# Create a Regex Model in Blue Read

To use a regex model A specific spatial arrangement of a set of features (Blue Locate and Blue Read tools only.) During a post-processing step, the Blue Locate and Blue Read tools can fit all of the features detected in an image to the models defined for the tool. The overall pose and identity of the model is then returned., do the following:

1. After adding the tool, configuring the ROI The Region of Interest (ROI) defines the area of operation for the tool. The ROI preserves the positions, angles, stretch and skew of the original image. () and setting the character Feature Size (), process the tool (press the Book icon).

2. To create your regex model, from the Tool menu, select Edit Models, and from the Model Editor dialog, select Regex Model.

3. Define your regular expression in the Regex field.

   Note:
   - When constructing your regular expression, the simplest wildcard is the period; it means "match any single character." You can then use modifiers after characters or wildcards to specify how many characters to match.
   - The minimum match length for the regex model is three characters (not including the space character) or longer.
4. The regex model will return the characters that match your regular expression within the ROI. The matched characters must lie along a single horizontal line, which is defined by using the Angle parameter, and is the allowable deviation from the horizontal axis of the ROI.
5. Close the dialog by pressing the X button in the top-right corner of the dialog.
6. The model will then be applied to the view A view of an image is a region of pixels in an image. Tool processing is limited to the pixels within the view. You can manually specify a view, or you can use the results of an upstream tool to generate a view. that was open when the Model Editor was launched.
7. Process the tool (press the Book icon) to apply the model to the rest of the views.
8. Review the results.