Image processing apparatus and method

An image processing method for performing sharpness correction for input image data, comprising:

• an extraction step of extracting lightness data and chromaticity data from the input image data;
• an edge amount extraction step of extracting an edge amount on the basis of the lightness data;
• a saturation extraction step of extracting a saturation component on the basis of the chromaticity data;
• a distribution step of distributing an emphasis amount of an edge portion on the basis of the edge amount extracted in the edge amount extraction step to the lightness data and chromaticity data in correspondence with the saturation component extracted in the saturation extraction step;
• and
• an edge emphasis step of correcting the lightness data and chromaticity data using the emphasis amount of the edge portion distributed in the distribution step.

An image processing apparatus comprising:

• generation means for generating lightness data and chromaticity data;
• extraction means for extracting data corresponding to spatial frequency characteristics on the basis of the lightness data;
• and
• control means for controlling the spatial frequency characteristics of the lightness data and chromaticity data on the basis of the data extracted by said extraction means.

An image processing method comprising:

• a generation step of generating lightness data and chromaticity data;
• an extraction step of extracting data corresponding to spatial frequency characteristics on the basis of the lightness data;
• and
• a control step of controlling the spatial frequency characteristics of the lightness data and chromaticity data on the basis of the data extracted in the extraction step.

An image processing apparatus comprising:

• generation means for generating lightness data and chromaticity data;
• first extraction means for extracting an edge amount on the basis of the lightness data;
• second extraction means for extracting a saturation component on the basis of the chromaticity data;
• and
• control means for controlling the spatial frequency characteristics of the lightness data or chromaticity data on the basis of the edge amount and the saturation component extracted by said first and second extraction means.

An image processing method comprising:

• a generation step of generating lightness data and chromaticity data;
• a first extraction step of extracting an edge amount on the basis of the lightness data;
• a second extraction step of extracting a saturation component on the basis of the chromaticity data;
• and
• a control step of controlling the spatial frequency characteristics of the lightness data or chromaticity data on the basis of the edge amount and the saturation component extracted in the first and second extraction steps.

An image processing apparatus comprising:

• generation means for generating lightness data and chromaticity data;
• delay means which can delay the lightness data by N liens and can delay the chromaticity data by N lines;
• extraction means for extracting an edge amount using the lightness data delayed by the N lines by said delay means;
• and
• control means for controlling spatial frequency characteristics of the chromaticity data delayed by N/2 lines by said delay means in accordance with the edge amount extracted by said extraction means.

An image processing apparatus comprising:

• generation means for generating lightness data and chromaticity data;
• and
• correction means for performing correction processing of spatial frequency characteristics on the chromaticity data,
• wherein said correction means performs the correction processing so that a hue of an image expressed by the lightness data and chromaticity data is preserved before and after the correction processing.

An image processing method comprising:

• a generation step of generating lightness data and chromaticity data;
• and
• a correction step of performing correction processing of spatial frequency characteristics for the chromaticity data,
• wherein, in the correction step, the correction processing is performed so that a hue of an image expressed by the lightness data and chromaticity data is preserved before and after the correction processing.

An image processing apparatus comprising:

• reading means for scanning an original and generating image data representing the original;
• determination means for determining based on the image data obtained by a first scan of the original by said reading means whether the original is a color original or monochrome original;
• and
• processing means for converting the image data obtained by the first scan of the original by said reading means into lightness data and chromaticity data, and fixing the chromaticity data at a predetermined value in accordance with a determination result of said determination means.

An image processing apparatus for determining whether an input image is a color image or monochrome image, comprising:

• input means for inputting color image data in units of pixels;
• edge decision means for deciding in accordance with the input color image data whether a pixel of interest is located at an edge portion of a line image;
• first determination means for determining in accordance with the color image data whether the pixel of interest is a chromatic color pixel or an achromatic color pixel;
• second determination means for determining based on a decision result of said edge decision means and a determination result of said first determination means whether the pixel of interest is a chromatic color pixel or an achromatic color pixel;
• and
• discrimination means for discriminating in accordance with a determination result of said second determination means whether the input image is a color image or monochrome image.

