Technical support for conducting examination of the authenticity of documents as one of the aspects of economic security. Article updated in 2023.

Trukhachev Valery Vladimirovich

TECHNICAL SUPPORT FOR CONDUCTING AN EXAMINATION OF THE AUTHENTICITY OF DOCUMENTS AS ONE OF THE ASPECTS OF ECONOMIC SECURITY

With the development of economic relations in society and the increase in the technical level of small-scale printing equipment, the number and frequency of various counterfeit documents inevitably increases sharply. Such “illegitimate doubles” include many types of counterfeit banknotes; securities; documents certifying identity or rights; special, excise and identification stamps; works of art and other two-dimensional objects.

In view of this, technical means of examination, i.e. devices and equipment that allow with a high degree of probability to guarantee the detection of falsified (in whole or in part) documents, are of particular relevance for protection against attempts at deception and fraud. In general, examination of such objects for authenticity includes:

• definition of a set of features characteristic of a genuine document (standard) and technologically difficult to reproduce;
• establishment of the presence or absence of these features in their entirety on the document being checked using technical means;
• making a decision on the authenticity of the document being checked.

At the same time, depending on the level of protection of the document from reproduction, the number of security features can be reduced to tens or even hundreds of individual elements (for example, for banknotes of some issuing countries). Such features can be various luminescent fragments; iris rolls; Orlov seal; sections of images with a metameric effect; fragments made with dyes with ferromagnetic properties and possessing spontaneous magnetization; microimages; fragments with features of printing types (metallography, offset, letterpress printing, etc.); two-tone and multi-tone watermarks; structure, adhesive composition and material of the paper carrier, as well as many other elements of increased technological complexity of reproduction.

Advantages of television systems for document examination.

With such a number of types of document security elements and a variety of their physical and chemical properties, technical means for conducting an examination of authenticity must have an adequate completeness of types of research (checks). Among all classes of similar technical devices for forensic examination of documents, devices based on television systems have the widest capabilities, since modern image sensors (CCD matrices) retain sensitivity to radiation in a wide spectral range from the near ultraviolet part to the near infrared region of the spectrum. It is these capabilities of television devices that provide them with a clear advantage in forensics over the human eye, which is capable of perceiving only radiation in the visible region of the spectrum (400 — 700 nm). The presence in such devices of optics with a variable focal length, illuminators with different directions of formed light fluxes and spectral ranges of radiation, as well as optical (corrective, cutting and narrow-band) camera filters makes them indispensable in the study of two-dimensional objects. Due to this, these devices are widely used to obtain images of objects in reflected, oblique, transmitted visible and infrared light, as well as to detect ultraviolet and infrared luminescence of dyes, inks and solvents (etching solutions).

The main manufacturers of equipment for this purpose are Projectina (Switzerland), Foster+Freeman (Great Britain) and ZAO EVS (Russia).

The number of television forensic systems produced by these companies exceeds hundreds of units. With the comparability of the main parameters of the equipment of the listed companies, it should be noted that foreign companies attach a more diverse range of auxiliary accessories to it, and the Russian company has more advanced software for comparing the examined images and maintaining its own user database.

Table 1 provides a comparative analysis of the main technical and economic parameters of television document examination equipment from domestic and foreign manufacturers of forensic equipment for checking document authenticity.

Table 1.

The brief comparative analysis of the technical capabilities of the equipment shows that the optimal indicator of the quality-price ratio and the maximum composition of the basic television equipment set is the forensic software and hardware complex «Expert-K», developed and manufactured by ZAO «EVS», Russia, St. Petersburg. Therefore, below is a description of the capabilities of forensic equipment for document examination using the example of the domestic complex.

Purpose and capabilities of the software and hardware complex «Expert-K».

The complex is designed for examination of documents, banknotes, securities and other two-dimensional objects by television means, as well as for electronic documentation and formation of a database of color images and accompanying text data.

