Abstract: Image measurement values of a measurement object, in particular a printed sheet, measured by means of a photoelectric image measuring unit operating on the basis of pixels are corrected with respect to at least one influencing variable which influences the measurement result with a view to at least partially eliminating the effect of this influencing variable on the measuring process. The image measurement values measured by the image measuring unit are converted by correction parameters of a parameter-based correction model into corrected image measurement values which no longer contain the influencing variable affecting the measuring process. The correction parameters used for the parameter-based correction model are automatically calculated using reference measurement values measured at reference measurements points on preferably the same measurement object by means of a reference measuring unit and the image measuring unit.

Abstract: A photoelectric color measuring head for measuring color properties of a measurement object includes an illumination device for exposing the measurement object to illuminating light and a wavelength-range-selective photoelectric receiver device (40) which intercepts measurement light remitted by the illuminated measurement object and converts it into corresponding electrical measurement signals. The illumination device includes an essentially white light-emitting diode (30) and means (60) for defining the angle of incidence range, so that the measurement object receives light only within an angle of incidence range, standardized for color measurement applications, of preferably 45°+/?5-10°. The receiver device includes a sensor field consisting of a multitude of photoelectric sensor pixels arranged in a line and the sensor pixels are made sensitive to different wavelength ranges through previously arranged color filters (420).

Abstract: Image measurement values of a measurement object, in particular a printed sheet, measured by means of a photoelectric image measuring unit operating on the basis of pixels are corrected with respect to at least one influencing variable which influences the measurement result with a view to at least partially eliminating the effect of this influencing variable on the measuring process. The image measurement values measured by the image measuring unit are converted by correction parameters of a parameter-based correction model into corrected image measurement values which no longer contain the influencing variable affecting the measuring process. The correction parameters used for the parameter-based correction model are automatically calculated using reference measurement values measured at reference measurements points on preferably the same measurement object by means of a reference measuring unit and the image measuring unit.

Abstract: For the generation of a color profile for a digital camera a user surface is made available which allows for the input or adjustment or selection of reproduction influencing quantities characterizing the transformation behavior of the profile (P) to be generated. From the input or adjusted or selected reproduction influencing quantities, corresponding optimization rules for the optimization of the parameters for the model of the digital camera used for the profile calculation and/or corresponding correction rules for the table values of the profile (P) are determined. The optimization of the parameters of the model of the digital camera is carried out by way of these optimization rules, and the table values of the profile (P) are changed according to these correction rules. The different reproduction influencing quantities are combined to sensible combinations and offered to the user with suitable pre-settings by way of the user surface for selection or individual assessment.

Abstract: In order to control ink application in a printing press, a sheet (3) printed by the printing press (1) is colorimetrically measured in a number of pixels (4) with respect to a selected color coordinate system that has been expanded to be four-dimensional by also taking into account an infrared component. Color difference vectors with respect to the desired color vectors, predefined or determined from a reference sheet (3) and referred to the same color coordinate system, are computed from the color vectors obtained for each pixel (4). A sensitivity matrix is determined for each measured pixel (4) of the sheet (3). The pixels (4) are classified by sensitivity class.