Method, apparatus and recording medium for image processing

An image processing apparatus comprising:

• generating means for generating image data from an image;
• multi-resolution conversion means for obtaining one multi-resolution image data in each of a plurality of frequency bands by converting the image data into multiple resolutions;
• and
• contrast-sense quantification means for quantifying a sense of contrast of an image, based on the multi-resolution image data, said contrast-sense quantification means comprises
• extracting means for extracting, as a light portion, an area in which a pixel value is equal to or larger than a predetermined threshold value from the multi-resolution image data in a first of said plurality of frequency bands;
• histogram generating means for generating histograms, corresponding to the light portion, for the multi-resolution image data in frequency bands higher than the first frequency band;
• and
• quantification means for quantifying the sense of contrast based on said histograms.

A computer-readable recording medium storing a program to cause a computer to execute an image processing method comprising the steps of:

• generating image data from an image;
• obtaining one multi-resolution image data in each of a plurality of frequency bands by converting the image data into multiple resolutions;
• and
• image quantifying a sense of contrast of an image based on the multi-resolution image data, said step of image quantifying comprises
• extracting, as a light portion, an area in which a pixel value is equal to or larger than a predetermined threshold value from the multi-resolution image data in a first of said plurality of frequency bands;
• generating histograms, corresponding to the light portion, for the multi-resolution image data in frequency bands higher than the first frequency band;
• and
• quantifying the sense of contrast based on said histograms.

An image processing method comprising the steps of:

• generating image data from an image;
• obtaining multi-resolution image data in the low, medium, and high frequency bands by converting the image data into multiple resolutions;
• image quantifying a sense of contrast of the image based on the multi-resolution image data in the the low, medium, and high frequency bands, said step of image quantifying comprising:
• extracting, as a light portion, an area in which the pixel value is equal to or larger than a first predetermined threshold value from the multi-resolution image data in the low frequency band;
• generating histograms, corresponding to the light portion, from the multi-resolution image data in the medium and high frequency bands;
• comparing the distribution width in the histogram of the multi-resolution data at least in the medium frequency band with a second predetermined threshold value;
• and
• judging the image to be a standard image in a case where the distribution width of the histogram of the multi-resolution data in the medium frequency band is larger than the second threshold value, and judging the image to be a low-contrast image in a case where the distribution width of the histogram of the multi-resolution data in the medium frequency band is equal to or smaller than the second threshold value.

An image processing apparatus comprising:

• generating means for generating image data from an image;
• multi-resolution conversion means for obtaining multi-resolution image data in the low, medium, and high frequency bands by converting the image data into multiple resolutions;
• contrast-sense quantification means for quantifying a sense of contrast of the image based on the multi-resolution image data in the the low, medium, and high frequency bands, said contrast-sense quantification means comprising:
• extracting means for extracting, as a light portion, an area in which the pixel value is equal to or larger than a first predetermined threshold value from the multi-resolution image data in the low frequency band;
• histogram generating means for generating histograms, corresponding to the light portion, from the multi-resolution image data in the medium and high frequency bands;
• quantification means for comparing the distribution width in the histogram of the multi-resolution data at least in the medium frequency band with a second predetermined threshold value, judging the image to be a standard image in a case where the distribution width of the histogram of the multi-resolution data in the medium frequency band is larger than the second threshold value, and judging the image to be a low-contrast image in a case where the distribution width of the histogram of the multi-resolution data in the medium frequency band is equal to or smaller than the second threshold value.

A computer-readable recording medium storing a program to cause a computer to execute an image processing method comprising the steps of:

• generating image data from an image;
• obtaining multi-resolution image data in the low, medium, and high frequency bands by converting the image data into multiple resolutions;
• image quantifying a sense of contrast of the image based on the multi-resolution image data in the the low, medium, and high frequency bands, said step of image quantifying comprising:
• extracting, as a light portion, an area in which the pixel value is equal to or larger than a first predetermined threshold value from the multi-resolution image data in the low frequency band;
• generating histograms, corresponding to the light portion, from the multi-resolution image data in the medium and high frequency bands;
• comparing the distribution width in the histogram of the multi-resolution data at least in the medium frequency band with a second predetermined threshold value;
• and
• judging the image to be a standard image in a case where the distribution width of the histogram of the multi-resolution data in the medium frequncy band is larger than the second threshold value, and judging the image to be a low-contrast image in a case where the distribution width of the histogram of the multi-resolution data in the medium frequency band is equal to or smaller than the second threshold value.