Image reading apparatus
AssigneeCanon Kabushiki Kaisha
InventorJunnosuke Kataoka
Life of this patent
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Abstract
In an image reading apparatus for reading an original image, an optimum charge storage time of a line image sensor (105) in generating shading correction data and an optimum charge storage time of the sensor in reading an original image using the generated data are stored in a storage time setting unit (103) in correspondence with each of the first reading mode in which the image of an original placed on an original table (201) is read while moving the sensor and the second reading mode in which the image of an original fed by an ADF one by one is read at a predetermined position while fixing the sensor at the position. To actually read an original image in the first or second reading mode, an optimum value is selected from the plurality of stored storage times and used.
Claims12
An image reading apparatus for reading an original image using a line sensor having a plurality of photoelectric conversion elements, comprising:
- a memory for storing a charge storage time of the photoelectric conversion elements in correspondence with each of first and second reading modes, wherein the first and second reading modes correspond to first and second original image sources, respectively;
- a first unit adapted to detect the first or second reading mode to be used to read the original image;
- and
- a second unit adapted to read out a charge storage time corresponding to the reading mode detected by said first unit from said memory and reading the original image with the line sensor in accordance with the selected charge storage time.
An image reading apparatus for reading an original image using a line sensor having a plurality of photoelectric conversion elements, comprising:
- a memory for storing a charge storage time of the photoelectric conversion elements in correspondence with each of first and second reading modes, wherein the first and second reading modes correspond to first and second original image sources, respectively;
- a first unit adapted to detect the first or second reading mode to be used to read the original image;
- and
- a second unit adapted to read out a charge storage time corresponding to the reading mode detected by said first unit from said memory and reading the original image with the line sensor in accordance with the selected charge storage time;
- wherein said memory stores a charge storage time for reading a reference portion and a charge storage time for reading an original image using data generated upon reading the reference portion in correspondence with each of the first and second reading modes.
An image reading apparatus for reading an original image using a line sensor having a plurality of photoelectric conversion elements, comprising:
- a memory for storing a charge storage time of the photoelectric conversion elements in correspondence with each of first and second reading modes, wherein the first and second reading modes correspond to first and second original image sources, respectively;
- a first unit adapted to detect the first or second reading mode to be used to read the original image;
- and
- a second unit adapted to read out a charge storage time corresponding to the reading mode detected by said first unit from said memory and reading the original image with the line sensor in accordance with the selected charge storage time;
- wherein said second unit reads
- in the first reading mode, an image of an original placed on an original table while moving the line sensor, and
- in the second reading mode, an image of a fed original at a predetermined position while fixing the line sensor at the predetermined position.
An image reading apparatus for reading an original image using a line sensor having a plurality of photoelectric conversion elements, comprising:
- a memory for storing a charge storage time of the photoelectric conversion elements in correspondence with each of first and second reading modes, wherein the first and second reading modes correspond to first and second original image sources, respectively;
- a first unit adapted to detect the first or second reading mode to be used to read the original image;
- and
- a second unit adapted to read out a charge storage time corresponding to the reading mode detected by said first unit from said memory and reading the original image with the line sensor in accordance with the selected charge storage time;
- wherein said memory also stores a reference charge storage time and correction information representing a change over time in light amount after turning on a light source for irradiating an original with light, and to read image of a plurality of originals, every time one original image is read, said second unit calculates an optimum charge storage time at present on the basis of the reference charge storage time and correction information which are stored in said memory, and reads the original image with the line sensor in accordance with the calculated charge storage time.
An image reading apparatus for reading an original image using a line sensor having a plurality of photoelectric conversion elements, comprising:
- a memory for storing a charge storage time of the photoelectric conversion elements in correspondence with each of first and second reading modes, wherein the first and second reading modes correspond to first and second original image sources, respectively;
- a first unit adapted to detect the first or second reading mode to be used to read the original image;
- and
- a second unit adapted to read out a charge storage time corresponding to the reading mode detected by said first unit from said memory and reading the original image with the line sensor in accordance with the selected charge storage time;
- wherein said memory also stores optimum charge storage times according to a change over time in light amount after turning on a light source for irradiating an original with light, and
- to read images of a plurality of originals, every time one original image is read, said second unit selects an optimum charge storage time at present from the charge storage times stored in said memory and reads the original image with the line sensor in accordance with the selected charge storage time.
An image reading apparatus for reading an original image using a line sensor having a plurality of photoelectric conversion elements, comprising:
- a memory for storing a charge storage time of the photoelectric conversion elements in correspondence with each of first and second reading modes, wherein the first and second reading modes correspond to first and second original image sources, respectively;
- a first unit adapted to detect the first or second reading mode to be used to read the original image;
- and
- a second unit adapted to read out a charge storage time corresponding to the reading mode detected by said first unit from said memory and reading the original image with the line sensor in accordance with the selected charge storage time;
- wherein the optimum charge storage time of the photoelectric conversion elements corresponds to a time that satisfies a condition that when a predetermined reference white base is read with the line sensor, an output from a converter which converts an output signal from the photoelectric conversion elements into a digital signal can maintain linearity with respect to a predetermined input range.
Dependencies are inferred from the claim text.