Image reading apparatus
AssigneeCanon Kabushiki Kaisha
InventorKenji Hiromatsu
Life of this patent
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Abstract
The deterioration of read-image quality caused by LED color-tone variations is suppressed in a case in which a white-color LED illumination module is used as a light source of a color-image reading apparatus. The color-image reading apparatus includes an illumination module formed of a plurality of white-color LEDs arranged in a main-scanning direction; an image sensor such as a CCD; a unit for moving the original and the image sensor relatively in a sub-scanning direction; and an input masking unit. The illumination module is formed of LEDs having the same color-tone rank. The color-image reading apparatus also includes a setting unit for setting a color-tone rank for the illumination module, and a control unit, such as a CPU, for switching a parameter of the input masking unit according to the color-tone rank.
Claims23
An image reading apparatus comprising:
- an illumination unit formed of a plurality of arranged light sources for illuminating an image to be read;
- a photoelectric conversion unit which reads an image to be read illuminated by said illumination unit and outputs a first signal;
- a rank setting unit which sets color-tone ranks for the plurality of light sources;
- a signal compensation unit which compensates the first signal output from said photoelectric conversion unit;
- and
- a control unit which calculates first data according to the ranks and controls compensation performed by said signal compensation unit, according to the first data.
A control method for an image reading apparatus having an illumination unit formed of a plurality of arranged light sources for illuminating an image to be read, comprising the steps of:
- setting color-tone ranks for the plurality of light sources;
- reading an image to be read illuminated by the illumination unit and outputting a first signal;
- and
- calculating first data according to the ranks and controlling such that the output first signal is compensated according to the first data.
An image reading apparatus comprising:
- an illumination unit formed of a plurality of light sources arranged in a first direction for illuminating an image to be read;
- a photoelectric conversion unit which reads an image to be read illuminated by said illumination unit and outputs a signal;
- and
- a control unit which controls such that a second signal output from said photoelectric conversion unit is compensated according to first data,
- wherein the first data is calculated by using a first signal output from said photoelectric conversion unit and information related to the first direction.
A control method for an image reading apparatus having an illumination unit formed of a plurality of light sources arranged in a first direction, for illuminating an image to be read, comprising the steps of:
- reading an image to be read illuminated by the illumination unit and for outputting a signal;
- and
- controlling such that a second signal output from a photoelectric conversion unit is compensated according to first data,
- wherein the first data is calculated by using a first signal output from the photoelectric conversion unit and information related to the first direction.
Dependencies are inferred from the claim text.