Abstract: At least two line segments of discrete elements forming part of a line of discrete elements are aligned to form a line. Each line segment is collected by a light sensitive sensor array (2, 3) having a number of light sensitive cells forming a segment vector (80). Each sensor array (2, 3) has a total visional field which is divided into an active visional field and a visional field edge, that aligning means, present in the coinciding visual field of two sensor arrays are imaged by initialization in at least one cell in the segment vector (80). The active visional fields of the sensory arrays are determined in dependence on the position of the aligning means in the segment vector (80). The line is joined by the cells (84) of the segment vectors, which cells (84) represent the active visional field, while the cells (82) representing the visional field edge are skipped.