Converting images to text is also known as OCR (Optical Character Recognition), and is very useful when scanning paper documents into your computer and then converting them to, say, MS Word format. OCR is considered a 'solved problem' these days as the OCR engines are now quite good and support a plethora of languages, alphabets and characters.

There are some freeware and open source applications which do a very good job of this. Sometimes, you may have only an image or screenshot of a text document and you need to manipulate the text. In such cases, an OCR application is indispensible.

The best Open Source (Free) software for Optical Character Recognition to date is Tesseract.

• The Tesseract Project Page at Google
• Download Tesseract
• Tesseract page at SourceForge (Migrating to Google)

About Tesseract

Tesseract is a free optical character recognition engine. It was originally developed as proprietary software at Hewlett-Packard between 1985 until 1995. For ten years it languished without any development, then Hewlett Packard and UNLV released it as open source in 2005. Tesseract is now being actively developed by Google and released under the Apache License, Version 2.0.

Listing of other OCR applications (Sortable table):

Name	License	Operating systems	Notes
ExperVision TypeReader & OpenRTK	Commercial	Windows,Mac OS X,Unix,Linux,OS/2
ABBYY FineReader OCR	Commercial	Windows	For working with localized interfaces, corresponding language support is required.
OmniPage	Commercial (Nuance EULA)	Windows, Mac OS	Product of Nuance Communications
Readiris	Commercial	Windows, Mac OS	I.R.I.S. Group of Belgium. Asian and Middle Eastern editions.
SmartZone (formerly known as Zonal OCR)	Commercial	Windows	SmartZone is the process by which Optical Character Recognition (OCR) applications "read" specifically zoned text from a scanned image.
Computhink's ViewWise & AnyDoc	Commercial	Windows	Document Management system
CuneiForm	BSD variant	Windows, Linux, BSD, MacOSX.	Enterprise-class system, multi language, can save text formatting and recognizes complicated tables of any structure
CVISION Technologies, Inc. PdfCompressor and Maestro Recognition Server	Commercial	Windows	Fast, accurate, high volume OCR
GOCR	GPL	Many (open source)	Early development
Microsoft Office Document Imaging	Commercial	Windows, Mac OS X	Microsoft Office has some OCR capabilities built-in.
Microsoft Office OneNote 2007	Commercial	Windows	$99.00 from Microsoft.
NovoDynamics VERUS	Commercial?	?	Specializes in languages of the Middle East
Ocrad	GPL	Unix-like, OS/2	Open Source
Brainware	Commercial	Windows	Data extraction and processing of data from documents into any backend system; sample document types include invoices, remittance statements, bills of lading and POs
HOCR	GPL	Linux	Hebrew OCR
OCRopus	Apache	Linux	Pluggable framework which can use Tesseract. State of the Art OCR for Linux.
OOCR	Open Source (GPL)	Windows	Open OCR
ReadSoft	Commercial	Windows	Scan, capture and classify business documents such forms, invoices and POs.
Alt-N Technologies' RelayFax Network Fax Manager	Commercial	Windows	Multi-language OCR Plug-in is used to convert faxed pages into editable document formats (doc, pdf, etc...) in many different languages.
Scantron Cognition	Commercial	Windows	For working with localized interfaces, corresponding language support is required.
SimpleOCR	Freeware and commercial versions	Windows	Free!
SmartScore	Commercial	Windows, Mac OS	For musical scores
Tesseract	Apache	Windows, Mac OS X, Linux, OS/2	HP initiative; now under development by Google