# Improve OCR

To get the best results from OCR, the ingested images or video must have sufficient contrast and be in focus.

The minimum height for a readable character in a high-quality image is approximately 10 pixels. In a poorer quality image, the characters must be larger.

If you know that all of the text in your images matches a specific character type, for example is upper case or only contains numbers, set the `CharacterTypes` configuration parameter. This can improve accuracy in some cases, because Media Server does not look for other character types.

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