EP1323293A1

EP1323293A1 - Device and method for digitally detecting a document having several individual images

Info

Publication number: EP1323293A1
Application number: EP01985315A
Authority: EP
Inventors: Hans-Georg Schindler; Volker Josel; Werner Oberndorfer
Original assignee: Agfa Gevaert AG
Current assignee: AgfaPhoto GmbH
Priority date: 2000-09-19
Filing date: 2001-09-12
Publication date: 2003-07-02
Also published as: DE10046357C2; US20030231351A1; DE10046357A1; WO2002025930A1

Abstract

The invention relates to a device for digitally detecting a document (12) having several individual images. Said device comprises a main scanning element (30, 32, 34, 36) by which means at least one main scanning section of the document (12) can be scanned during a main scanning operation. The inventive device also comprises a storage element (38) which enables main scanning values obtained during the main scanning operation to be stored. At least one document-specific parameter can be determined from at least one part of the main scanning values, and the stored main scanning values can be modified on the basis of said parameters during an automatic image processing operation. The at least one part of the main scanning values comprises main scanning values of at least two individual images. The invention also relates to a corresponding method.

Description

Device and method for digitally capturing a template with several individual images

The present invention relates to a device for digitally capturing a document with a plurality of individual images, comprising a main scanning element, by means of which at least one main scanning section of the original can be scanned in a main scan, and a memory element, by means of which main samples obtained in the main scan can be stored. The invention also relates to a corresponding method.

Such a generic device and such a method are known from the publication DE 198 05 048 A. This document describes a method and an apparatus for digitally capturing photographic films which have a large number of individual images. A film is first scanned with a first resolution in a prescan in which the film is advantageously measured in the colors blue, green and red according to its optical density. The positions of the individual images on the film and color-specific parameters for the exposure control during a subsequent main scanning with a second, higher resolution are then determined from the acquired pre-scanning values. This main scanning takes place in a phase in which the frame to be scanned is in the rest position. A so-called pre-scanning device is used for the pre-scanning with the lower resolution. While the film is being transported through the pre-scanner at a relatively high speed, three lines of the film arranged perpendicular to the direction of movement of the film are projected onto three sensor lines of the pre-scanner. The sensor lines are each covered with a color filter in order to obtain extracts from the film in the colors red, green and blue. Alternatively, however, there is also the possibility of dividing a line of the film arranged perpendicular to the direction of movement of the film into a red, green and blue line using a color divider and then projecting it onto the three sensor lines. As a result, each line-shaped section of the film, also called the pre-scanning section, is imaged simultaneously on the three sensor lines.

The acquired pre-samples flow to a computing unit in which the positions of the individual images and the color-specific parameters are determined from the color separations of the entire film. For the main scan with the higher resolution, the film is positioned by a positioning unit in such a way that a single image, i.e. a main scan section, is located in the imaging beam path of a main scanner and is projected onto a main scanning element, in this case an area CCD array , For this purpose, the area CCD array must have a size which ensures that the entire individual image is captured or a smaller array has to be shifted, with several subsections of an image being recorded and put together. The imaging can be done either directly or via a lens. The light for this main scan can be dyed using a suitable filter unit and the exposure can be carried out sequentially in the three colors red, green and blue. In the exposure control for the main scanning, the color-specific parameters determined in the preliminary scanning are taken into account.

Document DE 28 40 287 shows a method for determining the exposure quantities individually controlled in the individual colors serves from the presampling values of the presampling and is also known as the TFSftotal film scanning) method.

A disadvantage of the device described in the publication DE 198 05 048 A or the method described there, however, is that the two scanning devices used, the pre-scanning and the main scanning device, must be matched to one another spectrally very precisely, in order in particular for the original during the main scanning in terms of their colourfulness. If the spectral adjustment is insufficient, an exposure control determined on the basis of the presampled values can lead to extremely unsatisfactory results during the main scanning. However, since different optical systems, lighting elements and sensors are generally used in the two scanning devices, such a spectral adjustment is extremely difficult. In particular, the high requirements for the spectrally active components of the two scanning devices necessary for this have a negative effect on the manufacturing costs of the device. Such high manufacturing costs are also to be expected if almost the same high-quality components are selected for the pre-scanning device as for the main scanning device.

This disadvantage could be overcome by performing the pre-scan and the main scan with one and the same scanner. Such a device would, however, be unsuitable for lined-up originals, which are generally to be scanned immediately one after the other and are known and customary in particular as films in the form of batches. The lined-up templates would first have to be completely pre-scanned by the scanning device and then main scanned by the same scanning device. However, this approach is far too time consuming and therefore not practical.

