Patent US 8,418,924

The present invention provides a novel optical reader device and method for calibrating the device. The device executes a calibration module that locates the actual coordinates for a targeting symbol in a captured image. The coordinates are stored as calibration coordinates in the memory. During normal operation of the reader device, the stored calibration coordinates are used to locate a target, such as a bar code. In order to locate the targeting symbol, the calibration module may overlay a template on clusters that may be the targeting symbol. A reasonable accurate comparison identifies the cluster as the targeting symbol. Alternatively, the calibration module may approach a cluster from four frames of the image and identify the cluster's tangents and perimeter. Geometrical calculations are used to identify the center of an identified targeting symbol.