Method and apparatus for reading images using correction conditions to process fine scan data

An image reading apparatus for reading photoelectrically an original image that, when reading the image, performs prescan before performing fine scan intended to obtain output image data, and sets reading conditions for said fine scan in accordance with prescanned data obtained by the prescan, comprising:

• prescan analysis means for analyzing prescanned data of a preset area of the original image to calculate at least a preset density point of a density histogram of the prescanned data of said preset area as an image characteristic value thereof;
• memory means for storing fine scanned data obtained by fine scan;
• fine scan analysis means for analyzing fine scanned data of the preset area of said original image to calculate at least a preset density point of a density histogram of the fine scanned data of said preset area as an image characteristic value thereof;
• correction condition setting means for setting a correction condition for the fine scanned data such that both the image characteristic values calculated by said prescan analysis means and said fine scan analysis means match;
• and
• correction means for reading the fine scanned data from said memory means and correcting the read fine scanned data in accordance with the correction condition set by said condition setting means.

An image reading method comprising:

• performing a first scan of an image and generating first image data;
• performing a second scan of the image and generating second image data;
• generating a correction condition by processing the first image data and the second image data;
• and
• applying the correction condition to the second image data,
• wherein the first scan is performed at a first resolution and the second scan is performed at a second resolution, and
• wherein the step of generating the correction condition includes
• analyzing the first image data and generating at least respective preset density points of a density histogram of the first image data as a first image characteristic value;
• analyzing the second image data and generating at least respective preset density points of a density histogram of the second image data as a second image characteristic value;
• comparing the first image characteristic value and the second image characteristic value;
• and
• generating the correction condition such that the first image characteristic value matches the second image characteristic value.

An apparatus for reading an image comprising:

• a scanner adapted to perform a first scan of an image and a second scan of an image;
• a data processor adapted to generate image data from the image which has been scanned by the scanner;
• a correction condition setting subsection adapted to compare image data from the first scan and the second scan and develop a correction condition such that the first scan data and the second scan data match, the correction condition setting subsection comparing at least respective preset density points of density histograms of the first scan data and the second scan data;
• and
• a fine scanned data correction section which uses the correction condition to correct the image data from the second scan,
• wherein the first scan is performed at a first resolution and the second scan is performed at a second resolution.