A vision OCR engine grounds a figure far less precisely than it
transcribes one. Over all 138 figure regions of a 204-page issue the
transcribed contents were right while the boxes were routinely offset,
undersized, or sitting on the neighbouring text column -- page 23's card
grid was reported at x 0.24-0.54 where the graphic runs 0.41-0.95.
snap_visual_bboxes() reduces the page render to an ink-coverage grid,
seeds a connected-component search with the engine's box, and re-joins
tiles a gutter apart so a card grid comes back as one figure. Text
blocks are excluded from the mask, which is what stops a figure
swallowing the column beside it. A candidate must be solidly inked or
framed on nearly all of its rows and columns (admitting a white-interior
screenshot), may not shrink below 30% of the seed, and reverts when two
figures land on the same graphic; anything else keeps the box it had.
Runs before the figure crop in both OCR paths, so the images shown
during playback are framed correctly too. Replaces refine_picture_
bounds(), which only recognised coloured panels and had no text fence.
Also adds "Fix figure boundaries" in review and POST
/api/magazine/{id}/figures/refine behind it, so an issue ingested before
this pass can be corrected without re-running OCR. Verified live against
c't KI Wissen 2026: 78 of 138 boxes corrected, the rest declined.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Magazines break the audiobook pipeline's assumptions: several unrelated
articles share a page, columns run in parallel, adverts and sidebars
interrupt body copy, and a feature routinely jumps twenty pages to its
tail. Narrating page-by-page walks out of an article mid-sentence and
into an advert, so the canonical object is the article, not the page.
core/magazine.py reconstructs articles from a flat PDF: PyMuPDF extracts
blocks with bboxes and font metrics, tesseract supplies a TSV fallback so
scanned pages join the same column grouping, blocks are classified and
ordered column-major, and articles are anchored by the parsed table of
contents with "continued on page N" tails linked back.
routes/magazine.py adds 13 endpoints. Ingestion is a restart-safe
background job. Nothing is narrated until a human approves the
boundaries; podcast generation refuses unapproved articles.
Podcast mode renders an approved article as a 2-3 host discussion using
the configured LLM and voices the user picks, alongside narration rather
than instead of it.
Verified end-to-end over HTTP on a synthetic 8-page issue: the feature
came back as pages [3, 8] with its jump tail absorbed and the advert page
excluded, and an image-only rendering recovered all 47 blocks via OCR.
44 new tests; full suite 90 passing.
The Studio UI is not built — this is reachable only via the API.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
