JPS5757089A - Noise eliminating device - Google Patents

Abstract

PURPOSE:To prevent the noise from remaining in the inter-line part even if the ground level is comparatively high, by detecting whether a line to be converted to a binary is a character line or an inter-line part on the original and by outputting the white level for the inter-line part. CONSTITUTION:An input signal (a) is converted to a binary with three thresholds S1-S3 by a comparing circuit 1 and an accumulating circuit 2, and the number of black picture elements in one main scanning line is integrated, and integrated values C1-C3 are outputted synchronously with t2 and are cleared. These values C1-C3 are converted to binaries by a comparing circuit 3 and are stored in a pattern storage circuit 4. In an accumulating circuit 5 and a comparing circuit 6, the number of lines, which are estimated as character lines, in each stored pattern is integrated, and stored patterns which are proper as character lines and inter-line patterns are discriminated from each other by the integrated value. In disciminating logical operation circuit 7, it is discriminated on a basis of the proper pattern whether the noticed line scans characters or the inter-line part.