A process and apparatus for determining the location of a captured array from a larger image is described. A non-repeating sequence may be folded into a non-repeating array in which the array is unique for every neighboring window of a given size. A portion of the array of the neighboring window may be captured and a subset of extracted bits corresponding to the captured array is decoded to identify error bits. The location of the captured array is determined within the non-repeating array by further processing the decoded bits.