Method of robust alignment and payload recovery for data-bearing images

A system for recovering a payload for data-bearing images, comprising:

• a processor that is adapted to execute stored instructions;
• a memory device that stores instructions that are executable by the processor, the instructions comprising code configured to direct the processor to:
• compute global transformation parameters of a stegatone;
• compute local transformation parameters for individual vertical strips of the stegatone;
• compute a metric value that represents an alignment between a reference halftone and the stegatone;
• compute a location of the centroid of clustered-dots in each cell and determine a distance between each centroid and a corresponding centroid of the reference halftone;
• identify shifts in the clustered-dots of the stegatone in comparison to the reference halftone;
• and
• recover a payload of the stegatone.

A tangible, non-transitory computer-readable medium, comprising code to direct a processor to:

• receive a digitized version of a stegatone from an input device;
• compute global spatial transformation parameters of the stegatone;
• process individual vertical strips of the stegatone to determine local spatial transformation parameters;
• perform an alignment evaluation to compute a metric value that represents a quality of a local alignment between a reference halftone and the stegatone;
• select alignment parameters based on optimization of the metric value;
• map a shift of clustered-dots in each cell in comparison to the reference halftone;
• and
• recover a payload of the stegatone.