Technology
What is OCR? Optical Character Recognition Explained
Ever wondered how your phone can "read" text from a photo? It's not magic—it's OCR. Here is how this decades-old technology powers the modern web.
Optical Character Recognition (OCR) is the process that converts an image of text into a machine-readable text format. For example, if you scan a receipt or a magazine article, your computer just sees a picture (pixels). OCR software analyzes those pixels and says, "That shape looks like the letter 'A'."
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How It Works
- Pre-processing: The software turns the image to black and white to increase contrast.
- Character Recognition: It looks for patterns of light and dark. It knows that two diagonal lines meeting at the top is an 'A'.
- Post-processing: It uses a dictionary to correct errors. If it sees "App1e", it realizes you probably meant "Apple".
Why It Matters
Without OCR, the internet would be unsearchable. Google Books uses OCR to index millions of physical books. Law firms use it to search through millions of pages of evidence in seconds.
Note: Standard "Image to PDF" tools simply wrap the image in a PDF container. To make it searchable, you typically need specific OCR software.