# 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 (/).

Since the tool was pre-trained on a set of images with a consistent text and background polarity, i.e. dark text on a light background, if you happen to have a data set of images with an inverse polarity, you will need to change the polarity by selecting Inverted from the Polarity drop-down menu in the Sampling Tool Parameters section.

When this parameter is set to Inverted, the images in the Images display, as well as in the main display, will show the corrected polarity.

Note: This change in polarity only applies to the Blue Read tool, and any subsequent tools chained to it will keep the original image greyscale polarity.

However, there may be many instances where the characters in your image are organized into regular, consistent groups. You can create Models that describe the spatial relationship between a group of features, and also which character values are legal for each feature in the Model. 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.

You can easily create a Model from the features that the tool finds in an image. Simply select all of the yellow found features you want to include in the Model (shift-click or shift-drag to draw a box), then right-click anywhere and select Create Model. If you select Create Model with nothing selected, then the Model will be created from all of the features found in the image.