1. A method for detecting defects; the method comprises: acquiring, by an image acquisition unit and according to a scanning pattern, an acquired frame that comprises portions of multiple dice images; generating, by a processor of an inspection system, a reference frame that differs from a die image, in response to acquired frame spatial information and in response to a reference die image; wherein the reference frame comprises re-arranged portions of a reference die image, wherein locations of the portions of the reference die image correspond to locations of the portions of multiple dice images in the acquired frame; wherein if an upper right portion of the acquired frame comprises an image of a lower left portion of a first die and a lower right portion of the acquired frame comprises an image of an upper left portion of a second die then the generating comprises generating a reference frame that has an upper right portion that comprises a lower left portion of the reference die image and a lower right portion that comprises an upper left portion of the reference die image; comparing, by the processor of the inspection system, between multiple pixels of the acquired frame and multiple corresponding pixels of the reference frame to locate defects.