ScreenOCR

ScreenOCR is a free software tool for converting images on a computer screen into text, which can then be pasted into documents. It can be used to easily copy text from Google Books, locked PDFs, unprocessed document scans, and other hard-to-cite documents. It is available as a free download for Windows.

ScreenOCR is based on a tool built into Factsmith, a more comprehensive research software package, but is designed to be run as a stand-alone application. It was created by Daniel Gaskell.

Usage and technology
ScreenOCR runs in the background, in the user's system tray. When the user presses a key combination (Ctrl+Alt+Q), a cursor appears that allows them to select a portion of the screen, which is then copied as plain text to the clipboard. The user can then paste the text into a document.

Conversion is much more accurate on larger, crisper text, so zooming in as far as possible before trying to convert anything is recommended. ScreenOCR can usually convert text from Google Books with close to perfect accuracy, although it may have problems with punctuation marks, italic text, or blurry scans.

Internally, ScreenOCR uses the Tesseract OCR engine, an open-source project originally developed by Hewlett-Packard and now sponsored by Google.