JPS57183174A - Mark detecting circuit - Google Patents

Abstract

PURPOSE:To detect a mark in a two-dimensionally encoded mark sheet simultaneously with decoding operation and to shorten a processing time, by judging that there is a longitudinal line when encoded with vertical mode over prescribed (n) lines. CONSTITUTION:Mark sheet data encoded in two-dimensions are applied from an input terminal 1 to a decoding circuit 2. The decoding circuit 2 outputs a decoded binary original image signal P and a signal V, which shows a changed picture element position and is encoded in vertical mode, to a mark field detecting circuit 4 and a mark discriminating circuit 6 through a one-line delay circuit 21, and also output an encoding mode signal, which shows which of a pass mode, a vertical mode, and a horizontal line a code on an encoding line is in, to a vertical mode line discriminating circuit 3. When the output of the discriminating circuit 3 is a ''1'' continuously for a period equivalent to (n) scanning lines, the mark field detecting circuit 4 judges it as a mark and recognizes its mark position to operate a mark field timing generating circuit 5, thereby outputting a mark position timing signal to a mark discriminating circuit 6.