A further disadvantage of the described device or the described method is that the entire original, ie the entire, before the main scanning Film, or at least a significant portion of it, in which prescanning must be scanned to determine the color parameters for the main scan that are characteristic of the entire film. This results in a not inconsiderable amount of time.

Accordingly, it is an object of the invention to develop a device and a method of the type mentioned at the outset in such a way that the quality of the digital recording of the original is increased without simultaneously reducing the speed and / or increasing the production costs.

This object is inventively achieved in that the generic device is further formed such that at least a part of the main scanning at least one template-specific parameter is determined, the stored main scanning in an automatic Bildverarbe ^'Maintenance on the basis of which can be modified, wherein the at least one part of the Main Samples Includes main samples of at least two frames.

The invention is based on the knowledge that the at least one template-specific parameter, which can be determined in the prior art from the pre-sample values of the pre-scan, can also be determined from the main scan values of the main scan if the main sample values subsequently correspond to the determined template-specific parameter in automatic image processing are modifiable. In this way, the number and the requirements for the precision of the sizes to be determined during the preliminary scanning can be considerably reduced, so that an adaptation of the spectrally active components used during the preliminary scanning to the components used for the main scanning can be avoided. With numerous possible uses of the device according to the invention, prescan can even be dispensed with entirely. A first, particularly advantageous development of the invention provides that in each case at least two main scanning values can be combined for the determination of the at least one template-specific parameter. For example, in order to be able to carry out the above-mentioned TFS method for determining the at least one template-specific parameter including the TFS calculations with the aid of the device according to the invention within a reasonable period of time, it is expedient to reduce the mostly high-resolution main sample values by a suitable summary.

Thus, the at least one main scanning section of the original can be scanned in the main scanning with a first resolution, and by combining the at least two main scanning values in each case a second resolution can be achieved which is lower than the first resolution. As a result of the combination of the main samples, a resolution is achieved which corresponds, for example, to the resolution in the prior sample in the prior art. In contrast to the prior art, however, this second resolution can still be freely determined in the device according to the invention even after the main scanning values have been recorded and is only limited by the first resolution. The second resolution can be increased subsequently to improve the image processing, particularly in the case of templates that appear to be problematic.

In an extremely advantageous embodiment of the invention, the at least one main scanning section can be detected during the main scanning in color separations of the three primary colors red, green and blue, and the at least one template-specific parameter can be characteristic of the color behavior of the at least two individual images. This development of the invention enables the use of the TFS method already introduced above, in which, for example, a color cast of the original can be determined on the basis of the color behavior, in particular of several individual images of the original. Such a color cast can be corrected by the device according to the invention, since the Main scanning values can be modified on the basis of the at least one template-specific parameter which is characteristic of this color cast. With regard to the TFS method, reference is made in particular to documents DE 2840287 and DE 19 14360, in which the method is described in detail. A particular advantage of this embodiment of the invention can be seen in the fact that the entire original does not have to be pre-scanned before the main scanning in order to determine the at least one template-specific parameter which is characteristic of the color behavior of the original.

In addition, the template-specific parameter can include the position of at least one individual image, so that the individual image positions do not necessarily have to be determined in a preliminary scan.

The device can of course also have a prescanning element, by means of which at least one prescanning section of the original can be scanned in a prescanning, wherein at least one parameter relevant for the main scanning can be determined in the prescanning. For example, the at least one parameter can include at least one position of the at least one main scanning section on the template and / or a DX code on the template and / or at least one perforation of the template. A very simple and inexpensive pre-scanning element can be used for detecting the at least one position of the at least one main scanning section and / or the DX code on the template and / or the at least one perforation of the template. In addition, with such a prescanning, the original does not have to be completely scanned before it is subjected to the main scanning, which results in an enormous saving of time. This development of the invention appears to be particularly expedient if the original is a photographic film.

The at least one prescan section can be scanned in the prescan with a resolution which is lower than the resolution in the main scan, since no parameters have to be determined during the preliminary scanning, which require a high-resolution detection of the original. The resolution during the preliminary scanning can therefore also be lower than the resolution which is achieved by combining at least two main scanning values in each case for the determination of the at least one template-specific parameter.

The at least one prescanning section can also be detectable in the prescanning in color separations of the three primary colors red, green and blue, in order to obtain parameters for the exposure control during the main scanning. This development of the invention is particularly expedient if the digitally to be recorded original has a strong color cast, so that a rough correction should already be made by the exposure control.

The above-mentioned object is also achieved according to the invention by a method for digitally capturing a template with a plurality of individual images, comprising the following steps: First, at least one main scanning section of the template is scanned in a main scan by a main scanning element, and the main scanning values captured in the main scan are stored. At least one template-specific parameter is then determined from at least part of the main samples, which is used for * automatic image processing of the stored main samples, the at least part of the main samples comprising main samples of at least two individual images.