It provides the following types of examination:

a) examination of documents in reflected visible light;
b) examination in transmission in visible light (400 — 700 nm);
c) study of the nature and color of luminescence of objects in UV illumination from built-in sources with a central wavelength of 365 nm;
d) spectrozonal studies in narrow-band subranges of wavelengths of 570, 610, 645, 695, 780, 850 and 950 nm, as well as using 11 cut-off light filters;
d) study of the structure and nature of application of ferromagnetic materials contained in dyes;
e) study of documents in transmitted IR light (860 nm);
g) study of the relief of printing and embossing in oblique visible and IR illumination;
h) examination of microfragments, structure of materials (including fibrous ones), nature and sequence of application of dyes at medium and high magnifications;
i) examination of IR luminescence of dyes caused by intense blue-green light.

The hardware and software complex includes the following television, lighting devices and software:

• KTP-7625 “Kombi-K” (photo 1), providing checks according to items a) — d), e), g);
• BTP “Magnetoscope-2”, providing checks according to item d);
• BTP-7621 (color telemagnifier), providing verification according to paragraphs g) and h);
• BTP-7623, providing verification according to paragraph h);
• power supply unit for the BTP-7623 device, providing its autonomous use as a television attachment to the MBS-10 microscope;
• blue-green light sources with a variable spectrum IS-01S/Z with fiber optic input (2 pcs.), providing verification according to paragraphs i);
• a color image input board for a personal computer and specialized software (SPPO) on a CD for implementing image input into a PC, organizing a database and archiving files, as well as visual comparison and software comparison of images of documents and banknotes being examined, genuine and others (including counterfeit).

Photo 1.
General view of the basic device KTP-7625 of the Expert-K complex”
with external sources of intense blue-green light

When operating the complex, data on the scale of the image formed by the color television camera of the KTP-7625 device and on the operating position of each of its 25 light filters can be displayed on the monitor screen for the purpose of documenting research modes.

In addition, the KTP-7625 device has automatic focusing, automatic aperture and software control of the parameters of a color digital television camera (gain, accumulation, aperture, gamma and color correction coefficients, etc.). At the same time, the expert conducting the research has the opportunity to adapt the parameters of the TV camera to the characteristics of the object being studied. The maximum field of view of the device is 150×110 mm, the size of the object table corresponds to the A4 format, while the device has folding curtains for access from the front and left to the objects of study with a maximum height of up to 30 mm, as well as a through slit for the passage of documents.

Specialized application software allows you to:

• accumulate (integrate) a sequence of image frames in order to identify low-contrast objects against a noise background;
• remote control of research modes when working together with a PC and changing the details of specialized application software to meet the individual requirements of the user for maintaining his own database;
• comparison of two images by superposition, alternate presentation or subtraction with preliminary movement, scaling and rotation of the main image with an accuracy of up to one pixel, 0.01% and 0.01°, respectively, as well as additional image processing using standard graphic editors.

The complex reliably solves the problems of detecting and visualizing special security features: microprinting; UV and IR luminescence, dye metamerism, identifying the structure of various materials, printing technologies, low-contrast traces of impact, comparing fingerprints… In addition, with its help, various types of changes in documents can be identified and recorded in the database — additions, corrections, erasures, etching of inscriptions, etc.

In terms of its capabilities, the Expert-K complex is practically not inferior to the latest device VSC-2000Foster+Freeman (UK), which is an order of magnitude more expensive, and in terms of the possibility of analyzing the structure of ferromagnetic components in dyes using the Magnetoscope-2 retrofitting device, the domestic complex has no analogues at all. Some advantages of the VSC-2000 device include the presence of an automatic search for an object verification mode that provides maximum contrast of the detected document distortions, which allows low-skilled personnel to conduct research.

Device Docucenter (photo 2), in comparison with the equipment reviewed, can be equipped with an extended set of accessories: holders and clamps for the objects being examined, allowing for their convenient fixation on the object table; light sources for detecting fingerprints, etc. In addition, this device additionally includes a coaxial light source for visualizing latent security features of the 3M type”.