(A) calibrating the pen in order to obtain a calibration parameter;

(B) analyzing a watermarked document image in order to determine areas where x-y positions cannot be uniquely determined by m-array decoding;

(C) segmenting a maze pattern from an obstruction component of a captured image, wherein the obstruction component comprises document content that occludes the maze pattern;

(D) analyzing the maze pattern to extract bits from the maze pattern of the captured image;

(E) in response to (D), determining a transform that transforms image position coordinates to actual position coordinates, wherein the actual position coordinates identify a location of the pen tip in relation to the document;

(F) decoding the extracted bits associated with the captured image;

(G) in response to (F), if the image position coordinates of the captured image cannot be determined, matching the captured image with image information, comprising:

(i) warping the captured image to create a warped image; and

(ii) matching the warped image with an area of the document, where a corresponding x-y position cannot be uniquely determined by m-array decoding;

(H) determining image position coordinates of other image frames that are associated with a pen stroke, comprising:

(i) matching a corresponding captured image with a neighboring area of the image position coordinates of an image whose image position coordinates have been determined previously; and

(ii) repeating (i) until all image frames of the pen stroke are processed; and

(I) mapping the path of the pen tip from the transform, the calibration parameter, and the image position coordinates.