documentcloud/docsplit — pull request #124 by ntodd (2014-12-18 22:51:55+00:00)
Title: Add parallel processing to OCR text extraction of full documents

Leverage the GNU Parallel gem to OCR multiple pages in parallel. If Parallel is installed, a full document extraction will generate an image for each page and then spawn a tesseract process for each available core. If Parallel is not installed or a subset of pages are indicated, the old behavior will be used. This speeds up OCR processing significantly on multi-core machines.

With a bit more work, this could be leveraged by the other OCR code paths.