IMPROVEMENT OF OPTICAL MARK RECOGNITION OF PRINTED FORMS BY OBSTRUCTION DETECTION

摘要

An optical reader of a form is discussed where the form has a stored known boundary or boundaries. When the boundaries in a captured image do not match those of the stored known boundaries, it may be determined that an obstruction exists that will interfere with a correct reading of the form. The boundary may be printed, blank, and may include quiet areas, or combinations thereof in stored known patterns. A captured image of the form is compared to retrieved, stored boundary information and differences are noted. The differences may be thresholded to determine if an obstruction exists. If an obstruction is detected, the operator may be signaled, and the location may be displayed or highlighted. The form may be discarded or obstruction may be cleared and the form may be re-processed.