Process for influencing the quality images furnished by an electronic imaging system

Process for modifying the quality of images furnished by an electronic imaging system in the form of a set of image point signals representing gray-scale values, said images, in each case, being composed of a set of image points which are areally distributed in an orderly manner, said process comprising:

• defining image segments surrounding individual image points;
• determining a characteristic brightness value representing local brightness, and a characteristic contrast value representing local contrast, for each image segment, based on the image point signals of image points situated within such image segment;
• and
• modifying a background brightness and contrast component for each of the image point signals based on said characteristic values;
• wherein said step of defining image segments surrounding individual image points comprises:
• selecting a subset comprising a limited number of supporting points Spq from among said set of image points;
• and
• defining image segments surrounding each supporting point such that said image segments cover completely at least a selected area of said image;
• wherein said step of determining characteristic values comprises:
• determining a characteristic brightness value and a characteristic contrast value for each supporting point based on image point signals of image points situated within an image segment surround such supporting point;
• performing a two dimensional interpolation between the characteristic brightness and contrast values for adjacent supporting points to determine characteristic brightness and contrast values for intermediate image points therebetween;
• wherein a preset desired background brightness value is used to modify the respective background brightness HG of the image point signals in addition to the respective characteristic brightness value;
• and
• wherein the background brightness HG of the image point signals is determined according to the rule
• HG=Hs+k2(Hi−Hs),
• with 0≦k2≦1.

Process for modifying the quality of images furnished by an electronic imaging system in the form of a set of image point signals representing gray-scale values, said images, in each case, being composed of a set of image points which are areally distributed in an orderly manner, said process comprising:

• defining image segments surrounding individual image points;
• determining a characteristic brightness value representing local brightness, and a characteristic contrast value representing local contrast, for each image segment, based on the image point signals of image points situated within such image segment;
• and
• modifying a background brightness and contrast component for each of the image point signals based on said characteristic values;
• wherein said step of defining image segments surrounding individual image points comprises:
• selecting a subset comprising a limited number of supporting points Spq from among said set of image points;
• and
• defining image segments surrounding each supporting point such that said image segments cover completely at least a selected area of said image;
• wherein said step of determining characteristic values comprises:
• determining a characteristic brightness value and a characteristic contrast value for each supporting point based on image point signals of image points situated within an image segment surround such supporting point;
• and
• performing a two dimensional interpolation between the characteristic brightness and contrast values for adjacent supporting points to determine characteristic brightness and contrast values for intermediate image points therebetween;
• and
• wherein a comparative value Ks for contrast is given which, during modification of the respective contrast fraction of the image point signals appears in the numerator of an amplification factor V constructed as a quotient with the respective characteristic contrast value Ki(x,y) as the denominator.

Process for modifying the quality of images furnished by an electronic imaging system in the form of a set of image point signals representing gray-scale values, said images, in each case, being composed of a set of image points which are areally distributed in an orderly manner, said process comprising:

• defining image segments surrounding individual image points;
• determining a characteristic brightness value representing local brightness, and a characteristic contrast value representing local contrast, for each image segment, based on the image point signals of image points situated within such image segment;
• and
• modifying a background brightness and contrast component for each of the image point signals based on said characteristic values;
• wherein said step of defining image segments surrounding individual image points comprises:
• selecting a subset comprising a limited number of supporting points Spq from among said set of image points;
• and
• defining image segments surrounding each supporting point such that said image segments cover completely at least a selected area of said image;
• wherein said step of determining characteristic values comprises:
• determining a characteristic brightness value and a characteristic contrast value for each supporting point based on image point signals of image points situated within an image segment surround such supporting point;
• performing a two dimensional interpolation between the characteristic brightness and contrast values for adjacent supporting points to determine characteristic brightness and contrast values for intermediate image points therebetween;
• wherein a preset desired background brightness value is used to modify the respective background brightness HG of the image point signals in addition to the respective characteristic brightness value;
• and
• wherein desired and comparative values are uniformly selected for the whole image.

A process for modifying an electronic image furnished in the form of a set of image point signals representing respective gray scale values for a set of image points which are areally distributed in an orderly manner, said process comprising:

• selecting from among said set of image points a plurality of supporting points dispersed throughout said image;
• defining respective image segments surrounding said supporting points, said image segments collectively including at least all areas of interest in said electronic image;
• for each particular image segment, determining a local brightness characteristic value which is equal to a mean gray scale value for all image points existing therein;
• for each particular image segment, determining a local contrast characteristic value which is equal to a mean deviation of gray scale values for all image points existing within the particular image segment from the local brightness characteristic value determined for the particular image segment;
• determining local brightness and local contrast characteristic values for all image points within said image other than supporting points, as a function of local brightness and local contrast characteristic values determined for the image segments;
• expressing a gray scale value for each particular image point as the sum of a background brightness component based on the local brightness characteristic value determined for the particular image point, and a contrast component based on the local contrast characteristic value determined for the particular image point;
• and
• independently modifying at least one of said background brightness components and said contrast components by means of said local brightness and local contrast characteristic values.