Furthermore, the functions already mentioned above in connection with the device according to the invention can be implemented by the method according to the invention.

Exemplary embodiments of the invention are described in more detail below with reference to the attached figure, which shows the schematic structure of an exemplary embodiment of a device according to the invention. The figure shows the schematic structure of an exemplary embodiment of the device 10 according to the invention for digitally capturing a template 12. This exemplary embodiment does not have a pre-scanning device, since all required template-specific parameters are determined from the main scanning values recorded during the main scanning, the template-specific parameters representing the basis for a subsequent automatic image processing of the main scanning values. These template-specific parameters include the positions of the individual images on the template 12, in this exemplary embodiment a photographic film, and color information obtained from the main scanning values of the individual images. Two multicolored LED arrays 14 and 16 are used as lighting devices, the light of which is first focused by lens arrays 18 and then combined using a dichroic beam splitter 20. While the LED array 14 is made up of red and green LEDs, the LED array 16 has blue and infrared LEDs. The light from the LED arrays 14 and 16 brought together at the dichroic beam splitter 20 is guided via a condenser lens 22 through the mask of a film stage 24 onto a main scanning section of the original 12. The multicolored light passing through the main scanning section of the original 12 is focused by an imaging lens 26 onto a beam splitter prism complex 28 which realizes the light according to the respective spectral components on different main scanning elements - here by means of CCD arrays 30, 32, 34 and 36 - redirects. For example, the red color component is depicted on the CCD array 30, the green color component on the CCD array 32, the blue color component on the CCD array 34 and the infrared color component on the CCD array 36. The color components detected by the CCD array 36 are converted into defect signals, which provide information about defective areas of the original 12 and are stored in a storage element 38. The color components detected by the CCD arrays 30, 32 and 34 are also stored in the memory element 38 as main samples. By transporting the template 12 gradually other main scanning sections of the original 12 are scanned in the manner described by the device according to the invention and the corresponding main scanning values are stored in the storage element 38. The main samples are combined by a computing unit 40 in such a way that the positions of the individual images on the original 12 can be determined with sufficient accuracy on the basis of the combined main samples. By determining the individual image positions, the main images stored in the storage element 38 can be assigned to the individual images of the original. These main samples assigned to the individual images can be combined into areas for the TFS method to be carried out subsequently, the number of main samples combined for this purpose need not be identical to the number of main samples that were combined for determining the individual image positions.

In such a TFS method, two color density difference values are now formed for each area of the individual images in the computing unit 40, the first color density difference value being a difference between density values of two primary colors (red, blue, green) and the second color density difference value being a difference between a density value of one of the two primary colors and a density value of the third primary color. In addition, the average density is formed from the three primary colors for each area of the individual images, and a functional relationship describing the color behavior of the original with the average density is produced for a larger number of areas of the original by assigning the difference in color density to the associated average density. With the help of this functional relationship, the template-specific parameters are determined on the basis of the average density of a single image. On the basis of the template-specific parameters determined in this way, the main scanning values stored in the storage element 38 are modified in an automatic image processing. In an alternative TFS method, the average density for each scanned area is formed from the combined main scan values of all three primary colors, and for a larger number of areas of the individual images, the density values of the three primary colors are assigned to the associated average densities of the areas three functional relationships describing the color behavior of the template. With the help of these functional relationships, the template-specific parameters are determined on the basis of the average density of a single image. In this alternative TFS method, too, the main scanning values stored in the storage unit 38 are modified in an automatic image processing on the basis of the template-specific parameters.

In addition, the combined main sampling values of the individual images can be checked to determine whether there are areas whose density values differ significantly from the mean density of the totality of the individual images. If this is the case, depending on the color dominance, different image processing methods can be used for these areas.

With regard to further details of the TFS method, reference is made to the document DE 28 40 287.

In an alternative exemplary embodiment of the invention, the determination of the individual images and the TFS method listed above can be carried out virtually simultaneously in one method section.

A further exemplary embodiment of the device according to the invention has, in addition to the structure shown in the figure, a pre-scanning device by means of which the individual image positions of the original are determined and a DX code located on the original is read. In a prescanning carried out using the prescanning device, the original is recorded in sections, for example, in the three primary colors blue, green and red and with a resolution, which is significantly lower than the resolution of the main scan. The resolution can also be lower than the resolution achieved by the summary of the main scanning data described above. To determine the positions of the individual images on the template, perforations possibly present on the template can also be used in addition to the pre-samples obtained. If, as in this exemplary embodiment, the positions of the individual images of the original are determined before the main scan, these individual images are digitally recorded as main scan sections in the main scan. If a single image of the original has already been identified, the main scanning can be carried out immediately afterwards without first having to pre-scan the entire original. Partial and main scanning of the entire original can therefore be carried out in parallel in part. If parameters which are characteristic of the color behavior of the entire original and which are to be taken into account in the main scan are also to be determined in the pre-scan, the main scan can of course only be carried out if the pre-scan has been completed. The main scanning is carried out as in one of the exemplary embodiments listed above.

