Scanned PDFs and OCR

Who this page is for: the practice manager whose referrals arrive from a scanner or a fax gateway, and anyone asking what happens when a PDF contains pictures of words rather than words.

A referral PDF arrives in one of two forms. A digital PDF (exported from the referrer’s software) carries a text layer that is read directly. A scanned PDF (practice scanner, fax-to-email gateway, a photographed letter) is pages of images with no text layer at all - to a computer it is a picture. Refera detects which form each document is and recovers the text either way, so the extraction that fills the Inbox fields runs on every referral, not just the born-digital ones.

How detection works

Every PDF attachment is first checked for a usable text layer. If the layer yields real text, it is used verbatim and no OCR runs. If the document is image-only (or carries only the junk layer some scanner apps embed), each page is rasterised at 300 dpi and passed through optical character recognition. The recovered text then flows into the same deterministic extraction as typed text - DOB, referrer, Medicare number with its checksum verified, phone. Nothing about the document’s handling changes downstream; only the way the text was recovered differs, and that provenance is recorded with the result.

Confidence and manual review - never silent

OCR is honest about its own limits. Every recovered word carries a confidence score, and the document’s mean confidence travels with the extraction:

• At or above the review threshold - fields are extracted and shown beside the available source excerpt and attachment metadata.
• Below the threshold (a grainy fax, a skewed photocopy, handwriting) - the document is flagged for manual review. The recovered text and any fields it produced are still shown, marked unverified, with the available source excerpt and attachment metadata beside them. Nothing is silently dropped or guessed at.
• Unreadable or corrupt attachments are flagged the same way - one bad attachment never sinks the rest of the message.

Refera does not yet claim a deployed original-PDF archive. The practice keeps the original in its existing mailbox or document system while Refera’s connection checks use only patient-free test files. Real-data activation remains blocked until retention, authenticated retrieval, restore/readback and complete source export are proven end to end.

Patient-free test lane and launch checks

Two lanes, stated plainly:

• Patient-free setup: OCR runs locally on the capture host using open-source tooling (poppler-utils and Tesseract). Deterministic, auditable, and no document ever leaves the machine to be read. Capture-off setup accepts clearly tagged, patient-free test documents only.
• Real-data activation: the harder-document vision lane must use Amazon Bedrock in ap-southeast-2, under the Australian region policy, with the exact selected model and CloudTrail path verified before activation. The current Bedrock client is fail-closed until that production request path is implemented and proven. No real patient document is accepted until those checks pass.

What OCR does not do

OCR recovers text - that is the whole job. It does not interpret the referral, does not rank it, and does not compute anything from the clinical content. Referrals remain in arrival order, and any urgency wording is captured only as the referrer’s verbatim words. Refera tracks referral admin only. It does not triage patients.

Related

• Fax to email - where most scanned PDFs come from.
• Upload - paper and scans - the planned path for the paper pile, not currently available in the connected Inbox.
• Microsoft 365 mailbox - the mailbox the scans land in.