An image processing apparatus has a first color conversion unit that converts a signal value at an achromatic grid point in a first color space among achromatic grid points in a color space, the signal value being closer to white than a first predetermined signal value, into a signal value that is even closer to white, and a second color conversion unit that converts a signal value at a grid point among grid points in the color space, the signal value being closer to white than a second predetermined signal value, into white are provided. The image processing apparatus converts a signal value of an input image using the first color conversion unit, and thereafter converting the signal value using the second color conversion unit.

An image processing apparatus includes: a controller configured to perform: acquiring original image data representing an original image and corrected image data representing a corrected image, the corrected image data being generated by executing specific correction processing on the original image data; calculating a first index value and a second index value, the first index value relating to a color distribution of the original image by using the original image data, and the second index value relating to a color distribution of the corrected image by using the corrected image data; and determining which processing, among a plurality of processing candidates that are executable by the image processing apparatus, corresponds to the specific correction processing, based on comparison of the calculated first index value and the calculated second index value.

There is provided an image reading apparatus including a first reading sensor provided in a first reading unit and configured to read one surface of the sheet, a second reading sensor provided in a second reading unit provided to face the first reading sensor and configured to read an image on the other surface of the sheet, a first background portion serving as a reading background of the first reading sensor, a second background portion serving as a reading background of the second reading sensor, and a moving portion configured to integrally move the first reading sensor and the second background portion, wherein the first reading unit includes a sensor case in which the first reading sensor is provided, and the sensor case is fixed to the apparatus main body.

A target area of image data of a scanned document is set, in which the target area has a predetermined size and a target pixel, characteristic amounts indicating the brightness at two pixels among the plurality of pixels included in the set target area are obtained, a determination is made on whether or not the difference between the obtained characteristic amounts indicating the brightness is higher than a threshold, a brightness correction amount is decided based on a characteristic amount indicating the brightness of the target pixel and the result of the determination, and the brightness characteristic amount indicating the brightness of the target pixel is corrected based on the decided correction amount.

An image reading device includes a first unit to read one surface of a document in a first area facing a document path, a second unit disposed in the first area to read the other surface of the document, a first reference member facing the first unit at a first distance therefrom at a second position in a second area not facing the path, a second reference member facing the first unit at a second distance therefrom at a first position in the first area, a third reference member facing the second unit at the second distance therefrom, and a correction unit to correct, based on a difference between first data generated through reading of the first member by the first unit and second data generated through reading of the second member by the first unit, third data generated through reading of the third member by the second unit.

Under-color removal of show-through background from a scanned original, so as to retain chromatic highlights of the scanned image of the original. An under-color level defines a value at which signals having a higher luminance than a luminance of the under-color level are converted into white. Before under-color removal, and based on the scanned image of the original, an achromatic color is converted into a color closer to white than the under-color level for an achromatic color closer whose luminance falls in a specified range lower than the luminance of the under-color level; and a chromatic color is converted into a chromatic color having a lower luminance than the luminance of the under-color level for a chromatic color in the specified range. Under-color removal of the converted achromatic and chromatic colors is thereafter applied using the under-color level, by which signal values having a higher luminance than a luminance of the under-color level are converted into white.

An image processing apparatus includes: a controller configured to perform: acquiring original image data representing an original image and corrected image data representing a corrected image, the corrected image data being generated by executing specific correction processing on the original image data; calculating a first index value and a second index value, the first index value relating to a color distribution of the original image by using the original image data, and the second index value relating to a color distribution of the corrected image by using the corrected image data; and determining which processing, among a plurality of processing candidates that are executable by the image processing apparatus, corresponds to the specific correction processing, based on comparison of the calculated first index value and the calculated second index value.

An image processing apparatus includes a first correction amount acquiring unit and a first correction unit. The first correction amount acquiring unit acquires a first luminance correction amount of each block based on the luminance of each pixel in the block obtained by dividing a first image among multiple processing target images obtained by imaging a target object with multiple sheets bound together while opening the target object. The first correction unit corrects the luminance of each pixel in the multiple processing target images based on the first luminance correction amount of each block acquired by the first correction amount acquiring unit.

An image processing apparatus includes: a controller configured to perform: acquiring original image data representing an original image and corrected image data representing a corrected image, the corrected image data being generated by executing specific correction processing on the original image data; calculating a first index value and a second index value, the first index value relating to a color distribution of the original image by using the original image data, and the second index value relating to a color distribution of the corrected image by using the corrected image data; and determining which processing, among a plurality of processing candidates that are executable by the image processing apparatus, corresponds to the specific correction processing, based on comparison of the calculated first index value and the calculated second index value.

An image reading device includes a first unit to read one surface of a document in a first area facing a document path, a second unit disposed in the first area to read the other surface of the document, a first reference member facing the first unit at a first distance therefrom at a second position in a second area not facing the path, a second reference member facing the first unit at a second distance therefrom at a first position in the first area, a third reference member facing the second unit at the second distance therefrom, and a correction unit to correct, based on a difference between first data generated through reading of the first member by the first unit and second data generated through reading of the second member by the first unit, third data generated through reading of the third member by the second unit.