The features of the individual exemplary embodiments described can be combined as desired.

Claims

claims:

1. Device for digitally capturing a template (12) with a plurality of individual images with a main scanning element (30, 32, 34, 36), by means of which in a main scan at least one main scanning section of the

Template (12) can be scanned, and with a storage element (38), by means of which main scanned values obtained in the main scan can be stored, characterized in that at least one template-specific characteristic variable can be determined from at least part of the main scanned values, on the basis of which the stored main scanned values in a automatic image processing can be modified, wherein the at least part of the main samples comprises main samples of at least two individual images.

2. Device according to claim 1, characterized in that in each case at least two main samples for the determination of the at least one template-specific parameter can be summarized.

3. The device according to claim 2, characterized in that the at least one main scanning section of the template (12) can be scanned in the main scanning with a first resolution and that by combining the at least two main scanning values in each case a second resolution can be achieved which is lower than the first Resolution is.

4. Device according to one of the preceding claims, characterized in that the at least one main scanning section during the main scanning in color separations of the three primary colors red, green and blue can be detected and that at least one template-specific parameter is characteristic of the color behavior of the at least two individual images.

5. Device according to one of the preceding claims, characterized in that the at least one template-specific parameter comprises the position of at least one single image.

6. Device according to one of the preceding claims, characterized in that the device (10) has a pre-scanning element through which at least one pre-scanning section of the template (12) can be scanned in a pre-scan, wherein at least one parameter relevant for the main scanning can be determined in the pre-scanning is.

7. The device according to claim 6, characterized in that the at least one parameter at least one position of the at least one main scanning section on the template (12) and / or a DX code on the template (12) and / or at least one perforation of the template ( 12) includes.

8. Device according to one of claims 6 or 7, characterized in that the at least one main scanning section of the template (12) can be scanned in the main scanning with a first resolution and that the at least one pre-scanning section in the pre-scanning can be scanned with a further resolution which is less than the first resolution.

9. The device according to claim 8, characterized in that by combining at least two main scan values for determining the at least one template-specific parameter, a second resolution can be achieved and that the further resolution during the pre-scan is less than the second resolution.

10. The device according to one of claims 6 to 9, characterized in that the at least one prescan section in the prescan can be detected in color separations of the three primary colors red, green and blue.

11. Device according to one of the preceding claims, characterized in that the template (12) is a photographic film.

12. A method for digitally capturing a template (12) with a plurality of individual images, comprising the following steps:

a) scanning at least one main scanning section of the original (12) in one main scan by a main scanning element (30, 32, 34, 36);

b) storing main scan values captured in the main scan;

c) determining at least one template-specific parameter from at least part of the main samples, the at least part of the main samples comprising main samples from at least two individual images; and

d) using the at least one template-specific parameter for automatic image processing of the main scanning values stored in step b).

13. The method according to claim 12, characterized in that at least two main samples in step c) are first combined.

14. The method according to claim 13, characterized in that the sampling in step a) is carried out with a first resolution and that by combining the at least two main sampling values in each case a second resolution is achieved which is lower than the first resolution.

15. The method according to any one of claims 12 to 14, characterized in that the at least one main scanning section in step a) in color separations of the three primary colors red, green and blue is recorded and that at least one template-specific parameter is characteristic of the color behavior of the at least two individual images.

16. The method according to any one of claims 12 to 15, characterized in that the at least one template-specific parameter comprises at least one position of a single image.

17. The method according to any one of claims 12 to 16, characterized in that one before and / or during the main scanning

Pre-scanning of at least one pre-scanning section of the original is carried out by a pre-scanning element, in which at least one for the

Main scanning of relevant parameters is determined.

18. The method according to claim 17, characterized in that the at least one parameter at least one position of the at least one main scanning section to be scanned in the main scan and / or a DX code on the template (12) and / or at least one perforation on the template ( 12) includes.

19. The method according to any one of claims 17 or 18, characterized in that the scanning in step a) is carried out with a first resolution and that the pre-scanning is carried out with a further resolution that is lower than the first resolution.

20. The method according to claim 19, characterized in that a second resolution is achieved by one or the first combination of the at least two main samples in step c) and that the further resolution in the pre-scan is less than the second resolution.

21. The method according to any one of claims 17 to 20, characterized in that the at least one prescan section in the Prescan in the color separations of the three primary colors red, green and blue is recorded.