Optical character recognition (OCR) is the digital conversion of an image of text into machine-readable text. Many scanned PDF documents are image-only and thus an assistive technology device, such as a screen reader, cannot read the text in the document, nor can a student search the document for keywords or passages.
There are several free and low-cost tools available on the web to assist with this conversion process. The following have been tested and are recommend by COL:
Free: OCR Space and Online OCR
Paid: Sejda and Adobe Acrobat