# Character Strings

An OCRMax tool can analyze variable length strings containing any combination of numbers, letters or special characters, provided the character string meets the following minimum requirements:

- A stroke width greater than or equal to two pixels for each character
- A minimum character size of 8x8 pixels for alphanumeric characters and 2x2 pixels for small characters such as periods
- Consistent polarity throughout the string, either all dark characters on a light background or all light characters on a dark background
- A consistent value for rotation and skew exhibited throughout the string

The segmentation parameters the OCRMax tool uses to identify separate character symbols include parameters that define these qualities of the string, such as the MinPitch property, which defines the minimum distance, in pixels, that must occur between characters.

An OCRMax tool can be configured to determine the best setttings for the segmentation parameters automatically, or you can set these parameters manually. See the topic Choosing Segmentation Parameters for a description of all the segmentation parameters and how to set them based on your character strings.