Portable device for checking documents «Korund-MTV»..
KOVALEV Aleksey Alekseevich
POLYAKOV Yury Alekseevich
SINELNIKOVA Elena Nikolaevna
STUDITSKY Aleksandr Sergeevich
KHNYKOV Yury Alekseevich
PORTABLE DEVICE FOR CHECKING DOCUMENTS “KORUND-MTV”
The portable device “Korund-MTV” is designed for visual inspection of documents in non-stationary conditions. The device implements a combination of inspection methods in reflected infrared and visible fluorescent radiation of the optical range, which occurs when a document sheet is illuminated from infrared (IR) and ultraviolet (UV) radiation sources, respectively. These methods are the main ones when working at unequipped control points and in field conditions.
Functionally, the device includes control channels in UV and IR radiation.
The UV channel includes a matrix of UV LEDs with a dominant wavelength of 365 nm. Their radiation can excite visible luminescence in the paper substance and design elements, the spectrum, intensity and distribution of which over the sheet field can reveal signs of authenticity or counterfeiting of the document. The check is carried out by direct observation with the naked eye. Among the signs revealed in the form of luminescence, the following can be indicated:
— the presence and distribution of hidden typographic or handwritten security marks;
— traces of interaction with paper of etching and washing reagents;
— traces of glue;
— the presence and differences in the intensity and color of the luminescence of fillers and security fibers in paper, revealing the replacement of individual sheets of the document, perceived as identical upon cursory viewing in visible light.
The IR channel includes an IR illuminator, an IR LED matrix, a video camera recording reflected radiation, with a lens and an IR-transmitting filter, a microdisplay presenting an IR image, and an eyepiece with a diopter adjustment for increasing the image scale.
The IR radiation reflected from the object provides:
— detection of pairs of metameric dyes on the leaf field;
— reading of fragments filled with IR-transparent dyes;
— detection of additions and corrections made with a writing material that is the same color as the original material, but with a different level of IR absorption;
— recognition of IR-optically dense details on the back of a sheet and the next page (for example, when analyzing glued sheets, when looking for signs of re-gluing photographs).
Unlike existing analogues, the device uses an IR illuminator with two radiation wavelengths (IR1 and IR2). This allows, for example, when comparing images from them, to check for the presence of marks of special protective dyes, the absorption of radiation in which is different at selected wavelengths, which expands the capabilities and increases the reliability of the control results.
The device is designed as a single module with UV and IR channels, electronic boards and a battery compartment. The device body has buttons for switching on the IR1 and IR2 modes with indicators for switching them on, a button for switching on the UV channel and an indicator for the status of the batteries. Its appearance is shown in photo 1.
Photo 1. The “Korund-MTV” device
The electrical circuit of the device functionally includes secondary power supplies, a processor part and diode assemblies of IR and UV LEDs. The processor controls the operation of the device, sets the selected modes, monitors and indicates the battery charge level and switches off the device when the voltage drops below the permissible level.
On the front wall of the device there is a video camera lens with an input IR filter, a matrix of eight IR LEDs, four diodes of wavelengths IR1 and IR2, a matrix of three UV LEDs.
The device is powered by three AA batteries installed in the battery compartment. The battery status is displayed by an indicator on the back wall. Power is provided from an alternating current network of 220 V ±10%/50 Hz via a network adapter. When the adapter is connected, the power supply circuit from the batteries is disconnected.
Provision is made for connecting a video cable to output a video signal to external video devices, including and on a PC, for documenting IR images.
For stationary operation, the lower part of the module has a mounting point for a tripod.
Main technical characteristics
| UV channel | |
| UV LED matrix power |
~ 4.0 mW |
| Minimum/nominal working distance to the test object |
~ 40 mm/~ 80 mm |
| Illumination field size/UV illumination at 80 mm |
~ 25×15 mm/і 0.80 mW/cm2 |
| IR channel | |
| Power of IR1 and IR2 LED matrices |
і 45 mW |
| Native resolution of the video camera |
400 TVL |
| Working distance to the object (standard lens) |
~ 80 mm |
| Size of the observation field at the working distance |
~ 50.0 x 37.5 mm |
| Power |
~220 V/=5 V |
|
3 AA batteries |
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| Battery life (capacity є 2.3 Ah) |
і 1 hour |
| Weight/dimensions |
0.45 kg/125x85x65 mm |
Examples of the device's capabilities for checking documents and banknotes are shown in photos. 2 and 3.
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| a) | b) |
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| c) | d) |
Photo 2. Identification of pairs of metameric dyes: on a 20 euro banknote, on a 100 US dollar banknote, on a 100 Russian ruble banknote and on a sheet of a Russian citizen's passport. The image of the fragments is given in visible (top) and reflected IR radiation (bottom)
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| a ) | b) |
Photo 3. Detection of additions in single-color ink in the IK1 range (a) and reading of ink-filled inscriptions in the IK2 range (b)
The main goal of developing the “Korund-MTV” device is to replace the mass-produced “Korund” kit, which is now widely used by security, law enforcement and financial services to control documents, securities, banknotes mainly in non-stationary conditions, while maintaining cost indicators. The new device has a number of advantages compared to its analogue.
The new device is a monoblock, while the Korund kit includes separate UV and IR blocks. It has better weight and size characteristics (0.45 kg compared to the total weight of the IR and UV blocks of the Korund kit, equal to 1.1 kg). Comparative dimensions of both devices are shown in photo 4.
Photo 4. External appearance of the IR and UV blocks of the Korund kit and the Korund-MTV device
The device provides, under equal conditions, 2.5 — 3.5 times greater UV illumination compared to the UV block of the analog.
The IR channel of the Korund-MTV device has a wider range of spectral sensitivity with image presentation in two spectral ranges. The IR block of the currently used Korund kit does not provide a control mode in the IR2 range in terms of spectral sensitivity. The latter also provides only observation of object images, without the ability to memorize them. In addition, among the circuit solutions in the new device there is a controller that ensures disconnection of the battery power circuit when the batteries are discharged.
NIIIN MNPO «SPEKTR»
Moscow, st. Usacheva, 35, building 1
Postal address: 119048, Moscow, P.O. Box 148
Phone/Fax: (095) 245-52-00, 926-53-80, 926-53-81
E-mail: niiin@spektr6.ru
http://spektr6.ru