Patent Number: 6,945,626

Title: Correction table generation method and method of controlling correction table generation apparatus

Abstract: In a multi-valued printer that uses discontinuous index patterns, if a tone correction table is generated using sampled density patches, a table which is different from a table to be obtained and has no inflection point is obtained, and the print density characteristics after tone correction suffer discontinuity. To solve this problem, an output gamma table used to output measurement patches is set to linearly correct the printer print characteristics. Patches are output and their densities are measured. A reverse table of a "signal value--density" table is generated, and is smoothed using a recursive curve. The smoothed reverse table is finely adjusted to generate an intermediate output gamma table. The generated table undergoes index component correction, thus generating a tone correction table.

Inventors: Tsuchiya; Okinori (Kanagawa, JP), Nagoshi; Shigeyasu (Kanagawa, JP), Nakatani; Akihiko (Kanagawa, JP)

Assignee: Canon Kabushiki Kaisha

International Classification: B41J 2/205 (20060101); B41J 29/393 (20060101); G06K 15/00 (20060101); B41J 029/393 ()

Expiration Date: 9/20/02017