Binarizing circuit for picture signal

Abstract

Abstract PURPOSE:To reproduce an original with mixture of a character and an intermediate tone picture with excellent picture quality by outputting a character or an intermediate tone binarizing signal selectively in the unit of picture elements in response to the total sum of density difference absolute values between a noted picture element and its adjacent picture elements. CONSTITUTION:An output of the 1st binarizing circuit 3 deciding the white or black level of the noted picture element is selected depending on an output of a 2-dimension edge emphasis circuit 2 giving an emphasis signal emphasizing the density of the noted picture element in response to the density difference between the noted picture element and the adjacent four picture elements and on an output of an averaging circuit 1 giving a density mean value in the area around the noted picture element. Moreover, the output of a dither circuit 4 giving the 2nd binarizing signal being the result of binarizing the noted picture element based on the threshold level of the dither matrix varying periodically in the main scanning and the subscanning directions is outputted by selecting with the output of the differential circuit 6 outputted the total sum of the density difference absolute value between the noted picture element and the adjacent 4 picture elements. Thus, the intermediate tone and the character are reproduced in an excellent way.

Inventors

• 👤 Toru Takahara
• 👤 徹 高原

Bibliographic Details