Abstract: There is provided an image processing apparatus, image processing method, and a program product for image processing capable of reproducing character images against a background region clearly without white framed areas or turbid areas. An MTF corrector 21 includes a lightness-change controller 113. The lightness-change controller 113 is constituted by two AND circuits 114, 115 and a lightness-change filter 116. In the AND circuit 114, there are inputted a character-region against halftone solid-region signal (_BETA_MOJI) and an inversed signal of a character-region-discrimination inner edge signal (_INEDG). On the other hand, in the AND circuit 115, there are inputted a character-region against halftone-dot-region signal (_AMI_MOJI) and an inversed signal of a character-region-discrimination inner edge signal (_INEDG). Output signals from the AND circuits 114 and 115 are inputted to the lightness-change filter 116.

Abstract: Disclosed are an image processing apparatus that can decrease image quality deterioration caused by misjudgment of a halftone-dot area when its resolution is beyond an appropriate range etc., in the case where judgment of a halftone-dot area is based on the number of isolated pixels present in a predetermined area, and an image forming apparatus that utilizes the image processing apparatus. A white isolated pixel detection unit 442 (and a black isolated pixel detection unit) includes a plurality of filters 4421 and 4422 that each can detect an isolated pixel in a halftone-dot of a different size. When output is made indicating that a target pixel is an isolated pixel detected by at least one of the filters, the target pixel is judged to be an isolated pixel.

Abstract: There is provided an image processing apparatus, image processing method, and a program product for image processing capable of reproducing character images against a background region clearly without white framed areas or turbid areas. An MTF corrector 21 includes a lightness-change controller 113. The lightness-change controller 113 is constituted by two AND circuits 114, 115 and a lightness-change filter 116. In the AND circuit 114, there are inputted a character-region against halftone solid-region signal (_BETA_MOJI) and an inversed signal of a character-region-discrimination inner edge signal (_INEDG). On the other hand, in the AND circuit 115, there are inputted a character-region against halftone-dot-region signal (_AMI_MOJI) and an inversed signal of a character-region-discrimination inner edge signal (_INEDG). Output signals from the AND circuits 114 and 115 are inputted to the lightness-change filter 116.

Abstract: Disclosed are an image processing apparatus that can decrease image quality deterioration caused by misjudgment of a halftone-dot area when its resolution is beyond an appropriate range etc., in the case where judgment of a halftone-dot area is based on the number of isolated pixels present in a predetermined area, and an image forming apparatus that utilizes the image processing apparatus. A white isolated pixel detection unit 442 (and a black isolated pixel detection unit) includes a plurality of filters 4421 and 4422 that each can detect an isolated pixel in a halftone-dot of a different size. When output is made indicating that a target pixel is an isolated pixel detected by at least one of the filters, the target pixel is judged to be an isolated pixel.