Abstract:
A method of authenticating security documents and a mobile device, especially a smartphone, programmed to carry out the method, based on an analysis of features which are produced by intaglio printing, which analysis involves a decomposition of sample images of a candidate document to be authenticated based on Wavelets, each sample image being digitally processed by performing a Wavelet transform of the sample image in order to derive a set of classification features. The method is based on an adaptive approach, which includes the following steps: —prior to carrying out the Wavelet transform, defining a categorization map containing local information about different intaglio line structures that are found on the security documents; —carrying out a Wavelet selection amongst a pool of Wavelet types based on the categorization map; and —performing the Wavelet transform of the sample image on the basis of the selected Wavelet.
Abstract:
There is described a method for touchless counting of substantially planar substrates, especially banknotes, which are stacked in the form of stacks of substrates, said method comprising the following steps: taking at least one sample image of a portion of a side of a stack of substrates, which sample image contains contrast information representing substrate edges that extend along substantially a first direction in the sample image; processing the contrast information representing the substrate edges within the sample image (10), which processing includes subjecting at least one area of interest (20) within the sample image (10) to anisotropic diffusion to produce a processed image containing a substantially coherent set of continuous lines representing the substrate edges; and counting the number of substrate edges in said processed image.
Abstract:
There is described a method for checking the authenticity of security documents, in particular banknotes, wherein authentic security documents comprise security features (41-49; 30; 10; 51, 52) printed, applied or otherwise provided on the security documents, which security features comprise characteristic visual features intrinsic to the processes used for producing the security documents. The method comprises the step of digitally processing a sample image of at least one region of interest (R.o.I.) of the surface of a candidate document to be authenticated, which region of interest encompasses at least part of the security features, the digital processing including performing a decomposition of the sample image by means of wavelet transform (WT) of the sample image. Such decomposition of the sample image is based on a wavelet packet transform (WPT) of the sample image, preferably a so-called two-dimensional shift invariant WPT (2D-SIWPT).
Abstract:
There is described a method for controlling the quality of printed documents (1 ), such as banknotes and other similar documents, in an environment where only part of the surface of the printed documents is available for inspection, the method comprising the steps of (i) storing a reference image (6); (ii) acquiring a sample image (5) of a sample printed document to be controlled, which sample image covers only a limited portion of the sample printed document; (iii) selecting a search pattern (7) within the acquired sample image; (iv) searching the reference image (6) for a match with the selected search pattern (7), (v) determining control parameters linked to the position of the search pattern (7) within said sample image (5) and within said reference image (6), (vi) comparing the control parameters linked to the position of the search pattern (7) within the sample image (5) with the control parameters linked to the position of the search pattern (7) within the reference image (6); and (vii) based on the results of the comparison of the control parameters, accepting or rejecting the sample printed document.
Abstract:
There is described a sheet inspection system for a sheet-fed recto-verso printing press of the type comprising two printing cylinders (10, 20) for carrying out simultaneous recto-verso printing of the sheets, said sheet inspection system comprising at least a first inspection device (100) for taking an image of a first side of the printed sheets. The first inspection device (100) comprises a first line image sensor (110) for performing line-scanning image acquisition of the first side of the printed sheets, and the first inspection device (100) is disposed in such a way that the first line image sensor visually acquires an image of a printed sheet while the said printed sheet is still adhering onto the surface of a first one (10) of the two printing cylinders (10, 20) of the printing press and immediately before the said printed sheet is transferred to a chain gripper system (5) of the printing press. Also described is a printing press equipped with the inspection system.