The production of banknotes and documents by legitimate color laser printers is a prevailing form of counterfeiting nowadays. As an anti-counterfeiting measure, most brand color printers and copiers add to each page a unique, repeated pattern of tiny yellow dots that are barely visible to the naked eye and by which every printer specimen can be unambiguously identified.
Thus, the visualization and analysis of these yellow dots can help forensic experts to elicit facts of illegal printing as well as to identify a printing device used for counterfeiting and to reveal relationships between printed copies under consideration.
To verify the legality of its production, the banknote or document is scanned and entered into the PAPILLON-BLIP system where the image is automatically transformed from the RGB to the CMYK color model. Extracting the yellow color channel and visualizing it as a grayscale image make that marking of tiny yellow dots clearly visible. The pattern of dots revealed on the questionable banknote or document can be then compared with the patterns that appear on test-printed pages produced by a suspected printer(s).
- IImage acquisition directly from scanners, digital cameras, graphics files and files created and stored in PAPILLON RASTR databases. The objects the system can operate with can be classified as follows:
- Test-printed pages
- Any other documents
- Automatic visualization of the printer’s yellow tracking dots (by extracting the yellow color channel on the image)
- Automatic extraction of the code pattern identifying the printer
- Interactive outlining of a repeated fragment of the code pattern
- Saving images into the database together with some textual information: for test-printed pages – model and serial number of the printer; for banknotes – nominal value and number, date of withdrawal, case No, etc.)
- Automatic search of the database for other images of banknotes and test-printed pages with the same code pattern
- Side-by-side comparison of the images with matching code patterns to determine that two specimens were produced by the same printing device
- Transmission of matching images to PAPILLON RASTR for making up an examination report
- Export of data to other departments or agencies
- Import of data from other departments or agencies
PAPILLON-BLIP enables image acquisition in two modes – automatic and manual. The automatic mode is employed to process the images of banknotes. The manual mode is intended to scan only those fragments on the document that were selected by the examiner.
Image processing in PAPILLON-BLIP involves the automatic extraction of yellow dots produced by the printer. After that, the expert verifies the output of that processing and using special markers labels the printer markings found by the system.
The interactive coding operation consists in setting a frame outlining a fragment of the repeated code pattern (template). If necessary, the expert may correct the output of processing/coding by removing false markers placed in dirty spots, by adding the omitted and adjusting the mispositioned markers.
The screen for viewing and editing the processing/coding results empowers the examiner to virtually emulate the functions of a comparison microscope. Thus, he can compare side-by-side either the fragments of a particular banknote or document or the selected fragments of different banknotes or documents.
The program provides also a capability of pairwise comparison of the tracking dots on the code patterns of matching fragments.
Automatic searches are processes of comparing templates representing the code patterns of printers. The scope of comparison encompasses collections of counterfeit banknotes and documents as well as images of test-printed specimens produced by different models of printers and copiers including those suspected or obtained as evidence of fraud.
The match results returned by the system are reviewed by the examiner who makes comparative conclusions about identity of the equipment used for forgery. In case of need, the exhibit can be sent for re-processing, re-coding and re-search in order to exclude the possibility of erroneous judgment or to ensure that the initial identification was correct.