How Does OCR Work?

Thanks to scanners, we can digitize our physical documents, saving them as files on our computer. They’re typically PDF format which allows you to open and read them, but typically you’re unable to interact with text on the document like you would with a document that was created on the computer with a word processor or other program. You can’t copy text, edit it, or even highlight it because the computer just sees the scanned document as an image. That is unless you have an optical character recognition (OCR) tool.

OCR is a tool to allow computers to recognize the text from physical documents to be interpreted as data. When we read text on a document, whether it’s on physical paper or on the computer screen, we instantly know what letter or other symbols it is. However, for computers, it’s a little more complicated.

Certain programs use OCR to allow you to edit the text from the scanned document like you would in a word processor. You can highlight text, copy it to other documents or rewrite whole sections. Another use for OCR is to make full-text searching a possibility. Some OCR programs will add the text recognized from a scanned document as metadata to the file, allowing certain programs to search for the document using any text contained within the document.

How it Works

OCR software programs all work a little differently depending on the the developer and its intended purpose but still follow several common principles.

The software typically has a preprocessing phase that attempts to make the text in the document clearer and easier to read. No scanner is perfect, so with most modern, commercial scanners, there are bound to be imperfections in the scanned image. It does this by cleaning up the image and isolating the characters from everything else. It makes sure the lines of text are properly aligned and the pixels are smoothed out.

The next common step is for the software to isolate each individual character, recognizing the characters consisting of pixels and the spaces between them. This allows the program to process each individual character, as well as recognize that a grouping of characters makes up a word.

The next stage is the trickiest, and commonly the one that separates different OCR programs. Once the OCR program knows what constitutes a character that it must recognize, it’s time to figure out what the character it is, so it can assign the corresponding metadata to it. Simple OCR software backchecks the characters with common fonts from a library to recognize if they match and the data can assigned. However, for text that doesn’t match any recognizable fonts in a library, such as uncommon fonts or handwritten text, more sophisticated techniques are required.

More advanced OCR programs will continue comparing characters to common patterns that help it identify which character it is. They will know that the letter “A” consists of two diagonal lines with a line in the middle. The most intelligent OCR will use contextual clues to determine what characters and words are which. If it has trouble determining if a character is either “I” or “1”, it looks at the surrounding characters it does recognize and make an educated guess. It’s more likely to interpret the following sentence as “Invoice to be delivered,” rather than “1nvoice to be delivered.”

OCR in Document Management Solutions

OCR is an integral component of most document management solutions in order to properly digitize documents and make them useful beyond just archiving. eFileCabinet uses Zonal OCR which uses predefined templates to look for characters in specific zones of a document, making the process much more efficient when scanning documents in for workflow purposes.

Templates are created for each standard form that a business deals with, allowing them to highlight the text fields they want the Zonal OCR to read. Each field is categorized, so the system knows what type of data is in each field such as names, addresses, dollar amounts, as well as checkboxes. This allows the program to attach a profile of metadata to the document, allowing the system to perform a number of different actions, including full-text search.

eFileCabinet can search for a document that was processed with Zonal OCR using any data that was recorded in the profile. OCR is also essential for the systems automated workflow feature, that moves documents through a workflow based on factors based on the metadata in the document. For example, the system needs to know a certain dollar amount on an invoice before it knows where to send it in an accounts payable workflow. The system can also use metadata to automatically file documents to the drawer and folder you designate.

There are numerous applications for OCR, especially when paired with a sophisticated document management solution like eFileCabinet. It’s the key factor for transitioning to a paperless office. To find out how eFileCabinet uses OCR technology to improve your business, fill out the form below to view a free demo.