An image processing method for determining whether an input image is a color image or monochrome image, comprising:

• an input step of inputting color image data in units of pixels;
• an edge decision step of deciding in accordance with the input color image data whether a pixel of interest is located at an edge portion of a line image;
• a first determination step of determining in accordance with the color image data whether the pixel of interest is a chromatic color pixel or an achromatic color pixel;
• a second determination step of determining based on a decision result in the edge decision step and a determination result in the first determination step whether the pixel of interest is a chromatic color pixel or an achromatic color pixel;
• and
• a discrimination step of discriminating in accordance with a determination result in the second determination step whether the input image is a color image or monochrome image.

An image processing apparatus for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• input means for inputting the chromaticity data in units of predetermined areas;
• calculation means for calculating a saturation amount on the basis of the input chromaticity data in the predetermined area;
• and
• determination means for determining based on the saturation amount obtained by said calculation means if a pixel of interest is an achromatic color pixel or a chromatic color pixel.

An image-processing apparatus for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• calculation means for calculating a saturation amount on the basis of the chromaticity data;
• first determination means for determining based on the chromaticity data whether or not a pixel of interest belongs to a predetermined color region;
• threshold value setting means for setting a threshold value on the basis of a determination result of said first determination means;
• and
• second determination means for comparing the saturation amount calculated by said calculation means with the threshold value set by said threshold value setting means to determine if a pixel of interest is an achromatic color pixel or a chromatic color pixel.

An image processing apparatus for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• calculation means for calculating a saturation amount on the basis of the chromaticity data;
• determination means for determining a degree of lightness of a pixel of interest on the basis of the lightness data;
• threshold value setting means for setting a threshold value on the basis of a determination result of said determination means;
• and
• determination means for comparing the saturation amount calculated by said calculation means with the threshold value set by said threshold value setting means to determine if the pixel of interest is an achromatic color pixel or a chromatic color pixel.

An image processing apparatus for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• first and second achromatic color/chromatic color determination means,
• said first achromatic color determination means comprising
• calculation means for calculating a saturation amount on the basis of the chromaticity data,
• first determination means for determining based on the chromaticity data whether or not a pixel of interest belongs to a predetermined color region,
• first threshold value setting means for setting a first threshold value when said first determination means determines that the pixel of interest belongs to the predetermined color region, and
• second determination means for determining based on the saturation amount calculated by said calculation means and the first threshold value set by said first threshold value setting means if the pixel of interest is an achromatic color pixel or a chromatic color pixel, and
• said second achromatic color/chromatic color determination means comprising,
• when said first determination means determines that the pixel of interest does not belong to the predetermined color region,
• third determination means for determining a degree of lightness of the pixel of interest on the basis of the lightness data,
• second threshold value setting means for setting a threshold value on the basis of a determination result of said second determination means, and
• fourth determination means for comparing the saturation amount calculated by said calculation means and the threshold value set by said second threshold value setting means to determine if the pixel of interest is an achromatic color pixel or a chromatic color pixel.

An image processing method for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• an input step of inputting the chromaticity data in units of predetermined areas;
• a calculation step of calculating a saturation amount on the basis of the input chromaticity data in the predetermined area;
• and
• a determination step of determining based on the saturation amount obtained in the calculation step if a pixel of interest is an achromatic color pixel or a chromatic color pixel.

An image processing method for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• a calculation step of calculating a saturation amount on the basis of the chromaticity data;
• a first determination step of determining based on the chromaticity data whether or not a pixel of interest belongs to a predetermined color region;
• a threshold value setting step of setting a threshold value on the basis of a determination result in the first determination step;
• and
• a second determination step of comparing the saturation amount calculated in the calculation step with the threshold value set in the threshold value setting step to determine if a pixel of interest is an achromatic color pixel or a chromatic color pixel.

An image processing method for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• a calculation step of calculating a saturation amount on the basis of the chromaticity data;
• a determination step of determining a degree of lightness of a pixel of interest on the basis of the lightness data;
• a threshold value setting step of setting a threshold value on the basis of a determination result in the determination step;
• and
• a determination step of comparing the saturation amount calculated in the calculation step with the threshold value set in the threshold value setting step to determine if the pixel of interest is an achromatic color pixel or a chromatic color pixel.

