Method and device for fitness testing of value documents

Patent metadata

Field	Value
Publication number	US-10176660-B2
Application number	US-201515325925-A
Country	US
Kind code	B2
Filing date	Jul 14, 2015
Priority date	Jul 15, 2014
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

The invention relates to the fitness check of value documents. For at least two fitness criteria there is respectively determined with the aid of an unfit function an unfit degree of the particular value document. The unfit function clearly assigns an unfit degree to the fitness measurement values and has two threshold values, beyond which the unfit degree with respect to the relevant fitness criterion is 0 or 1. Between the threshold values there is an uncertainty range in which the unfit degree is, with respect to the relevant fitness criterion, between 0 and 1 and the unfit function behaves monotonously dropping or monotonously rising. Subsequently, the unfit degrees of different fitness criteria are combined into an unfit probability of the particular value document and on the basis of the unfit probability a fitness classification of the particular value document is carried out.

First claim

The invention claimed is:

1. A method for checking the fitness of value documents (A, B, C), comprising the following steps:
selecting at least two different fitness criteria (K 1 , K 2 ) of the value documents which are characteristic for the state of the value documents,
checking the value documents by picking up measurement data of the value documents, wherein, from the measurement data picked up for each of the selected fitness criteria, a fitness measurement value (M1, M2) for the particular value document is determined,
determining respectively an unfit degree (G 1 , G 2 ) for each of the selected fitness criteria (K 1 , K 2 ) from the particular fitness measurement value of the particular value document (A, B, C) with the aid of an unfit function (F 1 , F 2 ) which clearly assigns an unfit degree (G 1 , G 2 ) to each fitness measurement value (M1, M2), wherein each unfit function is characterized by a first threshold value (X 1 , X 2 ), a second threshold value (Y 1 , Y 2 ), and an uncertainty range (U 1 , U 2 ) being between the first and the second threshold value in which the particular unfit function either has a monotonously dropping course that drops from a maximum unfit degree to a minimum unfit degree or a monotonously rising course that rises from the minimum unfit degree to the maximum unfit degree, and
combining the unfit degrees (G 1 , G 2 ) of the different fitness criteria (K 1 , K 2 ) into an unfit probability (P) which is specific for the particular value document (A, B, C), and
fitness classification of the particular value document on the basis of the unfit probability (P) which was determined for the particular value document.

2. The method according to claim 1 , wherein the unfit function (F 1 , F 2 ) assigns to the fitness measurement values (M1, M2) being in the uncertainty range respectively one unfit degree (G 1 , G 2 ) which is greater than 0 and lower than 1 and between the first and second threshold value either assumes a monotonously dropping or monotonously rising, e.g. linear or nonlinear, course, wherein the unfit function assigns in particular an unfit degree of 0 to all fitness measurement values being beyond the first threshold value and assigns an unfit degree of 1 to all fitness measurement values being beyond the second threshold value.

3. The method according to claim 1 , wherein the selected fitness criteria (K 1 , K 2 ) relate to one or several of the following properties of the value documents: soiling, wear, damage, alien elements or limpness of the particular value document, wherein the selected fitness criteria preferably relate to at least two different ones of these properties.

4. The method according to claim 1 , wherein at least two such fitness criteria are selected in which the frequency distribution of the fit value documents and the frequency distribution of the unfit value documents overlap each other as little as possible, wherein the two frequency distributions preferably have a maximum overlap of 30%.

5. The method according to claim 1 , wherein upon combining the unfit degrees (G 1 , G 2 , . . . ) of the different fitness criteria (K 1 , K 2 ) into the unfit probability (P) there is carried out a multiplication of the unfit degrees of the different fitness criteria, in particular that the unfit probability (P) is determined from the unfit degrees (G 2 , G 2 ) according to the following formula:

P
=

1
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j

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(

1
-

G
j

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k
j

=

1
-

(

1
-

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1

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k
1

·

(

1
-

G
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k
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.

6. The method according to claim 1 , wherein upon combining the unfit degrees (G 1 , G 2 , . . . ) of the different fitness criteria into the unfit probability (P) there is formed a linear combination of the unfit degrees of the different fitness criteria, in particular by adding up the unfit degrees (G 1 , G 2 , . . . ) of the different fitness criteria, where applicable with different weighting of the unfit degrees.

7. The method according to claim 1 , wherein, for the fitness classification of the particular value document, the unfit probability (P) determined for the value document is compared with a fitness threshold (T) and the value document is classified as unfit, if the unfit probability (P) exceeds the fitness thresholds (T).

8. The method according to claim 1 , wherein upon the fitness classification of the value documents of a value document group to be checked for fitness there is carried out an advance calculation, in which, for different values of the fitness thresholds (T), respectively the expected unfit portion of the particular value document group is determined, which indicates the portion of value documents which are classified as unfit in the fitness classification of the particular value document group, and that information is generated about how the unfit portion depends on the value of the fitness threshold (T), wherein this information in particular is communicated to the user of a value-document processing apparatus carrying out the method for checking the fitness, e.g. by outputting it at a user interface of the value-document processing apparatus.

9. The method according to claim 1 , wherein prior to the fitness check the following steps are carried out:
providing a first group of fit value documents and a second group of unfit value documents, wherein the categorization of th

Assignees

• Giesecke & Devrient Gmbh
• Giesecke & Devrient Currency Technology Gmbh

Inventors

• Schmidt Alfred
• Schmeisser Marcus
• Stein Dieter
• Löffler Friedemann
• Kruglyk Sergii

Classifications

• G07D7/18

  Physics · mapped topic

• G07D7/181 Primary

  Testing mechanical properties or condition, e.g. wear or tear (G07D7/16 takes precedence) · CPC title

• G07D7/00

  Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency · CPC title