Method and device for characterizing the state of use of banknotes and their classification as suitable and not suitable for circulation

摘要

A METHOD FOR THE CHARACTERIZATION OF THE STATE OF USE OF BANK TICKETS AND ITS CLASSIFICATION AS SUITABLE AND NOT SUITABLE FOR CIRCULATION, comprising: - capturing (1) by reflection at least one image of at least one of the faces of the banknote bank to analyze, by means of a digital module for capturing images by reflection, - storing (2) the captured image in a standard format, - correcting (3) the color of the captured image, using the ICC color profile of the module used to image capture, - analyze (4) in the spatial domain the image captured according to the following phases: or decompose (4a) each image captured in the three RGB channels: Red (Red), Green (Green) and Blue (Blue), or calculate (4b) on at least one of the three channels R, G and B, and on the value of the pixels comprising said captured image, at least one statistic selected from arithmetic mean, standard deviation, median, mode, maximum, minimum, Kurtosis coefficient and symmetry coefficient; characterized in that it also comprises: - analyzing (5) in the frequency domain the image captured according to the following phases: or applying (5a) the mathematical transformation known as Fast Fourier Transform (FFT) to the image captured on at least one of the R, G and B channels, to obtain a new image called "power spectrum", or calculate (5b) on the pixels of the captured image, of the power spectrum at least one statistic selected from arithmetic mean, standard deviation, median, mode, maximum, minimum, Kurtosis coefficient and symmetry coefficient, - qualify (6) previously visually and individually, as suitable or unfit for circulation, a set of banknotes of the same denomination as the banknotes to be analyzed, by a group of experts, paying special interest in the region of the image captured from the banknote to be analyzed, - capture (7) the individual images of the together with previously visually qualified banknotes, where said images correspond to the images captured from the banknote to be analyzed, - analyze (8) in all RGB channels and in the spatial and frequency domains, the individual images of the visually qualified banknotes and obtain all the statistics previously mentioned, - analyze (9) the correlation between the visual classification performed by the group of experts and the data obtained in the analysis in the spatial domains and of the frequency of the individual images of said visually qualified banknotes, to establish the RGB channels and the statistics that offer a higher correlation and a better characterization of the state of use of the bill, - combine (13) at least one statistic obtained by analysis in the spatial domain with at least one statistic obtained by analysis in the frequency domain, of the banknote under analysis, to calculate a single value n numerical, called FV (Fitness Value), where in this calculation the statistics of the analysis (9) described in the previous point are used that offer a greater correlation in the visual classification (6) made by the group of experts, - obtain values of reference (12) of the statisticians with a greater correlation of the previous point, corresponding to a bill in perfect condition of the same type as the ticket to be analyzed, for which (10) individual images of the set of new bills of the same are captured denomination that the banknote to be analyzed, corresponding to the images captured from the banknote to be analyzed, the selected statistics that offer a higher correlation in the classification made visually are calculated (11), and the minimum values are taken as reference values (12), - set (14) a threshold PV and compare (15) the calculated PV, with the threshold PV, to classify the banknote analyzed as suitable or not suitable for circulation, based on tion that said calculated PV is lower or higher than the threshold PV.