Radiation imagery chemistry: process – composition – or product th – Including control feature responsive to a test or measurement
Patent
1995-09-21
1997-11-11
Huff, Mark F.
Radiation imagery chemistry: process, composition, or product th
Including control feature responsive to a test or measurement
356404, 356443, 356444, G03C 502, G01J 340, G03B 2773
Patent
active
056862105
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP95/00235 filed Jan. 23, 1995, now publication no. WO 95/20183.
FIELD OF THE INVENTION
The present invention relates to the identification of image-forming material type and is more particularly, although not exclusively, concerned with the identification of photographic transparency film types. The present invention is particularly useful in the identification of the film type of a mounted transparency.
BACKGROUND OF THE INVENTION
Photographic materials such as transparencies are normally mounted after processing so that they can be easily handled and positioned for viewing in a projector or another type of viewer. The mount is chosen so that only the image area is visible on inspection, and as a result, any identification present on the transparency prior to mounting is hidden by the mount itself.
In some instances, it may be necessary to determine the particular type of transparency or other type of photographic material. Such a situation arises where photographic images stored on conventional photographic materials are to be transferred to some other form, for example, a digital form such as video or photo CD (compact disc). In these instances, the image is scanned to break it down into a number of discrete pixels. These pixels are then electronically processed to correct for colour or sharpness deficiencies and then stored in the other form, for example, on a photo CD.
However, in order to carry out the colour correction process, the material type on which the image is initially stored needs to be known. When scanning negatives, it is a simple matter to examine the edge of the film strip for the film type codes. However, for transparencies, it is not possible to see the edge of the film without removing each transparency from its associated mount as mentioned above. Often, it is not easy to remove the transparency from its mount, and once removed, there is no guarantee that the single-frame of the initial strip will carry any identification.
Transparency materials tend to fall into two groups, namely, Kodachrome, and Ektachrome types. Both Kodachrome and Ektachrome are registered trade marks of Eastman Kodak Company.
It is known to identify transparency materials, for example, graphics arts materials, by measuring the density of the cyan dye on the long wavelength side using a Wratten 70 filter and a standard AA red filter. Such a method is described in Professional Printer, Volume 20, No. 1, by C Graebe. In this method, two readings are taken using the two filters and the ratio of the reading is then used to identify the film type.
GB-A-1 553 199 discloses an exposure control system for photographic colour printers and operates in a similar way to the method described above. However, in this case, the method is linked into the control system of a printer to control exposure.
Problem to be solved by the Invention
The method described above is not entirely satisfactory when distinguishing between the current Kodachrome and the Ektachrome types of transparencies.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method and apparatus for distinguishing between types of photographic materials, and in particular between Kodachrome and the Ektachrome types of transparencies.
In accordance with one aspect of the present invention, there is provided a method of identifying image-forming materials, the method comprising the steps of:
illuminating a sample of image-forming material with a radiation source operating at a plurality of wavelengths;
measuring a parameter indicative of the sample density at a plurality of points on a particular dye absorbency curve for the material;
calculating the ratios of the measured adjacent sample parameters from that dye absorbency curve; and
comparing the calculated ratios with reference data to determine the type of material.
In accordance with another aspect of the present invention, there is provided apparatus for identifying image-forming materials from a sample, the apparatus comprising
REFERENCES:
patent: 4150894 (1979-04-01), Meyer et al.
patent: 4829371 (1989-05-01), Hiramatsu et al.
patent: 4830501 (1989-05-01), Terashita
patent: 4917500 (1990-04-01), Lugos
patent: 5053808 (1991-10-01), Takagi
Graebe, C.M., Prof. Printer, vol. 20, No. 1 (1976), pp. 2-3, Jan. 1976.
Eastman Kodak Company
Huff Mark F.
Owens Raymond L.
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