# Blue Read Tool – Models

The Blue Read tool comes with a pre-trained model. This model was trained on a large database of images with text in numerous fonts and backgrounds. The characters of the pre-trained model are numerals (0-9), uppercase letters (A-Z, except "O"), hyphen (-), plus sign (+), ampersand (&), colon (:), and forward slash (/).

However, there may be many instances where the characters in your image are organized into regular, consistent groups, and defining a model will improve performance.

There are three types of models that you can define:

- Node Model
- String Model
- RegEx Model

Note: If you have defined one or more models, the tool will use the model information to improve its performance by attempting to fit found characters to the models that you have defined, using the model with the best score.