-detection algorithm like the Hough transform. Properly deskewed text should have prominent horizontal white lines.

- "Hough transform"

Oh, that one has much nicer properties—thank you!