Brother Kogyo Kabushiki-kaisha

Taiki Yamano

Takahiro Ikeno

Tetsuya Kato

Yuji Hori

Takashi Matsumi

Shuichi Sunako

An image scanning apparatus, comprising: a gray reference member; a scanning unit; a signal conversion unit; a controller configured to: calculate white and black difference data of one line by subtracting first black data of one line from white data of one line; calculate a white and black difference maximum value and obtain a particular pixel position corresponding to the white and black difference maximum value; calculate light gray black difference data of one line by subtracting second black data of one line from light gray data of one line; calculate a gray white ratio by dividing the white and black difference maximum value at the particular pixel position by the light gray black difference data at the particular pixel position; and calculate reference data of one line by multiplying light gray data of one line by the gray white ratio.

Image scanning apparatus

A controller is configured to set a reference gradation value when a gray reference member is illuminated. When the number of pixels, of which the gradation values is equal to or greater than the reference gradation value, is a target number of pixels, both are stored in association with each other. A correction target number which is a minimum target number of pixels from among a plurality of target numbers of pixels respectively providing differences, which is less than a predetermined value, between the reference gradation values stored in association with an M-th target number and an (M+1)-th target number. The controller further determines an anomaly pixel number which is the number of anomaly pixels having gradation values which are equal to or greater than a base gradation value. The gradation values of the determined number of anomaly pixels are corrected.

Growing community of inventors

Aichi, Japan

Taiki Yamano