An image processing method for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• a first and second achromatic color/chromatic color determination steps,
• a first achromatic color determination step comprising
• a calculation step of calculating a saturation amount on the basis of the chromaticity data,
• a first determination step of determining based on the chromaticity data whether or not a pixel of interest belongs to a predetermined color region,
• a first threshold value setting step of setting a first threshold value when it is determined in the first determination step that the pixel of interest belongs to the predetermined color region, and
• a second determination step of determining based on the saturation amount calculated in the calculation step and the first threshold value set in the first threshold value setting step if the pixel of interest is an achromatic color pixel or a chromatic color pixel, and
• a second achromatic color/chromatic color determination step comprising,
• when it is determined in the first determination step that the pixel of interest does not belong to the predetermined color region,
• a third determination step of determining a degree of lightness of the pixel of interest on the basis of the lightness data,
• a second threshold value setting step of setting a threshold value on the basis of a determination result in the second determination step, and
• a fourth determination step of comparing the saturation amount calculated in the calculation step and the threshold value set in the second threshold value setting step to determine if the pixel of interest is an achromatic color pixel or a chromatic color pixel.

A storage medium that stores a program code for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• a program code of the input step of inputting the chromaticity data in units of predetermined areas;
• a program code of the calculation step of calculating a saturation amount on the basis of the input chromaticity data in the predetermined area;
• and
• a program code of the determination step of determining based on the saturation amount obtained in the calculation step if a pixel of interest is an achromatic color pixel or a chromatic color pixel.

A storage medium that stores a program code for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• a program code of the calculation step of calculating a saturation amount on the basis of the chromaticity data;
• a program code of the first determination step of determining based on the chromaticity data whether or not a pixel of interest belongs to a predetermined color region;
• a program code of the threshold value setting step of setting a threshold value on the basis of a determination result in the first determination step;
• and
• a program code of the second determination step of comparing the saturation amount calculated in the calculation step with the threshold value set in the threshold value setting step to determine if a pixel of interest is an achromatic color pixel or a chromatic color pixel.

A storage medium that stores a program code for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• a program code of the calculation step of calculating a saturation amount on the basis of the chromaticity data;
• a program code of the determination step of determining a degree of lightness of a pixel of interest on the basis of the lightness data;
• a program code of the threshold value setting step of setting a threshold value on the basis of a determination result in the determination step;
• and
• a program code of the second determination step of comparing the saturation amount calculated in the calculation step with the threshold value set in the threshold value setting step to determine if the pixel of interest is an achromatic color pixel or a chromatic color pixel.

A storage medium that stores a program code for determining attributes in units of pixels on the basis of color image data in a color space expressed by lightness data and chromaticity data, comprising:

• program codes of the first and second achromatic color/chromatic color determination steps,
• the first achromatic color determination step comprising
• a program code of the calculation step of calculating a saturation amount on the basis of the chromaticity data,
• a program code of the first determination step of determining based on the chromaticity data whether or not a pixel of interest belongs to a predetermined color region,
• a program code of the first threshold value setting step of setting a first threshold value when it is determined in the first determination step that the pixel of interest belongs to the predetermined color region, and
• a program code of the second determination step of determining based on the saturation amount calculated in the calculation step and the first threshold value set in the first threshold value setting step if the pixel of interest is an achromatic color pixel or a chromatic color pixel, and
• the second achromatic color/chromatic color determination step comprising,
• when it is determined in the first determination step that the pixel of interest does not belong to the predetermined color region,
• a program code of the third determination step of determining a degree of lightness of the pixel of interest on the basis of the lightness data,
• a program code of the second threshold value setting step of setting a threshold value on the basis of a determination result in the second determination step, and
• a program code of the fourth determination step of comparing the saturation amount calculated in the calculation step and the threshold value set in the second threshold value setting step to determine if the pixel of interest is an achromatic color pixel or a chromatic color pixel.