Picture signal processing method

Abstract

Abstract PURPOSE:To discriminate exactly a character image and a halftone image by deriving a density difference of two peripheral picture elements existing in a position for pinching a notice picture element, and a density difference between the notice picture element and its adjacent picture element, and comparing them with a prescribed threshold level. CONSTITUTION:An analog picture signal from an image sensor 21 is applied to a series circuit of line memories 5, 31 and a series circuit of latches 261-263 through an A/D converter 22. Outputs of the line memories 25, 31 are provided to a series circuit of latches 264, 260 (notice picture element) and 265, and a series circuit of latches 266-268, respectively. Subsequently, peripheral picture elements existing in a position for pinching the notice picture element are applied to difference operating circuits 281-284, and a density difference is derived. On the other hand, the notice picture element and its adjacent picture element are applied to difference operating circuits 285-288, and a density difference is derived in the same way. These density differences are applied to comparing circuits 361-368, compared with prescribed threshold levels T1, T2, and as a result, synthesized, and applied as an image discriminating signal to a multiplexer 39.

Inventors

• 👤 Taiji Nagaoka
• 👤 永岡　大治
• 👤 Masami Kurata
• 👤 倉田　正實
• 👤 Hiroyuki Saito
• 👤 宏之 斎藤

Bibliographic Details