OCR Freeware Utilities and Free Web Services

Optical character recognition, usually abbreviated to OCR, is the mechanical or electronic translation of images of handwritten, typewritten or printed text (usually captured by a scanner) into machine-editable text. It is used to convert paper books and documents into electronic files, for instance, to computerize an old record-keeping system in an office, or perform soft copies of the printed tables for computer based filling.

When one scans a paper page into a computer, it produces just an image file, a photo of the page. The computer cannot understand the letters on the page, so you cannot search for words or edit it and have the words re-wrap as you type, or change the font, as in a word processor. You would use OCR software to convert it into a text or word processor file so that you could do those things. The result is much more flexible and compact than the original page photo.

OCR is a field of research in pattern recognition, artificial intelligence and computer vision. Though academic research in the field continues, the focus on OCR has shifted to implementation of proven techniques. Optical character recognition (using optical techniques such as mirrors and lenses) and digital character recognition (using scanners and computer algorithms) were originally considered separate fields. Because very few applications survive that use true optical techniques, the OCR term has now been broadened to include digital image processing as well.

Early systems required training to read a specific font; they needed to be programmed with images of each character, and it only worked on one font at a time. "Intelligent" systems with a high degree of recognition accuracy for most fonts are now common. Some systems are even capable of reproducing formatted output that closely approximates the original scanned page including images, columns and other non-textual components (From Wikipedia).