Mask for changing the brightness profile of a photographic copy

Abstract

Process for determining a mask for changing a brightness profile of a photographic copy with the following steps: photographic image data are derived from photographically recorded image information; optimized image data are obtained by correction of the photographic image data, wherein errors which were created to during the photographic recording of the image information are considered; a brightness mask, the values of which embody an influencing of the brightness profile of the photographic copy is determined based on the optimized image data.

1 . Process for determining a mask for changing the brightness profile of a photographic copy, comprising the steps of: 
 a) deriving photographic image data from photographically recorded image information;    b) obtaining optimized image data by correction of the photographic image data, whereby errors which were created during the photographic recording of the image information are considered;    c) a brightness mask, the values of which embody an influencing of the brightness profile of the photographic copy, is determined based on the optimized image data.    
     
     
         2 . Process according to  claim 1 , including the further steps of extracting attributes from the optimized image data for analysis of the optimized image data, and modifying the optimized image data before step c) and/or modifying the values of the brightness matrix in step c) depending on the extracted attributes.  
     
     
         3 . Process according to  claim 2 , wherein the image information to be copied is classified, based on the extracted attributes and the modification is carried out depending on the classification result.  
     
     
         4 . Process according to  claim 1 , wherein the values of the brightness mask are modified depending on attributes of one region of the photographic image data, optimized image data and/or the brightness mask associated with the respective local value.  
     
     
         5 . Process according to  claim 1 , wherein gray values are determined in step b) which correspond to the optimized image data and which are then referred to for the determination of the brightness matrix.  
     
     
         6 . Process according to  claim 1 , wherein a brightening of darker regions caused by the brightness matrix is no longer carried out or is attenuated, when the degree of darkness exceeds a preselected threshold.  
     
     
         7 . Process according to  claim 1 , wherein in step c) only one mask value is assigned to each optimized image datum, from which the brightness mask is then determined.  
     
     
         8 . Process according to  claim 7 , wherein the assigned mask values form matrix elements of a first mask matrix and the second mask matrix is calculated from the first mask matrix, whereby a matrix element of the first mask matrix is assigned to each matrix element of the second mask matrix and the value of each matrix element of the second mask matrix is calculated from those of the matrix elements of the first mask matrix which are included in an associated region of the first mask matrix and which includes the assigned matrix element and matrix elements surrounding the assigned matrix element, whereby the first mask matrix forms the brightness mask.  
     
     
         9 . Process according to  claim 8 , wherein for the calculation of each element of the second mask matrix the attributes of the region of the first mask matrix assigned to the element are considered.  
     
     
         10 . Process according to  claim 1 , wherein the derivation of the photographic image data according to step a) includes a loss associated reduction of the data volume.  
     
     
         11 . Process according to  claim 1 , wherein the number of mask values is less than 2000, preferably about 1000.  
     
     
         12 . Process for changing the brightness profile of a photographic copy, wherein a photographic copy is produced based on photographic image information and a brightness mask is calculated according to the process of  claim 1  and that the brightness mask is superimposed with the image information to be copied for influencing the brightness profile of the photographic copy.  
     
     
         13 . Process according to  claim 12 , wherein the superimposition is carried out optically with a light density control arrangement which controls the light density, resolved by area in the different regions of the copy to be produced and during the exposure of the copy material, by controlling the light density control arrangement based on the values of the brightness matrix.  
     
     
         14 . Process according to  claim 12 , wherein the superimposition is carried out in a computer and the calculated result is used for the control of a printout of the photographic copy.  
     
     
         15 . Optical printer for the manufacture of photographic copies, with a light density control arrangement with which the light density, resolved by area, is controllable in different regions of a photographic copy to be made during exposure of the photographic copy material, with a digital data processing device which determines a brightness mask according to the process of  claim 1  and controls the light density control device with the values of the brightness mask.  
     
     
         16 . Digital printer for the printing of photographic copies based on digital photographic image information, with a printing device for forming a photographic copy on the basis of the digital photographic image information, with a data processing device which determines a brightness mask from the digital photographic image information according to the process of  claim 1  and which superimposes the values of the determined brightness mask with additional photographic image information in a computer, whereby the result of the superimposition is printed out by the printing device.