Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making
Reexamination Certificate
2000-01-24
2002-10-01
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
C430S021000, C430S020000, C430S022000, C355S038000, C358S475000, C358S505000, C358S520000
Reexamination Certificate
active
06458492
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to process for determining a mask for changing the brightness profile of a photographic print or copy. Furthermore, the invention relates to a process for changing the brightness profile during the manufacture of a print or copy by way of the mask determined in accordance with the invention. Finally, the invention relates to an optimal printer and a digital printer which use the mask determined in accordance with invention.
2. Background Information
The term “photography”, as used herein, refers to the (permanent) recording of images produced by electromagnetic radiation (especially light) by means suited herefor (for example, a camera with film, a digital camera with CCD-chip, a film camera, a video camera, and the like).
The field of the present invention relates to the computer and/or optical processing of the photographic image information which represents the picture produced. The photographic image information is thereby obtained, for example, by scanning a photographic master (for example a film) and converted into digital image data. The photographic image information can also be already present in digital format. It can then be stored, for example, electronically (for example, CD-ROM, DVD), can be accessible through a network (for example LAN or Internet) or can be recorded, for example, with a digital camera.
Photographic image data can be copied such as conventional image data onto a physical medium. For example, photographic paper serves as physical medium onto which photographic films are exposed. The copying can also be carried out by way of a digital printer, which is controlled by the photographic image data, and onto normal paper or photographic paper. However, the quality of the thereby achieved photographic prints is often unsatisfactory.
An essential reason for this is that the dynamics of the luminescence included in the image information to be copied cannot be transposed onto the copying medium. The reason for that is, for example, that photographic paper compared to a photographic film has a highly reduced dynamic luminescence range. But also the dynamic luminescence region which can be illustrated with a printer is smaller than the typical dynamic luminescence range of photographic image information.
The above-mentioned disadvantages encountered during the physical realization of a photographic copy have as a result that the subjectively observed brightness profile during observation of the copy is negatively distinguished from the subjectively observed brightness profile of the photographic image information underlying of the copy. This means that the picture feel is not optimal for an average observer during observation of the copy.
For example, brightness differences which often are still distinguishable for an observer of the original photographic image information are no longer distinguishable for an observer of the photographic copy when those brightness differences are found in a dark or very bright region of the photographic copy.
In order to overcome this disadvantage, masks were proposed which cause a brightening or darkening of certain regions of the copy. Such masks are described, for example, in DE 19703063 A1 or in DE 4040498 A1. A calculated mask is used therein to control an LCD matrix. This LCD matrix is found during the exposure of a photographic film onto a photographic paper in the therefore required optical copying light path and changes the brightness of the manufactured copy by region. Image data obtained from the original (photographic) image information are exclusively used for the calculation of the masks.
It is a disadvantage of the previous processes, that photographic errors included in the original photographic image information, such as color errors or errors in the brightness distribution enter into the calculation of the mask. The photographic errors can be caused, for example, by errors during photography (underexposure or overexposure), specific film properties (color shifts caused by the film) or by the spectral sensitivity of the CCDs of the digital camera used.
However, when the photographic errors enter into the calculation of the matrix, no optimal manipulation of the brightness profile of the desired photographic copy can be achieved.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to optimize the calculation of a mask for the change of a brightness profile of a photographic copy in such a way that negative effects of photographic errors are suppressed.
A mask is calculated with the process in accordance with the invention which is used for changing the brightness profile of a photographic copy.
According to the process, photographic image data are first derived from photographic image information, which includes the image information to be copied, whereby preferably a reduction (associated with loss) of the image information content, especially the image resolution, takes place. The photographic image information can include more image information than is copied, for example, the photographic image information can represent a sequence of images (for example, a film with several individual pictures or a recording sequence of a digital camera), whereby in accordance with the invention the brightness profile of the copy of one of these images is changed or the mask required therefor is determined. The image information corresponding to the remaining images can be used in accordance with invention for determination of the brightness mask (for example by way of complete film analysis). Also, the image information of a whole image can be used, when only a section of the image is to be copied. The photographic image information can be, for example, a photographic film (complete film, individual picture). The photographic image data are preferably digitalized during derivation from the photographic image information and can be derived, for example, by scanning (for example of the complete film or of only an individual picture or a section thereof) and alternatively during further processing (for example data reduction and/or smoothing). However, the photographic image information can also be present in digital form, for example, when it originates from a digital camera or is transferred through a network, for example. The photographic image data can then be derived from these digital data, in that, for example, the digitally available photographic image information is taken over 1:1. However, an especially loss associated data reduction, especially a resolution reduction, and/or smoothing is carried out in order to minimize the subsequent calculation effort.
Overall it is preferred that the number of data which include the derived photographic image data (especially per individual picture), is about 10,000 or less, preferably less than 2000 and especially preferably about 1000 (or less). Good results can be achieved in practical use even with such a reduced data volume. The calculation effort is simultaneously minimized. Especially for the generation of photographic image data by scanning an original film, one can choose an only coarse scanning from the start so that the time required for the scanning process is significantly reduced compared to a fine scanning (as is common in the prior art) and the number of the photographic image data is at the same time reduced to the desired amount.
The reduction has the further advantage that finer details of the photographic image information (of the photographic original or the scene illustrated thereby) have no influence on the masking. The already mentioned smoothing can also be of use for this purpose, whereby, for example, the image data which are reduced during the derivation from the image information to a desired number (for example in the form of a reduced image matrix) are subjected to a low pass filtering. It is advantageous in the case of color photo image data (for example a colored image matrix) to transform the color values into a color area wherein one of the
Burns Doane , Swecker, Mathis LLP
Gretag Imaging Trading AG
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