Linotype-hell Ag

Kurt-Helfried Winkelman

A method and apparatus for the analysis and correction of the image gradation of an image original to be reproduced by evaluating image values acquired by point-by-point and line-by-line, optoelectronic scanning with an input device in apparatus and systems for image processing. The image original is geometrically subdivided into a plurality of sub-images. The frequency distribution of the image values or, respectively, of the luminance components of the color values in a corresponding sub-image is separately identified as a sub-image histogram. The sub-image histograms of the individual sub-images are evaluated and the sub-images relevant for the image gradation are identified by means of the evaluation. An aggregate histogram that corresponds to the frequency distribution of the image values or, respectively, of the luminance component of the color values in the relevant sub-images is calculated from the sub-image histograms of the relevant sub-images. Correction values for the correction of the image gradation characteristic of the image original are subsequently calculated from the aggregate histogram according to the method of histogram modification.

Method and apparatus for the analysis and correction of the image

A method and apparatus for analysis of an image original to be reproduced by evaluating image values (R, G, B) acquired by the point-by-point and line-by-line, trichromatic scanning. The image values of a first color space allocated to the input apparatus are transformed into image values of a second color space that is independent of the first color space. The analysis of the image original for calculating setting values for image processing is implemented on the basis of the transformed image values of the second color space. The master analysis on the basis of the image values is implemented in view of image scope, image gradation and/or color cast.

Method and apparatus for the automatic analysis of density range, color

A method and apparatus for the analysis of a color cast in a color original to be reproduced, by evaluating color values acquired by point-by-point and line-by-line, trichromatic scanning with an image processing input device. For acquiring a color cast in the color original, a region of high luminance values (light image region) and/or a region of low luminance values (dark image region) of the luminance component L* of the color values L*, a*, b* in the color original to be analyzed is/are subdivided into at least one luminance region. The value of a potentially existing color cast in the luminance region is identified by averaging the color components a*, b* of the color values L*, a*, b* in the luminance region. The color cast value to be utilized for the evaluation of the color cast analysis is formed by selection and/or combination of color cast values identified for individual luminance regions. In addition, at least one luminance region is demarcated to form an analysis region in view of the chrominance c* by forming chrominance regions around the gray axis of the color space, whereby the demarcated analysis region is then utilized for calculating a potential color cast.

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Kiel, Germany

Kurt-Helfried Winkelman