Compare two scanned documents word by word
Two versions of a contract, both scanned. Your tool shows 40 differences. Thirty-nine are the OCR engine having a different day. Which one is the real change?
Read one page of either version free and see the words with their boxes, the list a comparison runs on.
Own run on 300 public pages with the CTC reading engine. Which means: when a comparison shows a difference, it is in the documents, not in the reading. Use a fast reading pipeline for comparisons: identical bytes at any load.
Why comparing a scanned PDF needs the same result every time
A comparison is only as good as the sameness of the text. If the same image can come back with a different word on a second run, every diff carries noise, and a person has to sort it out by hand.
Pipelines are pinned as name@version and stay fixed, so a result you compare next year was made by the same steps. Read more: deterministic OCR whatever the batch size
How to compare a scanned PDF with a newer version
- Send both versions with
format=json. - For each page, make the list of words in reading order.
- Run a diff on the two lists of words, not on the raw text. Any diff tool does it.
- For every difference, show the box of the word in both scans.
- If a word on either side has a low confidence, mark the difference as unsafe and let a person look.
The diff and the display of changes are yours; the service delivers the words, the boxes and the confidences they stand on. The word list follows reading order, so a moved block shows as removed in one place and added in another.
Reproducible OCR for comparison: same image, same words
The same image
Gives the same result with a fast reading pipeline, byte for byte. Re-running a comparison returns the same changes.
A new scan
A new image can be read differently, even of the same paper. Step 5 marks those differences as unsafe.
Contracts and drafts stay in your own network when the comparison runs on your own server.
Try OCR for document comparison free
Read a page of your own free, or open the OCR demo gallery to see the same page read the same way every time.
Production use, high volume or your own server?
Private use and tests are free. For a company in production, a server of your own or a pipeline built on your pages, send the kind of page and the volume, and get a written offer, or a clear no when the fit is not there.
